Leached superabrasive elements and systems, methods and assemblies for processing superabrasive materials

A method of processing a polycrystalline diamond material includes exposing at least a portion of a polycrystalline diamond material to a processing solution, the polycrystalline diamond material including a metallic material disposed in interstitial spaces defined within the polycrystalline diamond material. The method includes exposing an electrode to the processing solution, applying a positive charge to the polycrystalline diamond material, and applying a negative charge to the electrode. An assembly for processing a polycrystalline diamond body includes a polycrystalline diamond body and an electrode that are in electrical communication with a volume of processing solution, and a power source configured to apply a positive charge to the polycrystalline diamond body and a negative charge to the electrode.

BACKGROUND

Wear-resistant, superabrasive materials are traditionally utilized for a variety of mechanical applications. For example, polycrystalline diamond (“PCD”) materials are often used in drilling tools (e.g., cutting elements, gage trimmers, etc.), machining equipment, bearing apparatuses, wire-drawing machinery, and in other mechanical systems. Conventional superabrasive materials have found utility as superabrasive cutting elements in rotary drill bits, such as roller cone drill bits and fixed-cutter drill bits. A conventional cutting element may include a superabrasive layer or table, such as a PCD table. The cutting element may be brazed, press-fit, or otherwise secured into a preformed pocket, socket, or other receptacle formed in the rotary drill bit. In another configuration, the substrate may be brazed or otherwise joined to an attachment member such as a stud or a cylindrical backing. Generally, a rotary drill bit may include one or more PCD cutting elements affixed to a bit body of the rotary drill bit.

As mentioned above, conventional superabrasive materials have found utility as bearing elements, which may include bearing elements utilized in thrust bearing and radial bearing apparatuses. A conventional bearing element typically includes a superabrasive layer or table, such as a PCD table, bonded to a substrate. One or more bearing elements may be mounted to a bearing rotor or stator by press-fitting, brazing, or through other suitable methods of attachment. Typically, bearing elements mounted to a bearing rotor have superabrasive faces configured to contact corresponding superabrasive faces of bearing elements mounted to an adjacent bearing stator.

Cutting elements having a PCD table may be formed and bonded to a substrate using an ultra-high pressure, ultra-high temperature (“HPHT”) sintering process. Often, cutting elements having a PCD table are fabricated by placing a cemented carbide substrate, such as a cobalt-cemented tungsten carbide substrate, into a container or cartridge with a volume of diamond particles positioned on a surface of the cemented carbide substrate. A number of such cartridges may be loaded into a HPHT press. The substrates and diamond particle volumes may then be processed under HPHT conditions in the presence of a catalyst material that causes the diamond particles to bond to one another to form a diamond table having a matrix of bonded diamond crystals. The catalyst material is often a metal-solvent catalyst, such as cobalt, nickel, and/or iron, that facilitates intergrowth and bonding of the diamond crystals.

In one conventional approach, a constituent of the cemented-carbide substrate, such as cobalt from a cobalt-cemented tungsten carbide substrate, liquefies and sweeps from a region adjacent to the volume of diamond particles into interstitial regions between the diamond particles during the HPHT process. The cobalt may act as a catalyst to facilitate the formation of bonded diamond crystals. A metal-solvent catalyst may also be mixed with a volume of diamond particles prior to subjecting the diamond particles and substrate to the HPHT process.

The metal-solvent catalyst may dissolve carbon from the diamond particles and portions of the diamond particles that graphitize due to the high temperatures used in the HPHT process. The solubility of the stable diamond phase in the metal-solvent catalyst may be lower than that of the metastable graphite phase under HPHT conditions. As a result of the solubility difference, the graphite tends to dissolve into the metal-solvent catalyst and the diamond tends to deposit onto existing diamond particles to form diamond-to-diamond bonds. Accordingly, diamond grains may become mutually bonded to form a matrix of polycrystalline diamond, with interstitial regions defined between the bonded diamond grains being occupied by the metal-solvent catalyst. In addition to dissolving carbon and graphite, the metal-solvent catalyst may also carry tungsten, tungsten carbide, and/or other materials from the substrate into the PCD layer of the cutting element.

The presence of the metal-solvent catalyst and/or other materials in the diamond table may reduce the thermal stability of the diamond table at elevated temperatures. For example, the difference in thermal expansion coefficient between the diamond grains and the solvent catalyst is believed to lead to chipping or cracking in the PCD table of a cutting element during drilling or cutting operations. The chipping or cracking in the PCD table may degrade the mechanical properties of the cutting element or lead to failure of the cutting element. Additionally, at high temperatures, diamond grains may undergo a chemical breakdown or back-conversion with the metal-solvent catalyst. Further, portions of diamond grains may transform to carbon monoxide, carbon dioxide, graphite, or combinations thereof, thereby degrading the mechanical properties of the PCD material.

Accordingly, it is desirable to remove metallic materials, such as metal-solvent catalysts, from a PCD material in situations where the PCD material may be exposed to high temperatures. Chemical leaching is often used to dissolve and remove various materials from the PCD layer. For example, chemical leaching may be used to remove metal-solvent catalysts, such as cobalt, from regions of a PCD layer that may experience elevated temperatures during drilling, such as regions adjacent to the working surfaces of the PCD layer.

During conventional leaching of a PCD table, exposed surface regions of the PCD table are immersed in a leaching solution until interstitial components, such as a metal-solvent catalyst, are removed to a desired depth from the exposed surface regions. The process of chemical leaching often involves the use of highly concentrated and/or corrosive solutions, such as aqua regia and mixtures including hydrofluoric acid (HF), to dissolve and remove metal-solvent catalysts from polycrystalline diamond materials. Moreover, in addition to dissolving metal-solvent catalysts from a PCD material, leaching solutions may be difficult to control, may take a long time, and may dissolve any accessible portions of a substrate to which the PCD material is attached. Therefore, improved methods for leaching PCD materials that reduce or mitigate difficulties with conventional leaching are desired.

SUMMARY

The instant disclosure is directed to exemplary methods and assemblies for processing superabrasive elements. In some examples, the method may comprise exposing at least a portion of a polycrystalline diamond material to a processing solution, exposing an electrode to the processing solution, applying a positive charge to the polycrystalline diamond material, and applying a negative charge to the electrode. The polycrystalline diamond material may comprise a metallic material (e.g., cobalt, nickel, iron, and/or tungsten) disposed in interstitial spaces defined within the polycrystalline diamond material.

The processing solution may comprise a suitable solution that leaches the metallic material from interstitial spaces within at least a volume of the polycrystalline diamond material. According to at least one embodiment, the rate at which the processing solution leaches the metallic material from the interstitial spaces within at least the volume of the polycrystalline diamond material is increased in the presence of an electrical current between the polycrystalline diamond material and the electrode. According to various embodiments, the electrode may be disposed near at least the portion of the polycrystalline diamond material. The electrode may be disposed such that the electrode does not directly contact the polycrystalline diamond material.

The processing solution may at least partially oxidize the metallic material when the polycrystalline diamond material is processed. According to at least one embodiment, the processing solution may comprise an aqueous solution. According to some embodiments, the processing solution may comprise a buffered or a non-buffered electrolyte solution. In various embodiments, the processing solution may comprise at least one of acetic acid, ammonium chloride, arsenic acid, ascorbic acid, citric acid, formic acid, hydrobromic acid, hydrofluoric acid, hydroiodic acid, lactic acid, malic acid, nitric acid, oxalic acid, phosphoric acid, propionic acid, pyruvic acid, succinic acid, tartaric acid, and/or any suitable carboxylic acid (e.g., monocarboxylic acid, polycarboxylic acid, etc.); the processing solution may additionally or alternatively comprise at least one of an ion, a salt, and an ester of at least one of the foregoing. The electrode may comprise at least one of copper, tungsten carbide, cobalt, zinc, iron, platinum, palladium, niobium, graphite, graphene, nichrome, gold, and silver. According to various embodiments, a masking layer may be disposed over at least a portion of the polycrystalline diamond material.

In some embodiments, a cation of the metallic material may be present in the processing solution following application of the positive charge to the polycrystalline diamond material and application of the negative charge to the electrode. The cation of the metallic material may reduced and electrodeposited on the electrode. The processing solution may comprise a first processing solution and the method may further comprise exposing at least the portion of the polycrystalline diamond material to a second processing solution (e.g., a more acidic solution than the first processing solution). At least a portion of the polycrystalline diamond material may be exposed to the second processing solution following exposure of at least the portion of the polycrystalline diamond material to the first processing solution. Additionally, at least the portion of the polycrystalline diamond material may be exposed to the second processing solution prior to exposure of at least the portion of the polycrystalline diamond material to the first processing solution. In some embodiments, an electrode for applying the positive charge abuts the polycrystalline diamond material.

According to some embodiments, a method of processing a superabrasive element may include providing a superabrasive element, exposing at least a portion of the superabrasive element to a processing solution, exposing an electrode to the processing solution, applying a first charge to the polycrystalline diamond table, and applying a second charge to the electrode. The polycrystalline diamond element may comprise a substrate and a polycrystalline diamond table bonded to the substrate, the polycrystalline diamond table comprising a metallic material disposed in interstitial spaces defined within the polycrystalline diamond table. According to various embodiments, the first charge may be applied to the polycrystalline diamond table via the substrate. In some examples, a masking layer may be disposed over at least a portion of the polycrystalline diamond table.

According to at least one embodiment, an assembly for processing a polycrystalline diamond body may include a volume of processing solution, a polycrystalline diamond body, an electrode, and a power source configured to apply a positive charge to the polycrystalline diamond body and a negative charge to the electrode. The polycrystalline diamond body and the electrode may both be in electrical communication with the processing solution. The polycrystalline diamond body may comprise a metallic material disposed in interstitial spaces defined within the polycrystalline diamond body. At least a portion of the polycrystalline diamond body and the electrode may be exposed to the volume of processing solution. The assembly may additionally include a first wire electrically connecting the power source to the polycrystalline diamond body and a second wire electrically connecting the power source to the electrode. The assembly may further include a substrate bonded to the polycrystalline diamond body, the first wire being electrically connected to the substrate by an electrode disposed on a surface portion of the substrate.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The instant disclosure is directed to exemplary leached superabrasive elements and leaching systems, methods, and assemblies for processing superabrasive elements. Such superabrasive elements may be used as cutting elements for use in a variety of applications, such as drilling tools, machining equipment, cutting tools, and other apparatuses, without limitation. Superabrasive elements, as disclosed herein, may also be used as bearing elements in a variety of bearing applications, such as thrust bearings, radial bearings, and other bearing apparatuses, without limitation.

The terms “superabrasive” and “superhard,” as used herein, may refer to any material having a hardness that is at least equal to a hardness of tungsten carbide. For example, a superabrasive article may represent an article of manufacture, at least a portion of which may exhibit a hardness that is equal to or greater than the hardness of tungsten carbide. Additionally, the term “solvent,” as used herein, may refer to a single solvent compound, a mixture of two or more solvent compounds, and/or a mixture of one or more solvent compounds and one or more dissolved compounds. The term “molar concentration,” as used herein, may refer to a concentration in units of mol/L at a temperature of approximately 25° C. For example, a solution comprising solute A at a molar concentration of 1 M may comprise 1 mol of solute A per liter of solution. Moreover, the term “cutting,” as used herein, may refer to machining processes, drilling processes, boring processes, and/or any other material removal process utilizing a cutting element and/or other cutting apparatus, without limitation.

FIGS. 1 and 2illustrate an exemplary superabrasive element10according to at least one embodiment. As illustrated inFIGS. 1 and 2, superabrasive element10may comprise a superabrasive table14affixed to or formed upon a substrate12. Superabrasive table14may be affixed to substrate12at interface26, which may be a planar or non-planar interface. Superabrasive element10may comprise a rear surface18, a superabrasive face20, and an element side surface15. In some embodiments, element side surface15may include a substrate side surface16formed by substrate12and a superabrasive side surface22formed by superabrasive table14. Rear surface18may be formed by substrate12.

Superabrasive element10may also comprise a chamfer24(i.e., sloped or angled) formed by superabrasive table14. Chamfer24may comprise an angular and/or rounded edge formed at the intersection of superabrasive side surface22and superabrasive face20. Any other suitable surface shape may also be formed at the intersection of superabrasive side surface22and superabrasive face20, including, without limitation, an arcuate surface (e.g., a radius, an ovoid shape, or any other rounded shape), a sharp edge, multiple chamfers/radii, a honed edge, and/or combinations of the foregoing. At least one edge may be formed at the intersection of chamfer24and superabrasive face20and/or at the intersection of chamfer24and superabrasive side surface22. For example, cutting element10may comprise one or more cutting edges, such as an edge27and/or or an edge28. Edge27and/or edge28may be formed adjacent to chamfer24and may be configured to be exposed to and/or in contact with a mining formation during drilling.

In some embodiments, superabrasive element10may be utilized as a cutting element for a drill bit, in which chamfer24acts as a cutting edge. The phrase “cutting edge” may refer, without limitation, to a portion of a cutting element that is configured to be exposed to and/or in contact with a subterranean formation during drilling. In at least one embodiment, superabrasive element10may be utilized as a bearing element (e.g., with superabrasive face20acting as a bearing surface) configured to contact oppositely facing bearing elements.

According to various embodiments, superabrasive element10may also comprise a substrate chamfer13formed by substrate12. For example, a chamfer comprising an angular and/or rounded edge may be formed by substrate12at the intersection of substrate side surface16and rear surface18. Any other suitable surface shape may also be formed at the intersection of substrate side surface16and rear surface18, including, without limitation, an arcuate surface (e.g., a radius, an ovoid shape, or any other rounded shape), a sharp edge, multiple chamfers/radii, a honed edge, and/or combinations of the foregoing.

Superabrasive element10may comprise any suitable size, shape, and/or geometry, without limitation. According to at least one embodiment, at least a portion of superabrasive element10may have a substantially cylindrical shape. For example, superabrasive element10may comprise a substantially cylindrical outer surface surrounding a central axis29of superabrasive element10, as illustrated inFIGS. 1 and 2. Substrate side surface16and superabrasive side surface22may, for example, be substantially cylindrical and may have any suitable diameters relative to central axis29, without limitation. According to various embodiments, substrate side surface16and superabrasive side surface22may have substantially the same outer diameter relative to central axis29. Superabrasive element10may also comprise any other suitable shape, including, for example, an oval, ellipsoid, triangular, pyramidal, square, cubic, rectangular, and/or composite shape, and/or a combination of the foregoing, without limitation.

According to various embodiments, superabrasive element10may also comprise a rear chamfer19. For example, a rear chamfer19comprising an angular and/or rounded edge may be formed by superabrasive element10at the intersection of substrate side surface16and rear surface18. Any other suitable surface shape may also be formed at the intersection of substrate side surface16and rear surface18, including, without limitation, an arcuate surface (e.g., a radius, an ovoid shape, or any other rounded shape), a sharp edge, multiple chamfers/radii, a honed edge, and/or combinations of the foregoing.

Substrate12may comprise any suitable material on which superabrasive table14may be formed. In at least one embodiment, substrate12may comprise a cemented carbide material, such as a cobalt-cemented tungsten carbide material and/or any other suitable material. In some embodiments, substrate12may include a suitable metal-solvent catalyst material, such as, for example, cobalt, nickel, iron, and/or alloys thereof. Substrate12may also include any suitable material including, without limitation, cemented carbides such as titanium carbide, niobium carbide, tantalum carbide, vanadium carbide, chromium carbide, and/or combinations of any of the preceding carbides cemented with iron, nickel, cobalt, and/or alloys thereof. Superabrasive table14may be formed of any suitable superabrasive and/or superhard material or combination of materials, including, for example PCD. According to additional embodiments, superabrasive table14may comprise cubic boron nitride, silicon carbide, polycrystalline diamond, and/or mixtures or composites including one or more of the foregoing materials, without limitation.

Superabrasive table14may be formed using any suitable technique. According to some embodiments, superabrasive table14may comprise a PCD table fabricated by subjecting a plurality of diamond particles to an HPHT sintering process in the presence of a metal-solvent catalyst (e.g., cobalt, nickel, iron, or alloys thereof) to facilitate intergrowth between the diamond particles and form a PCD body comprised of bonded diamond grains that exhibit diamond-to-diamond bonding therebetween. For example, the metal-solvent catalyst may be mixed with the diamond particles, infiltrated from a metal-solvent catalyst foil or powder adjacent to the diamond particles, infiltrated from a metal-solvent catalyst present in a cemented carbide substrate, or combinations of the foregoing. The bonded diamond grains (e.g., sp3-bonded diamond grains), so-formed by HPHT sintering the diamond particles, define interstitial regions with the metal-solvent catalyst disposed within the interstitial regions of the as-sintered PCD body. The diamond particles may exhibit a selected diamond particle size distribution. Polycrystalline diamond elements, such as those disclosed in U.S. Pat. Nos. 7,866,418 and 8,297,382, the disclosure of each of which is incorporated herein, in its entirety, by this reference, may have magnetic properties in at least some regions as disclosed therein and leached regions in other regions as disclosed herein.

Following sintering, various materials, such as a metal-solvent catalyst, remaining in interstitial regions within the as-sintered PCD body may reduce the thermal stability of superabrasive table14at elevated temperatures. In some examples, differences in thermal expansion coefficients between diamond grains in the as-sintered PCD body and a metal-solvent catalyst in interstitial regions between the diamond grains may weaken portions of superabrasive table14that are exposed to elevated temperatures, such as temperatures developed during drilling and/or cutting operations. The weakened portions of superabrasive table14may be excessively worn and/or damaged during the drilling and/or cutting operations.

Removing the metal-solvent catalyst and/or other materials from the as-sintered PCD body may improve the heat resistance and/or thermal stability of superabrasive table14, particularly in situations where the PCD material may be exposed to elevated temperatures. A metal-solvent catalyst and/or other materials may be removed from the as-sintered PCD body using any suitable technique, including, for example, electrochemical leaching. In at least one embodiment, a metal-solvent catalyst, such as cobalt, may be removed from regions of the as-sintered PCD body, such as regions adjacent to the working surfaces of superabrasive table14. Removing a metal-solvent catalyst from the as-sintered PCD body may reduce damage to the PCD material of superabrasive table14caused by expansion of the metal-solvent catalyst.

At least a portion of a metal-solvent catalyst, such as cobalt, as well as other materials, may be removed from at least a portion of the as-sintered PCD body using any suitable technique, without limitation. For example, electrochemical, chemical and/or gaseous leaching may be used to remove a metal-solvent catalyst from the as-sintered PCD body up to a desired depth from a surface thereof. The as-sintered PCD body may be electrochemically leached by immersion in an acid or acid solution, such as a solution including acetic acid, ammonium chloride, arsenic acid, ascorbic acid, citric acid, formic acid, hydrobromic acid, hydrofluoric acid, hydroiodic acid, lactic acid, malic acid, nitric acid, oxalic acid, phosphoric acid, propionic acid, pyruvic acid, succinic acid, tartaric acid, and/or any suitable carboxylic acid (e.g., monocarboxylic acid, polycarboxylic acid, etc.), in the presence of an electrode, such as copper, tungsten carbide, cobalt, zinc, iron, platinum, palladium, niobium, graphite, graphene, nichrome, gold, and/or silver electrode, wherein a charge is applied to the as-sintered PCD body and an opposite charge is applied to the electrode or subjected to another suitable process to remove at least a portion of the metal-solvent catalyst from the interstitial regions of the PCD body and form superabrasive table14comprising a PCD table. For example, the as-sintered PCD body may be immersed in an acid solution in the presence of an electrode, a positive charge may be applied to the as-sintered PCD body and a negative charge may be applied to the electrode for a selected amount of time. For example, a PCD body may be positively charged and an electrode may be negatively charged for more than 4 hours, more than 10 hours, between 24 hours to 48 hours, about 2 to about 7 days (e.g., about 3, 5, or 7 days), for a few weeks (e.g., about 4 weeks), or for 1-2 months, depending on the process employed.

