Patent Description:
Abrasive articles used in machining applications typically include bonded abrasive articles and coated abrasive articles. A bonded abrasive article generally has a bond matrix containing abrasive particles. Bonded abrasive articles can be mounted onto a suitable machining apparatus and used in various applications, such as shaping, grinding, polishing, and cutting. The industry continues to demand improved abrasive tools to meet needs of gear grinding.

From <CIT> there is known an abrasive article comprising a bonded abrasive body comprising a bond material comprising an inorganic material and abrasive particles contained within the bonded abrasive body.

The following is generally directed to bonded abrasive articles suitable for use in material removal operations. The bonded abrasive articles can be used in various applications, including for example, surface grinding, precision grinding operations (e.g., gear grinding operations), and the like. In one particular aspect, the abrasive article may include a bonded abrasive having a high degree amount of porosity.

Reference herein to bonded abrasive articles includes reference to a three dimensional volume of an abrasive material having abrasive particles contained within a volume of a bond material. Bonded abrasive articles can be distinct from coated abrasive articles that may utilize a single layer of abrasive particles contained in a layer of bond or adhesive material. Moreover, the bonded abrasive articles of embodiments herein may include some porosity within the three-dimensional volume of the body.

<FIG> includes a flowchart for forming an abrasive article in accordance with an embodiment. As illustrated the process for forming the abrasive article can begin at step <NUM> by forming a mixture. The mixture can be a slurry including a plurality of components homogeneously mixed in therein. In accordance with an embodiment, the process of forming the mixture can include providing a carrier material. A carrier material may be a liquid suitable for containing solid components therein. For example, in one particular embodiment, the carrier can include water, more particularly, may consist essentially of water such as deionized water.

The process of forming the mixture includes adding a foaming agent to the carrier. A foaming agent may be a material that is a reactant for a foaming reaction that creates bubbles that facilitate the formation of an abrasive article having a high porosity content. In accordance with an embodiment, the foaming agent can include a liquid, gas, or solid material. In one embodiment, the foaming can include an inorganic material or organic material. In one particular embodiment, the foaming agent can include at least one of <NUM>,<NUM>,<NUM>,<NUM>,<NUM> - pentafluoropropane 141b - <NUM>,<NUM>-Dichloro-<NUM>-fluoroethane (e.g., <NUM> fa Ennovate 141b), dicyclohexylcarbodiimide, sodium N-lauroylsarcosinate (e.g., Perlastan L30), hydrogen peroxide, sodium or potassium salts of long chain carboxylic acids, sodium stearate, disodium laureth sulfosuccinate, sodium sarcosinate or any combination thereof. According to one particular embodiment, the foaming agent is preferably hydrogen peroxide.

In accordance with one embodiment, the foaming agent may be added in a particular content. For example, mixture may include at least <NUM> wt% of the foaming agent for a total weight of the mixture, such as at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt%. Still, in one non-limiting embodiment, the mixture may include not greater than <NUM> wt% of the foaming agent for a total weight of the mixture, such as not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt%. The mixture may include a content of the foaming agent in an amount within a range including any of the minimum and maximum percentages noted above.

The addition of the foaming agent to the mixture may be completed at various times, including for example, prior to the addition of any dry components. In one particular embodiment, the foaming agent may be added first to the mixture, prior to the addition of any other components. The foaming agent may be a reactant to a foaming process that facilitates the formation of bubbles formed in the mixture or gel and further facilitates the formation of porosity in the final-formed abrasive article. One or more foaming processes can be used in combination with the foaming agent to facilitate a foaming process.

The process of forming the mixture further includes adding a bond precursor material to the carrier. A bond precursor material may be a material that becomes the bond material of the final- formed abrasive article. In accordance with an embodiment, the bond precursor material can include a powder material configured to form the bond material of the final-formed abrasive article. In one embodiment, the bond precursor material can include an inorganic material, such as, but not limited to, metals, metal alloys, ceramics, vitreous materials or frit materials, or any combination thereof. The bond precursor material may include inorganic material in an amorphous phase, polycrystalline phase, monocrystalline phase, or any combination thereof.

In accordance with one embodiment, the bond precursor material may be added in a particular content. For example, mixture may include at least <NUM> wt% of the precursor bond material for a total weight of the mixture, such as at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt%. Still, in one non-limiting embodiment, the mixture may include not greater than <NUM> wt% of the precursor bond material for a total weight of the mixture, such as not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt%. The mixture may include a content of the bond precursor material in an amount within a range including any of the minimum and maximum percentages noted above.

In accordance with another embodiment, the process of forming mixture includes adding a gelling agent to the mixture. The addition of the gelling agent to the mixture may be completed at various times, including for example, prior to the addition of any dry components. The gelling agent may be a material that facilitates changing the mixture into a gel. A gelling agent may be used in combination with gelling processes, including for example, the addition of heat, to facilitate the gelation process.

