Producing polycrystalline diamond compact cutters with coatings

A polycrystalline diamond is formed on a substrate to form a polycrystalline diamond compact (PDC) cutter for a tool. The polycrystalline diamond has a cross-sectional dimension of at least 4 millimeters. The substrate includes tungsten carbide. An outer surface of the PDC cutter is at least partially surrounded with at least a single layer of coating by atomic layer deposition. The single layer of coating is configured to protect the PDC cutter from thermal degradation in response to exposure to a temperature greater than 700 degrees Celsius (° C.) and less than about 1050° C.

TECHNICAL FIELD

This disclosure relates to production of polycrystalline diamond compact (PDC) cutters and, particularly, PDC cutters with coatings for use in the oil and gas industry.

BACKGROUND

Drilling hard, abrasive, and interbedded formations poses a difficult challenge for conventional PDC drill bits. Historically, a conventional polycrystalline diamond material, generally forming a cutting layer, also called diamond table, dulls quickly due to abrasive wear, impact damage, and thermal fatigue. Thus, hardness, fracture toughness, and thermal stability of polycrystalline diamond materials represent three limiting factors for an effective PDC drill bit.

SUMMARY

Certain aspects of the subject matter described can be implemented as a method. A polycrystalline diamond layer is formed on a substrate to form a polycrystalline diamond compact (PDC) cutter for a tool. The polycrystalline diamond has a cross-sectional dimension of at least 4 millimeters. The substrate includes tungsten carbide. An outer surface of the PDC cutter is at least partially surrounded with a single layer of coating by atomic layer deposition. The single layer of coating is configured to protect the PDC cutter from thermal degradation in response to exposure to a temperature greater than 700 degrees Celsius (° C.) and less than about 1050° C.

This, and other aspects, can include one or more of the following features. Forming the polycrystalline diamond layer on the substrate can include placing a powder on the substrate by high pressure, high temperature (HPHT) hot pressing. The powder can include at least one of polycrystalline diamond powder or graphite powder. For example, the powder can include polycrystalline diamond powder, graphite powder, or both polycrystalline diamond powder and graphite powder. In some implementations, the powder has a particle size within a range of from about 0.1 micrometers (μm) to about 50 μm. Forming the polycrystalline diamond layer on the substrate can include sintering the powder into the substrate, which is a rigid substrate material, while also bonding the polycrystalline diamond layer to the rigid substrate material. In some implementations, the substrate includes a WC-Co powder having a Co content within a range of from about 1% to about 20% by weight. In some implementations, the WC-Co powder has an average particle size within a range of from about 1 nanometer (nm) to about 50 μm. At least partially surrounding the outer surface of the PDC cutter with the single layer of coating by atomic layer deposition can include depositing the single layer of coating on top of at least a portion of the outer surface of the PDC cutter by atomic layer deposition performed at a temperature in a range of from about 200° C. to about 400° C. In some implementations, the single layer of coating has a thickness in a range of from 1 nm to 100 nm. The entire outer surface of the PDC cutter can be completely encapsulated by the single layer of coating. In some implementations, the single layer of coating includes aluminum oxide (Al2O3), silicon oxide (SiO2), zirconium oxide (Zr2O), zinc oxide (ZnO), cesium oxide (CeO2), aluminum-doped ZnO, titanium nitride (TiN), zirconium nitride (ZrN), tantalum nitride (TaN), zinc sulfide (ZnS), or molybdenum sulfide (MoS2).

Certain aspects of the subject matter described can be implemented as a method. A polycrystalline diamond layer is formed on a substrate to form a polycrystalline diamond compact (PDC) cutter for a tool. The polycrystalline diamond has a cross-sectional dimension of at least 4 millimeters. The substrate includes tungsten carbide. An outer surface of the PDC cutter is at least partially surrounded with multiple layers of coating by atomic layer deposition. The multiple layers of coating are configured to protect the PDC cutter from thermal degradation in response to exposure to a temperature greater than 700 degrees Celsius (° C.) and less than about 1050° C.

This, and other aspects, can include one or more of the following features. Forming the polycrystalline diamond layer on the substrate can include placing a powder on the substrate by HPHT hot pressing. The powder can include at least one of polycrystalline diamond powder or graphite powder. For example, the powder can include polycrystalline diamond powder, graphite powder, or both polycrystalline diamond powder and graphite powder. In some implementations, the powder has a particle size within a range of from about 0.1 micrometers (μm) to about 50 μm. Forming the polycrystalline diamond layer on the substrate can include sintering the powder into the substrate, which is a rigid substrate material, while also bonding the polycrystalline diamond layer to the rigid substrate material. In some implementations, the substrate includes a WC-Co powder having a Co content within a range of from about 1% to about 20% by weight. In some implementations, the WC-Co powder has an average particle size within a range of from about 1 nanometer (nm) to about 50 μm. At least partially surrounding the outer surface of the PDC cutter with the multiple layers of coating by atomic layer deposition can include depositing the multiple layers of coating on top of at least a portion of the outer surface of the PDC cutter by atomic layer deposition performed at a temperature in a range of from about 200° C. to about 400° C. Each of the layers of coating can be deposited layer by layer via atomic layer deposition. In some implementations, the multiple layers of coating have an overall thickness in a range of from 1 nm to 100 nm. In some implementations, each layer of the multiple layers of coating has a thickness in a range of from 1 nm to 100 nm. The entire outer surface of the PDC cutter can be completely encapsulated by the multiple layers of coating. Each layer of the multiple layers of coating can include at least one of aluminum oxide (Al2O3), silicon oxide (SiO2), zirconium oxide (Zr2O), zinc oxide (ZnO), cesium oxide (CeO2), aluminum-doped ZnO, titanium nitride (TiN), zirconium nitride (ZrN), tantalum nitride (TaN), zinc sulfide (ZnS), or molybdenum sulfide (MoS2).