Even after leaching, a residual, detectable amount of the metal-solvent catalyst may be present in the at least partially leached superabrasive table14. It is noted that when the metal-solvent catalyst is infiltrated into the diamond particles from a cemented tungsten carbide substrate including tungsten carbide particles cemented with a metal-solvent catalyst (e.g., cobalt, nickel, iron, or alloys thereof), the infiltrated metal-solvent catalyst may carry tungsten and/or tungsten carbide therewith and the as-sintered PCD body may include such tungsten and/or tungsten carbide therein disposed interstitially between the bonded diamond grains. The tungsten and/or tungsten carbide may be at least partially removed by the selected leaching process or may be relatively unaffected by the selected leaching process.

In some embodiments, only selected portions of the as-sintered PCD body may be leached, leaving remaining portions of resulting superabrasive table14unleached. For example, some portions of one or more surfaces of the as-sintered PCD body may be masked or otherwise protected from exposure to a processing solution and/or gas mixture while other portions of one or more surfaces of the as-sintered PCD body may be exposed to the processing solution and/or gas mixture. Other suitable techniques may be used for removing a metal-solvent catalyst and/or other materials from the as-sintered PCD body or may be used to accelerate an electrochemical leaching process, as will be described in greater detail below. For example, exposing the as-sintered PCD body to heat, pressure, microwave radiation, and/or ultrasound may be employed to leach or to accelerate an electrochemical leaching process, without limitation. Following leaching, superabrasive table14may comprise a volume of PCD material that is at least partially free or substantially free of a metal-solvent catalyst.

The plurality of diamond particles used to form superabrasive table14comprising the PCD material may exhibit one or more selected sizes. The one or more selected sizes may be determined, for example, by passing the diamond particles through one or more sizing sieves or by any other method. In an embodiment, the plurality of diamond particles may include a relatively larger size and at least one relatively smaller size. As used herein, the phrases “relatively larger” and “relatively smaller” refer to particle sizes determined by any suitable method, which differ by at least a factor of two (e.g., 40 μm and 20 μm). More particularly, in various embodiments, the plurality of diamond particles may include a portion exhibiting a relatively larger size (e.g., 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 15 μm, 12 μm, 10 μm, 8 μm) and another portion exhibiting at least one relatively smaller size (e.g., 30 μm, 20 μm, 15 μm, 12 μm, 10 μm, 8 μm, 4 μm, 2 μm, 1 μm, 0.5 μm, less than 0.5 μm, 0.1 μm, less than 0.1 μm). In another embodiment, the plurality of diamond particles may include a portion exhibiting a relatively larger size between about 40 μm and about 15 μm and another portion exhibiting a relatively smaller size between about 12 μm and 2 μm. Of course, the plurality of diamond particles may also include three or more different sizes (e.g., one relatively larger size and two or more relatively smaller sizes), without limitation. Different sizes of diamond particle may be disposed in different locations within a polycrystalline diamond volume, without limitation. According to at least one embodiment, disposing different sizes of diamond particles in different locations may facilitate control of a leach depth, as will be described in greater detail below.

FIGS. 3 and 4illustrate an exemplary superabrasive element110according to various embodiments. Superabrasive element110may comprise a superabrasive table114that is not attached to a substrate. As shown inFIGS. 3 and 4, superabrasive element110may include a rear surface118, a superabrasive face120, and an element side surface122formed by superabrasive table114. Superabrasive element110may also comprise a chamfer124(i.e., sloped or angled) and/or any other suitable surface shape at the intersection of element side surface122and superabrasive face120, including, without limitation, an arcuate surface (e.g., a radius, an ovoid shape, or any other rounded shape), a sharp edge, multiple chamfers/radii, a honed edge, and/or combinations of the foregoing. At least one edge, such as an edge127and/or or an edge128, may be formed at the intersection of chamfer124and each of superabrasive face120and element side surface122, respectively. Element side surface122of superabrasive element110may radially surround a central axis129of superabrasive element110.

According to various embodiments, superabrasive element110may also comprise a rear chamfer119. For example, a rear chamfer119comprising an angular and/or rounded edge may be formed by superabrasive element110at the intersection of element side surface122and rear surface118. Any other suitable surface shape may also be formed at the intersection of element side surface122and rear surface118, including, without limitation, an arcuate surface (e.g., a radius, an ovoid shape, or any other rounded shape), a sharp edge, multiple chamfers/radii, a honed edge, and/or combinations of the foregoing.

Superabrasive element110may be formed using any suitable technique, including, for example, HPHT sintering, as described above. In some examples, superabrasive element110may be created by first forming a superabrasive element10that includes a substrate12and a superabrasive table14, as detailed above in reference toFIGS. 1 and 2. Once superabrasive element10has been produced, superabrasive table14may be separated from substrate12to form superabrasive element110. For example, prior to or following leaching, superabrasive table14may be separated from substrate12using any suitable process, including a lapping process, a grinding process, a wire-electrical-discharge machining (“wire EDM”) process, or any other suitable material-removal process, without limitation.

According to some embodiments, superabrasive element110may be processed and utilized either with or without an attached substrate. For example, following leaching, superabrasive element may be secured directly to a cutting tool, such as a drill bit, or to a bearing component, such as a rotor or stator. In various embodiments, following processing, superabrasive element110may be attached to a substrate. For example, rear surface118of superabrasive element110may be brazed, welded, soldered, threadedly coupled, and/or otherwise adhered and/or fastened to a substrate, such as tungsten carbide substrate or any other suitable substrate, without limitation. Polycrystalline diamond elements having pre-sintered polycrystalline diamond bodies including an infiltrant, such as those disclosed in U.S. Pat. No. 8,323,367, the disclosure of which is incorporated herein, in its entirety, by this reference, may be leached a second time according to the processes disclosed herein after reattachment of the pre-sintered polycrystalline diamond bodies.

FIG. 5is a cross-sectional side view of a portion of an exemplary superabrasive table214, such as the superabrasive tables14and114illustrated inFIGS. 1-4. Superabrasive table14may comprise a composite material, such as a PCD material. A PCD material may include a matrix of bonded diamond grains and interstitial regions defined between the bonded diamond grains. Such interstitial regions may be at least partially filled with various materials. In some embodiments, a metal-solvent catalyst may be disposed in interstitial regions in superabrasive table14. Tungsten and/or tungsten carbide may also be present in the interstitial regions.

According to various embodiments, materials may be deposited in interstitial regions during processing of superabrasive table14. For example, material components of substrate12may migrate into a mass of diamond particles used to form a superabrasive table14during HPHT sintering. As the mass of diamond particles is sintered, a metal-solvent catalyst may melt and flow from substrate12into the mass of diamond particles. As the metal-solvent flows into superabrasive table14, it may dissolve and/or carry additional materials, such as tungsten and/or tungsten carbide, from substrate12into the mass of diamond particles. As the metal-solvent catalyst flows into the mass of diamond particles, the metal-solvent catalyst, and any dissolved and/or undissolved materials, may at least partially fill spaces between the diamond particles. The metal-solvent catalyst may facilitate bonding of adjacent diamond particles to form a PCD layer. Following sintering, any materials, such as, for example, the metal-solvent catalyst, tungsten, and/or tungsten carbide, may remain in interstitial regions within superabrasive table14.

To improve the performance and heat resistance of a surface of superabrasive table14, at least a portion of a metal-solvent catalyst, such as cobalt, may be removed from at least a portion of superabrasive table14. Optionally, tungsten and/or tungsten carbide may be removed from at least a portion of superabrasive table14. A metal-solvent catalyst, as well as other materials, may be removed from superabrasive table14using any suitable technique, without limitation.

For example, electrochemical leaching may be used to remove a metal-solvent catalyst from superabrasive table214up to a depth D from a surface of superabrasive table214, as illustrated inFIG. 5. As shown inFIG. 5, depth D may be measured relative to an external surface of superabrasive table214, such as superabrasive face220, superabrasive side surface222, and/or chamfer224. In some examples, a metal-solvent catalyst may be removed from superabrasive table214up to a depth D of approximately 2500 μm. In additional examples, a metal-solvent catalyst may be removed from superabrasive table214up to a depth D of between approximately 100 and 1000 μm.

Following leaching, superabrasive table214may comprise a first volume221and a second volume223. Following leaching, superabrasive table214may comprise, for example, a first volume221that contains a metal-solvent catalyst. An amount of metal-solvent catalyst in first volume221may be substantially the same prior to and following leaching. In various embodiments, first volume221may be remote from one or more exposed surfaces of superabrasive table214.

Second volume223may comprise a volume of superabrasive table214having a lower concentration of the interstitial material than first volume221. For example, second volume223may be substantially free of a metal-solvent catalyst. However, small amounts of catalyst may remain within interstices that are inaccessible to the leaching process. Second volume223may extend from one or more surfaces of superabrasive table214(e.g., superabrasive face220, superabrasive side surface222, and/or chamfer224) to a depth D from the one or more surfaces. Second volume223may be located adjacent one or more surfaces of superabrasive table214. An amount of metal-solvent catalyst in first volume221and/or second volume223may vary at different depths in superabrasive table214.

In at least one embodiment, superabrasive table214may include a transition region225between first volume221and second volume223. Transition region225may include amounts of metal-solvent catalyst varying between an amount of metal-solvent catalyst in first volume221and an amount of metal-solvent catalyst in second volume223. In various examples, transition region225may comprise a relatively narrow region between first volume221and second volume223.

FIGS. 6A and 6Bare magnified cross-sectional side views of a portion of the superabrasive table214illustrated inFIG. 5according to various embodiments. As shown inFIGS. 6A and 6B, superabrasive table214may comprise grains234and interstitial regions236between grains234defined by grain surfaces238. Grains234may comprise grains formed of any suitable superabrasive material, including, for example, diamond grains. At least some of grains234may be bonded to one or more adjacent grains234, forming a polycrystalline diamond matrix.

Interstitial material239may be disposed in at least some of interstitial regions236. Interstitial material239may comprise any suitable material, such as, for example, a metal-solvent catalyst, tungsten, and/or tungsten carbide. As shown inFIG. 6A, interstitial material239may not be present in at least some of interstitial regions236. At least a portion of interstitial material239may be removed from at least some of interstitial regions236during a leaching procedure. For example, a substantial portion of interstitial material239may be removed from second volume223during a leaching procedure. Additionally interstitial material239may remain in a first volume221following a leaching procedure. In some embodiments, as shown inFIG. 6B, at least some of interstitial regions236may be partially filled with interstitial material231that is not removed by leaching. For example, in one embodiment, cobalt may be substantially removed from at least some of interstitial regions236of first volume221and/or second volume223, while tungsten and/or tungsten carbide may remain in the at least some of interstitial regions236of first volume221and/or second volume223.

In some examples, interstitial material239may be removed from table214to a depth that improves the performance and/or heat resistance of a surface of superabrasive table214to a desired degree. In some embodiments, interstitial material239may be removed from superabrasive table214to a practical limit. In order to remove interstitial material239from superabrasive table214to a depth beyond the practical limit, for example, significantly more time, temperature, and/or other process parameter may be required. In some embodiments, interstitial material239may be removed from superabrasive table214to a practical limit or desired degree where interstitial material remains in at least a portion of superabrasive table214. In various embodiments, superabrasive table214may be fully leached so that interstitial material239is substantially removed from a substantial portion of superabrasive table214.

In at least one embodiment, as will be described in greater detail below, interstitial material239may be leached from a superabrasive material, such as a PCD material in superabrasive table214, by exposing the superabrasive material to a suitable processing solution in the presence of an electrode and applying a charge (e.g., a positive charge) to the superabrasive material and an opposite charge (e.g., a negative charge) to the electrode. Interstitial material239may include a metal-solvent catalyst, such as cobalt, nickel, iron, and/or alloys thereof.

FIGS. 7-28show exemplary configurations of superabrasive elements and electrodes for leaching the superabrasive elements. The configurations illustrated in these figures may enable selective leaching of portions of the superabrasive elements to form desired leach profiles within the superabrasive elements. While certain configurations of superabrasive elements are shown and described herein for purposes of illustration, the apparatuses and methods described herein may be applied to any superabrasive article having any suitable material, shape, and configuration, without limitation.

FIGS. 7 and 8illustrate an exemplary superabrasive element10disposed near an exemplary electrode40according to at least one embodiment. As illustrated inFIGS. 7 and 8, superabrasive element10may comprise a superabrasive table14affixed to or formed upon a substrate12. Superabrasive table14may be affixed to substrate12at interface26, which may be a planar or non-planar interface. Superabrasive element10may comprise a rear surface18, a superabrasive face20, and an element side surface15. In some embodiments, element side surface15may include a substrate side surface16formed by substrate12and a superabrasive side surface22formed by superabrasive table14. Rear surface18may be formed by substrate12.

Superabrasive element10may also comprise a chamfer24(i.e., sloped or angled) formed by superabrasive table14. Chamfer24may comprise an angular and/or rounded edge formed at the intersection of superabrasive side surface22and superabrasive face20. Any other suitable surface shape may also be formed at the intersection of superabrasive side surface22and superabrasive face20, including, without limitation, an arcuate surface (e.g., a radius, an ovoid shape, or any other rounded shape), a sharp edge, multiple chamfers/radii, a honed edge, and/or combinations of the foregoing.

Electrode40may comprise any suitable size, shape, and/or geometry, without limitation. According to at least one embodiment, at least a portion of electrode40may have a substantially cylindrical shape. For example, electrode40may comprise a substantially cylindrical outer surface surrounding a central axis of electrode40, as illustrated inFIGS. 7 and 8. Electrode40may comprise any suitable material that may conduct electricity. Electrode40may have an outer diameter that is substantially the same as the outer diameter of element side surface15of superabrasive element10. In at least one embodiment, electrode40may comprise copper. Electrode40may comprise any suitable electrically conductive material, such as, for example, copper, tungsten carbide, cobalt, zinc, iron, platinum, palladium, niobium, graphite, graphene, nichrome, gold, silver, alloys thereof, any suitable metallic material, and/or any other suitable electrically conductive material, without limitation.

According to various embodiments, a charge may be applied to superabrasive element10and electrode40through electrical conductors (e.g., wires or any suitable electrical conductor)44and42, respectively. For example, in order to apply a current to processing solution for processing superabrasive element10, superabrasive element10and electrical conductor44may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge (e.g., a positive charge) may be applied to at least a portion of substrate12(e.g., rear surface18) of superabrasive element10through electrical conductor44and an opposite charge (e.g., a negative charge) may be applied to electrode40through electrical conductor42. In at least one embodiment, electrical conductor44may be electrically connected to substrate12by an electrode electrically connected to (e.g., positioned abutting) substrate12. In some embodiments, electrical conductor44may be directly connected to superabrasive table14by an electrode electrically connected to (e.g., positioned abutting) superabrasive table14.

When superabrasive element10is disposed in a processing solution such that at least a portion of superabrasive table14and electrode40are exposed to the processing solution when a voltage is applied to the processing solution via electrode40and superabrasive table14, interstitial materials may be removed from at least a portion of superabrasive table14of superabrasive element10near electrode40.

FIGS. 9A and 9Billustrate an exemplary superabrasive element10disposed near an exemplary electrode40and positioned within a protective leaching cup30according to at least one embodiment. As illustrated inFIGS. 9A and 9B, superabrasive element10may comprise a superabrasive table14affixed to or formed upon a substrate12. Superabrasive table14may be affixed to substrate12at interface26, which may be a planar or non-planar interface. Superabrasive element10may comprise a rear surface18, a superabrasive face20, and an element side surface15. In some embodiments, element side surface15may include a substrate side surface16formed by substrate12and a superabrasive side surface22formed by superabrasive table14. Rear surface18may be formed by substrate12. Superabrasive element10may also comprise a chamfer24formed by superabrasive table14. Chamfer24may comprise an angular and/or rounded edge formed between superabrasive side surface22and superabrasive face20.

As shown inFIGS. 9A and 9B, superabrasive element10may be positioned within protective leaching cup30such that protective leaching cup30surrounds at least a portion of superabrasive element10, including substrate12. When superabrasive element10is positioned within protective leaching cup30, at least a portion of superabrasive element10, such as superabrasive table14and/or substrate12, may be positioned adjacent to and/or contacting a portion of protective leaching cup30. For example, protective leaching cup30may be configured to contact at least a portion of element side surface15of superabrasive element10, forming a seal between protective leaching cup30and superabrasive element10, where the leaching cup30is partially or fully impermeable to various fluids, such as a leaching material (e.g., a leaching solution).

Protective leaching cup30may be formed of any suitable material, without limitation. For example, protective leaching cup30may comprise a flexible, elastic, malleable, and/or otherwise deformable material configured to surround and/or contact at least a portion of superabrasive element10. Protective leaching cup30may prevent damage to superabrasive element10when at least a portion of superabrasive element10is exposed to various reactive agents. For example, protective leaching cup30may prevent a leaching solution from chemically damaging certain portions of superabrasive element10, such as portions of substrate12, portions of superabrasive table14, or both, during leaching. Protective leaching cup30may be formed with an opening32configured to allow electrical conductor44to contract rear surface18of superabrasive element10. Optionally, opening32may be sealed with a sealant (e.g., silicone, epoxy, etc.) to prevent the leaching solution from damaging substrate12, if necessary.

In various embodiments, protective layer30may comprise one or more materials that are substantially inert and/or otherwise resistant to acids, bases, and/or other reactive components present in a leaching solution used to leach superabrasive element10. In some embodiments, protective layer30may comprise one or more materials exhibiting significant stability at various temperatures and/or pressures, including selected temperatures and/or pressures used in leaching and/or otherwise processing superabrasive element10. In some embodiments, protective leaching cup30may include one or more polymeric materials, such as, for example, nylon, polytetrafluoroethylene (PTFE), polyethylene, polypropylene, rubber, silicone, and/or other polymers, and/or a combination of any of the foregoing, without limitation. For example, protective leaching cup30may comprise PTFE blended with one or more other polymeric materials.

Electrode40may be disposed near and/or abutting superabrasive element10. For example, as shown inFIG. 9A, electrode40may be disposed near, but separated from, superabrasive table14of superabrasive element10. Electrode40may be disposed any suitable distance away from superabrasive element10. Optionally, as illustrated inFIG. 9B, electrode40may be disposed adjacent to at least a portion of superabrasive element10. For example, electrode40may be electrically connected to (e.g., positioned abutting) a portion of superabrasive table14, such as superabrasive face20. Although not shown, electrode40may be disposed adjacent to any other suitable portion of superabrasive table14, such as, for example, superabrasive side surface22and/or chamfer24.