In accordance with an embodiment the gelling agent may be an organic material, such as a gum. For example, the gelling agent may be selected from the group consisting of agar, agarose, xanthan gum, carboxy methyl cellulose, gellan gum, carrageenan gum, guar gum, tara gum, cellulose gum, locust bean gum, or any combination thereof. According to one particular embodiment, the gelling agent may be preferably a gellan gum.

For certain embodiments, the mixture may include a certain content of the gelling agent to facilitate the formation of an improved abrasive article. For example, the mixture may include at least <NUM> wt% of the gelling agent for a total weight of the mixture, such as at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt%. In one non-limiting examples, the mixture may include not greater than <NUM> wt% of the gelling agent for a total weight of the mixture, such as not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt%. The mixture may include a content of the gelling agent in an amount within a range including any of the minimum and maximum percentages noted above.

The mixture may further include abrasive particles configured to form the abrasive component of the final- formed abrasive article. The abrasive particles may be added to the mixture at various times, including for example, after the addition of the bond precursor material to the mixture. Still, it will be appreciated, in other embodiments, the abrasive particles may be added in combination with one or more of the other components in the mixture, including for example, but not limited to the gelling agent, the bond precursor material, or one or more additives. The abrasive particles may include a material such as from the group consisting of oxides, borides, nitrides, carbides, oxynitrides, oxycarbides, amorphous, monocrystalline, polycrystalline, superabrasive or any combination thereof. In one particular embodiment, the abrasive particles can include alumina, and may consist essentially of alumina.

The mixture may include a certain content of abrasive particles to facilitate suitable manufacturing and/or improved performance of the abrasive article. For example, in one embodiment, the mixture may include at least <NUM> wt% of the abrasive particles for a total weight of the mixture, such as at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt%. In another non-limiting embodiment, the mixture may include not greater than <NUM> wt% of the abrasive particles for a total weight of the mixture, such as not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt%, such as not greater than <NUM> wt%. The mixture may include a content of the abrasive particles in an amount within a range including any of the minimum and maximum percentages noted above.

The mixture may further include one or more additives which may facilitate improved manufacturing and/or performance of the abrasive article. Some exemplary additives may include, but not limited to, dispersants, surfactants, cationic agents, foaming catalyst or any combination thereof. As used herein, a dispersant may prevent flocculation of the mixture by electrostatic or steric repulsion. As used herein, a surfactant may lower the surface tension between two liquids, a solid and liquid or a gas and liquid. As used herein a cationic agent may be an ionic compound (e.g., a salt) that cross-links with the gelling agent, which may be an anionic material. As used herein, a foaming catalyst may be any chemical that is configured to facilitate the decomposition of the foaming agent (e.g., hydrogen peroxide).

The one or more additives may be added to the mixture at various times, including for example, after the addition of the solid components to the mixture, including for example, the bond precursor material and the abrasive particles. Still, it will be appreciated, in other embodiments, the one or more additives may be added in combination with one or more of the other components in the mixture, including for example, but not limited to the foaming agent, the gelling agent, the bond precursor material, or one or more additives. The order the additives are added may also be significant to facilitate suitable formation of the abrasive article. For example, in at least one embodiment, the cationic agent may be added after at least one of the other additives. For certain processes, the cationic agent may be added after the addition of the of the dispersant and/or surfactant. In other instances, the foaming catalyst may be added after the addition of at least one of the additives, such as the dispersant, surfactant and/or cationic agent. In at least one embodiment, the foaming catalyst may be the final component added to the mixture.

Suitable examples of a foaming catalyst can include an inorganic material, such as a solid inorganic material. For example, the foaming catalyst can include an oxide or iodide composition. In one particular embodiment, the foaming catalyst can be potassium iodide, iron oxide, magnesium oxide, copper oxide, or any combination thereof. In certain instances, the foaming catalyst can consist of potassium iodide.

The mixture may include a particular content of foaming catalyst to facilitate improved manufacturing and/or performance of the abrasive article. For example, the mixture can include at least <NUM> wt% of the foaming catalysts for a total weight of the mixture, such as at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt%. In another non-limiting embodiment, the mixture may include not greater than <NUM> wt% of the foaming catalysts for a total weight of the mixture, such as not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt%. The mixture may include a content of the foaming catalysts in an amount within a range including any of the minimum and maximum percentages noted above.

The dispersant can include at least one of sodium polyacrylate (e.g., Darvan <NUM>), copolymer with pigment affinic group (e.g., BYK192), ammonium polymeta acrylate (e.g., Darvan C-N), ammonium polyacrylate (e.g., Darvan 821A), polyacrylic acid, ammonium salt in an acrylic polymer in water (e.g., Dispex), citric acid, sodium dodecylbenzenesulfonate, cetyltrimethyl ammonium bromide or any combination thereof.

The mixture may include a particular content of dispersant to facilitate improved manufacturing and/or performance of the abrasive article. For example, the mixture can include at least <NUM> wt% of the dispersant for a total weight of the mixture, such as at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt%. In another non-limiting embodiment, the mixture may include not greater than <NUM> wt% of the dispersant for a total weight of the mixture, such as not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt%. The mixture may include a content of the dispersant in an amount within a range including any of the minimum and maximum percentages noted above.