Certain aspects of the subject matter described can be implemented as a method. A polycrystalline diamond is affixed to a substrate to form a PDC cutter for a tool. The polycrystalline diamond has a cross-sectional dimension of at least 4 millimeters. The substrate includes tungsten carbide. An outer surface of the PDC cutter is at least partially surrounded with a single layer of coating by atomic layer deposition. The single layer of coating is configured to protect the PDC cutter from thermal degradation in response to exposure to a temperature greater than 700° C. and less than about 1050° C.

This, and other aspects, can include one or more of the following features. Affixing the polycrystalline diamond to the substrate can include placing the polycrystalline diamond in contact with a powder form of the substrate. The polycrystalline diamond can be synthesized from diamond powder with a particle size within a range of from about 0.1 μm to about 50 μm. Affixing the polycrystalline diamond to the substrate can include sintering the powder form of the substrate into a rigid material while also bonding the substrate to the polycrystalline diamond. In some implementations, the powder form of the substrate includes a WC-Co powder having a Co content within a range of from about 1% to about 20% by weight. In some implementations, the WC-Co powder has an average particle size within a range of from about 1 nm to about 50 μm. At least partially surrounding the outer surface of the PDC cutter with the single layer of coating includes depositing the single layer of coating on top of at least a portion of the outer surface of the PDC cutter by atomic layer deposition performed at a temperature in a range of from about 200° C. to about 400° C. In some implementations, the single layer of coating has a thickness in a range of from 1 nm to 100 nm. The entire outer surface of the PDC cutter can be completely encapsulated by the single layer of coating. In some implementations, the single layer of coating includes aluminum oxide (Al2O3), silicon oxide (SiO2), zirconium oxide (Zr2O), zinc oxide (ZnO), cesium oxide (CeO2), aluminum-doped ZnO, titanium nitride (TiN), zirconium nitride (ZrN), tantalum nitride (TaN), zinc sulfide (ZnS), or molybdenum sulfide (MoS2).

Certain aspects of the subject matter described can be implemented as a method. A polycrystalline diamond is affixed to a substrate to form a PDC cutter for a tool. The polycrystalline diamond has a cross-sectional dimension of at least 4 millimeters. The substrate includes tungsten carbide. An outer surface of the PDC cutter is at least partially surrounded by multiple layers of coating by atomic layer deposition. The multiple layers of coating are configured to protect the PDC cutter from thermal degradation in response to exposure to a temperature greater than 700° C. and less than about 1050° C.

This, and other aspects, can include one or more of the following features. Affixing the polycrystalline diamond to the substrate can include placing the polycrystalline diamond in contact with a powder form of the substrate. The polycrystalline diamond can be synthesized from diamond powder with a particle size within a range of from about 0.1 μm to about 50 μm. Affixing the crystalline diamond to the substrate can include sintering the powder form of the substrate into a rigid material while also bonding the substrate to the polycrystalline diamond. In some implementations, the powder form of the substrate includes a WC-Co powder having a Co content within a range of from about 1% to about 20% by weight. In some implementations, the WC-Co powder has an average particle size within a range of from about 1 nm to about 50 μm. At least partially surrounding the outer surface of the PDC cutter with the multiple layers of coating can include depositing the multiple layers of coating on top of at least a portion of the outer surface of the PDC cutter by atomic layer deposition performed at a temperature in a range of from about 200° C. to about 400° C. Each of the layers of coating can be deposited layer by layer via atomic layer deposition. In some implementations, the multiple layers of coating have an overall thickness in a range of from 1 nm to 100 nm. In some implementations, each layer of the multiple layers of coating has a thickness in a range of from 1 nm to 100 nm. The entire outer surface of the PDC cutter can be completely encapsulated by the multiple layers of coating. Each layer of the multiple layers of coating can include at least one of aluminum oxide (Al2O3), silicon oxide (SiO2), zirconium oxide (Zr2O), zinc oxide (ZnO), cesium oxide (CeO2), aluminum-doped ZnO, titanium nitride (TiN), zirconium nitride (ZrN), tantalum nitride (TaN), zinc sulfide (ZnS), or molybdenum sulfide (MoS2).

DETAILED DESCRIPTION

This present disclosure relates to the manufacture of polycrystalline diamond compact (PDC) cutters for use in, for example, oil and gas wellbore formations. The polycrystalline diamond materials are formed and coated to form coated PDC cutters. The coated PDC cutters provide superior abrasive wear, impact damage, and thermal fatigue, thereby overcoming the deficiencies of current polycrystalline diamond materials. The coatings of the present disclosure can protect the polycrystalline diamond material from physical wear and thermal degradation. As a result, the coated PDC cutters of the present disclosure provides increased tool performance, improved tool life, and improved cutting efficiency. For example, the coatings of the disclosed PDC cutters can be included in, for example, drill bits, hybrid drill bits, reamers, mill heads, electric submersible pumps, downhole bearings (such as mud motor system), and/or other downhole tools, in which enhanced physical characteristics (such as improved resistance to abrasive wear, impact damage, and thermal fatigue) are desired.