FIG. 9Cis a cross-sectional side view of an exemplary leaching assembly according to at least one embodiment. As illustrated inFIG. 9C, superabrasive element10may be positioned within a protective leaching cup30and disposed near electrode40. Superabrasive element10, electrode40, and protective leaching cup30may further be positioned within a processing vessel70.

As shown inFIG. 9C, processing vessel70may have a rear wall74and a side wall73defining a cavity76. Rear wall74and side wall73may have any suitable shape, without limitation. Processing vessel70may include an opening78opposite rear wall74. Cavity76may contain a processing solution72such that at least a portion of superabrasive element10is exposed to processing solution72. Superabrasive element10may be positioned in cavity76so that superabrasive element10is positioned adjacent to or near rear wall74of processing vessel70. In some embodiments, superabrasive element10may be positioned and/or secured within processing vessel70using any suitable mechanism, without limitation. Processing vessel70may be larger than leaching cup30, so that there are gaps between leaching cup30and processing vessel70. In other embodiments, more than one superabrasive element10and protective leaching cup30(e.g., 10 or more, 20 or more, etc.) may be placed within a single processing vessel70for loading.

According to some embodiments, processing solution72may comprise a conductive solution (e.g., a conductive aqueous solution, a conductive non-aqueous solution, etc.). Solvents in such processing solution72may comprise water and/or any other suitable solvent, without limitation. Processing solution72may also comprise dissolved electrolytes. Such electrolytes may comprise any suitable electrolyte compounds, including, without limitation, acetic acid, ammonium chloride, arsenic acid, ascorbic acid, citric acid, formic acid, hydrobromic acid, hydrofluoric acid, hydroiodic acid, lactic acid, malic acid, nitric acid, oxalic acid, phosphoric acid, propionic acid, pyruvic acid, succinic acid, tartaric acid, and/or any suitable carboxylic acid (e.g., monocarboxylic acid, polycarboxylic acid, etc.), and/or ions, salts, and/or esters of any of the foregoing, and/or any combination of the foregoing. Such electrolytes may be present in processing solution72at any suitable concentration, without limitation. For example, one or more electrolytes may be present in processing solution72at a concentration of, for example, less than approximately 5 M. In certain embodiments, one or more electrolytes may be present in processing solution72at a concentration of, for example, less than approximately 0.01 M. In at least one embodiment, one or more electrolytes may be present in processing solution72at a concentration of, for example, between approximately 0.01 M and approximately 3 M. In some embodiments, one or more electrolytes may be present in processing solution72at a concentration of, for example, between approximately 0.1 M and approximately 1 M. In additional embodiments, one or more electrolytes may be present in processing solution72at a concentration of, for example, between approximately 0.2 M and approximately 0.4 M. In at least one embodiment, one or more electrolytes may be present in processing solution72at a concentration of, for example, approximately 0.3 M.

Processing solution72may have a pH of between approximately 1 and approximately 12. In certain embodiments, processing solution72may have a pH below approximately 1. In some embodiments, processing solution72may have a pH of between approximately 1 and approximately 7. In at least one embodiment, for example, processing solution72may have a pH approximately 2.0.

In some embodiments, processing solution72may include metal salts, such as cobalt salts, iron salts, nickel salts, copper salts, and/or any other suitable transition metal salts, and/or any other suitable metal ion salts, without limitation. Such metal salts may include, for example, cobalt chloride, cobalt nitrate, iron chloride, and/or any other suitable metal salts, without limitation. One or more metal salts may be present in processing solution72at any suitable concentration, including, for example, a concentration of less than approximately 2 M. In at least one embodiment, one or more metal salts may be present in processing solution72at a concentration of, for example, between approximately 0.01 M and approximately 1 M. In some embodiments, one or more metal salts may be present in processing solution72at a concentration of, for example, between approximately 0.03 M and approximately 0.5 M. In additional embodiments, one or more metal salts may be present in processing solution72at a concentration of, for example, between approximately 0.05 M and approximately 0.3 M. In at least one embodiment, for example, one or more compounds may be dissolved in processing solution72at a concentration of, for example, approximately 0.1 M.

Processing solution72may further include any other suitable components, without limitation, including, for example, a buffering agent (e.g., boric acid, an amine compound such as ethylenediamine, triethanolamine, ethanolamine, etc.), a pH control agent (e.g., sodium hydroxide, etc.), and/or a conducting agent (e.g., sodium sulfate, ammonium citrate, etc.). In some examples, processing solution72may comprise an acid (e.g., a mineral acid) suitable for increasing the solubility of a metallic material, such as cobalt or any other material, with respect to processing solution72, including, for example, nitric acid, hydrochloric acid, phosphoric acid, sulfuric acid, boric acid, hydrofluoric acid, and/or any combination of the foregoing mineral acids. The acid may be selected for its ability to attack and/or dissolve a metallic material within superabrasive table14. Processing solution72may then carry the dissolved metallic material out of superabrasive table14. In some examples, a suitable acid may be configured to increase the solubility of a metallic material, such as cobalt, in the processing mixture, thereby facilitating leaching of the metallic material from superabrasive table14using the processing mixture. In additional examples, an acid may be configured to increase the solubility of iron, tungsten, and/or nickel in the processing mixture.

Processing solution72may comprise a complexing agent dissolved in the solvent. The complexing agent may comprise a compound suitable for forming metal complexes with various interstitial materials, including, for example, tungsten and/or tungsten carbide. The complexing agent may form metal complexes with tungsten and/or tungsten carbide present in a superabrasive material, thereby inhibiting or preventing the formation and/or build-up of tungsten oxides, such as WO2, W2O5, and WO3, in the superabrasive material. Metal complexes formed between the complexing agent and tungsten and/or tungsten carbide may be soluble in processing solution72, thereby enabling the metal complexes to be easily removed from superabrasive table14. Accordingly, the complexing agent may facilitate the removal of tungsten and/or tungsten carbide from a leached portion of superabrasive table14, thereby reducing the amount of residual tungsten, tungsten carbide, and/or tungsten oxide present in a leached region of superabrasive table14. The complexing agent may also facilitate removal of additional metal compounds that may be present in superabrasive table14. Examples of suitable compounds that may function as complexing agents include, without limitation, phosphoric acid, citric acid, tartaric acid, oxalic acid, ammonium chloride, and/or any combination of the foregoing.

According to various embodiments, a charge may be applied to superabrasive element10and electrode40through electrical conductors44and42, respectively. For example, in order to apply a current to processing solution72for processing superabrasive element10, at least a portion of superabrasive element10may be positioned in processing solution72and a charge may be applied to at least a portion of superabrasive element10(e.g., rear surface18of substrate12) through electrical conductor44. For example, a positive charge may be applied to substrate12such that at least a portion of superabrasive element10acts as an anode. An opposite charge may be applied to electrode40through electrical conductor42. For example, a negative charge may be applied to electrode40such that electrode40acts as a cathode. In at least one embodiment, electrical conductor44may be electrically connected to substrate12by an electrode electrically connected to (e.g., positioned abutting) substrate12. In some embodiments, electrical conductor44may be directly connected to superabrasive table14by an electrode electrically connected to (e.g., positioned abutting and/or disposed at least partially within) superabrasive table14.

According to some embodiments, a voltage of less than approximately 10 V may be applied to processing solution72via electrode40and superabrasive element10. In some embodiments, a voltage of between approximately 0.01 V and approximately 5 V may be applied to processing solution72. In some embodiments, a voltage of between approximately 0.5 V and approximately 3 V may be applied to processing solution72. In some embodiments, a voltage of between approximately 0.1 V and approximately 3 V may be applied to processing solution72. In additional embodiments, a voltage of between approximately 0.4 V and approximately 2.4 V may be applied to processing solution72. In some embodiments, a voltage of approximately 0.5 V, 0.6 V, 0.7 V, 0.8 V, 0.9 V, or 1.0 V may be applied to processing solution72.

In various embodiments, a voltage applied to processing solution72may be changed one or more times while superabrasive element10is exposed to processing solution72. For example, the electrical conductivity of processing solution72may change during processing of superabrasive element10such that different voltages are required over time to maintain a desired current flow between superabrasive element10and electrode40. In at least one embodiment, for example, materials removed from superabrasive element10and dissolved in processing solution72during processing may cause processing solution72to decrease in electrical conductivity and increase in electrical resistance. The voltage between superabrasive element10and electrode40may be increased in conjunction with the decrease in electrical conductivity/increase in electrical resistance so as to maintain a desired current flow through superabrasive element10and/or processing solution72.

When superabrasive element10and electrode40are disposed in the processing solution72such that at least a portion of superabrasive table14and electrode40are exposed to processing solution72and a voltage is applied to processing solution72via electrode40and superabrasive table14, interstitial materials may be removed from at least a portion of superabrasive table14and electrodeposited onto a portion of electrode40exposed to electroplating solution72. For example, a metallic material, such as cobalt, present in at least a portion of superabrasive table14may be electrolytically oxidized in the presence of a current flowing between superabrasive element10and electrode40. The oxidized metallic material may then be leached into processing solution72as dissolved metal cations. Dissolved metal cations (e.g., cobalt cations) present in processing solution72may then be reduced at electrode40to form a metal coating on a surface portion of electrode40. Accordingly, a metallic material, such as cobalt, may be effectively transferred from at least a portion of superabrasive table14of superabrasive element10to a surface portion of electrode40through electrodeposition of the metallic material onto the surface portion of electrode40.

In additional embodiments, a negative charge may be applied to superabrasive element10such that at least a portion of superabrasive element10acts as a cathode and a positive charge may be applied to electrode40such that electrode40acts as an anode. A metallic material present in superabrasive table14may be reduced to form metal anions that are dissolved in processing solution72and the dissolved metallic anions may then be electrodeposited through oxidation onto a surface portion of electrode40.

According to various embodiments, superabrasive table14may be exposed to processing solution72at a desired temperature and/or pressure prior to and/or during leaching. Exposing superabrasive table14to a selected temperature and/or pressure during leaching may increase the depth to which the superabrasive table14may be leached. Exposing superabrasive table14to a selected temperature and/or pressure during leaching may decrease an amount of time required to leach superabrasive table14to a desired degree.

In various examples, at least a portion of superabrasive element10and processing solution72may be heated to a temperature of between approximately 15° C. and approximately 280° C. during leaching. According to additional embodiments, at least a portion of a superabrasive element10and processing solution72may be heated to a temperature of between approximately 20° C. and approximately 95° C. during leaching. For example, at least a portion of a superabrasive element10and processing solution72may be heated to a temperature of approximately 25° C.

In various embodiments, at least a portion of superabrasive element10and processing solution72may be exposed to a pressure of between approximately 0 bar and approximately 100 bar during leaching. In additional embodiments, at least a portion of superabrasive element10and processing solution72may be exposed to a pressure of between approximately 20 bar and approximately 80 bar during leaching. In at least one example, at least a portion of superabrasive element10and processing solution72may be exposed to a pressure of approximately 50 bar during leaching.

According to additional embodiments, at least a portion of superabrasive element10and processing solution72may be exposed to at least one of microwave radiation, and/or ultrasonic energy. By exposing at least a portion of superabrasive element10to microwave radiation, induction heating, and/or ultrasonic energy as superabrasive element10is exposed to processing solution72, the rate at which superabrasive table14is leached may be increased.

FIGS. 10A-10Eshow exemplary superabrasive elements110and assemblies for leaching superabrasive elements110.FIG. 10Ais a cross-sectional side view of an exemplary leaching assembly according to at least one embodiment. As shown inFIG. 10A, superabrasive element110may be disposed near an electrode140. Superabrasive element110may comprise a superabrasive table114that is not affixed to or formed upon a substrate (see superabrasive element110illustrated inFIGS. 3 and 4). Superabrasive element110may comprise a rear surface118, a superabrasive face120, and an element side surface122. Superabrasive element110may also comprise a chamfer124formed by superabrasive table114. Chamfer124may comprise an angular and/or rounded edge formed between superabrasive side surface122and superabrasive face120. Superabrasive element110may also comprise a rear chamfer119formed by superabrasive table114at the intersection of element side surface122and rear surface118.

In some embodiments, as illustrated inFIG. 10A, superabrasive element110may not be surrounded by a protective covering, such as a leaching cup. Optionally, superabrasive element110may be at least partially covered by a protective layer, such as a leaching cup and/or a masking layer. Superabrasive element110and electrode140may be positioned within a processing vessel170. Processing vessel170may have a rear wall174and a side wall173defining a cavity176. Rear wall174and side wall173may have any suitable shape, without limitation. Processing vessel170may include an opening178opposite rear wall174. Cavity176may contain a suitable processing solution172such that at least a portion of superabrasive element110is exposed to processing solution172. Superabrasive element110may be positioned in cavity176so that superabrasive element110is disposed near and/or electrically connected to (e.g., abutting) electrode140.

According to various embodiments, a charge may be applied to superabrasive element110and electrode140through electrical conductors144and142, respectively. For example, in order to apply a current to processing solution172for processing superabrasive element110, at least a portion of superabrasive element110may be positioned in processing solution172and a charge may be applied to at least a portion of superabrasive element110(e.g., rear surface118of substrate112) through electrical conductor144and an opposite charge may be applied to electrode140through electrical conductor142. In some embodiments, as shown inFIG. 10A, superabrasive element110may be disposed on an electrode145, which electrically connects electrical conductor144to superabrasive element110. Electrode145may separate superabrasive element110from processing vessel170, thereby facilitating contact between a greater surface area of superabrasive element110and processing solution172. Additionally, electrode145may facilitate positioning of superabrasive element110near electrode140. Optionally, superabrasive element110may be positioned near rear wall174of processing vessel170and/or may be connected to electrical conductor144without electrode145.

In some embodiments, superabrasive element110may be coupled to electrode145, or optionally, to electrical conductor144, through brazing, welding, soldering, adhesive bonding, mechanical fastening, and/or any other suitable bonding technique. For example, superabrasive element110may be bonded to electrode145or electrical conductor144by a braze joint (e.g., a carbide forming braze such as a titanium-based braze, etc.). In at least one embodiment, such a braze joint may be coated with a protective layer (e.g., paint layer, epoxy layer, etc.).

In at least one embodiment, a positive charge may be applied to superabrasive element110, which acts as an anode, via electrical conductor144and electrode145. An opposite charge may be applied to electrode140through electrical conductor142. For example, a negative charge may be applied to electrode140such that electrode140acts as a cathode. When superabrasive element110and electrode140are disposed in the processing solution172such that at least a portion of superabrasive table114and electrode140are exposed to processing solution172and a voltage is applied to processing solution172via electrode140and superabrasive table114, interstitial materials may be removed from at least a portion of superabrasive table114and electrodeposited onto a portion of electrode140exposed to electroplating solution172. Superabrasive element110may be exposed to processing solution172and/or a charge may be applied to processing solution172until a desired level of leaching is obtained.

FIGS. 10B and 10Cillustrate superabrasive elements that have been leached to different extents.FIG. 10Bshows a superabrasive element110that has been leached substantially throughout superabrasive table114. Accordingly, superabrasive table114may have a leached volume123that substantially occupies the entire volume of superabrasive table114. According to various embodiments, at least some of interstitial regions in leached volume123may be at least partially filled with interstitial material that is not removed by leaching.

FIG. 10Cshows a superabrasive element110that has been partially leached. Superabrasive table114may include a first volume121comprising an interstitial material and a second volume123having a lower concentration of the interstitial material than first volume121. As shown inFIG. 10B, first volume121may be surrounded by second volume123such that substantially all surface portions (i.e., superabrasive face120, element side surface122, chamfer124, chamfer119) of superabrasive table114are defined by second volume123, from which the interstitial material has been substantially removed.

FIGS. 10D and 10Eshow cross-sectional side views of exemplary leaching assemblies according to various embodiments. As shown inFIGS. 10D and 10E, superabrasive element110may be disposed near a plurality of electrodes, including at least electrodes140A and140B. Superabrasive element110may comprise a superabrasive table114that is not affixed to or formed upon a substrate (see superabrasive element110illustrated inFIGS. 3 and 4). Superabrasive element110may comprise a rear surface118, a superabrasive face120, an element side surface122, a chamfer124between superabrasive side surface122and superabrasive face120, and a rear chamfer119between element side surface122and rear surface118.

In some embodiments, as illustrated inFIGS. 10D and 10E, superabrasive element110may not be surrounded by a protective covering, such as a leaching cup. Optionally, superabrasive element110may be at least partially covered by a protective layer, such as a leaching cup and/or a masking layer. Superabrasive element110and electrodes140A and140B may be positioned within a processing vessel170. Processing vessel170may have a rear wall174and a side wall173defining a cavity176. Rear wall174and side wall173may have any suitable shape, without limitation. Processing vessel170may include an opening178opposite rear wall174. Cavity176may contain a suitable processing solution172such that at least a portion of superabrasive element110is exposed to processing solution172. Superabrasive element110may be positioned in cavity176so that superabrasive element110is disposed near and/or electrically connected to (e.g., abutting) electrode140.

Electrodes140A and140B may comprise any suitable size, shape, and/or geometry, without limitation. According to at least one embodiment, at least a portion of each of electrode140A and/or electrode140B may be substantially disk shaped. For example, electrode140A and/or electrode140B may comprise a disk shape having a circular or non-circular periphery. In some embodiments, electrode140A and/or electrode140B may have a suitable concave and/or convex surface shape. Electrode140may comprise a suitable electrically conductive material, such as, for example, a metallic, semi-metallic, and/or graphitic material.

Electrodes140A and140B may be disposed at any suitable locations with respect to superabrasive element110and each other. For example, electrode140A and electrode140B may be disposed on opposite sides of superabrasive element110. For example, as illustrated inFIG. 10D, electrode140A may be positioned near superabrasive face120and electrode140B may be positioned near rear surface118. As illustrated inFIG. 10E, electrode140A may be positioned near a portion of element side surface122and electrode140B may be positioned near another portion element side surface122. Optionally, electrodes140A and140B may be disposed near the same and/or adjacent sides of superabrasive element110. In certain embodiments, electrode140A and/or electrode140B may be electrically connected to (e.g., positioned abutting) at least a portion of superabrasive element110.

In some embodiments, electrodes140A and140B may represent portions of an annular or ring-shaped electrode peripherally surrounding superabrasive element110, and electrical conductor142A and/or electrical conductor142B may be electrically connected to the annular or ring-shaped electrode at one or more locations. For example, electrodes140A and140B may comprise sections or portions of an annular or ring-shaped body, and electrical conductors142A and142B may be electrically connected to each section.

According to various embodiments, a charge may be applied to superabrasive element110through one or more electrical connections. For example, a charge may be applied to superabrasive element110through electrical conductor144A and/or electrical conductor144B. A charge may be applied to electrode140A and/or electrode140B through electrical conductor142A and/or electrical conductor142B, respectively. In order to apply a current to processing solution172for processing superabrasive element110, at least a portion of superabrasive element110may be positioned in processing solution172and a charge may be applied to at least a portion of superabrasive element110through electrical conductor144A and/or electrical conductor144B and an opposite charge may be applied to electrode140A and/or electrode140B through electrical conductor142A and/or electrical conductor142B.