Suitable examples of surfactants can include inorganic materials, organic materials or a combination thereof. A suitable surfactant may include a sulfate, a sarconsinate, a laurate, a stearate, lecithin, and the like. In one particular embodiment, the surfactant can include sodium lauroyl sarcosinate, sodium laurel sulfate, sodium laurate, sodium stearate, sodium alkyl sulfate, sodium dodecyl sulfate, sorbitan, polyethylene glycol, polysorbate, glycerol monosterate, egg lecithin or any combination thereof.

The mixture may include a particular content of surfactant that may facilitate improved manufacturing and/or performance of the abrasive article. For example, the mixture can include at least <NUM> wt% of the surfactant for a total weight of the mixture, such as at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt%. In another non-limiting embodiment, the mixture may include not greater than <NUM> wt% of the surfactant for a total weight of the mixture, such as not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt%. The mixture may include a content of the surfactant in an amount within a range including any of the minimum and maximum percentages noted above.

Some suitable examples of cationic agents can include inorganic compounds, particularly salts, such as sulfates, chlorides, chromates, nitrates, carbonates (e.g., bicarbonates), hydrates, and the like. In particular instances, the cationic agent may include a compound including an alkali element, alkali earth element, transition metal element, hydrogen, or a combination thereof. More particularly, the cationic agent may include a compound including sodium, potassium, lithium, ammonium, copper, magnesium, iron, calcium, or any combination thereof. In one particular embodiment, the cationic agent is preferably calcium chloride or sodium chloride. For example, the cationic agent may consist of calcium chloride or sodium chloride.

The cationic agent may be added to the mixture at various times, including for example, after the addition of the solid components (e.g., abrasive particles, one or more fillers, bond precursor mixture) to the mixture. In one particular embodiment, the cationic agent may be the last component added to the slurry prior to gelation. Still, it will be appreciated, in other embodiments, the cationic agent may be added in combination with one or more of the other components in the mixture, including for example, but not limited to the gelling agent, the bond precursor material, abrasive particles or one or more additives.

The mixture may include a particular content of cationic agent that may facilitate improved manufacturing and/or performance of the abrasive article. For example, the mixture can include at least <NUM> wt% of the cationic agent for a total weight of the mixture, such as at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt% or at least <NUM> wt%. In another non-limiting embodiment, the mixture may include not greater than <NUM> wt% of the cationic agent for a total weight of the mixture, such as not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt% or not greater than <NUM> wt%. The mixture may include a content of the cationic agent in an amount within a range including any of the minimum and maximum percentages noted above.

The method of forming mixture may include continuous mixing while the one or more components are added. In particular, mixing may continue throughout the process of adding the components. In certain instances, the components may be added in a particular order, for example the gelling agent may be added first, followed by the addition of the bond precursor material and abrasive particles. One or more of the additives such as the dispersant, surfactant and cationic age may be added before or after the addition of the precursor bond material and/or abrasive particles. In a particular embodiment, the cationic agent can be added prior to the addition of a foaming catalyst. According to one embodiment, the foaming catalyst can be added to the mixture after adding the foaming agent, wherein the foaming catalyst interacts with the foaming agent to create bubbles in the mixture or gel. In certain instances, the foaming agent can be added to the mixture prior to the addition of a gelling agent and the foaming catalyst can be added to the mixture after the addition of the gelling agent.

In at least one embodiment, the method of making the abrasive article includes changing the mixture to a gel. The gelling of the mixture can be facilitated by the addition of one or more of the components, including for example, the gelling agent and/or one or more additives. In accordance with one particular embodiment, the process of forming mixture into a gel can include forming a mixture first including the gel and the carrier, such as water. After forming the mixture including the gel and water, the process may continue by adding at least one of a bond precursor material, abrasive particles, and one or more additives, or any combination thereof. After adding the bond precursor material, abrasive particles, and/or one or more additives to the mixture, the process can continue by adding the cationic agent to the mixture. In particular instances, the cationic agent may be added in the final step of forming the mixture prior to forming the mixture into a gel.

In particular, the process of forming the gel can include heating the mixture to a gelling temperature. More particularly, the mixture can be mixed while heating the mixture to the gelling temperature. In at least one embodiment, the gelling temperature can be at least <NUM>, such as at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM>. Still, in one non-limiting embodiment, the gelling temperature may be not greater than <NUM>, such as not greater than <NUM> or not greater than <NUM> or not greater than <NUM>. It will be appreciated that the gelling temperature can be within a range including any of the minimum and maximum temperatures noted above.

The process for forming the mixture into the bonded abrasive body can further include a foaming process. The foaming process includes a reaction in the mixture or gel to create bubbles that are entrained in the mixture or gel that are later removed to leave porosity formed in the green body and the final-formed abrasive article. More specifically, the foaming catalyst can be added to the mixture or gel to react with the foaming agent, which may cause decomposition of the foaming agent to release oxygen that form bubbles in the mixture or gel. The foaming process can be conducted on the mixture or on the gel. In a particular embodiment, the foaming process can be completed prior to the gelling process. In another embodiment, the foaming process can be completed after the gelling process and the mixture is changed into a gel. In still another embodiment, the foaming process can be conducted simultaneously with the gelling process. Furthermore, in at least one embodiment, mixing is conducted throughout.