FIG.1is a perspective view of an example drill bit100used in the oil and gas industry for forming a wellbore. The drill bit100includes a plurality of PDC cutters102. The PDC cutters102operate to cut into rock to form a wellbore. In some implementations, the PDC cutters102are synthesized using a catalyst, such as a catalyst based from cobalt, nickel, a Group VIII metal (for example, iron, ruthenium, osmium, and hassium) or any of their alloys, aluminum, titanium, chromium, manganese, tantalum, nickel aluminide (Ni3Al), or boron-containing nickel aluminide. In some implementations, the PDC cutters102are synthesized free of a catalyst—that is, the PDC cutters102can be synthesized without the use of a catalyst. As previously stated, the PDC cutters102can be used in other tools without departing from the scope of the disclosure.

FIG.2is a perspective view of an example PDC cutter200. For example, one or more of the PDC cutters102of drill bit100shown inFIG.1can be implementations of the PDC cutter200shown inFIG.2. In some implementations, the PDC cutter200is disc-shaped. The PDC cutter200includes a polycrystalline diamond layer202(also referred to as a diamond table) and a substrate204. In some implementations, the polycrystalline diamond layer202has a thickness within a range of from 2 millimeters (mm) to 4 mm. In some implementations, the polycrystalline diamond layer202has a thickness greater than 4 mm or less than 2 mm. In some implementations, the substrate204is formed from a mixture of tungsten carbide (WC) and cobalt (Co). In some implementations, cobalt may form 1% to 20% by weight of the WC-Co mixture. In some implementations, the substrate204is formed from WC and Co by sintering-hot isostatic pressing (sintering-HIP), and then the polycrystalline diamond layer202is formed on top of the substrate204by high pressure, high temperature (HPHT) technology, which can include the infiltration of Co from the substrate204into the polycrystalline diamond layer202. In some implementations, the substrate204is formed from a powder during manufacturing of the PDC cutter200. In some implementations, the substrate204has a thickness within a range of from 9 mm to 11 mm. In some implementations, the substrate204has a thickness greater than 11 mm or less than 9 mm.

In the illustrated example ofFIG.2, the PDC cutter200has a circular cross-sectional shape. A cross-sectional dimension (for example, diameter) D of the PDC cutter200may vary according to a desired size of the PDC cutter200. In some implementations, the PDC cutter200has a cross-sectional dimension D within a range of from 4 mm to 48 mm. In some implementations, the cross-sectional dimension D of the PDC cutter200is greater than 48 mm or less than 4 mm. As shown inFIG.2, the PDC cutter200can have a cylindrical shape. In some implementations, a cross-sectional size of the polycrystalline diamond layer202is different from a cross-sectional size of the substrate204. In some implementations, the cross-sectional shape of the PDC cutter200may be other than circular. In some implementations, the PDC cutter200has a non-circular cross-sectional shape. For example, the PDC cutter200may be oval, square, rectangular, or have an irregular shape. The cross-sectional dimension of the PDC cutter200may be within a range of from 4 mm to 48 mm. In some implementations, the polycrystalline diamond layer202has a non-planar surface. For example, a top surface of the polycrystalline diamond layer202can be oval, chiseled, axe-bladed, or sharp-pointed.

FIG.3Ais a cross-sectional view of a fully coated PDC cutter300. One or more of the PDC cutters102of drill bit100shown inFIG.1can be implementations of the PDC cutter300shown inFIG.3A. The PDC cutter300can be, for example, an implementation of the PDC cutter200that is fully coated by a single layer of coating301. The coating301is configured to provide a layer of protection for the PDC cutter200. The coating301is configured to protect the PDC cutter200from thermal degradation in response to exposure to a temperature greater than 700 degrees Celsius (° C.) and less than about 1050° C. In some implementations, the coating301is configured to protect the PDC cutter200from thermal degradation in response to exposure to a temperature greater than 850° C. and less than about 1050° C. The coating301can be made of an oxide, a nitride, a sulfide, or another material. Some non-limiting examples of suitable oxides for the coating301include aluminum oxide (Al2O3), silicon oxide (SiO2), zirconium oxide (Zr2O), zinc oxide (ZnO), cesium oxide (CeO2), and aluminum-doped ZnO. Some non-limiting examples of suitable nitrides for the coating301include titanium nitride (TiN), zirconium nitride (ZrN), and tantalum nitride (TaN). Some non-limiting examples of suitable sulfides for the coating301include zinc sulfide (ZnS) and molybdenum sulfide (MoS2).

As shown inFIG.3A, the single layer of coating301fully encapsulates the PDC cutter200. In some implementations, the single layer of coating301has a thickness in a range of from 1 nanometer (nm) to 100 nm. In some implementations, the single layer of coating301has a thickness in a range of from 10 nm to 50 nm. In some implementations, the single layer of coating301has a thickness in a range of from 20 nm to 30 nm.

FIG.3Bis a cross-sectional view of a partially coated PDC cutter350. One or more of the PDC cutters102of drill bit100shown inFIG.1can be implementations of the PDC cutter350shown inFIG.3B. The PDC cutter350can be, for example, an implementation of the PDC cutter200that is partially coated by a single layer of coating351. The coating351is configured to provide a layer of protection for the PDC cutter200. As shown inFIG.3B, the coating351partially coats the outer surface of the PDC cutter200. In some implementations, the coating351completely covers at least the polycrystalline diamond layer202of the PDC cutter200, such that none of the outer surface of the polycrystalline diamond layer202is left exposed. The coating351is configured to protect the polycrystalline diamond layer202of the PDC cutter200from thermal degradation in response to exposure to a temperature greater than 700 degrees Celsius (° C.) and less than about 1050° C. In some implementations, the coating351is configured to protect the polycrystalline diamond layer202of the PDC cutter200from thermal degradation in response to exposure to a temperature greater than 850° C. and less than about 1050° C. The coating351can be substantially the same as the coating301. For example, the coating351can be made from the same material as the coating301. In some implementations, the single layer of coating351has a thickness in a range of from 1 nm to 100 nm. In some implementations, the single layer of coating351has a thickness in a range of from 10 nm to 50 nm. In some implementations, the single layer of coating351has a thickness in a range of from 20 nm to 30 nm.