In some embodiments, superabrasive element110may be coupled to electrical conductor144A and/or electrical conductor144B at any suitable location (e.g., element side surface122as shown inFIG. 10D, or superabrasive face120and/or rear surface118as shown inFIG. 10E) through brazing, welding, soldering, adhesive bonding, mechanical fastening, and/or any other suitable bonding technique. For example, superabrasive element110may be bonded to electrode145or electrical conductor144by a braze joint (e.g., a carbide forming braze such as a titanium-based braze, etc.). In at least one embodiment, such a braze joint may be coated with a protective layer (e.g., paint layer, epoxy layer, etc.).

As shown inFIGS. 10D and 10E, a positive charge may be applied to superabrasive element110, which acts as an anode, via electrical conductor144A and/or electrical conductor144B. A negative charge may be applied to electrode140A and/or140B through electrical conductor142A and/or electrical conductor142B, respectively, such that electrode140A and/or140B acts as a cathode. When superabrasive element110and electrodes140A and140B are disposed in the processing solution172such that at least a portion of superabrasive table114and electrodes140A and140B are exposed to processing solution172and a voltage is applied to processing solution172via superabrasive table114and electrode140A and/or electrode140B, interstitial materials may be removed from at least a portion of superabrasive table114and electrodeposited onto at least a portion of electrode140A and/or electrode140B exposed to electroplating solution172. Superabrasive element110may be exposed to processing solution172and/or a charge may be applied to processing solution172until a desired level of leaching is obtained.

According to some embodiments, once interstitial materials have been removed from a substantial portion of superabrasive table or once interstitial materials have been removed from superabrasive element110to a selected leach depth, a material coupling electrical conductor144A and/or electrical conductor144B to superabrasive element110may be at least partially degraded by processing solution172. For example, a braze joint bonding electrical conductor144A and/or electrical conductor144B to superabrasive table114may have a more positive reduction potential than an interstitial material (e.g., cobalt) within superabrasive table114. Accordingly, the interstitial material may be preferentially degraded by processing solution172prior to substantial degradation of the braze joint. Once the interstitial material is substantially removed from superabrasive table114during leaching, processing solution172may more aggressively degrade the braze joint such that electrical conductor144A and/or electrical conductor144B are electrically and/or physically disconnected from superabrasive element110.

FIGS. 11 and 12illustrate an exemplary superabrasive element310positioned near an exemplary electrode340according to at least one embodiment. Electrode340may comprise any suitable size, shape and/or geometry, without limitation. As illustrated inFIGS. 11 and 12, superabrasive element310may comprise a superabrasive table314affixed to or formed upon a substrate312. Superabrasive table314may be affixed to substrate312at interface326, which may be a planar or non-planar interface. Superabrasive element310may comprise a rear surface318, a superabrasive face320, and an element side surface315. In some embodiments, element side surface315may include a substrate side surface316formed by substrate312and a superabrasive side surface322formed by superabrasive table314. Rear surface318may be formed by substrate312. Superabrasive element310may also comprise a chamfer324formed by superabrasive table314.

According to various embodiments, a charge may be applied to superabrasive element310and electrode340through electrical conductors (e.g., wires or any suitable electrical conductor)344and342, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated inFIG. 9C) for processing superabrasive element310, superabrasive element310and electrical conductor344may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate312(e.g., rear surface318) of superabrasive element310through electrical conductor344and an opposite charge may be applied to electrode340through electrical conductor342. In at least one embodiment, electrical conductor344may be electrically connected to substrate312by an electrode electrically connected to (e.g., positioned abutting) substrate312. In some embodiments, electrical conductor344may be directly connected to superabrasive table314by an electrode electrically connected to (e.g., positioned abutting) superabrasive table314.

According to at least one embodiment, at least a portion of electrode340may comprise a substantially annular or ring-shaped body. For example, electrode340may comprise a substantially annular ring surrounding a central axis (e.g., central axis29shown inFIGS. 1-2), as illustrated inFIGS. 11 and 12. When superabrasive element310and electrode340are disposed in a processing solution such that at least a portion of superabrasive table314and electrode340are exposed to the processing solution and a voltage is applied to the processing solution via electrode340and superabrasive table314, interstitial materials may be removed from at least a portion of superabrasive table314of superabrasive element310exposed to the processing solution. In some embodiments, interstitial materials may be removed to greater depths from surface portions of superabrasive table314disposed in relatively closer proximity to electrode340than other surface portions of superabrasive table314. Accordingly, a peripheral region of superabrasive table314defining chamfer324may be leached to a greater depth than a central region of superabrasive table314.

FIGS. 13 and 14illustrate an exemplary superabrasive element410positioned near an exemplary electrode440according to at least one embodiment. As illustrated inFIGS. 13 and 14, superabrasive element410may comprise a superabrasive table414affixed to or formed upon a substrate412. Superabrasive element410may comprise a rear surface418, a superabrasive face420, and an element side surface415. In some embodiments, element side surface415may include a substrate side surface416formed by substrate412and a superabrasive side surface422formed by superabrasive table414. Rear surface418may be formed by substrate412. Superabrasive element410may also comprise a chamfer424formed by superabrasive table414.

According to various embodiments, a charge may be applied to superabrasive element410and electrode440through electrical conductors (e.g., wires or any suitable electrical conductor)444and442, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated inFIG. 9C) for processing superabrasive element410, superabrasive element410and electrical conductor444may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate412(e.g., rear surface418) of superabrasive element410through electrical conductor444and an opposite charge may be applied to electrode440through electrical conductor442. In at least one embodiment, electrical conductor444may be electrically connected to substrate412by an electrode electrically connected to (e.g., positioned abutting) substrate412. In some embodiments, electrical conductor444may be directly connected to superabrasive table414by an electrode electrically connected to (e.g., positioned abutting) superabrasive table414.

According to at least one embodiment, at least a portion of electrode440may comprise a disk shape. For example, electrode440may comprise a disk having a substantially circular outer periphery surface surrounding a central axis (e.g., central axis29shown inFIGS. 1-2), as illustrated inFIGS. 13 and 14. In some embodiments, electrode440may have an outer diameter that is smaller than the outer diameter of element side surface415of superabrasive element410and/or smaller than an inner diameter of chamfer424. When superabrasive element410and electrode440are disposed in a processing solution such that at least a portion of superabrasive table414and electrode440are exposed to the processing solution and a voltage is applied to the processing solution via electrode440and superabrasive table414, interstitial materials may be removed from at least a portion of superabrasive table414of superabrasive element410exposed to the processing solution. In some embodiments, interstitial materials may be removed to greater depths from surface portions of superabrasive table414disposed in relatively closer proximity to electrode440than other surface portions of superabrasive table414. Accordingly, an axially central region of superabrasive table414may be leached to a greater depth than an outer peripheral region.

FIGS. 15-21illustrate superabrasive elements and electrodes in cross-sectional views. The electrodes illustrated in these figures are intended to be disk-shaped and/or ring-shaped (see, e.g., electrodes340and440respectively shown inFIGS. 11 and 13).

FIG. 15shows a cross-sectional side view of an exemplary superabrasive element510and an exemplary electrode540according to at least one embodiment. As illustrated inFIG. 15, superabrasive element510may comprise a superabrasive table514affixed to or formed upon a substrate512. Superabrasive table514may be affixed to substrate512at interface526. Superabrasive element510may comprise a rear surface518, a superabrasive face520, and an element side surface515, which may include a substrate side surface516formed by substrate512and a superabrasive side surface522formed by superabrasive table514. Superabrasive element510may also comprise a chamfer524formed by superabrasive table514.

According to various embodiments, a charge may be applied to superabrasive element510and electrode540through electrical conductors (e.g., wires or any suitable electrical conductor)544and542, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated inFIG. 9C) for processing superabrasive element510, superabrasive element510and electrical conductor544may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate512(e.g., rear surface518) of superabrasive element510through electrical conductor544and an opposite charge may be applied to electrode540through electrical conductor542.

According to at least one embodiment, at least a portion of electrode540may comprise a substantially cylindrical shape defining a recess546. For example, electrode540may comprise a substantially cylindrical outer surface, as illustrated inFIG. 15. Recess546may be defined within electrode540and may have a diameter that is greater than the outer diameter of element side surface515of superabrasive element510. Electrode540may be disposed such that at least a portion of recess546surrounds at least a portion of superabrasive table514of superabrasive element510, as shown inFIG. 15. When superabrasive element510and electrode540are disposed in the processing solution such that at least a portion of superabrasive table514and electrode540are exposed to the processing solution and a voltage is applied to the processing solution via electrode540and superabrasive table514, interstitial materials may be removed from at least a portion of superabrasive table514exposed to the processing solution.

FIG. 16shows a cross-sectional side view of an exemplary superabrasive element610positioned near an exemplary electrode640according to at least one embodiment. As illustrated inFIG. 16, superabrasive element610may comprise a superabrasive table614affixed to or formed upon a substrate612. Superabrasive table614may be affixed to substrate612at interface626. Superabrasive element610may comprise a rear surface618, a superabrasive face620, and an element side surface615, which may include a substrate side surface616formed by substrate612and a superabrasive side surface622formed by superabrasive table614. Superabrasive element610may also comprise a chamfer624formed by superabrasive table614.

According to various embodiments, a charge may be applied to superabrasive element610and electrode640through electrical conductors (e.g., wires or any suitable electrical conductor)644and642, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated inFIG. 9C) for processing superabrasive element610, superabrasive element610and electrical conductor644may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate612(e.g., rear surface618) of superabrasive element610through electrical conductor644and an opposite charge may be applied to electrode640through electrical conductor642.

According to at least one embodiment, at least a portion of electrode640may comprise a substantially cylindrical shape defining a recess646. For example, electrode640may comprise a substantially cylindrical outer surface, as illustrated inFIG. 16. Recess646may be defined within electrode640and may have a diameter that is substantially the same as or smaller than the outer diameter of element side surface615of superabrasive element610. When superabrasive element610and electrode640are disposed in the processing solution such that at least a portion of superabrasive table614and electrode640are exposed to the processing solution and a voltage is applied to the processing solution via electrode640and superabrasive table614, interstitial materials may be removed from at least a portion of superabrasive table614of superabrasive element610exposed to the processing solution.

FIG. 17shows a cross-sectional side view of an exemplary superabrasive element710positioned near an exemplary electrode740according to at least one embodiment. As illustrated inFIG. 17, superabrasive element710may comprise a superabrasive table714affixed to or formed upon a substrate712. Superabrasive table714may be affixed to substrate712at interface726. Superabrasive element710may comprise a rear surface718, a superabrasive face720, and an element side surface715, which may include a substrate side surface716formed by substrate712and a superabrasive side surface722formed by superabrasive table714. Superabrasive element710may also comprise a chamfer724formed by superabrasive table714.

According to various embodiments, a charge may be applied to superabrasive element710and electrode740through electrical conductors (e.g., wires or any suitable electrical conductor)744and742, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated inFIG. 9C) for processing superabrasive element710, superabrasive element710and electrical conductor744may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate712(e.g., rear surface718) of superabrasive element710through electrical conductor744and an opposite charge may be applied to electrode740through electrical conductor742.

According to at least one embodiment, at least a portion of electrode740may comprise a substantially cylindrical shape with a peripheral recess748defined therein and extending circumferentially around at least a peripheral portion of electrode740. For example, peripheral recess748may be defined between a face of electrode740located nearest superabrasive element710and an outer peripheral surface of electrode740, as illustrated inFIG. 17. When superabrasive element710and electrode740are disposed in a processing solution such that at least a portion of superabrasive table714and electrode740are exposed to the processing solution and a voltage is applied to the processing solution via electrode740and superabrasive table714, interstitial materials may be removed from at least a portion of superabrasive table714of superabrasive element710exposed to the processing solution.

FIG. 18shows a cross-sectional side view of an exemplary superabrasive element810and an exemplary electrode840according to at least one embodiment. As illustrated inFIG. 18, superabrasive element810may comprise a superabrasive table814affixed to or formed upon a substrate812. Superabrasive table814may be affixed to substrate812at interface826. Superabrasive element810may comprise a rear surface818, a superabrasive face820, and an element side surface815, which may include a substrate side surface816formed by substrate812and a superabrasive side surface822formed by superabrasive table814. Superabrasive element810may also comprise a chamfer824formed by superabrasive table814.

According to various embodiments, a charge may be applied to superabrasive element810and electrode840through electrical conductors (e.g., wires or any suitable electrical conductor)844and842, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated inFIG. 9C) for processing superabrasive element810, superabrasive element810and electrical conductor844may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate812(e.g., rear surface818) of superabrasive element810through electrical conductor844and an opposite charge may be applied to electrode840through electrical conductor842.

Electrode840may be annular or ring-shaped and electrical conductor842may be electrically connected to electrode840at one or more locations. For example, electrode840may comprise sections or portions of an annular or ring-shaped body, and electrical conductor842may be electrically connected to each section. In at least one embodiment, electrical conductor844may be electrically connected to substrate812by an electrode electrically connected to (e.g., positioned abutting) substrate812. In some embodiments, electrical conductor844may be directly connected to superabrasive table814by an electrode electrically connected to (e.g., positioned abutting) superabrasive table814.

According to at least one embodiment, at least a portion of electrode840may comprise a substantially tilted annular or ring-shaped body. For example, electrode840may comprise an annular ring surrounding a central axis (e.g., central axis29shown inFIGS. 1-2) and tilted at an angle, as illustrated inFIG. 18. Electrode840may be disposed in a position such that at least a portion of electrode840surrounds at least a portion of superabrasive table814of superabrasive element810, such as chamfer824, as shown inFIG. 18. In some embodiments, electrode840may be tilted at substantially the same angle as chamfer824. When superabrasive element810and electrode840are disposed in the processing solution such that at least a portion of superabrasive table814and electrode840are exposed to the processing solution and a voltage is applied to the processing solution via electrode840and superabrasive table814, interstitial materials may be removed from at least a portion of superabrasive table814of superabrasive element810exposed to the processing solution. In some embodiments, interstitial materials may be removed to greater depths from surface portions of superabrasive table814disposed in relatively closer proximity to electrode840than other surface portions of superabrasive table814. Accordingly, a peripheral region of superabrasive table814defining chamfer824may be leached to a greater depth than a central region of superabrasive table814.

FIG. 19shows a cross-sectional side view of an exemplary superabrasive element910and an exemplary electrode940according to at least one embodiment. As illustrated inFIG. 19, superabrasive element910may comprise a superabrasive table914affixed to or formed upon a substrate912. Superabrasive table914may be affixed to substrate912at interface926. Superabrasive element910may comprise a rear surface918, a superabrasive face920, and an element side surface915, which may include a substrate side surface916formed by substrate912and a superabrasive side surface922formed by superabrasive table914. Superabrasive element910may also comprise a chamfer924formed by superabrasive table914.

According to various embodiments, a charge may be applied to superabrasive element910and electrode940through electrical conductors (e.g., wires or any suitable electrical conductor)944and942, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated inFIG. 9C) for processing superabrasive element910, superabrasive element910and electrical conductor944may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate912(e.g., rear surface918) of superabrasive element910through electrical conductor944and an opposite charge may be applied to electrode940through electrical conductor942.

Electrode940may be annular or ring-shaped and electrical conductor942may be electrically connected to electrode940at one or more locations. For example, electrode940may comprise sections or portions of an annular or ring-shaped body, and electrical conductor942may be electrically connected to each section. In at least one embodiment, electrical conductor944may be electrically connected to substrate912by an electrode electrically connected to (e.g., positioned abutting) substrate912. In some embodiments, electrical conductor944may be directly connected to superabrasive table914by an electrode electrically connected to (e.g., positioned abutting) superabrasive table914.

According to at least one embodiment, at least a portion of electrode940may comprise a substantially annular or ring-shaped body. For example, electrode940may comprise a substantially annular ring surrounding a central axis (e.g., central axis29shown inFIGS. 1-2), as illustrated inFIG. 19. In at least one embodiment, electrode940may have an inner diameter that is greater than the outer diameter of element side surface915of superabrasive element910. Electrode940may be disposed in a position such that at least a portion of electrode940surrounds at least a portion of superabrasive table914of superabrasive element910, as shown inFIG. 19. When superabrasive element910and electrode940are disposed in the processing solution such that at least a portion of superabrasive table914and electrode940are exposed to the processing solution and a voltage is applied to the processing solution via electrode940and superabrasive table914, interstitial materials may be removed from at least a portion of superabrasive table914of superabrasive element910exposed to the processing solution. In some embodiments, interstitial materials may be removed to greater depths from surface portions of superabrasive table914disposed in relatively closer proximity to electrode940than other surface portions of superabrasive table914. Accordingly, a peripheral region of superabrasive table914defining chamfer924and/or superabrasive side surface922may be leached to a greater depth than a central region of superabrasive table914.

FIG. 20shows a cross-sectional side view of an exemplary superabrasive element1010and an exemplary electrode1040according to at least one embodiment. As illustrated inFIG. 20, superabrasive element1010may comprise a superabrasive table1014affixed to or formed upon a substrate1012. Superabrasive table1014may be affixed to substrate1012at interface1026. Superabrasive element1010may comprise a rear surface1018, a superabrasive face1020, and an element side surface1015, which may include a substrate side surface1016formed by substrate1012and a superabrasive side surface1022formed by superabrasive table1014. Superabrasive element1010may also comprise a chamfer1024formed by superabrasive table1014.

According to various embodiments, a charge may be applied to superabrasive element1010and electrode1040through electrical conductors (e.g., wires or any suitable electrical conductor)1044and1042, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated in FIG.9C) for processing superabrasive element1010, superabrasive element1010and electrical conductor1044may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate1012(e.g., rear surface1018) of superabrasive element1010through electrical conductor1044and an opposite charge may be applied to electrode1040through electrical conductor1042.

Electrode1040may be annular or ring-shaped and electrical conductor1042may be electrically connected to electrode1040at one or more locations. For example, electrode1040may comprise sections or portions of an annular or ring-shaped body, and electrical conductor1042may be electrically connected to each section. In at least one embodiment, electrical conductor1044may be electrically connected to substrate1012by an electrode electrically connected to (e.g., positioned abutting) substrate1012. In some embodiments, electrical conductor1044may be directly connected to superabrasive table1014by an electrode electrically connected to (e.g., positioned abutting) superabrasive table1014.

According to at least one embodiment, at least a portion of electrode1040may comprise a substantially annular or ring-shaped body and may define a recess1046, as illustrated inFIG. 20. In at least one embodiment, a surface of electrode1040defining recess1046may have a diameter that is greater than the outer diameter of element side surface1015of superabrasive element1010. Electrode1040may be disposed in a position such that at least a portion of recess1046surrounds at least a portion of superabrasive table1014of superabrasive element1010, as shown inFIG. 20. When superabrasive element1010and electrode1040are disposed in the processing solution such that at least a portion of superabrasive table1014and electrode1040are exposed to the processing solution and a voltage is applied to the processing solution via electrode1040and superabrasive table1014, interstitial materials may be removed from at least a portion of superabrasive table1014of superabrasive element1010exposed to the processing solution. In some embodiments, interstitial materials may be removed to greater depths from surface portions of superabrasive table1014disposed in relatively closer proximity to electrode1040than other surface portions of superabrasive table1014. Accordingly, a peripheral region of superabrasive table1014defining chamfer1024and/or superabrasive side surface1022may be leached to a greater depth than a central region of superabrasive table1014.