After forming the gel, which may also be referred to herein as a foamed gel, the process can continue by forming a green body from the gel. In accordance with an embodiment, the process of forming the green body can include at least one process from the group of pressing, molding, casting, drying, freezing, cooling or any combination thereof. In one particular embodiment, the process of forming the green body can include casting. Casting can be completed by pouring the gel into a production tool or cast of a suitable shape and size. During the process of forming the green body, some of the gel may still be forming. That is, gelation need not necessarily be completed during the forming of the green body. Still, in certain instances it may be desirable that the mixture is entirely gelled prior to the process of forming the green body. As used herein, reference to a gel includes a solid self-supporting structure that includes water contained in an integrated network defined by the solid particles in the gel. The gel may have a particular yield stress, such that it is self-supportive. For example, the gel can have a yield stress of at least <NUM> Pa, such as at least <NUM> Pa or at least <NUM> Pa.

After the green body has been formed, further processes may be conducted on the green body to change or convert the green body into a bonded abrasive body. After completing step <NUM>, the process may continue at step <NUM> by forming a bonded abrasive body having a certain Solid Phase Variation. For example, one or more processes for converting the green body into the final-formed bonded abrasive body can include drying, sintering, cooling, pressing, vitrifying, or any combination thereof. In one particular embodiment, the process can include casting, cooling, drying and firing. In the context of a vitrified bond material, the firing conditions can be suitable for forming a vitreous bond material. For example, the firing temperature can be at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM>. Still, in one embodiment, the firing temperature can be not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM>.

The final-formed abrasive article may be a bonded abrasive body defining an interconnected network of bond material that contains abrasive particles in the three-dimensional volume (i.e., matrix) of the bond material. Furthermore, the bonded abrasive body may have an amount of porosity distributed throughout the body and defining a phase that is distinct from the phases of the bond material and abrasive particles.

Bonded abrasive bodies formed by the processes of the embodiments herein may have particular features. For example, the bonded abrasive bodies may have relatively high degree of porosity and a high degree of uniformity of the structure throughout the body, which has not previously been achieved in the industry of bonded abrasives. In particular, the bonded abrasive article of an embodiment herein can be a foamed bonded abrasive body. In another aspect, the bonded abrasive body may be essentially free of a pore former or residual pore-forming material.

<FIG> includes a perspective view image of a bonded abrasive body in accordance with an embodiment. The abrasive article <NUM> can include a bonded abrasive body <NUM>. The bonded abrasive body <NUM> can include an arbor hole <NUM> configured to engage with a spindle of a grinding machine for rotation of the abrasive article <NUM> relative to a workpiece. As further illustrated in <FIG>, the bonded abrasive body includes an axial axis <NUM> defining an axial direction and a lateral axis <NUM> defining an axis in a radial direction. The axial axis <NUM> extends in the vertical direction as defined by a thickness (t) of the bonded abrasive body <NUM>. The lateral axis <NUM> extends in a radial direction defined by the diameter (D) of the bonded abrasive body <NUM>.

According to one embodiment, the bonded abrasive body <NUM> may have a diameter (D) of at least <NUM>, such as at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM>. Still, in one non-limiting embodiment, the bonded abrasive body may have a diameter (D) of not greater than <NUM>, such as not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM>. It will be appreciated that the diameter (D) can be within a range including any of the minimum and maximum values noted above. Reference herein to a diameter may be an average diameter of the bonded abrasive body, which is averaged from multiple measurements.

In another embodiment, the bonded abrasive body <NUM> may have a particular volume depending upon the application. For example, the volume of the bonded abrasive body <NUM> can be at least <NUM><NUM>. In other instances, the volume of the bonded abrasive body <NUM> can be at least <NUM><NUM> or at least <NUM><NUM> or at least <NUM><NUM> or at least <NUM><NUM> or at least <NUM><NUM> or at least <NUM><NUM>. Still, in another non-limiting embodiment, the body may have a volume of not greater than <NUM><NUM> or not greater than <NUM><NUM> or not greater than <NUM><NUM> or not greater than <NUM><NUM> or not greater than <NUM><NUM> or not greater than <NUM><NUM>. It will be appreciated that the volume of the bonded abrasive body can be within a range including any of the minimum and maximum values noted above, such as a volume of at least <NUM><NUM> to not greater than <NUM><NUM>.

In still another embodiment, the bonded abrasive body <NUM> may have a particular thickness (t) configured for use in certain applications. For example, the bonded abrasive body <NUM> can have a thickness the body comprises a thickness of at least <NUM>, such as at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM>. Still, in another embodiment, the thickness (t) of the bonded abrasive body <NUM> can be not greater than <NUM>, such as not greater than <NUM> or at least <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM>. It will be appreciated that the thickness (t) of the bonded abrasive body <NUM> can be within a range including any of the minimum and maximum values noted above, such as a volume of at least <NUM> to not greater than <NUM>. Reference herein to a thickness may be an average thickness of the bonded abrasive body, which is averaged from multiple measurements.