FIG.4Ais a cross-sectional view of a fully coated PDC cutter400. One or more of the PDC cutters102of drill bit100shown inFIG.1can be implementations of the PDC cutter400shown inFIG.4A. The PDC cutter400can be, for example, an implementation of the PDC cutter200that is fully coated by multiple layers of coating401. The multiple layers of coating401are configured to provide protection for the PDC cutter200. The multiple layers of coating401are configured to protect the PDC cutter200from thermal degradation in response to exposure to a temperature greater than 700 degrees Celsius (° C.) and less than about 1050° C. In some implementations, the multiple layers of coating401are configured to protect the PDC cutter200from thermal degradation in response to exposure to a temperature greater than 850° C. and less than about 1050° C.

The multiple layers of coating401can be substantially the same as the coating301. For example, each of the layers of coating401can be made of an oxide, a nitride, a sulfide, or another material. Some non-limiting examples of suitable oxides for the multiple layers of coating401include aluminum oxide (Al2O3), silicon oxide (SiO2), zirconium oxide (Zr2O), zinc oxide (ZnO), cesium oxide (CeO2), and aluminum-doped ZnO. Some non-limiting examples of suitable nitrides for multiple layers of coating401include titanium nitride (TiN), zirconium nitride (ZrN), and tantalum nitride (TaN). Some non-limiting examples of suitable sulfides for the multiple layers of coating401include zinc sulfide (ZnS) and molybdenum sulfide (MoS2). In some implementations, every layer of the multiple layers of coating401are made of the same material. In some implementations, the multiple layers of coating401can include layers made from different materials. For example, the multiple layers of coating401can be made of alternating layers of a first material and a second material. For example, the multiple layers of coating401can be made of a combination of materials layered in a desired order.

In some implementations, the multiple layers of coating401altogether have a thickness in a range of from 1 nm to 100 nm. In some implementations, the multiple layers of coating401altogether have a thickness in a range of from 10 nm to 50 nm. In some implementations, the multiple layers of coating401altogether have a thickness in a range of from 20 nm to 30 nm. In some implementations, each of the layers of coating401separately have a thickness in a range of from 1 nm to 100 nm. In some implementations, each of the layers of coating401separately have a thickness in a range of from 10 nm to 50 nm. In some implementations, each of the layers of coating401separately have a thickness in a range of from 20 nm to 30 nm.

FIG.4Bis a cross-sectional view of a partially coated PDC cutter450. One or more of the PDC cutters102of drill bit100shown inFIG.1can be implementations of the PDC cutter450shown inFIG.4B. The PDC cutter450can be, for example, an implementation of the PDC cutter200that is partially coated by multiple layers of coating451. The multiple layers of coating451is configured to provide protection for the PDC cutter200. As shown inFIG.4B, the multiple layers of coating451partially coats the outer surface of the PDC cutter200. In some implementations, the multiple layers of coating451completely covers at least the polycrystalline diamond layer202of the PDC cutter200, such that none of the outer surface of the polycrystalline diamond layer202is left exposed. The multiple layers of coating451is configured to protect the polycrystalline diamond layer202of the PDC cutter200from thermal degradation in response to exposure to a temperature greater than 700 degrees Celsius (° C.) and less than about 1050° C. In some implementations, the multiple layers of coating451is configured to protect the polycrystalline diamond layer202of the PDC cutter200from thermal degradation in response to exposure to a temperature greater than 850° C. and less than about 1050° C.

The multiple layers of coating451can be substantially the same as the multiple layers of coating401. For example, the multiple layers of coating451can be made from the same material as the multiple layers of coating401. In some implementations, every layer of the multiple layers of coating451are made of the same material. In some implementations, the multiple layers of coating451can include layers made from different materials. For example, the multiple layers of coating451can be made of alternating layers of a first material and a second material. For example, the multiple layers of coating451can be made of a combination of materials layered in a desired order.

In some implementations, the multiple layers of coating451altogether have a thickness in a range of from 1 nm to 100 nm. In some implementations, the multiple layers of coating451altogether have a thickness in a range of from 10 nm to 50 nm. In some implementations, the multiple layers of coating451altogether have a thickness in a range of from 20 nm to 30 nm. In some implementations, each of the layers of coating451separately have a thickness in a range of from 1 nm to 100 nm. In some implementations, each of the layers of coating451separately have a thickness in a range of from 10 nm to 50 nm. In some implementations, each of the layers of coating451separately have a thickness in a range of from 20 nm to 30 nm.

FIG.5is a flow chart of a method500for forming a PDC cutter, for example, the coated PDC cutter300or partially coated PDC cutter350shown inFIG.3A or3B, respectively. At block501, a substrate (such as the substrate204) is provided. The substrate204provided at block501includes tungsten carbide.

At block503, a polycrystalline diamond layer (such as the polycrystalline diamond202) is formed on the substrate204(provided at block501) to form a PDC cutter (such as the PDC cutter200) for a tool (such as the drill bit100). The polycrystalline diamond layer202formed at block503has a cross-sectional dimension of at least 4 millimeters. In some implementations, forming the polycrystalline diamond layer202on the substrate204at block503includes placing a powder on the substrate204by HPHT hot pressing. The powder can include at least one of polycrystalline diamond powder or graphite powder. In some implementations, the powder has a particle size within a range of from about 0.1 μm to about 50 μm. In some implementations, forming the polycrystalline diamond layer202on the substrate204at block503includes sintering the powder into the substrate204, which is a rigid substrate material, while also bonding the polycrystalline diamond layer202to the rigid substrate material. In some implementations, the substrate204is pre-formed and includes a WC-Co powder having a Co content within a range of from about 1% to about 20% by weight. In some implementations, the WC-Co powder has an average particle size within a range of about 1 nm to about 50 μm.