FIG. 21shows a cross-sectional side view of an exemplary superabrasive element1110and an exemplary electrode assembly1140comprising a first electrode1141and a second electrode1143according to at least one embodiment. As illustrated inFIG. 21, superabrasive element1110may comprise a superabrasive table1114affixed to or formed upon a substrate1112. Superabrasive table1114may be affixed to substrate1112at interface1126. Superabrasive element1110may comprise a rear surface1118, a superabrasive face1120, and an element side surface1115, which may include a substrate side surface1116formed by substrate1112and a superabrasive side surface1122formed by superabrasive table1114. Superabrasive element1110may also comprise a chamfer1124formed by superabrasive table1114.

According to various embodiments, a charge may be applied to superabrasive element1110and electrode assembly1140through electrical conductors (e.g., wires or any suitable electrical conductor)1144and1142, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated inFIG. 9C) for processing superabrasive element1110, superabrasive element1110and electrical conductor1144may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate1112(e.g., rear surface1118) of superabrasive element1110through electrical conductor1144and an opposite charge may be applied to electrode assembly1140through electrical conductor1142.

At least a portion of electrode assembly1140may be annular or ring-shaped and electrical conductor1142may be electrically connected to electrode assembly1140at one or more locations. For example, second electrode1143may comprise sections or portions of an annular or ring-shaped body, and electrical conductor1142may be electrically connected to each section. In at least one embodiment, electrical conductor1144may be electrically connected to substrate1112by an electrode electrically connected to (e.g., positioned abutting) substrate1112. In some embodiments, electrical conductor1144may be directly connected to superabrasive table1114by an electrode electrically connected to (e.g., positioned abutting) superabrasive table1114.

According to at least one embodiment, first electrode1141may comprise a disk-shaped electrode positioned near superabrasive face1120of superabrasive table1114. Second electrode1143may comprise a substantially annular or ring-shaped body with an inner diameter that is greater than an outer diameter of element side surface1115of superabrasive element1110. Second electrode1143of electrode assembly1140may be disposed in a position such that at least a portion of second electrode1143surrounds at least a portion of superabrasive table1114of superabrasive element1110, as shown inFIG. 21. When superabrasive element1110and electrode assembly1140are disposed in the processing solution such that at least a portion of superabrasive table1114, first electrode1141, and second electrode1143are exposed to the processing solution and a voltage is applied to the processing solution via electrode assembly1140and superabrasive table1114, interstitial materials may be removed from at least a portion of superabrasive table1114of superabrasive element1110exposed to the processing solution. In some embodiments, interstitial materials may be removed to greater depths from surface portions of superabrasive table1114disposed in relatively closer proximity to first electrode1141and/or second electrode1143of electrode assembly1140than other surface portions of superabrasive table1114.

FIG. 22shows a cross-sectional side view of an exemplary superabrasive element1210and exemplary electrodes1240and1249according to at least one embodiment. As illustrated inFIG. 22, superabrasive element1210may comprise a superabrasive table1214affixed to or formed upon a substrate1212. Superabrasive table1214may be affixed to substrate1212at interface1226. Superabrasive element1210may comprise a rear surface1218, a superabrasive face1220, and an element side surface1215, which may include a substrate side surface1216formed by substrate1212and a superabrasive side surface1222formed by superabrasive table1214. Superabrasive element1210may also comprise a chamfer1224formed by superabrasive table1214.

As shown inFIG. 22, electrode1249may be disposed adjacent to at least portion of superabrasive table1214. For example, electrode1249may be electrically connected to (e.g., positioned abutting) superabrasive face1220and/or any other suitable surface of superabrasive table1214. According to various embodiments, a charge may be applied to electrode1240and electrode1249, and likewise to superabrasive table1214, through electrical conductors (e.g., wires or any suitable electrical conductor)1242and1244, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated inFIG. 9C) for processing superabrasive element1210, superabrasive element1210and electrode1249may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of superabrasive table1214through electrical conductor1244and electrode1249, and an opposite charge may be applied to electrode1240through electrical conductor1242.

According to at least one embodiment, electrode1249may comprise a disk-shaped electrode. In some embodiments, superabrasive table1214may be coupled to electrode1249through brazing, welding, soldering, adhesive bonding, mechanical fastening, and/or any other suitable bonding technique. For example, superabrasive table1214may be bonded to electrode1249by a braze joint (e.g., a carbide forming braze such as a titanium-based braze, etc.). In at least one embodiment, such a braze joint may be coated with a protective layer (e.g., paint layer, epoxy layer, etc.).

At least a portion of electrode1240may be annular or ring-shaped and electrical conductor1242may be electrically connected to electrode1240at one or more locations. For example, electrode1240may comprise sections or portions of an annular or ring-shaped body, and electrical conductor1242may be electrically connected to each section. Electrode1240may be disposed in a position such that at least a portion of electrode1240surrounds at least a portion of superabrasive table1214of superabrasive element1210, as shown inFIG. 22. When superabrasive element1210and electrode1240are disposed in the processing solution such that at least a portion of superabrasive table1214and electrode1240are exposed to the processing solution and a voltage is applied to the processing solution via electrode1240, electrode1249, and/or superabrasive table1214, interstitial materials may be removed from at least a portion of superabrasive table1214exposed to the processing solution. In some embodiments, interstitial materials may be removed to greater depths from surface portions of superabrasive table1214disposed in relatively closer proximity to electrode1240than other surface portions of superabrasive table1214.

FIGS. 23A and 23Bshow an exemplary superabrasive element1310coated with masking layers and disposed near an exemplary electrode1340. According to various embodiments, portions of superabrasive element1310may be coated or otherwise covered with one or more masking layers that prevent and/or delay a leaching agent from contacting selected regions of superabrasive element1310during leaching. For example, a first masking layer1333and a second masking layer1335may be formed on or disposed abutting at least a portion of superabrasive element1310.

As illustrated inFIGS. 23A and 23B, superabrasive element1310may comprise a superabrasive table1314affixed to or formed upon a substrate1312. Superabrasive table1314may be affixed to substrate1312at interface1326. Superabrasive element1310may comprise a rear surface1318, a superabrasive face1320, and an element side surface1315, which may include a substrate side surface1316formed by substrate1312and a superabrasive side surface1322formed by superabrasive table1314. Superabrasive element1310may also comprise a chamfer1324formed by superabrasive table1314.

As shown inFIGS. 23A and 23B, first masking layer1333may be disposed on at least a portion of superabrasive face1320, such as a central portion of superabrasive face1320surrounding a central axis (e.g., central axis29shown inFIGS. 1-2). Second masking layer1335may be disposed on at least a portion of element side surface1315and rear surface1318of superabrasive element1310so as to surround at least a portion of superabrasive table1314and/or substrate1312. First masking layer1333and second masking layer1335may prevent damage to selected portions of superabrasive element1310and may provide a desired leach profile when superabrasive element1310is exposed to various leaching agents. For example, first masking layer1333and/or second masking layer1335may prevent or delay a leaching solution from contacting certain portions of superabrasive element1310, such as portions of substrate1312, portions of superabrasive table1314, or both, during leaching.

In various examples, first masking layer1333and/or second masking layer1335may comprise one or more materials that are substantially inert and/or otherwise resistant and/or impermeable to acids, bases, and/or other reactive compounds present in a leaching solution used to leach superabrasive element1310. Optionally, first masking layer1333and/or second masking layer1335may comprise a material that breaks down or degrades in the presence of a leaching agent, such as a material that is at least partially degraded (e.g., at least partially dissolved) at a selected rate during exposure to the leaching agent.

In some embodiments, first masking layer1333and/or second masking layer1335may comprise one or more materials exhibiting significant stability during exposure to a leaching agent. According to various embodiments, first masking layer1333and second masking layer1335may comprise any suitable material, including metals, alloys, polymers, carbon allotropes, oxides, carbides, glass materials, ceramics, composites, membrane materials (e.g. permeable or semi-permeable materials), and/or any combination of the foregoing, without limitation. First masking layer1333and second masking layer1335may be affixed to superabrasive element1310through any suitable mechanism, without limitation, including, for example, direct bonding, bonding via an intermediate layer, such as an adhesive or braze joint, mechanical attachment, such as mechanical fastening, frictional attachment, and/or interference fitting. In some embodiments, first masking layer1333and/or second masking layer1335may comprise a coating or layer of material that is formed on or otherwise adhered to at least a portion of superabrasive element1310. In additional embodiments, first masking layer1333and/or second masking layer1335may comprise a material that is temporarily fixed to superabrasive element1310. For example, first masking layer1333may comprise a polymer member (e.g., o-ring, gasket, disk) that is mechanically held in place (e.g., by clamping) during exposure to a leaching agent.

First masking layer1333and second masking layer1335may be formed over any suitable portions superabrasive element1310. For example, as illustrated inFIGS. 23A and 23B, first masking layer1333may be formed over a central portion of superabrasive face1320about a central axis (e.g., central axis29shown inFIGS. 1-2). First masking layer1333may be separated from chamfer1324. For example, first masking layer1333may not be directly adjacent to and/or in contact with edge1327formed at the intersection of superabrasive face1320and chamfer1324. Second masking layer1333may be formed over at least a portion of substrate1312and superabrasive table1314. For example, as shown inFIGS. 23A and 23B, second masking layer1335may be formed over rear surface1318and substrate side surface1316of substrate1312so as to substantially surround substrate1312. Optionally, second masking layer1335may be formed over a portion of superabrasive side surface1322. In some embodiments, second masking layer1335may also be separated from chamfer1324. For example, second masking layer1335may not be directly adjacent to and/or in contact with edge1328formed at the intersection of superabrasive side surface1322and chamfer1324.

According to various embodiments, a charge may be applied to superabrasive element1310and electrode1340through electrical conductors (e.g., wires or any suitable electrical conductor)1344and1342, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated inFIG. 9C) for processing superabrasive element1310, superabrasive element1310and electrical conductor1344may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate1312(e.g., rear surface1318) of superabrasive element1310through electrical conductor1344and an opposite charge may be applied to electrode1340through electrical conductor1342. In at least one embodiment, electrical conductor1344may be electrically connected to substrate1312by an electrode electrically connected to (e.g., positioned abutting) substrate1312. In some embodiments, electrical conductor1344may be directly connected to superabrasive table1314by an electrode electrically connected to (e.g., positioned abutting) superabrasive table1314.

Electrode1340may comprise any suitable size, shape, and/or geometry, without limitation. In some embodiments, electrode1340may comprise a circular or non-circular disk shape. For example, electrode1340may have a substantially circular outer periphery surrounding a central axis (e.g., central axis29shown inFIGS. 1-2). Electrode1340may have an outer diameter that is larger than, the same as, or smaller than the outer diameter of element side surface1315of superabrasive element1310, as shown inFIGS. 23A and 23B. Electrodes and/or combinations of electrodes according to any of the configurations disclosed herein may also be utilized in addition to or in place of electrode1340for processing superabrasive element1310. When superabrasive element1310and electrode1340are disposed in the processing solution (e.g., processing solution72as shown inFIG. 9C) such that at least a portion of superabrasive table1314and electrode1340are exposed to the processing solution and a voltage is applied to the processing solution via electrode1340and superabrasive table1314, interstitial materials may be removed from at least a portion of superabrasive table1314of superabrasive element1310exposed to the processing solution and disposed near electrode1340.

The configuration illustrated inFIGS. 23A and 23Bmay enable selective leaching of portions of superabrasive element1310to form a desired leach profile within superabrasive table1314. For example, a volume of superabrasive table1314adjacent to an uncovered region between first masking layer1333and second masking layer1335may be leached to a greater depth than surrounding portions of superabrasive table1314covered by first masking layer1333and second masking layer1335. The configurations illustrated inFIGS. 23A and 23Bmay result in the formation of leached volumes in portions of superabrasive table1314located near chamfer1324during leaching. In some embodiments, the leached volumes may extend from chamfer1324to a region adjacent to and/or abutting interface1326.

Following exposure to a leaching solution, first masking layer1333and/or second masking layer1335may be substantially removed from superabrasive table1314and/or substrate1312using any suitable technique, including, for example, lapping, grinding, and/or removal using suitable chemical agents. According to certain embodiments, first masking layer1333and/or second masking layer1335may be peeled, cut, ground, lapped, and/or otherwise physically, thermally, or chemically removed from superabrasive element1310. In some embodiments, following or during removal of first masking layer1333and/or second masking layer1335, one or more surfaces of superabrasive table1314and/or substrate1312may be processed to form a desired surface texture and/or finish using any suitable technique, including, for example, lapping, grinding, and/or otherwise physically and/or chemically treating the one or more surfaces.

FIGS. 24 and 25illustrate masking layers formed over portions of a superabrasive element1410having an edge1417formed at the intersection of superabrasive face1420and superabrasive side surface1422. As illustrated, for example, inFIG. 24, first masking layer1433may be formed over a central portion of superabrasive face1420about a central axis (e.g., central axis29shown inFIGS. 1-2). First masking layer1433may not be directly adjacent to and/or in contact with edge1417. In additional embodiments, first masking layer1433may be formed adjacent to and/or in contact with edge1417. Second masking layer1435may be formed over at least a portion of substrate1412and superabrasive table1414. For example, as shown inFIG. 24, second masking layer1435may be formed over rear surface1418and substrate side surface1416of substrate1412so as to substantially surround substrate1412. Optionally, second masking layer1435may be formed over a portion of superabrasive side surface1422. In some embodiments, second masking layer1435may not be directly adjacent to and/or in contact with edge1417, as shown inFIG. 24.

According to various embodiments, a charge may be applied to superabrasive element1410and electrode1440through electrical conductors (e.g., wires or any suitable electrical conductor)1444and1442, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated inFIG. 9C) for processing superabrasive element1410, superabrasive element1410and electrical conductor1444may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate1412(e.g., rear surface1418) of superabrasive element1410through electrical conductor1444and an opposite charge may be applied to electrode1440through electrical conductor1442. In at least one embodiment, electrical conductor1444may be electrically connected to substrate1412by an electrode electrically connected to (e.g., positioned abutting) substrate1412. In some embodiments, electrical conductor1444may be directly connected to superabrasive table1414by an electrode electrically connected to (e.g., positioned abutting) superabrasive table1414.

Electrode1440may comprise any suitable size, shape, and/or geometry, without limitation. In some embodiments, electrode1440may comprise a circular or non-circular disk shape. For example, electrode1440may have a substantially circular outer periphery surrounding a central axis (e.g., central axis29shown inFIGS. 1-2). Electrode1440may have an outer diameter that is larger than, the same as, or smaller than the outer diameter of element side surface1415of superabrasive element1410, as shown inFIG. 24. Electrodes according to any of the configurations disclosed herein may also be utilized in addition to or in place of electrode1440for processing superabrasive element1410. When superabrasive element1410and electrode1440are disposed in the processing solution such that at least a portion of superabrasive table1414and electrode1440are exposed to the processing solution and a voltage is applied to the processing solution via electrode1440and superabrasive table1414, interstitial materials may be removed from at least a portion of superabrasive table1414of superabrasive element1410exposed to the processing solution and disposed near electrode1440.

FIG. 25illustrates masking layers formed over portions of a superabrasive element1410having an edge1417formed at the intersection of superabrasive face1420and superabrasive side surface1422. As illustrated, for example, inFIG. 25, first masking layer1433may be formed over a central portion of superabrasive face1420about a central axis (e.g., central axis29shown inFIGS. 1-2). First masking layer1433may not be directly adjacent to and/or in contact with edge1417. In additional embodiments, first masking layer1433may be formed adjacent to and/or in contact with edge1417. Second masking layer1435may be formed over at least a portion of substrate1412and superabrasive table1414. For example, as shown inFIG. 25, second masking layer1435may be formed over rear surface1418and substrate side surface1416of substrate1412so as to substantially surround substrate1412. Optionally, second masking layer1435may be formed over a portion of superabrasive side surface1422. In some embodiments, second masking layer1435may be disposed adjacent to and/or in contact with edge1417, as shown inFIG. 25.

According to various embodiments, a charge may be applied to superabrasive element1410and electrode1440through electrical conductors (e.g., wires or any suitable electrical conductor)1444and1442, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated inFIG. 9C) for processing superabrasive element1410, superabrasive element1410and electrical conductor1444may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate1412(e.g., rear surface1418) of superabrasive element1410through electrical conductor1444and an opposite charge may be applied to electrode1440through electrical conductor1442. In at least one embodiment, electrical conductor1444may be electrically connected to substrate1412by an electrode electrically connected to (e.g., positioned abutting) substrate1412. In some embodiments, electrical conductor1444may be directly connected to superabrasive table1414by an electrode electrically connected to (e.g., positioned abutting) superabrasive table1414.

Electrode1440may comprise any suitable size, shape, and/or geometry, without limitation. In some embodiments, electrode1440may comprise a circular or non-circular disk shape. For example, electrode1440may have a substantially circular outer periphery surrounding a central axis (e.g., central axis29shown inFIGS. 1-2). Electrode1440may have an outer diameter that is larger than, the same as, or smaller than the outer diameter of element side surface1415of superabrasive element1410, as shown inFIG. 25. When superabrasive element1410and electrode1440are disposed in the processing solution such that at least a portion of superabrasive table1414and electrode1440are exposed to the processing solution and a voltage is applied to the processing solution via electrode1440and superabrasive table1414, interstitial materials may be removed from at least a portion of superabrasive table1414of superabrasive element1410exposed to the processing solution and disposed near electrode1440.

FIG. 26shows an exemplary superabrasive element1510coated with masking layers and disposed near an exemplary electrode1540. According to various embodiments, portions of superabrasive element1510may be coated or otherwise covered with one or more masking layers that prevent and/or delay a leaching agent from contacting selected regions of superabrasive element1510during leaching. For example, a first masking layer1533and, optionally, a second masking layer1535may be formed on or disposed abutting at least a portion of superabrasive element1510.

Superabrasive element1510may comprise a superabrasive table1514affixed to or formed upon a substrate1512. Superabrasive table1514may be affixed to substrate1512at interface1526. Superabrasive element1510may comprise a rear surface1518, a superabrasive face1520, and an element side surface1515, which may include a substrate side surface1516formed by substrate1512and a superabrasive side surface1522formed by superabrasive table1514. Superabrasive element1510may also comprise a chamfer1524formed by superabrasive table1514.

According to some embodiments, first masking layer1533and/or second masking layer1535may be disposed adjacent to and/or in contact with at least a portion of chamfer1524. For example, as illustrated inFIG. 26, first masking layer1533may substantially cover superabrasive face1520such that first masking layer1533is formed adjacent to edge1527of superabrasive table1514. Optionally, second masking layer1535may substantially cover superabrasive side surface1522such that second masking layer1535is formed adjacent to edge1528of superabrasive table1514. In some embodiments, first masking layer1533and/or second masking layer1535may be formed over at least a portion chamfer1524.

According to various embodiments, a charge may be applied to superabrasive element1510and electrode1540through electrical conductors (e.g., wires or any suitable electrical conductor)1544and1542, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated inFIG. 9C) for processing superabrasive element1510, superabrasive element1510and electrical conductor1544may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate1512(e.g., rear surface1518) of superabrasive element1510through electrical conductor1544and an opposite charge may be applied to electrode1540through electrical conductor1542. In at least one embodiment, electrical conductor1544may be electrically connected to substrate1512by an electrode electrically connected to (e.g., positioned abutting) substrate1512. In some embodiments, electrical conductor1544may be directly connected to superabrasive table1514by an electrode electrically connected to (e.g., positioned abutting) superabrasive table1514.