The bonded abrasive body <NUM> may have a particular aspect ratio (D:t) of at least <NUM>:<NUM>, such as at least <NUM>:<NUM> or at least <NUM>:<NUM> or at least <NUM>:<NUM> or at least <NUM>:<NUM>, such as at least <NUM>:<NUM> or at least <NUM>:<NUM> or at least <NUM>:<NUM> or at least <NUM>:<NUM> or at least <NUM>:<NUM> or at least <NUM>:<NUM> or at least <NUM>:<NUM> or at least <NUM>:<NUM> or at least <NUM>:<NUM> or at least <NUM>:<NUM>. Still, in another non-limiting embodiment, the aspect ratio (D:t) may be not greater than <NUM>,<NUM>:<NUM> or not greater than <NUM>,<NUM>:<NUM> or not greater than <NUM>:<NUM> or not greater than <NUM>:<NUM> or not greater than <NUM>:<NUM> or not greater than <NUM>:<NUM> or not greater than <NUM>:<NUM>. It will be appreciated that the aspect ratio can be within a range including any of the minimum to maximum ratios noted above.

The bonded abrasive body <NUM> may include abrasive particles having an average particle size (D50) of at least <NUM> microns, such as at least <NUM> micron or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns. In another embodiment, the abrasive particles may have an average particle size (D50) of not greater than <NUM> microns, such as not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns. The abrasive particles may have an average particle size (D50) within a range including any of the minimum and maximum values noted above. In certain instances, the bonded abrasive bodies herein may utilize relatively large size abrasive particles, which have historically proven difficult to homogeneously distribute throughout the mixture and resulting bonded abrasive body. The impact of settling may be even more significant when attempting to form abrasive bodies having a high degree of porosity. Notably, due to their relatively larger sizes, such abrasive particles have a tendency to segregate and agglomerate in the gel and mixture, resulting in abrasive products with in homogeneities and density variations. In one particular embodiment, the abrasive particles can have an average particle size (D50) within a range of at least <NUM> microns to not greater than <NUM> microns or within a range of at least <NUM> micros to not greater than <NUM> microns or within a range of at least <NUM> microns to not greater than <NUM> microns or even within a range of at least <NUM> microns to not greater than <NUM> microns.

The abrasive particles may have various compositions, shapes, sizes, and other features. For example, the abrasive particles may include an abrasive particle type such as from the group of claimed unagglomerated particles, agglomerated particles, shaped abrasive particles, shaped abrasive composites, constant thickness abrasive particles (CTAP), randomly shaped abrasive particles, or any combination thereof. In another embodiment, the abrasive particles may include a material such as from the group of oxides, borides, nitrides, carbides, oxynitrides, oxycarbides, amorphous, monocrystalline, polycrystalline, superabrasive or any combination thereof. According to one embodiment, the abrasive particles can include unagglomerated and randomly shaped particles comprising alumina, and more particularly, consisting essentially of alumina.

In accordance with one embodiment, the bonded abrasive body <NUM> may have a particular structure that may facilitate improved performance. For example, the bonded abrasive body <NUM> may include a content of abrasive particles of at least <NUM> vol% for a total volume of the bonded abrasive body <NUM>, such as at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol%. Still, in one non-limiting embodiment, the bonded abrasive body <NUM> may include a content of abrasive particles of not greater than <NUM> vol% for a total volume of the bonded abrasive body, such as not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol%. The content of abrasive particles in the bonded abrasive body <NUM> can be within a range including any of the minimum and maximum percentages noted above.

In one particular aspect, the bonded abrasive body <NUM> can include a bond material including an inorganic material. Some suitable examples of an inorganic material can include a metal, metal alloy, ceramic, vitreous phase, or any combination thereof. Furthermore, the bond material may include at least one of a vitreous phase, amorphous phase, a polycrystalline phase, a monocrystalline phase, or any combination thereof. In certain instances, the bond material can consist essentially of a polycrystalline phase, a vitreous phase, or a monocrystalline phase.

For at least one embodiment, the bond material may include an oxide, such as a vitreous oxide-containing material. Some suitable examples of oxides can include silicon dioxide, boron oxide, aluminum oxide, alkali oxide (M<NUM>O), alkaline earth oxide (MO) transition metal oxide, rare earth metal oxide, or any combination thereof. In particular instances, the bond material may be a soda-lime vitreous material, borosilicate material, or aluminosilicate material.

The bonded abrasive body <NUM> may include a particular content of bond material that may facilitate improved performance. For example, the bonded abrasive body 201may include a content of bond material of at least <NUM> vol% for a total volume of the bonded abrasive body or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol%. Still, in one non-limiting embodiment, the bonded abrasive body <NUM> can include a content of bond material of not greater than <NUM> vol% for a total volume of the bonded abrasive body, such as not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol%. It will be appreciated that the content of bond material can be within a range including any of the minimum and maximum values noted above.