At block505, an outer surface of the PDC cutter200is at least partially surrounded with a single layer of coating by atomic layer deposition. The coating is configured to protect the PDC cutter200from thermal degradation in response to exposure to a temperature greater than 700° C. and less than about 1050° C. In some implementations, the entire outer surface of the PDC cutter200is covered by the single layer of coating at block505(an example is the PDC cutter300shown inFIG.3A). For example, in the PDC cutter300shown inFIG.3A, the PDC cutter200is completely encapsulated by the single layer of coating301. In some implementations, only a portion of the outer surface of the PDC cutter200is covered by the single layer of coating at block505(an example is the PDC cutter350shown inFIG.3B).

The outer surface of the PDC cutter200can be at least partially surrounded with the single layer of coating by atomic layer deposition at block505by depositing the single layer of coating on top of at least a portion of the outer surface of the PDC cutter200by atomic layer deposition. The atomic layer deposition can be performed at a temperature in a range of from about 200° C. to about 400° C. Atomic layer deposition is a thin-film deposition process that includes pulsed introduction of gaseous reactants. A chemical reaction occurs on a surface and the single layer of coating is deposited uniformly across the topography of the surface. Atomic layer deposition can be implemented independent of a line of sight, such that even convoluted/complicated surfaces can be coated by the single layer of coating via atomic layer deposition. Atomic layer deposition can provide precise thickness control on the order of Angstroms to minimize inherent stress. The thickness of the coating can be controlled by adjusting the number of cycles and durations of the pulsed introduction of the gaseous reactants. Another advantage of atomic layer deposition is that the coating layer can be fully dense without defects from de-bonding or cracking. The PDC cutter200is configured to withstand the temperatures associated with atomic layer deposition (for example, temperatures in a range of from about 200° C. to about 400° C.), so there is no expected risk of thermal degradation of the PDC cutter200throughout the atomic layer deposition process.

In some implementations, the single layer of coating has a thickness in a range of from 1 nm to 100 nm, from 10 nm to 50 nm, or from 20 nm to 30 nm. In some implementations, the single layer of coating comprises aluminum oxide (Al2O3), silicon oxide (SiO2), zirconium oxide (Zr2O), zinc oxide (ZnO), cesium oxide (CeO2), aluminum-doped ZnO, titanium nitride (TiN), zirconium nitride (ZrN), tantalum nitride (TaN), zinc sulfide (ZnS), or molybdenum sulfide (MoS2).

FIG.6is a flow chart of a method600for forming a PDC cutter, for example, the coated PDC cutter400or partially coated PDC cutter450shown inFIG.4A or4B, respectively. At block601, a substrate (such as the substrate204) is provided. The substrate204provided at block601includes tungsten carbide.

At block603, a polycrystalline diamond layer (such as the polycrystalline diamond202) is formed on the substrate204(provided at block601) to form a PDC cutter (such as the PDC cutter200) for a tool (such as the drill bit100). The polycrystalline diamond layer202formed at block603has a cross-sectional dimension of at least 4 millimeters. In some implementations, forming the polycrystalline diamond layer202on the substrate204at block603includes placing a powder on the substrate204by HPHT hot pressing. The powder can include at least one of polycrystalline diamond powder or graphite powder. In some implementations, the powder has a particle size within a range of from about 0.1 μm to about 50 μm. In some implementations, forming the polycrystalline diamond layer202on the substrate204at block603includes sintering the powder into the substrate204, which is a rigid substrate material, while also bonding the polycrystalline diamond layer202to the rigid substrate material. In some implementations, the substrate204is pre-formed and includes a WC-Co powder having a Co content within a range of from about 1% to about 20% by weight. In some implementations, the WC-Co powder has an average particle size within a range of about 1 nm to about 50 μm.

At block605, an outer surface of the PDC cutter200is at least partially surrounded with multiple layers of coating by atomic layer deposition. The multiple layers of coating are configured to protect the PDC cutter200from thermal degradation in response to exposure to a temperature greater than 700° C. and less than about 1050° C. In some implementations, the entire outer surface of the PDC cutter200is covered by the multiple layers of coating at block605(an example is the PDC cutter400shown inFIG.4A). For example, in the PDC cutter400shown inFIG.4A, the PDC cutter200is completely encapsulated by the multiple layers of coating401. In some implementations, only a portion of the outer surface of the PDC cutter200is covered by the multiple layers of coating at block605(an example is the PDC cutter450shown inFIG.4B).

The outer surface of the PDC cutter200can be at least partially surrounded with the multiple layers of coating by atomic layer deposition at block605by depositing the multiple layers of coating on top of at least a portion of the outer surface of the PDC cutter200by atomic layer deposition. The atomic layer deposition can be performed at a temperature in a range of from about 200° C. to about 400° C. The PDC cutter200is configured to withstand the temperatures associated with atomic layer deposition (for example, temperatures in a range of from about 200° C. to about 400° C.), so there is no expected risk of thermal degradation of the PDC cutter200throughout the atomic layer deposition process.