Electrode1540may comprise any suitable size, shape, and/or geometry, without limitation. In some embodiments, electrode1540may comprise a circular or non-circular disk shape. For example, electrode1540may have a substantially circular outer periphery surrounding a central axis (e.g., central axis29shown inFIGS. 1-2). Electrode1540may have an outer diameter that is larger than, the same as, or smaller than the outer diameter of element side surface1515of superabrasive element1510, as shown inFIG. 27. When superabrasive element1510and electrode1540are disposed in the processing solution such that at least a portion of superabrasive table1514and electrode1540are exposed to the processing solution and a voltage is applied to the processing solution via electrode1540and superabrasive table1514, interstitial materials may be removed from at least a portion of superabrasive table1514of superabrasive element1510exposed to the processing solution and disposed near electrode1540. Accordingly, a peripheral region of superabrasive table1514defining chamfer1524may be leached to a greater depth than a central region of superabrasive table1514.

FIG. 27is a cross-sectional side view of an exemplary superabrasive element1610coated with masking layers according to at least one embodiment. As shown inFIG. 27, superabrasive element1610may be coated with various masking layers that prevent and/or delay a leaching agent from contacting selected regions of superabrasive element1610during leaching. According to some embodiments, a first protective masking layer1633and a second protective masking layer1635may be formed on at least a portion of superabrasive element1610. Optionally, a first at-least-partially-degrading masking layer1637and a second at-least-partially-degrading masking layer1647may be formed on at least a portion of superabrasive element1610.

As illustrated inFIG. 27, superabrasive element1610may comprise a superabrasive table1614affixed to or formed upon a substrate1612. Superabrasive table1614may be affixed to substrate1612at interface1626. Superabrasive element1610may comprise a rear surface1618, a superabrasive face1620, and an element side surface1615, which may include a substrate side surface1616formed by substrate1612and a superabrasive side surface1622formed by superabrasive table1614. Superabrasive element1610may also comprise a chamfer1624formed by superabrasive table1614.

As shown inFIG. 27, first protective masking layer1633may be formed on at least a portion of superabrasive face1620, such as a central portion of superabrasive face1620surrounding a central axis (e.g., central axis29shown inFIGS. 1-2). Second protective masking layer1635may be formed on at least a portion of element side surface1615and rear surface1618of superabrasive element1610so as to surround at least a portion of superabrasive table1614and/or substrate1612. First protective masking layer1633and second protective masking layer1635may prevent damage to selected portions of superabrasive element10and may provide a desired leach profile when superabrasive element1610is exposed to various reactive agents. For example, first protective masking layer1633and/or second protective masking layer1635may prevent or delay a leaching solution from contacting certain portions of superabrasive element1610, such as portions of substrate1612, portions of superabrasive table1614, or both, during leaching. In various examples, first protective masking layer1633and/or second protective masking layer1635may comprise one or more materials that are substantially inert and/or otherwise resistant and/or impermeable to acids, bases, and/or other reactive compounds present in a leaching solution used to leach superabrasive element1610.

First at-least-partially-degrading masking layer1637may be formed on at least a portion of superabrasive element1610adjacent to first protective masking layer1633. For example, first at-least-partially-degrading masking layer1637may be formed on portions of superabrasive face1620and/or chamfer1624. Second at-least-partially-degrading masking layer1647may be formed on at least a portion of superabrasive element1610adjacent to second protective masking layer1635. For example, second at-least-partially-degrading masking layer1647may be formed on portions of superabrasive side surface1622and/or chamfer1624. As shown inFIG. 27, first at-least-partially-degrading masking layer1637may be separated from second at-least-partially-degrading masking layer1647. For example, a space between first at-least-partially-degrading masking layer1637and second at-least-partially-degrading masking layer1647may be formed over at least a portion of superabrasive table1614, such as, for example, at least a portion of chamfer1624. Optionally, a space between first at-least-partially-degrading masking layer1637and second at-least-partially-degrading masking layer1647may also be formed over a portion of superabrasive face1620and/or superabrasive side surface1622.

According to at least one embodiment, first at-least-partially-degrading masking layer1637and/or second at-least-partially-degrading masking layer1647may comprise a material that breaks down in the presence of a leaching agent. First at-least-partially-degrading masking layer1637and/or second at-least-partially-degrading masking layer1647may comprise, for example, a polymeric material that breaks down at a desired rate during exposure to the leaching agent. As first at-least-partially-degrading masking layer1637and second at-least-partially-degrading masking layer1647disintegrate during leaching, portions of superabrasive element1610that were covered by first at-least-partially-degrading masking layer1637and second at-least-partially-degrading masking layer1647may become exposed to the leaching agent. According to additional embodiments, first at-least-partially-degrading masking layer1637and/or second at-least-partially-degrading masking layer1647may comprise a material that is more permeable to a leaching agent than first protective masking layer1633and/or second protective masking layer1635. In at least one embodiment, first at-least-partially-degrading masking layer1637and/or second at-least-partially-degrading masking layer1647may be not substantially degrade when exposed to a leaching agent but may be semi-permeable or permeable to the leaching agent.

First protective masking layer1633, second protective masking layer1635, first at-least-partially-degrading masking layer1637, and second at-least-partially-degrading masking layer1647may each comprise any suitable material, including metals, alloys, polymers, carbon allotropes, oxides, carbides, glass materials, ceramics, composites, membrane materials (e.g. permeable or semi-permeable materials), and/or any combination of the foregoing, without limitation. Further, first protective masking layer1633, second protective masking layer1635, first at-least-partially-degrading masking layer1637, and second at-least-partially-degrading masking layer1647may be affixed to superabrasive element1610through any suitable mechanism, without limitation, including, for example, direct bonding, bonding via an intermediate layer, such as an adhesive or braze joint, mechanical attachment, such as mechanical fastening, frictional attachment, and/or interference fitting.

The configuration illustrated inFIG. 27may enable selective leaching of portions of superabrasive element1610to form a desired leach profile within superabrasive table1614. For example, a volume of superabrasive table1614adjacent to an uncovered region between first at-least-partially-degrading masking layer1637and second at-least-partially-degrading masking layer1647may be leached to a greater depth than surrounding portions of superabrasive table1614. As first at-least-partially-degrading masking layer1637and second at-least-partially-degrading masking layer1647are degraded during leaching, portions of superabrasive table1614that were covered by first at-least-partially-degrading masking layer1637and second at-least-partially-degrading masking layer1647may subsequently be exposed to the leaching agent. Accordingly, volumes of superabrasive table1614adjacent to the regions previously covered by first at-least-partially-degrading masking layer1637and second at-least-partially-degrading masking layer1647may be exposed to the leaching agent upon degradation of first at-least-partially-degrading masking layer1637and second at-least-partially-degrading masking layer1647.

Accordingly, the regions of superabrasive table1614that were originally adjacent to first at-least-partially-degrading masking layer1637and second at-least-partially-degrading masking layer1647may have a shallower leach depth than regions of superabrasive table1614that were adjacent to the uncovered region between first at-least-partially-degrading masking layer1637and second at-least-partially-degrading masking layer1647. For example, the configuration illustrated inFIG. 27may result in a leach profile having a maximum leach depth in the volume of superabrasive table1614adjacent to a central portion of chamfer1624.

According to various embodiments, a charge may be applied to superabrasive element1610and electrode1640through electrical conductors (e.g., wires or any suitable electrical conductor)1644and1642, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated in FIG.9C) for processing superabrasive element1610, superabrasive element1610and electrical conductor1644may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate1612(e.g., rear surface1618) of superabrasive element1610through electrical conductor1644and an opposite charge may be applied to electrode1640through electrical conductor1642. In at least one embodiment, electrical conductor1644may be electrically connected to substrate1612by an electrode electrically connected to (e.g., positioned abutting) substrate1612. In some embodiments, electrical conductor1644may be directly connected to superabrasive table1614by an electrode electrically connected to (e.g., positioned abutting) superabrasive table1614.

Electrode1640may comprise any suitable size, shape, and/or geometry, without limitation. In some embodiments, electrode1640may comprise a circular or non-circular disk shape. For example, electrode1640may have a substantially circular outer periphery surrounding a central axis (e.g., central axis29shown inFIGS. 1-2). Electrode1640may have an outer diameter that is larger than, the same as, or smaller than the outer diameter of element side surface1615of superabrasive element1610, as shown inFIG. 27. When superabrasive element1610and electrode1640are disposed in the processing solution such that at least a portion of superabrasive table1614and electrode1640are exposed to the processing solution and a voltage is applied to the processing solution via electrode1640and superabrasive table1614, interstitial materials may be removed from at least a portion of superabrasive table1614of superabrasive element1610exposed to the processing solution and disposed near electrode1640. Accordingly, a peripheral region of superabrasive table1614defining chamfer1624may be leached to a greater depth than a central region of superabrasive table1614.

FIG. 28is a cross-sectional side view of an exemplary superabrasive element1710coated with a masking layer and positioned within a leaching cup1730according to at least one embodiment. As illustrated inFIG. 28, a masking layer1733may be formed on or disposed adjacent to at least a portion of superabrasive face1720, such as a central portion of superabrasive face1720surrounding a central axis (e.g., central axis29shown inFIGS. 1-2). According to at least one embodiment, masking layer1733may comprise one or more materials that are substantially inert and/or otherwise resistant and/or impermeable to acids, bases, and/or other reactive compounds present in a leaching solution used to leach superabrasive element1710.

As illustrated inFIG. 28, superabrasive element1710may comprise a superabrasive table1714affixed to or formed upon a substrate1712. Superabrasive table1714may be affixed to substrate1712at interface1726. Superabrasive element1710may comprise a rear surface1718, a superabrasive face1720, and an element side surface1715, which may include a substrate side surface1716formed by substrate1712and a superabrasive side surface1722formed by superabrasive table1714. Superabrasive element1710may also comprise a chamfer1724formed by superabrasive table1714.

As shown inFIG. 28, superabrasive element1710may be positioned within protective leaching cup1730such that protective leaching cup1730surrounds at least a portion of superabrasive element1710, including substrate1712. When superabrasive element1710is positioned within protective leaching cup1730, at least a portion of superabrasive element1710, such as superabrasive table1714and/or substrate1712, may be positioned adjacent to and/or contacting a portion of protective leaching cup1730. For example, protective leaching cup1730may be configured to contact at least a portion of element side surface1715of superabrasive element1710, forming a seal between protective leaching cup1730and superabrasive element1710that is partially or fully impermeable to various fluids, such as a leaching material (e.g., a leaching solution).

Protective leaching cup1730may be formed of any suitable material, without limitation. For example, protective leaching cup1730may comprise a flexible, elastic, malleable, and/or otherwise deformable material configured to surround and/or contact at least a portion of superabrasive element1710. Protective leaching cup1730may prevent damage to superabrasive element1710when at least a portion of superabrasive element1710is exposed to various leaching agents. For example, protective leaching cup1730may prevent a leaching solution from chemically contacting and/or damaging certain portions of superabrasive element1710, such as portions of substrate1712, portions of superabrasive table1714, or both, during leaching.

In various embodiments, protective leaching cup1730may comprise one or more materials that are substantially inert and/or otherwise resistant to acids, bases, and/or other reactive components present in a leaching solution used to leach superabrasive element1710. In some embodiments, protective leaching cup1730may comprise one or more materials exhibiting significant stability at various temperatures and/or pressures. In some embodiments, protective leaching cup1730may include one or more polymeric materials, such as, for example, nylon, polytetrafluoroethylene (PTFE), polyethylene, polypropylene, rubber, silicone, and/or other polymers, and/or a combination of any of the foregoing, without limitation. For example, protective leaching cup1730may comprise PTFE blended with one or more other polymeric materials. Protective leaching cup1730may be formed using any suitable technique. For example, protective leaching cup1730may comprise a polymeric material that is shaped through a molding process (e.g., injection molding, blow molding, compression molding, drawing, etc.) and/or a machining process (e.g., grinding, lapping, milling, boring, etc.).

In at least one embodiment, protective leaching cup1730may comprise a material that is configured to conform to an exterior portion of superabrasive element1710. For example, protective leaching cup1730may include a malleable and/or elastically deformable material that conforms to an exterior shape of a portion of superabrasive table1714abutting protective leaching cup1730, such as superabrasive side surface1722. According to some embodiments, protective leaching cup1730may comprise a material, such as a polymeric material (e.g., elastomer, rubber, plastic, etc.), that conforms to surface imperfections of superabrasive side surface1722and/or substrate side surface1716. Heat and/or pressure may be applied to protective leaching cup1730to cause a portion of protective leaching cup1730abutting superabrasive side surface1722to more closely conform to superabrasive side surface1722. Accordingly, a seal between superabrasive side surface1722and a portion of protective leaching cup1730abutting superabrasive side surface1722may be improved, thereby inhibiting passage of a leaching agent between superabrasive element1710and protective leaching cup1730.

When superabrasive element1710is positioned within protective leaching cup1730, at least a portion of superabrasive element1710, such as superabrasive table1714and/or substrate1712, may be positioned adjacent to and/or contacting a portion of protective leaching cup1730. For example, at least a portion of a seal region of protective leaching cup1730may be configured to contact at least a portion of element side surface1715of superabrasive element1710, forming a seal between protective leaching cup1730and superabrasive element1710that is partially or fully impermeable to various fluids, such as a leaching agent. As shown inFIG. 28, superabrasive element1710may be positioned within protective leaching cup1730so that at least a portion of the seal region of protective leaching cup1730contacts and forms a seal with at least a portion of element side surface1715, such as at least a portion of superabrasive side surface1722and/or at least a portion of substrate side surface1716.

According to various embodiments, a charge may be applied to superabrasive element1710and electrode1740through electrical conductors (e.g., wires or any suitable electrical conductor)1744and1742, respectively. For example, in order to apply a current to a processing solution (e.g., processing solution72illustrated inFIG. 9C) for processing superabrasive element1710, superabrasive element1710and electrical conductor1744may be positioned in the processing solution (e.g., optionally, with a leaching cup30or other protective covering) and a charge may be applied to at least a portion of substrate1712(e.g., rear surface1718) of superabrasive element1710through electrical conductor1744and an opposite charge may be applied to electrode1740through electrical conductor1742. In at least one embodiment, electrical conductor1744may be electrically connected to substrate1712by an electrode electrically connected to (e.g., positioned abutting) substrate1712. In some embodiments, electrical conductor1744may be directly connected to superabrasive table1714by an electrode electrically connected to (e.g., positioned abutting) superabrasive table1714.

Electrode1740may comprise any suitable size, shape, and/or geometry, without limitation. In some embodiments, electrode1740may comprise a circular or non-circular disk shape. For example, electrode1740may have a substantially circular outer periphery surrounding a central axis (e.g., central axis29shown inFIGS. 1-2). Superabrasive element1710may comprise any suitable size, shape, and/or geometry, without limitation. For example, superabrasive element1710may comprise a substantially cylindrical or non-cylindrical outer surface surrounding a central axis (e.g., central axis29shown inFIGS. 1-2) of superabrasive element1710. Electrode1740may have an outer diameter that is larger than, the same as, or smaller than the outer diameter of element side surface1715of superabrasive element1710, as shown inFIG. 28. When superabrasive element1710and electrode1740are disposed in the processing solution such that at least a portion of superabrasive table1714and electrode1740are exposed to the processing solution and a voltage is applied to the processing solution via electrode1740and superabrasive table1714, interstitial materials may be removed from at least a portion of superabrasive table1714of superabrasive element1710exposed to the processing solution and disposed near electrode1740.

The configuration illustrated inFIG. 28may enable selective leaching of portions of superabrasive element1710to form a desired leach profile within superabrasive table1714. For example, a volume of superabrasive table1714adjacent to an uncovered region between masking layer1733and the seal region of protective leaching cup1730may be leached to a greater depth than surrounding portions of superabrasive table1714covered by masking layer1733or the seal region. Leaching such a configuration may result in the formation of leached volumes in portions of superabrasive table1714located near chamfer1724during leaching.

FIG. 29is a perspective view of an exemplary leaching assembly61according to at least one embodiment. As illustrated inFIG. 29, leaching assembly61may comprise a lower tray60and an upper tray62. Lower tray60and upper tray62may comprise any suitable shape, such as, for example, substantially disk-shaped bodies. According to various embodiments, lower tray60and upper tray62may be connected by a cylindrical shaft68supporting lower tray60and upper tray62. At least one of lower tray60and upper tray62may be movable along shaft68such that lower tray60and upper tray62may be supported adjacent to or separated from each other as desired.

A plurality of holes64(not all labeled) may be defined in lower tray60. In some embodiments, a plurality of holes66(not all labeled) may also be defined in upper tray62. Holes64may each be configured to hold a superabrasive element10. Holes64may be configured such that superabrasive elements10are recessed in holes64. Holes64may extend partially or fully through lower tray60. Holes64may extend through lower tray60such that electrical conductors44(not all labeled) may be electrically connected to superabrasive elements10. Holes66defined in upper tray62may each be configured to hold an electrode40and/or electrical conductor connected to electrode40. In some embodiments, holes66may be configured such that each electrode40(not all labeled) is disposed near, but not contacting, a respective superabrasive element10when lower tray60and upper tray62are positioned adjacent to each other. Holes66may be configured such that at least a portion of each electrode40protrudes from upper tray62toward lower tray60. Holes66may extend through upper tray62such that electrical conductors42(not all labeled) may be electrically connected to electrodes40.

According to at least one embodiment, leaching assembly61may be configured such that a volume of a processing solution72(e.g., processing solution72illustrated in10) is disposed in each of holes64. For example, processing solution72may be disposed in each hole64such that processing solution72contacts and/or surrounds at least a portion of each superabrasive element10. Accordingly, at least a portion of each superabrasive element10, such as at least a portion of superabrasive table14, may be exposed to processing solution72. Alternatively, lower tray60may be at least partially submersed in a processing solution and upper tray62may be at least partially submersed in the processing solution.

Upper tray62containing electrodes40disposed in and/or protruding from holes66may be positioned adjacent to lower tray60containing superabrasive elements10and processing solution72in holes64. Upper tray62and lower tray60may be positioned such that at least a portion of each electrode40is disposed in holes64in contact with processing solution72. According to various embodiments, at least a portion of lower tray60and upper tray62may be sealed together so as to prevent processing solution72from leaking from leaching assembly61during processing.

According to various embodiments, a charge may be applied to superabrasive element10and electrode40through electrical conductors44and42, respectively. For example, in order to apply a current to processing solution72for processing superabrasive elements10, a charge may be applied to at least a portion of each superabrasive element10through electrical conductors44and an opposite charge may be applied to each electrode40through electrical conductors42.

FIGS. 30-41Bshow superabrasive elements having exemplary leach profiles that may be obtained by exemplary leach apparatuses disclosed herein.