The bonded abrasive body <NUM> may include a particular structure such that it has a controlled content of the bond material relative to the content of abrasive particles. For example, in one instance, the body can have an ABR Factor (Cb/Cap) within a range of at least <NUM> to not greater than <NUM>, wherein Cb represents the vol% of the bond material for the total volume of the bonded abrasive body <NUM> and Cap represents the vol% of the abrasive particles for the total volume of the bonded abrasive body <NUM>. In particular instances, the bonded abrasive body <NUM> may have an ABR Factor (Cb/Cap) of at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM>. Still, in another non-limiting embodiment, the bonded abrasive body <NUM> can have an ABR Factor (Cb/Cap) of not greater than <NUM>, such as not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM>. It will be appreciated that the ABR Factor (Cb/Cap) can be within a range including any of the minimum and maximum values noted above.

In another embodiment, the bond abrasive body <NUM> may have a particular type and content of porosity that may facilitate improved performance of the abrasive article. For example, the bonded abrasive body <NUM> can have an average pore size of at least <NUM> microns, such as at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns. Still, in one non-limiting embodiment, the average pore size of the porosity of the bonded abrasive body <NUM> can be not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns. It will be appreciated that the average pore size can be within a range including any of the minimum and maximum values noted above.

The bonded abrasive body <NUM> may have a particular content of porosity that may facilitate improved performance. For example, the bonded abrasive body <NUM> may include at least <NUM> vol% porosity for a total volume of the bonded abrasive body <NUM>, such as at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol%. Still, in one non-limiting embodiment, the bonded abrasive body <NUM> can include not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% for a total volume of the bonded abrasive body or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol%. It will be appreciated that the content of porosity in the bonded abrasive body <NUM> can be within a range including any of the minimum and maximum percentages noted above, such as within a range of at least <NUM> vol% and not greater than <NUM> vol% for a total volume of the bonded abrasive body or within a range of at least <NUM> vol% and not greater than <NUM> vol% for a total volume of the bonded abrasive body or within a range of at least <NUM> vol% and not greater than <NUM> vol% for a total volume of the bonded abrasive body.

The porosity of the bonded abrasive body <NUM> may include open porosity, closed porosity, or a combination thereof. Open porosity can be defined as interconnected channels extending through the bonded abrasive body <NUM>. Closed porosity can define discrete and isolated voids contained in the bond material. In accordance with an embodiment,.

In accordance with an embodiment, the bonded abrasive body <NUM> may include a particular content of open porosity that may facilitate improved performance. For example, the bonded abrasive body <NUM> may include at least <NUM> vol% open porosity for a total content of the porosity in the bonded abrasive body, such as at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol%. Still, in one non-limiting embodiment, the bonded abrasive body <NUM> can include not greater than <NUM> vol% open porosity for a total volume of the porosity in the bonded abrasive body <NUM>, such as not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol%. In at least one embodiment, all of the porosity in the bonded abrasive body <NUM> can be open porosity. It will be appreciated that the content of open porosity can be within a range including any of the minimum and maximum percentages noted above.

In accordance with an embodiment, the bonded abrasive body <NUM> may include a particular content of closed porosity that may facilitate improved performance. For example, the bonded abrasive body <NUM> may include at least <NUM> vol% closed porosity for a total content of the porosity in the bonded abrasive body, such as at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol% or at least <NUM> vol%. Still, in one non-limiting embodiment, the bonded abrasive body <NUM> can include not greater than <NUM> vol% closed porosity for a total content of the porosity in the bonded abrasive body, such as not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol% or not greater than <NUM> vol%. In at least one embodiment, the bonded abrasive body <NUM> can be free of closed porosity. It will be appreciated that the content of closed porosity can be within a range including any of the minimum and maximum percentages noted above.

In accordance with an embodiment, the bonded abrasive body <NUM> may have a particular pore size distribution as achieved by the forming processes disclosed herein and that may facilitate improved performance. For example, the porosity on the bonded abrasive body <NUM> can have a D90 pore size of at least of at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns. Still, in one non-limiting embodiment, the D90 pore size of the bonded abrasive body <NUM> can be not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns. It will be appreciated that the D90 pore size can be within a range including any of the minimum and maximum values noted above. As used herein, a D90 pore size defines the size of the pores at the <NUM>% percentile of the pore size distribution. Stated alternatively it is the pore size at which only <NUM> % of the pores have a larger pore size.

In another aspect, the porosity on the bonded abrasive body <NUM> can have a D10 pore size of at least of at least <NUM> microns or at least <NUM> microns or at least <NUM> micron or at least <NUM> microns or at least <NUM> microns or at least or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns or at least <NUM> microns. Still, in one non-limiting embodiment, the D10 pore size of the bonded abrasive body <NUM> can be not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> microns or not greater than <NUM> micron or not greater than <NUM> microns. It will be appreciated that the D10 pore size can be within a range including any of the minimum and maximum values noted above. As used herein, a D10 pore size defines the size of the pores at the <NUM>% percentile of the pore size distribution. Stated alternatively it is the pore size at which only <NUM> % of the pores have a smaller pore size.

