A method for forming an abrasive article via an additive manufacturing technique including forming a layer of powder material comprising a precursor bond material and abrasive particles, compacting at least a portion of the layer to form a compacted layer, binding at least a portion of the compacted layer and repeating the steps of forming, compacting and binding to form a green body abrasive article.

[Problem] To provide a polishing sheet in which a hard material such as a metal product can be efficiently polished to form a smooth surface with low convexities and concavities, and to form a uniform smooth surface even when repeated polishing is performed on the same polishing surface. [Resolution Means] A polishing sheet includes a substrate, a plurality of three-dimensional elements that includes diamond abrasive particles and a bonding material, and forms a polishing surface, and an intermediate layer that is provided between the substrate and the three-dimensional element and bonds the substrate and the three-dimensional element N together, wherein a ratio C.sub.2/C.sub.1 of a content of the diamond abrasive particles C.sub.2 to a content of the bonding material C.sub.1 is 0.05 to 1.5 in terms of mass ratio.

[Problem] To provide a polishing sheet in which a hard material such as a metal product can be efficiently polished to form a smooth surface with low convexities and concavities, and to form a uniform smooth surface even when repeated polishing is performed on the same polishing surface. [Resolution Means] A polishing sheet includes a substrate, a plurality of three-dimensional elements that includes diamond abrasive particles and a bonding material, and forms a polishing surface, and an intermediate layer that is provided between the substrate and the three-dimensional element and bonds the substrate and the three-dimensional element N together, wherein a ratio C.sub.2/C.sub.1 of a content of the diamond abrasive particles C.sub.2 to a content of the bonding material C.sub.1 is 0.05 to 1.5 in terms of mass ratio.

Methods of forming a polycrystalline diamond compact for use in an earth-boring tool include forming a body of polycrystalline diamond material including a first material disposed in interstitial spaces between inter-bonded diamond crystals in the body, removing the first material from interstitial spaces in a portion of the body, selecting a second material promoting a higher rate of degradation of the polycrystalline diamond compact than the first material under similar elevated temperature conditions and providing the second material in interstitial spaces in the portion of the body. Methods of drilling include engaging at least one cutter with a formation and wearing a second region of polycrystalline diamond material comprising a second material faster than the first region of polycrystalline diamond material comprising a first material. Polycrystalline diamond compacts and earth-boring tools including such compacts.

Methods of forming a polycrystalline diamond compact for use in an earth-boring tool include forming a body of polycrystalline diamond material including a first material disposed in interstitial spaces between inter-bonded diamond crystals in the body, removing the first material from interstitial spaces in a portion of the body, selecting a second material promoting a higher rate of degradation of the polycrystalline diamond compact than the first material under similar elevated temperature conditions and providing the second material in interstitial spaces in the portion of the body. Methods of drilling include engaging at least one cutter with a formation and wearing a second region of polycrystalline diamond material comprising a second material faster than the first region of polycrystalline diamond material comprising a first material. Polycrystalline diamond compacts and earth-boring tools including such compacts.

A cutting element may include a substrate and a volume of polycrystalline diamond material affixed to the substrate at an interface. The volume of polycrystalline diamond may include a front cutting face with at least one substantially planar portion and at least one recess. The at least one recess may extend from a plane defined by the at least one substantially planar portion a first depth into the volume of polycrystalline diamond material in an axial direction parallel to a central axis of the cutting element. The volume of polycrystalline diamond material may comprise a region including a catalyst material. At least one region substantially free of the catalyst material may extend from the at least one substantially planar portion of the front cutting face a second depth into the volume of polycrystalline diamond in the axial direction. Methods of forming cutting elements.

A cutting element may include a substrate and a volume of polycrystalline diamond material affixed to the substrate at an interface. The volume of polycrystalline diamond may include a front cutting face with at least one substantially planar portion and at least one recess. The at least one recess may extend from a plane defined by the at least one substantially planar portion a first depth into the volume of polycrystalline diamond material in an axial direction parallel to a central axis of the cutting element. The volume of polycrystalline diamond material may comprise a region including a catalyst material. At least one region substantially free of the catalyst material may extend from the at least one substantially planar portion of the front cutting face a second depth into the volume of polycrystalline diamond in the axial direction. Methods of forming cutting elements.

A cutting element for an earth-boring drill bit may include a thermally stable cutting table comprising a polycrystalline diamond material. The polycrystalline diamond material may consist essentially of a matrix of diamond particles bonded to one another and a silicon, silicon carbide, or silicon and silicon carbide material located within interstitial spaces among interbonded diamond particles of the matrix of diamond particles. The cutting table may be at least substantially free of Group VIII metal or alloy catalyst material. The cutting element may further include a substrate and an adhesion material between and bonded to the cutting table and the substrate. The adhesion material may include diamond particles bonded to one another and to the cutting table and the substrate after formation of the preformed cutting table.

A cutting element for an earth-boring drill bit may include a thermally stable cutting table comprising a polycrystalline diamond material. The polycrystalline diamond material may consist essentially of a matrix of diamond particles bonded to one another and a silicon, silicon carbide, or silicon and silicon carbide material located within interstitial spaces among interbonded diamond particles of the matrix of diamond particles. The cutting table may be at least substantially free of Group VIII metal or alloy catalyst material. The cutting element may further include a substrate and an adhesion material between and bonded to the cutting table and the substrate. The adhesion material may include diamond particles bonded to one another and to the cutting table and the substrate after formation of the preformed cutting table.

An abrasive article configured to grind a workpiece having a fracture toughness of at least about 5.5 MPa.Math.m.sup.0.5 may include a body comprising abrasive particles contained within a bond material comprising a metal, wherein the body comprises a ratio of V.sub.AG/V.sub.BM of at least about 1.3, wherein V.sub.AG is a volume percent of abrasive particles within a total volume of the body and V.sub.BM is a volume percent of bond material within the total volume of the body, and wherein the abrasive particles have an average particle size of at least about 1 micron and not greater than about 20 microns.