FIG. 30shows a cross-sectional side view of an exemplary superabrasive element1810according to at least one embodiment. As illustrated inFIG. 30, superabrasive element1810may comprise a superabrasive table1814affixed to or formed upon a substrate1812. Superabrasive table1814may be affixed to substrate1812at interface1826. Superabrasive element1810may comprise a rear surface1818, a superabrasive face1820, and an element side surface1815, which may include a substrate side surface1816formed by substrate1812and a superabrasive side surface1822formed by superabrasive table1814. Superabrasive element1810may also comprise a chamfer1824formed by superabrasive table1814.

As illustrated inFIG. 30, superabrasive table1814may include a first volume1821comprising an interstitial material and a second volume1823having a lower concentration of the interstitial material than first volume1821. Portions of superabrasive table1814, such as second volume1823may be leached or otherwise processed to remove interstitial materials, such as a metal-solvent catalyst, from the interstitial regions. Second volume1823may be created during leaching of superabrasive table1812according to any suitable leaching technique. For example, second volume1823may be selectively leached by disposing portions of superabrasive table1814of superabrasive element1810near an electrode during an electrochemical leaching process (e.g., electrochemical leaching referenced inFIG. 9C). In some embodiments, superabrasive element1810may first be leached, after which portions of superabrasive element1810may be removed to modify the shape of first volume1821and/or second volume1823according to one or more methods discussed herein.

A transition region1825may extend between first volume1821and second volume1823. Transition region1825may include amounts of metal-solvent catalyst varying between an amount of metal-solvent catalyst in first volume1821and an amount of metal-solvent catalyst in second volume1823. As illustrated inFIG. 30, first volume1821may be located adjacent to a central portion of superabrasive face1820. For example, first volume1821may be disposed about central axis1829. First volume1821may extend between interface1826and superabrasive face1820with first volume1821forming at least a portion of superabrasive face1820such that the central portion of superabrasive face1820located about central axis1829is defined by first volume1821, as shown inFIG. 30. In some embodiments, first volume1821and superabrasive face1820may be separated by a thin layer of leached polycrystalline diamond material located adjacent to a central region of superabrasive face1820.

Second volume1823may be formed around at least a portion of first volume1821. For example, second volume1823may comprise an annular volume surrounding at least a portion of first volume1821such that an outer portion of superabrasive face1820relative to central axis1829is defined by second volume1823. As shown inFIG. 30, second volume1823may be located adjacent to superabrasive face1820and/or chamfer1824so as to at least partially surround a portion of first volume1821that is also adjacent to superabrasive face1820. Second volume1823may be located adjacent to element side surface1815. Second volume1823may be separated from interface1826between substrate1812and superabrasive table1814so as to prevent corrosion of substrate1812by a leaching solution used to form second volume1823.

First volume1821, second volume1823, and transition region1825may be formed to any suitable size and/or shape within superabrasive table1814, without limitation. For example, transition region1825may extend along a generally straight, angular, curved, and/or variable (e.g., zigzag, undulating) profile between first volume1821and second volume1823. In various embodiments, transition region1825may comprise a relatively narrow region between first volume1821and second volume1823, while transition region1825may optionally comprise a relatively wider region between first volume1821and second volume1823.

As shown inFIG. 30, second volume1823may have a depth1836from superabrasive face1820in a direction substantially perpendicular to superabrasive face1820. Second volume1823may comprise a generally annular-shaped volume defined between a first diameter1857and a second diameter1858surrounding central axis1829. The portion of first volume1821surrounded by second volume1823may be generally defined by first diameter1857. Second diameter1858may represent a diameter of element side surface1815. Edge1827formed at the intersection of chamfer1824and superabrasive face1820may be located at a third diameter1859relative to central axis1829.

Superabrasive elements1810having superabrasive table1814comprising first volume1821and second volume1823may exhibit properties of increased thermal stability, fatigue resistance, strength, and/or wear resistance. Such properties may be enhanced by the shape, size, and/or locations of first volume1821, second volume1823, and/or transition region1825of superabrasive table1814. Accordingly, the superabrasive element configuration illustrated inFIG. 30, as well as other configurations illustrated and described herein, may provide significant resistance to undesired spalling, cracking, and/or thermal damage of superabrasive portions, such as superabrasive table1814, of the superabrasive elements during drilling.

FIG. 31shows a cross-sectional side view of an exemplary superabrasive element1910according to at least one embodiment. As illustrated inFIG. 31, superabrasive element1910may comprise a superabrasive table1914affixed to or formed upon a substrate1912. Superabrasive table1914may be affixed to substrate1912at interface1926. Superabrasive element1910may comprise a rear surface1918, a superabrasive face1920, and an element side surface1915, which may include a substrate side surface1916formed by substrate1912and a superabrasive side surface1922formed by superabrasive table1914. Superabrasive element1910may also comprise a chamfer1924formed by superabrasive table1914.

Superabrasive element1910may include a first volume1921comprising an interstitial material and a second volume1923having a lower concentration of the interstitial material than first volume1921. Portions of superabrasive table1914, such as second volume1923, may be leached or otherwise processed to remove interstitial materials, such as a metal-solvent catalyst, from the interstitial regions. A transition region1925may extend between first volume1921and second volume1923so as to border at least a portion of first volume1921and second volume1923. Transition region1925may include amounts of an interstitial material varying between an amount of the interstitial material in first volume1921and an amount of the interstitial material in second volume1923. In other embodiments, the boundary may be well defined (i.e., transition region1925may be thin compared to a depth of second volume1923).

Transition region1925located between first volume1921and second volume1923may extend along any suitable profile within superabrasive table1914. For example, as illustrated inFIG. 31, sloped boundary portion1955of transition region1925may extend between chamfer1924and central boundary portion1954along any suitable profile, including, for example, a generally straight, angular, curved, and/or variable (e.g., zigzag, undulating) profile. According to at least one embodiment, superabrasive element1910may be processed such that transition region1925intersects chamfer1924and/or a surface region adjacent to chamfer1924(e.g., superabrasive side surface1922). Accordingly, as shown inFIG. 31, second volume1923may be located directly adjacent to a central portion of superabrasive face1920. For example, second volume1923may be disposed about central axis1929. A portion of first volume1921, such as a portion adjacent to chamfer1924, may peripherally surround at least a portion of second volume1923.

FIG. 32shows a cross-sectional side view of an exemplary superabrasive element2010according to at least one embodiment. As illustrated inFIG. 32, superabrasive element2010may comprise a superabrasive table2014affixed to or formed upon a substrate2012. Superabrasive table2014may be affixed to substrate2012at interface2026. Superabrasive element2010may comprise a rear surface2018, a superabrasive face2020, and an element side surface2015, which may include a substrate side surface2016formed by substrate2012and a superabrasive side surface2022formed by superabrasive table2014. Superabrasive element2010may also comprise a chamfer2024formed by superabrasive table2014.

Superabrasive element2010may include a first volume2021comprising an interstitial material and a second volume2023having a lower concentration of the interstitial material than first volume2021. Portions of superabrasive table2014, such as second volume2023, may be leached or otherwise processed to remove interstitial materials, such as a metal-solvent catalyst, from the interstitial regions. A transition region2025may extend between first volume2021and second volume2023so as to border at least a portion of first volume2021and second volume2023. Transition region2025may include amounts of an interstitial material varying between an amount of the interstitial material in first volume2021and an amount of the interstitial material in second volume2023. In other embodiments, the boundary may be well defined (i.e., transition region2025may be thin compared to a depth of second volume2023).

FIGS. 33-41Bshow cross-sectional views of superabrasive elements comprising superabrasive tables having exemplary leach profiles that may be obtained by exemplary leach apparatuses disclosed herein. While superabrasive elements illustrated inFIGS. 33-41Bshown as superabrasive tables without a substrate, the leach profiles illustrated in these figures may also apply to superabrasive elements (e.g., superabrasive element10shown inFIGS. 1-2) comprising a superabrasive element bonded to a substrate. According to some embodiments, the superabrasive elements illustrated inFIGS. 33-41Bmay be formed by leaching a superabrasive element comprising a substrate and a superabrasive table according to any of the techniques described herein and subsequently separating (e.g., by lapping, grinding, wire EDM, etc.) the superabrasive table from the substrate. Alternatively, a superabrasive element may be formed with a substrate, the substrate may be removed, and then the superabrasive table may be leached.

FIG. 33shows an exemplary superabrasive element2110comprising a superabrasive table2114having a rear surface2118, a superabrasive face2120, and an element side surface2115. Superabrasive element2110may comprise an edge2117(i.e., sloped or angled) and/or any other suitable surface shape at the intersection of element side surface2115and superabrasive face2120, including, without limitation, an arcuate surface (e.g., a radius, an ovoid shape, or any other rounded shape), a sharp edge, multiple chamfers/radii, a honed edge, and/or combinations of the foregoing. Element side surface2115of superabrasive element2110may radially surround a central axis2129of superabrasive element2110.

Superabrasive element2110may include a first volume2121comprising an interstitial material and a second volume2123having a lower concentration of the interstitial material than first volume2121. Portions of superabrasive table2114, such as second volume2123, may be leached or otherwise processed to remove interstitial materials, such as a metal-solvent catalyst, from the interstitial regions. A transition region2125may extend between first volume2121and second volume2123so as to border at least a portion of first volume2121and second volume2123. Transition region2125may include amounts of an interstitial material varying between an amount of the interstitial material in first volume2121and an amount of the interstitial material in second volume2123. In other embodiments, the boundary may be well defined (i.e., transition region2125may be thin compared to a depth of second volume2123).

As shown inFIG. 33, first volume2121may extend between rear surface2118and transition region2125. Second volume2123may be formed adjacent to a substantial portion of superabrasive face2120. Transition region2125bordering second volume2123may extend in a direction generally parallel to superabrasive face2120. Optionally, a portion of second volume2123may extend along at least a portion of element side surface2115so as to radially surround at least a portion of first volume2121. A portion of transition region2125may extend in a direction generally parallel to element side surface2115. According to some embodiments, transition region2125may have a substantially consistent thickness along element side surface2115and/or along superabrasive face2120.

FIG. 34shows an exemplary superabrasive element2210comprising a superabrasive table2214having a rear surface2218, a superabrasive face2220, and an element side surface2215. Superabrasive table2214may also form a chamfer2224and one or more cutting edges, such as edge2227and edge2228, adjacent to chamfer2224. Element side surface2215of superabrasive element2210may radially surround a central axis2229of superabrasive element2210.

Superabrasive element2210may include a first volume2221comprising an interstitial material and a second volume2223having a lower concentration of the interstitial material than first volume2221. Portions of superabrasive table2214, such as second volume2223, may be leached or otherwise processed to remove interstitial materials, such as a metal-solvent catalyst, from the interstitial regions. A transition region2225may extend between first volume2221and second volume2223so as to border at least a portion of first volume2221and second volume2223. Transition region2225may include amounts of an interstitial material varying between an amount of the interstitial material in first volume2221and an amount of the interstitial material in second volume2223. In other embodiments, the boundary may be well defined (i.e., transition region2225may be thin compared to a depth of second volume2223).

As shown inFIG. 34, second volume2223may be formed adjacent to chamfer2224and superabrasive face2220, and transition region2225may extend from superabrasive face2220to edge2228formed at the intersection of chamfer2224and element side surface2215, with a portion of transition region2225extending generally parallel to chamfer2224.

FIG. 35shows an exemplary superabrasive element2310comprising a superabrasive table2314having a rear surface2318, a superabrasive face2320, and an element side surface2315. Superabrasive table2314may also form a chamfer2324and one or more cutting edges, such as edge2327and edge2328, adjacent to chamfer2324. Element side surface2315of superabrasive element2310may radially surround a central axis2329of superabrasive element2310.

Superabrasive element2310may include a first volume2321comprising an interstitial material and a second volume2323having a lower concentration of the interstitial material than first volume2321. Portions of superabrasive table2314, such as second volume2323, may be leached or otherwise processed to remove interstitial materials, such as a metal-solvent catalyst, from the interstitial regions. A transition region2325may extend between first volume2321and second volume2323so as to border at least a portion of first volume2321and second volume2323. Transition region2325may include amounts of an interstitial material varying between an amount of the interstitial material in first volume2321and an amount of the interstitial material in second volume2323. In other embodiments, the boundary may be well defined (i.e., transition region2325may be thin compared to a depth of second volume2323).

As shown inFIG. 35, second volume2323may be formed adjacent to chamfer2324, superabrasive face2320, and element side surface2315, and transition region2325may extend generally parallel to chamfer2324from superabrasive face2320to element side surface2315.

FIG. 36shows an exemplary superabrasive element2410comprising a superabrasive table2414having a rear surface2418, a superabrasive face2420, and an element side surface2415. Superabrasive table2414may also form a chamfer2424and one or more cutting edges, such as edge2427and edge2428, adjacent to chamfer2424. Element side surface2415of superabrasive element2410may radially surround a central axis2429of superabrasive element2410.

Superabrasive element2410may include a first volume2421comprising an interstitial material and a second volume2423having a lower concentration of the interstitial material than first volume2421. Portions of superabrasive table2414, such as second volume2423, may be leached or otherwise processed to remove interstitial materials, such as a metal-solvent catalyst, from the interstitial regions. A transition region2425may extend between first volume2421and second volume2423so as to border at least a portion of first volume2421and second volume2423. Transition region2425may include amounts of an interstitial material varying between an amount of the interstitial material in first volume2421and an amount of the interstitial material in second volume2423. In other embodiments, the boundary may be well defined (i.e., transition region2425may be thin compared to a depth of second volume2423).

As shown inFIG. 36, second volume2423may be formed adjacent to chamfer2424, superabrasive face2420, and element side surface2415, and transition region2425may extend from superabrasive face2420to element side surface2415, with a portion of transition region2425extending generally parallel to chamfer2424and another portion of transition region2425extending generally parallel to element side surface2415.

FIG. 37shows an exemplary superabrasive element2510comprising a superabrasive table2514having a rear surface2518, a superabrasive face2520, and an element side surface2515. Superabrasive table2514may also form a chamfer2524and one or more cutting edges, such as edge2527and edge2528, adjacent to chamfer2524. Element side surface2515of superabrasive element2510may radially surround a central axis2529of superabrasive element2510.

Superabrasive element2510may include a first volume2521comprising an interstitial material and a second volume2523having a lower concentration of the interstitial material than first volume2521. Portions of superabrasive table2514, such as second volume2523, may be leached or otherwise processed to remove interstitial materials, such as a metal-solvent catalyst, from the interstitial regions. A transition region2525may extend between first volume2521and second volume2523so as to border at least a portion of first volume2521and second volume2523. Transition region2525may include amounts of an interstitial material varying between an amount of the interstitial material in first volume2521and an amount of the interstitial material in second volume2523. In other embodiments, the boundary may be well defined (i.e., transition region2525may be thin compared to a depth of second volume2523).

As shown inFIG. 37, second volume2523may be formed adjacent to chamfer2524and element side surface2515, and transition region2525may extend from edge2527formed at the intersection of chamfer2524and superabrasive face2520to element side surface2515, with a portion of transition region2525extending generally parallel to element side surface2515.

FIG. 38shows an exemplary superabrasive element2610comprising a superabrasive table2614having a rear surface2618, a superabrasive face2620, and an element side surface2615. Superabrasive table2614may also form a chamfer2624and one or more cutting edges, such as edge2627and edge2628, adjacent to chamfer2624. Element side surface2615of superabrasive element2610may radially surround a central axis2629of superabrasive element2610.

Superabrasive element2610may include a first volume2621comprising an interstitial material and a second volume2623having a lower concentration of the interstitial material than first volume2621. Portions of superabrasive table2614, such as second volume2623, may be leached or otherwise processed to remove interstitial materials, such as a metal-solvent catalyst, from the interstitial regions. A transition region2625may extend between first volume2621and second volume2623so as to border at least a portion of first volume2621and second volume2623. Transition region2625may include amounts of an interstitial material varying between an amount of the interstitial material in first volume2621and an amount of the interstitial material in second volume2623. In other embodiments, the boundary may be well defined (i.e., transition region2625may be thin compared to a depth of second volume2623).

As shown inFIG. 38, second volume2623may be formed adjacent to chamfer2624and transition region2625may extend from edge2627to edge2628, which are each adjacent to chamfer2624. Transition region2625may extend along any suitable profile between edge2627and edge2628, without limitation. According to some embodiments, transition region2625may comprise an angular profile, as illustrated inFIG. 38. A thickness or depth of second volume2623, as measured perpendicular to a surface of chamfer2624, may be maximum generally near the center of chamfer2624.

FIG. 39shows an exemplary superabrasive element2710comprising a superabrasive table2714having a rear surface2718, a superabrasive face2720, and an element side surface2715. Superabrasive table2714may also form a chamfer2724and one or more cutting edges, such as edge2727and edge2728, adjacent to chamfer2724. Element side surface2715of superabrasive element2710may radially surround a central axis2729of superabrasive element2710.

Superabrasive element2710may include a first volume2721comprising an interstitial material and a second volume2723having a lower concentration of the interstitial material than first volume2721. Portions of superabrasive table2714, such as second volume2723, may be leached or otherwise processed to remove interstitial materials, such as a metal-solvent catalyst, from the interstitial regions. A transition region2725may extend between first volume2721and second volume2723so as to border at least a portion of first volume2721and second volume2723. Transition region2725may include amounts of an interstitial material varying between an amount of the interstitial material in first volume2721and an amount of the interstitial material in second volume2723. In other embodiments, the boundary may be well defined (i.e., transition region2725may be thin compared to a depth of second volume2723).

As shown inFIG. 39, second volume2723may be formed adjacent to chamfer2724and transition region2725may extend from edge2727to edge2728, which are each adjacent to chamfer2724. Transition region2725may extend along any suitable profile between edge2727and edge2728, without limitation. According to some embodiments, transition region2725may comprise an arcuate profile, as illustrated inFIG. 39. A thickness or depth of second volume2723, as measured perpendicular to a surface of chamfer2724, may be maximum generally near the center of chamfer2724.

FIG. 40Ashows an exemplary superabrasive element2810comprising a superabrasive table2814having a rear surface2818, a superabrasive face2820, and an element side surface2815. Superabrasive table2814may also form a chamfer2824and one or more cutting edges, such as edge2827and edge2828, adjacent to chamfer2824. Element side surface2815of superabrasive element2810may radially surround a central axis2829of superabrasive element2810.

Superabrasive element2810may include a first volume2821comprising an interstitial material and a second volume2823having a lower concentration of the interstitial material than first volume2821. Portions of superabrasive table2814, such as second volume2823, may be leached or otherwise processed to remove interstitial materials, such as a metal-solvent catalyst, from the interstitial regions. A transition region2825may extend between first volume2821and second volume2823so as to border at least a portion of first volume2821and second volume2823. Transition region2825may include amounts of an interstitial material varying between an amount of the interstitial material in first volume2821and an amount of the interstitial material in second volume2823. In other embodiments, the boundary may be well defined (i.e., transition region2825may be thin compared to a depth of second volume2823).

As shown inFIG. 40A, second volume2823may be formed adjacent to chamfer2824and transition region2825may extend from superabrasive face2820to element side surface2815. Transition region2825may extend along any suitable profile between superabrasive face2820and element side surface2815, without limitation. Transition region2825may comprise, for example, a profile that generally slopes between superabrasive face2820and element side surface2815. For example, transition region2825may extend from a region of element side surface2815near edge2828to a region of superabrasive face2820disposed apart from edge2827. According to some embodiments, as shown inFIG. 40A, the generally annular-shaped second volume2823may comprise a generally ring-shaped volume that is not perfectly symmetric but is irregular in one or more dimensions. For example, second volume2823may vary in leach depth and/or profile shape, as defined by transition region2825, at different peripheral regions about central axis2829.