In some implementations, the multiple layers of coating altogether has a thickness in a range of from 1 nm to 100 nm, from 10 nm to 50 nm, or from 20 nm to 30 nm. In some implementations, each of the layers of the coating have a thickness in a range of from 1 nm to 100 nm, from 10 nm to 50 nm, or from 20 nm to 30 nm. In some implementations, each of the layers of the coating includes aluminum oxide (Al2O3), silicon oxide (SiO2), zirconium oxide (Zr2O), zinc oxide (ZnO), cesium oxide (CeO2), aluminum-doped ZnO, titanium nitride (TiN), zirconium nitride (ZrN), tantalum nitride (TaN), zinc sulfide (ZnS), or molybdenum sulfide (MoS2). In some implementations, each of the layers of the coating are made of the same material. In some implementations, the material from which the layers of the coating are made can vary.

FIG.7is a flow chart of a method700for forming a PDC cutter, for example, the coated PDC cutter300or partially coated PDC cutter350shown inFIG.3A or3B, respectively. At block701, a polycrystalline diamond (such as the polycrystalline diamond layer202) is provided. The polycrystalline diamond202provided at block701has a cross-sectional dimension of at least 4 millimeters. In some implementations, providing the polycrystalline diamond202at block701includes synthesizing the polycrystalline diamond202from diamond powder with a particle size within a range of from about 0.1 μm to about 50 μm. At block703, a substrate (such as the substrate204) is provided. The substrate204provided at block703includes tungsten carbide.

At block705, the polycrystalline diamond202(provided at block701) is affixed to the substrate204(provided at block703) to form a PDC cutter (such as the PDC cutter200) for a tool (such as the drill bit100). In some implementations, affixing the polycrystalline diamond202to the substrate204at block705includes placing the polycrystalline diamond202in contact with a powder form of the substrate204. In some implementations, affixing the polycrystalline diamond202to the substrate204at block705includes sintering the powder form of the substrate204into a rigid material while also bonding the substrate204to the polycrystalline diamond202. In some implementations, the powder form of the substrate204includes a WC-Co powder having a Co content within a range of from about 1% to about 20% by weight. In some implementations, the WC-Co powder has an average particle size within a range of about 1 nm to about 50 μm.

At block707, an outer surface of the PDC cutter200is at least partially surrounded with a single layer of coating. The coating is configured to protect the PDC cutter200from thermal degradation in response to exposure to a temperature greater than 700° C. and less than about 1050° C. In some implementations, the entire outer surface of the PDC cutter200is covered by the single layer of coating at block707(an example is the PDC cutter300shown inFIG.3A). For example, in the PDC cutter300shown inFIG.3A, the PDC cutter200is completely encapsulated by the single layer of coating301. In some implementations, only a portion of the outer surface of the PDC cutter200is covered by the single layer of coating at block707(an example is the PDC cutter350shown inFIG.3B).

The outer surface of the PDC cutter200can be at least partially surrounded with the single layer of coating at block707by depositing the single layer of coating on top of at least a portion of the outer surface of the PDC cutter200by atomic layer deposition. The atomic layer deposition can be performed at a temperature in a range of from about 200° C. to about 400° C. The PDC cutter200is configured to withstand the temperatures associated with atomic layer deposition (for example, temperatures in a range of from about 200° C. to about 400° C.), so there is no expected risk of thermal degradation of the PDC cutter200throughout the atomic layer deposition process.

In some implementations, the single layer of coating has a thickness in a range of from 1 nm to 100 nm, from 10 nm to 50 nm, or from 20 nm to 30 nm. In some implementations, the single layer of coating comprises aluminum oxide (Al2O3), silicon oxide (SiO2), zirconium oxide (Zr2O), zinc oxide (ZnO), cesium oxide (CeO2), aluminum-doped ZnO, titanium nitride (TiN), zirconium nitride (ZrN), tantalum nitride (TaN), zinc sulfide (ZnS), or molybdenum sulfide (MoS2).

FIG.8is a flow chart of a method800for forming a PDC cutter, for example, the coated PDC cutter400or partially coated PDC cutter450shown inFIG.4A or4B, respectively. At block801, a polycrystalline diamond (such as the polycrystalline diamond layer202) is provided. The polycrystalline diamond202provided at block801has a cross-sectional dimension of at least 4 millimeters. In some implementations, providing the polycrystalline diamond202at block801includes synthesizing the polycrystalline diamond202from diamond powder with a particle size within a range of from about 0.1 μm to about 50 μm. At block803, a substrate (such as the substrate204) is provided. The substrate204provided at block803includes tungsten carbide.

At block805, the polycrystalline diamond202(provided at block801) is affixed to the substrate204(provided at block803) to form a PDC cutter (such as the PDC cutter200) for a tool (such as the drill bit100). In some implementations, affixing the polycrystalline diamond202to the substrate204at block805includes placing the polycrystalline diamond202in contact with a powder form of the substrate204. In some implementations, affixing the polycrystalline diamond202to the substrate204at block805includes sintering the powder form of the substrate204into a rigid material while also bonding the substrate204to the polycrystalline diamond202. In some implementations, the powder form of the substrate204includes a WC-Co powder having a Co content within a range of from about 1% to about 20% by weight. In some implementations, the WC-Co powder has an average particle size within a range of about 1 nm to about 50 μm.

At block807, an outer surface of the PDC cutter200is at least partially surrounded with multiple layers of coating. The multiple layers of coating are configured to protect the PDC cutter200from thermal degradation in response to exposure to a temperature greater than 700° C. and less than about 1050° C. In some implementations, the entire outer surface of the PDC cutter200is covered by the multiple layers of coating at block807(an example is the PDC cutter400shown inFIG.4A). For example, in the PDC cutter400shown inFIG.4A, the PDC cutter200is completely encapsulated by the multiple layers of coating401. In some implementations, only a portion of the outer surface of the PDC cutter200is covered by the multiple layers of coating at block807(an example is the PDC cutter450shown inFIG.4B).