The bonded abrasive body <NUM> can have a particular microstructure based on the methods of making according to embodiments herein. For example, the bonded abrasive body <NUM> can have a permeability as defined by Darcy's number of at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM> or at least <NUM>. Still, in one non-limiting embodiment the permeability can be defined by a Darcy's number of not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM> or not greater than <NUM>. The permeability can be measured according to ASTM D4525-13e2.

The processes of the embodiments herein may facilitate formation of bonded abrasive articles having particular grades and/or structures utilizing relatively large abrasive particles and having a superior homogeneity in terms of the distribution of phases throughout the body in a manner that it was not previously achieved by conventional processing. Notably, the bonded abrasive body <NUM> has a Solid Phase Variation of not greater than <NUM>%. A low Solid Phase Variation indicates a superior homogeneity of the bonded abrasive body compared to other high porosity bonded abrasives made through other processes. Notably, the controlled reaction and timing of gelling and foaming facilitates the superior homogenous distribution of the phases throughout the bonded abrasive, which appears to facilitate improved operations of the bonded abrasives formed according to the embodiments herein. In one embodiment, the Solid Phase Variation is not greater than <NUM>%, such as not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>% or not greater than <NUM>%. Still, in another non-limiting embodiment, the Solid Phase Variation can be at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% or at least <NUM>% at least <NUM>% or at least <NUM>%. It will be appreciated that the Solid Phase Variation can be within a range including any of the minimum and maximum percentages noted above.

The Solid Phase Variation is evaluated using a computed tomography (CT) scan via X-rays. To evaluate the Solid Phase Variation of a bonded abrasive body, multiple random samples are cut from a bonded abrasive product at various locations. It is preferable that each sample or series of samples accounts for the entire thickness of the bonded abrasive body so that one can evaluate the difference in solid phase content across the entire thickness of the body. For example, a single sample can be taken from the bonded abrasive body that accounts for the entire thickness of the body. Another method includes taking multiple cuts from the wheel at the same location to get multiple samples that account for the entire thickness of the bonded abrasive body.

The sample or samples are marked and then scanned using X-rays for evaluation by computed tomography. The evaluations herein were conducted using an X-ray machine available as GE Phoenix V - tome xs225. On the opposite side of the sample from the X-ray machine an image intensifier or detector is positioned. The detector is commercially available as Dynamic <NUM>-<NUM> from GE Digital Solutions. The detector is coupled to a computer system for sending analog video signals to the computer. The system also includes a tunable interface unit that is connected to the computer controlled turntable holding the sample. The tunable interface unit is also connected to the computer.

The raw data from the X-ray scanning process is sent to the computer and an image is created based on tomographic reconstruction using Phoenix datosx CT software. <FIG> includes a representative image of an original CT scan image. Note that if multiple samples are used, they can be cut and pasted together to generate a composite CT scan image that is representative of the microstructure throughout the thickness of the body. The original CT scan image is then modified to an <NUM>-bit black and white image using suitable image analysis software, such as ImageJ. ImageJ uses an Otsu's method for creating the black and white image from the original CT scan image. <FIG> includes a representative <NUM> bit black and white image of the image of <FIG>. The black and white image is then modified using an "outline" function in ImageJ to create an outline image of the solid phase material (i.e., black) in the black and white image. <FIG> includes an image of <FIG> after conducting an "outline" function.

Under the analysis feature in ImageJ the "set scale" function is used to correlate the number of pixels in the image to an actual distance (e.g., microns). This function is then used to select a box as shown in <FIG>, wherein the box has a width (W) equivalent to twice the average particle size of particles used in the bonded abrasive body. For example, if the D50 of the abrasive particles in the body is <NUM> microns, the width (W) of the box is <NUM> microns. As illustrated, a box is drawn on both sides of the image to evaluate the homogeneity of the solid material on both sides of the image. Note that both boxes are drawn such that one side intersects the upper surface of the body and extends into the depth of the body for the predetermined distance according to 2x the D50 as noted herein.

After selecting the appropriate area of the outline image by drawing a box, the area in the box is analyzed according to the "analyze particles" function in the ImageJ software. The "analyze particles" function counts the number of solid phase regions in the selected area and produces a set of data. This data is used to create a plot of percent area versus location as illustrated in <FIG>. The difference in the percent area between the left and right sides of the images is the Solid Phase Variation. For example, if the percent area of solid material on the right side is <NUM>% and the percent area of the solid material on the left side is <NUM>%, the Solid Phase Variation is <NUM>% (i.e., <NUM>%-<NUM>% = <NUM>%).

Many different aspects and embodiments are possible. Some of those aspects and embodiments are described herein. After reading this specification, skilled artisans will appreciate that those aspects and embodiments are only illustrative and do not limit the scope of the present invention.