FIG. 40Bshows an exemplary superabrasive element2910comprising a superabrasive table2914having a rear surface2918, a superabrasive face2920, and an element side surface2915. Superabrasive table2914may also form a chamfer2924and one or more cutting edges, such as edge2927and edge2928, adjacent to chamfer2924. Element side surface2915of superabrasive element2910may radially surround a central axis2929of superabrasive element2910.

Superabrasive element2910may include a first volume2921comprising an interstitial material and a second volume2923having a lower concentration of the interstitial material than first volume2921. Portions of superabrasive table2914, such as second volume2923, may be leached or otherwise processed to remove interstitial materials, such as a metal-solvent catalyst, from the interstitial regions. A transition region2925may extend between first volume2921and second volume2923so as to border at least a portion of first volume2921and second volume2923. Transition region2925may include amounts of an interstitial material varying between an amount of the interstitial material in first volume2921and an amount of the interstitial material in second volume2923. In other embodiments, the boundary may be well defined (i.e., transition region2925may be thin compared to a depth of second volume2923).

As shown inFIG. 40B, second volume2923may be formed adjacent to chamfer2924and transition region2925may extend from superabrasive face2920to element side surface2915. Transition region2925may extend along any suitable profile between superabrasive face2920and element side surface2915, without limitation. Transition region2925may comprise, for example, a profile that generally slopes between superabrasive face2920and element side surface2915. For example, transition region2925may extend from a region of element side surface2915near edge2928to a region of superabrasive face2920disposed apart from edge2927. According to some embodiments, as shown inFIG. 40B, the generally annular-shaped second volume2923may comprise a generally ring-shaped volume that is not perfectly symmetric but is irregular in one or more dimensions. For example, second volume2923may vary in leach depth and/or profile shape, as defined by transition region2925, at different peripheral regions about central axis2929.

FIG. 41Ashows an exemplary superabrasive element3010comprising a superabrasive table3014having a rear surface3018, a superabrasive face3020, and an element side surface3015. Superabrasive table3014may also form a chamfer3024and one or more cutting edges, such as edge3027and edge3028, adjacent to chamfer3024. Element side surface3015of superabrasive element3010may radially surround a central axis3029of superabrasive element3010.

Superabrasive element3010may include a first volume3021comprising an interstitial material and a second volume3023having a lower concentration of the interstitial material than first volume3021. Portions of superabrasive table3014, such as second volume3023, may be leached or otherwise processed to remove interstitial materials, such as a metal-solvent catalyst, from the interstitial regions. A transition region3025may extend between first volume3021and second volume3023so as to border at least a portion of first volume3021and second volume3023. Transition region3025may include amounts of an interstitial material varying between an amount of the interstitial material in first volume3021and an amount of the interstitial material in second volume3023. In other embodiments, the boundary may be well defined (i.e., transition region3025may be thin compared to a depth of second volume3023).

As shown inFIG. 41A, second volume3023may be formed adjacent to chamfer3024, superabrasive face3020, and element side surface3015, and transition region3025may extend from superabrasive face3020to rear surface3018(or to an interface between superabrasive table3014and an adjacent substrate), with transition region3025extending generally parallel to element side surface3015.

FIG. 41Bshows an exemplary superabrasive element3110comprising a superabrasive table3114having a rear surface3118, a superabrasive face3120, and an element side surface3115. Superabrasive table3114may also form a chamfer3124and one or more cutting edges, such as edge3127and edge3128, adjacent to chamfer3124. Element side surface3115of superabrasive element3110may radially surround a central axis3129of superabrasive element3110.

Superabrasive element3110may include a first volume3121comprising an interstitial material and a second volume3123having a lower concentration of the interstitial material than first volume3121. Portions of superabrasive table3114, such as second volume3123, may be leached or otherwise processed to remove interstitial materials, such as a metal-solvent catalyst, from the interstitial regions. A transition region3125may extend between first volume3121and second volume3123so as to border at least a portion of first volume3121and second volume3123. Transition region3125may include amounts of an interstitial material varying between an amount of the interstitial material in first volume3121and an amount of the interstitial material in second volume3123. In other embodiments, the boundary may be well defined (i.e., transition region3125may be thin compared to a depth of second volume3123).

As shown inFIG. 41B, second volume3123may be formed adjacent to chamfer3124, superabrasive face3120, and element side surface3115, and transition region3125may extend from superabrasive face3120to rear surface3118(or to an interface between superabrasive table3114and an adjacent substrate).

FIG. 42is a perspective view of an exemplary drill bit80according to at least one embodiment. Drill bit80may represent any type or form of earth-boring or drilling tool, including, for example, a rotary drill bit. As illustrated inFIG. 42, drill bit80may comprise a bit body81having a longitudinal axis84. Bit body81may define a leading end structure for drilling into a subterranean formation by rotating bit body81about longitudinal axis84and applying weight to bit body81. Bit body81may include radially and longitudinally extending blades79with leading faces82and a threaded pin connection83for connecting bit body81to a drill string.

At least one superabrasive element according to any of the embodiments disclosed herein may be coupled to bit body81. For example, as shown inFIG. 42, a plurality of superabrasive elements10may be coupled to blades79. Drill bit80may utilize any of the disclosed superabrasive elements10as cutting elements. Circumferentially adjacent blades79may define so-called junk slots85therebetween. Junk slots85may be configured to channel debris, such as rock or formation cuttings, away from superabrasive elements10during drilling. Drill bit80may also include a plurality of nozzle cavities86for communicating drilling fluid from the interior of drill bit80to superabrasive elements10.

FIG. 42depicts an example of a drill bit80that employs at least one cutting element10. Drill bit80may represent any number of earth-boring tools or drilling tools, including, for example, core bits, roller-cone bits, fixed-cutter bits, eccentric bits, bicenter bits, reamers, reamer wings, and/or any other downhole tools comprising superabrasive cutting elements and/or discs, without limitation. Superabrasive elements10disclosed herein may also be utilized in applications other than cutting technology. For example, embodiments of superabrasive elements10disclosed herein may also form all or part of heat sinks, wire dies, bearing elements, cutting elements, cutting inserts (e.g., on a roller cone type drill bit), machining inserts, or any other article of manufacture, as known in the art. According to some examples, superabrasive elements10, as disclosed herein, may be employed in medical device applications, including, without limitation, hip joints, back joints, or any other suitable medical joints. Thus, superabrasive elements10, as disclosed herein, may be employed in any suitable article of manufacture. Other examples of articles of manufacture that may incorporate superabrasive elements as disclosed herein may be found in U.S. Pat. Nos. 4,811,801; 4,268,276; 4,468,138; 4,738,322; 4,913,247; 5,016,718; 5,092,687; 5,120,327; 5,135,061; 5,154,245; 5,460,233; 5,544,713; and 6,793,681, the disclosure of each of which is incorporated herein, in its entirety, by this reference.

In additional embodiments, a rotor and a stator, such as a rotor and a stator used in a thrust bearing apparatus, may each include at least one superabrasive element according to the embodiments disclosed herein. By way of example, U.S. Pat. Nos. 4,410,054; 4,560,014; 5,364,192; 5,368,398; and 5,480,233, the disclosure of each of which is incorporated herein, in its entirety, by this reference, disclose subterranean drilling systems that include bearing apparatuses utilizing superabrasive elements10as disclosed herein.

FIG. 43is partial cross-sectional perspective view of an exemplary thrust-bearing apparatus87according to at least one embodiment. Thrust-bearing apparatus87may utilize any of the disclosed superabrasive elements10as bearing elements. Thrust-bearing apparatus87may also include bearing assemblies88A and88B. Each of bearing assembly88A and88B may include a support ring89fabricated from a material, such as steel, stainless steel, or any other suitable material, without limitation.

Each support ring89may include a plurality of recesses90configured to receive corresponding superabrasive elements10. Each superabrasive element10may be mounted to a corresponding support ring89within a corresponding recess90by brazing, welding, press-fitting, using fasteners, or any another suitable mounting technique, without limitation. In at least one embodiment, one or more of superabrasive elements10may be configured according to any of the superabrasive element embodiments described herein. For example, each superabrasive element10may include a substrate12and a superabrasive table14comprising a PCD material. Each superabrasive table14may form a superabrasive face20that is utilized as a bearing surface.

Superabrasive faces20of bearing assembly88A may bear against opposing superabrasive faces20of bearing assembly88B in thrust-bearing apparatus87, as illustrated inFIG. 43. For example, bearing assembly88A of thrust-bearing apparatus87may be termed a “rotor.” The rotor may be operably coupled to a rotational shaft. Bearing assembly88B of thrust-bearing apparatus87may be held substantially stationary relative to the bearing assembly88A and may be termed a “stator.”

FIG. 44is a perspective view of a radial bearing apparatus91according to another embodiment. Radial bearing apparatus91may utilize any of the disclosed superabrasive element embodiments as bearing elements10A and10B. Radial bearing apparatus91may include an inner race92A positioned generally within an outer race92B. Inner race92A may include a plurality of bearing elements10A affixed thereto, and outer race92B may include a plurality of corresponding bearing elements10B affixed thereto. One or more of bearing elements10A and10B may be configured in accordance with any of the superabrasive element embodiments disclosed herein.

Inner race92A may be positioned generally within outer race92B. Thus, inner race92A and outer race92B may be configured such that bearing surfaces20A defined by bearing elements10A and bearing surfaces20B defined by bearing elements10B may at least partially contact one another and move relative to one another as inner race92A and outer race92B rotate relative to each other. According to various embodiments, thrust-bearing apparatus87and/or radial bearing apparatus91may be incorporated into a subterranean drilling system.

FIG. 45is a partial cross-sectional perspective view of an exemplary subterranean drilling system93that includes a thrust-bearing apparatus87, as shown inFIG. 43, according to at least one embodiment. The subterranean drilling system93may include a housing94enclosing a downhole drilling motor95(i.e., a motor, turbine, or any other suitable device capable of rotating an output shaft, without limitation) that is operably connected to an output shaft96.

The thrust-bearing apparatus87shown inFIG. 43may be operably coupled to downhole drilling motor95. A rotary drill bit97, such as a rotary drill bit configured to engage a subterranean formation and drill a borehole, may be connected to output shaft96. As illustrated inFIG. 45, rotary drill bit97may be a roller cone bit comprising a plurality of roller cones98. According to additional embodiments, rotary drill bit97may comprise any suitable type of rotary drill bit, such as, for example, a so-called fixed-cutter drill bit. As a borehole is drilled using rotary drill bit97, pipe sections may be connected to subterranean drilling system93to form a drill string capable of progressively drilling the borehole to a greater depth within a subterranean formation.

A thrust-bearing assembly88A in thrust-bearing apparatus87may be configured as a rotor that is attached to output shaft96and a thrust-bearing assembly88B in thrust-bearing apparatus87may be configured as a stator. During a drilling operation using subterranean drilling system93, the rotor may rotate in conjunction with output shaft96and the stator may remain substantially stationary relative to the rotor.

According to various embodiments, drilling fluid may be circulated through downhole drilling motor95to generate torque and effect rotation of output shaft96and rotary drill bit97attached thereto so that a borehole may be drilled. A portion of the drilling fluid may also be used to lubricate opposing bearing surfaces of superabrasive elements10on thrust-bearing assemblies88A and88B.

FIG. 46illustrates an exemplary method3000for processing a polycrystalline diamond element according to at least one embodiment. As shown in FIG.46, at least a portion of a polycrystalline diamond material may be exposed to a processing solution, the polycrystalline the polycrystalline diamond material comprising a metallic material disposed in interstitial spaces defined within the polycrystalline diamond material (process3202). In some embodiments, for example, a superabrasive element10comprising a superabrasive table14and a substrate12may be disposed in a protective leaching cup30such that the protective leaching cup surrounds substrate12and/or at least a portion of superabrasive table14. Superabrasive element10and protective leaching cup30may be disposed in a cavity76of a processing vessel70such that a processing solution72contacts at least a portion of superabrasive element10as illustrated inFIG. 9C.

An electrode may be exposed to the processing solution (process3204). For example, as shown inFIG. 9C, an electrode40may be disposed in processing vessel70such that electrode40and superabrasive element10surrounded by protective leaching cup30are at least partially submerged in processing solution72. Electrode40may be exposed to processing solution72such that processing solution72contacts at least a portion of electrode40.

A first charge may be applied to the polycrystalline diamond material (process3206). For example, as shown inFIG. 9C, a charge may be applied to superabrasive element10through an electrical conductor44. In some embodiments, a positive charge may be applied to at least a portion of substrate12(e.g., rear surface18) of superabrasive element10through electrical conductor44. In at least one embodiment, electrical conductor44may be electrically connected to substrate12by an electrode electrically connected to (e.g., positioned abutting) substrate12. In some embodiments, electrical conductor44may be directly connected to superabrasive table14by an electrode electrically connected to (e.g., positioned abutting) superabrasive table14.

A second charge may be applied to the electrode (process3208). For example, as shown inFIG. 9C, a charge may be applied to electrode40through an electrical conductor42. In some embodiments, an opposite charge (e.g., a negative charge) may be applied to electrode40through electrical conductor42.

FIG. 47illustrates an exemplary method3300for processing a polycrystalline diamond element according to at least one embodiment. As shown inFIG. 47, a superabrasive element may be provided, the superabrasive element comprising a substrate and a polycrystalline diamond table bonded to the substrate, the polycrystalline diamond table comprising a metallic material disposed in interstitial spaces defined within the polycrystalline diamond table (process3302). For example, as shown inFIGS. 1 and 2, a superabrasive element10comprising a substrate12bonded to a superabrasive table14may be provided. Superabrasive table14may comprise a polycrystalline diamond table with metal-solvent catalyst and/or other materials (e.g. interstitial material39) disposed in interstitial spaces (e.g. interstitial regions36) defined within the polycrystalline diamond table, as illustrated inFIGS. 5-6.

At least a portion of the polycrystalline diamond table may be exposed to a processing solution (process3304). In some embodiments, for example, a superabrasive element10may be disposed in a protective leaching cup30such that the protective leaching cup surrounds substrate12and/or at least a portion of superabrasive table14. Superabrasive element10and protective leaching cup30may be disposed in a cavity76of a processing vessel70such that a processing solution72contacts at least a portion of superabrasive element10as illustrated inFIG. 9C.

An electrode may be exposed to the processing solution (process3306). For example, as shown inFIG. 9C, an electrode40may be disposed in processing vessel70such that electrode40and superabrasive element10surrounded by protective leaching cup30are at least partially submerged in processing solution72. Electrode40may be exposed to processing solution72such that processing solution72contacts at least a portion of electrode40.

A first charge may be applied to the metallic material (process3308). For example, as shown inFIG. 9C, a charge may be applied to superabrasive element10through an electrical conductor44.

A second charge may be applied to the electrode (process3310). For example, as shown inFIG. 9C, an opposite charge may be applied to electrode40through an electrical conductor42.

The following examples set forth various methods used to form superabrasive elements as disclosed herein. The following examples provide further detail in connection with the specific embodiments described above.

Cutting elements, each comprising a PCD table attached to a tungsten carbide substrate, were formed by HPHT sintering diamond particles in the presence of cobalt. The sintered-polycrystalline-diamond tables included cobalt and tungsten within the interstitial regions between the bonded diamond grains.

The PCD tables were leached using an aqueous processing solution having a molar concentration of 0.29 M citric acid. The processing solution for processing each cutting element contacted both the PCD table and a corresponding disk-shaped copper electrode disposed near the PCD table. A negative charge was applied to each electrode and a positive charge was applied to the substrate of each cutting element such that a voltage of 0.8 V was generated in the processing solution. The PCD tables were leached at a temperature of approximately 75° C. and atmospheric pressure for between 24 and 168 hours. Following leaching, leached depths of the PCD tables were determined for various portions of the PCD tables, including leached depths measured from the cutting faces, side surfaces, and chamfered cutting edges of the PCD tables, and the leached depths were averaged.

Following 24 hours of leaching, a first PCD table included a leached depth of approximately 167 μm.

Following 72 hours of leaching, a second PCD table included a leached depth of approximately 308 μm.

Following 168 hours of leaching, a third PCD table included a leached depth of approximately 611 μm.

Cutting elements, each comprising a PCD table attached to a tungsten carbide substrate, were formed by HPHT sintering diamond particles in the presence of cobalt. The sintered-polycrystalline-diamond tables included cobalt and tungsten within the interstitial regions between the bonded diamond grains.

The PCD tables were leached using an aqueous processing solution having a citrate buffer comprising a molar concentration of 0.24 M sodium citrate and 0.05 M citric acid and having a pH of 6.5. The processing solution for processing each cutting element contacted both the PCD table and a corresponding disk-shaped copper electrode disposed near the PCD table. A negative charge was applied to each electrode and a positive charge was applied to the substrate of each cutting element such that a voltage of 0.8 V was generated in the processing solution. The PCD tables were leached at a temperature of approximately 75° C. and atmospheric pressure for between 24 and 72 hours. Following leaching, leached depths of the PCD tables were determined for various portions of the PCD tables, including leached depths measured from the cutting faces, side surfaces, and chamfered cutting edges of the PCD tables, and the leached depths were averaged.

Following 24 hours of leaching, a first PCD table included a leached depth of approximately 120 μm.

Following 72 hours of leaching, a second PCD table included a leached depth of approximately 250 μm.

Cutting elements, each comprising a PCD table attached to a tungsten carbide substrate, were formed by HPHT sintering diamond particles in the presence of cobalt. The sintered-polycrystalline-diamond tables included cobalt and tungsten within the interstitial regions between the bonded diamond grains.

The PCD tables were each leached in one of a plurality of aqueous processing solutions having a molar concentration of 0.29 M citric acid and various concentrations of cobalt chloride. The processing solutions for processing each cutting element contacted both the PCD table and a corresponding disk-shaped copper electrode disposed near the PCD table. A negative charge was applied to each electrode and a positive charge was applied to the substrate of each cutting element such that a voltage of 0.8 V was generated in the processing solution. The PCD tables were leached at a temperature of approximately 75° C. and atmospheric pressure for 72 hours. Following leaching, leached depths of the PCD tables were determined for various portions of the PCD tables, including leached depths measured from the cutting faces, side surfaces, and chamfered cutting edges of the PCD tables, and the leached depths were averaged.

Following leaching in a processing solution containing no cobalt chloride, a first PCD table included a leached depth of approximately 188 μm.

Following leaching in a processing solution having a molar concentration of 0.05 M cobalt chloride, a first PCD table included a leached depth of approximately 219 μm.

Following leaching in a processing solution having a molar concentration of 0.1 M cobalt chloride, a first PCD table included a leached depth of approximately 233 μm.

The preceding description has been provided to enable others skilled in the art to best utilize various aspects of the exemplary embodiments described herein. This exemplary description is not intended to be exhaustive or to be limited to any precise form disclosed. Many modifications and variations are possible without departing from the spirit and scope of the instant disclosure. It is desired that the embodiments described herein be considered in all respects illustrative and not restrictive and that reference be made to the appended claims and their equivalents for determining the scope of the instant disclosure.