The outer surface of the PDC cutter200can be at least partially surrounded with the multiple layers of coating at block807by depositing the multiple layers of coating on top of at least a portion of the outer surface of the PDC cutter200by atomic layer deposition. The atomic layer deposition can be performed at a temperature in a range of from about 200° C. to about 400° C. The PDC cutter200is configured to withstand the temperatures associated with atomic layer deposition (for example, temperatures in a range of from about 200° C. to about 400° C.), so there is no expected risk of thermal degradation of the PDC cutter200throughout the atomic layer deposition process.

In some implementations, the multiple layers of coating altogether has a thickness in a range of from 1 nm to 100 nm, from 10 nm to 50 nm, or from 20 nm to 30 nm. In some implementations, each of the layers of the coating have a thickness in a range of from 1 nm to 100 nm, from 10 nm to 50 nm, or from 20 nm to 30 nm. In some implementations, each of the layers of the coating includes aluminum oxide (Al2O3), silicon oxide (SiO2), zirconium oxide (Zr2O), zinc oxide (ZnO), cesium oxide (CeO2), aluminum-doped ZnO, titanium nitride (TiN), zirconium nitride (ZrN), tantalum nitride (TaN), zinc sulfide (ZnS), or molybdenum sulfide (MoS2). In some implementations, each of the layers of the coating are made of the same material. In some implementations, the material from which the layers of the coating are made can vary.

The PDC cutters102can be formed from a polycrystalline diamond material formed using HPHT technology or ultra-high pressure, high temperature (UHPHT) technology. UHPHT technology can involve forming the polycrystalline diamond material using compressive pressures within a range of 10 gigapascals (GPa) to 35 GPa and temperatures within a range of 2000 Kelvin (K) to 3000 K. The UHPHT methods cause the diamond powder to form a polycrystalline form. The UHPHT systems and methods described in the present disclosure can exclude the use of a catalyst to promote sintering and the formation of polycrystalline diamond. The polycrystalline diamond material formed using traditional methods are formed at lower pressures and require the use of a catalyst, such as cobalt, to promote sintering and the formation of the polycrystalline diamond. However, during drilling, the catalyst heats and expands, damaging bonding between the polycrystalline diamond and the underlying substrate, causing separation of the polycrystalline diamond individual grains within the diamond table and as well the interface from the substrate and, hence, the drilling bit. As a result, drilling performance is dramatically reduced.

The higher pressures associated with the UHPHT systems and methods of the present disclosure can promote sintering of the diamond particles to form polycrystalline diamond without the use of a catalyst. As a consequence, the polycrystalline diamond material and associated PDC drill bits of the present disclosure do not suffer from the problems experienced by current drill bits containing polycrystalline diamond as a result of the use of a catalyst.

Current PDC cutters range in size between 4 mm and 22 mm. For drilling applications, the minimum diameter of the ultra-strong PDC cutting material should be 4 mm. To form cutters, the synthesized UHPHT polycrystalline diamond material is joined to a substrate, such as a substrate formed from WC-Co. Various forming methods, including vacuum diffusion bonding, hot pressing, spark plasma sintering, microwave joining, or HPHT bonding technology may be used to joining the UHPHT polycrystalline diamond material to the substrate.

Conventionally, the substrate is pre-pressed and diamond is in powder form prior to forming PDC cutter by traditional technologies. In some of the approaches described below, the substrate is in the form of a powder when placed in contact with the polycrystalline diamond material. The pressures and temperatures experienced during the joining method can sinter the substrate material into a rigid material while also bonding the substrate to the UHPHT polycrystalline diamond material to form a PDC cutter, similar to the PDC cutter102shown inFIGS.1and2. In some implementations, a starting material of the substrate may be a WC-Co powder having a Co content within a range of one percent to 20 percent by weight. The WC-Co powder may have a particle size within a range of from about 0.1 micrometers (μm) to about 50 μm.

As mentioned above, cutters can be formed with a HPHT (conventional pressures ranging 5-7 GPa) bonding/joining technology using WC/Co powder while bonding to UHPHT catalyst-free polycrystalline diamond cutting materials or disks. Current UHPHT technology can also be applied to join polycrystalline diamond to the substrate in the form of a powder. For other proposed methods such as SPS and HP, we may use solid or pre-pressed WC substrate may be used instead of WC/Co powder to join or bond to the polycrystalline diamond materials. Besides HPHT and UHPHT joining methods, SPS methods may use the substrate in the form of a power due to using mold and its applying pressures higher to 1 GPa.

For vacuum bonding, the polycrystalline diamond material and substrate material are placed under a vacuum within a range of 10−2Torr to 10−6Torr, and exposed to bonding temperatures are within a range of 600° C. to 1200° C. Vacuum joining or brazing takes advantage of the “absence of air” in a hot zone environment where braze filler metals can be melted in a non-contaminating environment. In contrast to typical vacuum joining techniques, this approach includes a pressure is applied to the polycrystalline diamond material and substrate material. The applied pressure is in a range of 10 MPa to 1 GPa. These pressures overcome conventional low-vacuum joining bonding strength issues. A filler metal, such as niobium (Nb), molybdenum (Mo), titanium (Ti), or tungsten (W) may be included at an interface between the polycrystalline diamond material and the substrate material in order to promote bonding and to reduce joining temperatures.