A representative sample (Sample S1) is made according to the following process. A carrier of deionized water is obtained and approximately <NUM> of water is measured. Approximately <NUM>,<NUM> of abrasive particles having an average particle size (D50) of approximately <NUM> microns, and commercially available as white fused alundum from Saint-Gobain Corporation, is prepared. Approximately <NUM> of bond precursor material, commercially available as Vitrium from Saint-Gobain Corporation, is also prepared. Approximately <NUM> of a surfactant, commercially available as Perlastan L30 from Schill & Seilacher GmbH, is also prepared. Approximately <NUM> of a gelling agent, commercially available as Kelcogel from CP Kelco Corporation, is prepared. Approximately <NUM> of a dispersant commercially available as Darvan 821A from Vanderbilt Minerals is also prepared. Approximately <NUM> of a cationic agent commercially available as calcium chloride from Fisher Scientific is prepared. Approximately <NUM> of a foaming agent commercially available as hydrogen peroxide from Fisher Scientific is prepared. Finally, approximately <NUM> of a foaming catalyst commercially available as potassium iodide from Fisher Scientific is prepared.

First, the foaming agent is added to the water while mixing. The gelling agent is then added to the water and foaming agent while mixing. During mixing the mixture is heated at a gelling temperature of approximately <NUM>-<NUM>. The bond precursor material is then added to the gel, followed by the dispersant, then the abrasive particles, followed by the surfactant, and then the cationic agent. The addition of the cationic agent initiates cross-linking and the formation of the gel.

After adding the gelling agent, the foaming catalyst is added to the mixture to initiate the foaming process, thus the mixture is gelling and foaming simultaneously. The result of the gelling and foaming process is a foamed gel. Mixing is continued in normal atmospheric conditions to facilitate the formation of a suitable foamed gel.

The foamed gel is then poured into a production tool to cast a green body. During casting, no additional pressure or temperature is applied to the foamed gel, and the gel is free cast to form the green body. The foamed gel dries, and the green body stabilizes. It will be understood, that other processes may optionally apply pressure to the foamed gel to form the green body.

After forming the green body, the green body is fired to create a vitreous bond material from the bond precursor material. The firing schedule includes a ramp of approximately <NUM>/hr from room temperature to a firing temperature of approximately <NUM>-<NUM> with a hold for approximately <NUM> hours under a normal atmosphere. After a suitable time at the firing temperature, the fired body is cooled with a ramp down of approximately <NUM>/hr.

The abrasive article undergoes finishing to finalize the dimensions of the bonded abrasive body. The bonded abrasive body has a Solid Phase Variation of <NUM>%, <NUM> vol% bond material that consists essentially of a vitreous material, approximately <NUM> vol% abrasive particles having an average particle size (D50) of <NUM> microns, approximately <NUM> vol% porosity, including a majority content of open porosity for the total content of porosity, and an average pore size (D50) of approximately <NUM> microns, a D90 pore size of approximately <NUM> microns, and a D10 pore size of approximately <NUM> microns. Sample S1 had a permeability as defined by a Darcy's number of approximately <NUM>.

<FIG> includes a black and white image generated from a CT scan of a portion of the bonded abrasive body of Sample S1 used to evaluate the Solid Phase Variation.

A second sample (Sample S2) is formed using a similar process used to form Sample S1, except that a cationic agent is not added. It had a similar structure to Sample S1 in terms of content of bond material, abrasive particles and porosity. Sample S2 had a Homogeneity Factor of <NUM>.

<FIG> includes a black and white image generated from a CT scan of a portion of the bonded abrasive body of Sample S2. <FIG> includes plots of percent area used to evaluate the Homogeneity Factor for Samples S1 and S2.

The specification and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The specification and illustrations are not intended to serve as an exhaustive and comprehensive description of all of the elements and features of apparatus and systems that use the structures or methods described herein. Separate embodiments may also be provided in combination in a single embodiment, and conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any sub combination. Further, reference to values stated in ranges includes each and every value within that range. Many other embodiments may be apparent to skilled artisans only after reading this specification. Other embodiments may be used and derived from the disclosure, such that a structural substitution, logical substitution, or another change may be made without departing from the scope of the disclosure. Accordingly, the disclosure is to be regarded as illustrative rather than restrictive.

The description in combination with the figures is provided to assist in understanding the teachings disclosed herein. The following discussion will focus on specific implementations and embodiments of the teachings. This focus is provided to assist in describing the teachings and should not be interpreted as a limitation on the scope or applicability of the teachings. However, other teachings can certainly be used in this application.

This description should be read to include one or at least one and the singular also includes the plural, or vice versa, unless it is clear that it is meant otherwise.

The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent not described herein, many details regarding specific materials and processing acts are conventional and may be found in reference books and other sources within the structural arts and corresponding manufacturing arts.

Claim 1:
An abrasive article (<NUM>) comprising:
a bonded abrasive body (<NUM>) comprising:
a bond material comprising an inorganic material;
abrasive particles contained within the bonded abrasive body;
porosity within a range of at least <NUM> vol% to not greater than <NUM> vol% for a total volume of the bonded abrasive body; and
a Solid Phase Variation, determined by using a computed tomography (CT) scan via X-rays as described in the description, of not greater than <NUM>%,
wherein the bonded abrasive body (<NUM>) is a foamed body.