In some implementations, a hot pressing system includes a chamber into which a polycrystalline diamond material and a substrate material can be placed between pistons. The polycrystalline diamond material and the substrate material can be stacked and define an interface. In some implementations, the pistons are formed of graphite. In some implementations, the substrate material may be in powdered form when introduced into the chamber. In some implementations, the substrate material may be in a compressed form (i.e., already formed into a unitary solid) when introduced into the chamber. The pistons apply a load to the polycrystalline material and substrate material in order to bond the two components together and form a PDC cutter (such as the PDC cutter100). A filler metal, such as niobium (Nb), molybdenum (Mo), titanium (Ti), or tungsten (W) may be included at the interface between the PCD material and the substrate material in order to promote bonding and to reduce joining temperatures.

In operation, the chamber can be placed under a vacuum with a range of 10−2Torr to 10−4Torr, and the chamber can be heated to a temperature within a range of 600° C. to 1200° C. Additionally, an inert gas, such as argon (Ar), is introduced into the chamber to prevent atmospheric contamination, such as from O2or N2, as described earlier. In some implementations, loading applied by the pistons may produce compressive pressures in the range of 10 MPa to 2 GPa.

Conventional hot pressing technologies are capable of generating a maximum compressive pressure of approximately 100 MPa. However, the present disclosure provides for pressures beyond 100 MPa, including pressures up to 2 GPa, with the use of pistons formed from diamond or boron nitride (BN). The hot pressing is carried out under vacuum or inert atmosphere to prevent diamond oxidation and graphitization. It can also apply a pressure to the NPI interface to form better bonding strength.

Spark plasma sintering may also be used to join the polycrystalline diamond material, formed via a UHPHT process, to a substrate. Spark plasma sintering, also known as field assisted sintering or pulsed electric current sintering, involves a pulsed or un-pulsed DC or AC current passed directly through a graphite die or piston used to compress the polycrystalline diamond material and substrate material together. In some instances where the substrate is initially in the form of a powder, the piston is also used to compact the powder. In some implementations, the substrate may be compacted prior to spark plasma sintering. Joule heating (also known as resistive heating) is used to heat the polycrystalline diamond material and substrate material. The pressure applied by the piston and increased temperature achieves a near theoretical density of the substrate at lower sintering temperatures compared to conventional sintering techniques. The heat generated is internal to the polycrystalline diamond and substrate, in contrast to conventional hot pressing, where heat is provided by an external heater. The internal heating can provide higher heating and cooling rates are possible with other sintering methods. As a consequence, sintering occurs more rapidly compared to other sintering methods.

In a trial operation, the polycrystalline diamond material and substrate material were heated to a temperature within a range of 600° C. to 1200° C. within at atmospheric pressure within a range of 10−2Torr to 10−6Torr. Temperature was increased by passing a pulsed or direct electric current of 1000 amps (A) to 2000 A through the PCD material and substrate material. The current may be applied using a voltage of approximately 10 volts (V). In some implementations, the polycrystalline diamond material and substrate material are heated in a stepwise fashion from ambient room temperature to a desired joining temperature. The low pressure atmosphere may be generated by application of a vacuum to a compartment containing the polycrystalline diamond material and substrate material.

The polycrystalline diamond material and substrate material may be heated at a rate of approximately 1000 K per minute. Heating at this rate reduces stress concentrations. Heating rates of between 10K per minute to 1000K per minute in the low pressure atmosphere described earlier are anticipated to provide the reduced stress concentrations. The rate at which the polycrystallind diamond material and substrate material are cooled may also be approximately 1000 K per minute. These heating and cooling rates reduce stress concentrations and increase bonding strength. Besides inert or vacuum atmosphere, SPS has faster heating rates than other methods to effectively avoid diamond degradation at high bonding temperatures.

Microwave joining may be used to join the polycrystalline diamond material formed via a UHPHT process to a substrate, whether initially in the form of a powder or a compacted material. Microwave energy is applied to the stacked polycrystalline diamond material and substrate material to heat these materials so as to bond the materials and form the PDC cutter100for oil and gas drilling. In some implementations, microwave energy is applied to the polycrystalline diamond material and substrate material for 10 minutes, causing the polycrystalline diamond material and substrate material to reach 1200° C. Heating rates within a range of approximately 400° C. per minute to approximately 1000° C. per minute may be used to reduce the stress concentrations at an interface between the polycrystalline diamond material and substrate material as well as to enhance a bond strength between these materials. Microwaves can heat the materials internally, thus greatly shortening the bonding processing time at high temperature to prevent diamond degradation such as oxidization and graphitization.

HPHT sintering technology may also be used to join a polycrystalline diamond formed using a UHPHT process to a substrate material. In some implementations, a binder is included at an interface between the polycrystalline diamond material and the substrate material. In some implementations, the substrate may be in the form of a powder or in a compacted form. A pressure imparted to the polycrystalline diamond material and substrate material pressure includes pressures up to 8 GPa, and temperature applied may be within a range of approximately 1200° C. to approximately 1500° C. Where the substrate material is a powdered form of WC-Co, sintering temperatures can be reduced to approximately 1450° C.

As used in this disclosure, the term “about” or “approximately” can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range.

Values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a range of “0.1% to about 5%” or “0.1% to 5%” should be interpreted to include about 0.1% to about 5%, as well as the individual values (for example, 1%, 2%, 3%, and 4%) and the sub-ranges (for example, 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. The statement “X to Y” has the same meaning as “about X to about Y,” unless indicated otherwise. Likewise, the statement “X, Y, or Z” has the same meaning as “about X, about Y, or about Z,” unless indicated otherwise.

Moreover, the separation or integration of various system modules and components in the previously described implementations should not be understood as requiring such separation or integration in all implementations, and it should be understood that the described components and systems can generally be integrated together or packaged into multiple products.