The present disclosure relates a spark plasma sintered polycrystalline diamond and methods of spark plasma sintering leached polycrystalline diamond. Spark plasma sintering produces plasma from a reactant gas found in the pores left by catalyst removal from leached polycrystalline diamond. The plasma forms diamond bonds and/or carbide structures in the pores, which may produce polycrystalline diamond that is has a higher impact strength than the leached polycrystalline diamond or other improved properties.

Cutting elements having accelerated leaching rates and methods of making the same are disclosed herein. In one embodiment, a method of forming a cutting element includes assembling a reaction cell having diamond particles, a non-catalyst material, a catalyst material, and a substrate within a refractory metal container, where the non-catalyst material is generally immiscible in the catalyst material at a sintering temperature and pressure. The method also includes subjecting the reaction cell and its contents to a high pressure high temperature sintering process to form a polycrystalline diamond body that is attached to the substrate. The method further includes contacting at least a portion of the polycrystalline diamond body with a leaching agent to remove catalyst material and non-catalyst material from the diamond body, where a leaching rate of the catalyst material and the non-catalyst material exceeds a conventional leaching rate profile by at least about 30%.

Induced material segregation methods of manufacturing a polycrystalline diamond compact (PDC) cutter result in formation of a polycrystalline diamond/tungsten carbide (WC) composite material having a smooth compositional gradient from maximum WC concentration at one face to maximum diamond concentration at another face. Because the compositional gradient is smooth, very little or no mismatch of coefficient of thermal expansion occurs, which improves a service lifetime of the PDC cutter.

A method of forming a polycrystalline diamond cutting element includes assembling a diamond material, a substrate, and a source of catalyst material or infiltrant material distinct from the substrate, the source of catalyst material or infiltrant material being adjacent to the diamond material to form an assembly. The substrate includes an attachment material including a refractory metal. The assembly is subjected to a first high-pressure/high temperature condition to cause the catalyst material or infiltrant material to melt and infiltrate into the diamond material and subjected to a second high-pressure/high temperature condition to cause the attachment material to melt and infiltrate a portion of the infiltrated diamond material to bond the infiltrated diamond material to the substrate.

A cBN sintered body including cBN and a binder phase, wherein a content ratio of the cBN is 80 to 94 volume %, a content ratio of the binder phase is 6 to 20 volume %, the binder phase contains a metal phase, a V compound, and an Al compound, the metal phase contains one or more selected from the group consisting of Ni, and a Ni-containing alloy and solid solution, the Ni-containing alloy and solid solution each contain Ni and one or more elements selected from the group consisting of Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W, and Co, the V compound contains one or more selected from the group consisting of VN, VCN, and VC, the Al compound contains one or more selected from the group consisting of Al.sub.2O.sub.3, AlN, and AlB.sub.2, a maximum peak position 2 of a 200 plane of the metal phase is less than 51.60, and I.sub.1/(I.sub.1+I.sub.2) is 0.40 to 0.80, where I.sub.1 denotes an X-ray diffraction peak intensity of a 220 plane of the V compound, and I.sub.2 denotes an X-ray diffraction peak intensity of a 200 plane of the metal phase.

A cubic boron nitride sintered material of the present disclosure includes 35 to 100 volume % of a cubic boron nitride grain and 0 to 65 volume % of a binder, wherein: a lattice constant of the cubic boron nitride grain is 3.6140 to 3.6161 , a silicon content in the cubic boron nitride grain is 0.02 mass % or less, and the binder material includes at least one selected from a group consisting of a compound and a solid solution of the compound, the compound consisting of at least one element selected from a group consisting of a group 4 element, a group 5 element, a group 6 element in the periodic table, aluminum, silicon, iron, cobalt and nickel, and at least one element selected from a group consisting of carbon, nitrogen, boron and oxygen.

A cubic boron nitride sintered material includes cubic boron nitride and a binder. The binder includes a first material and a second material. The first material is one or two or more first chemical species each including at least one first metallic element selected from the group consisting of tungsten, cobalt, and aluminum. Each of the first chemical species is a metal, an alloy, an intermetallic compound, a compound, or a solid solution. The second material is one or two or more second chemical species each including at least one second metallic element selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, and chromium. Each of the second chemical species is a solid solution derived from at least one selected from the group consisting of nitride, carbide, and carbonitride. In each of the second chemical species, 0.1 atom % to 10 atom % of aluminum is dissolved.

A cutting element for a cutting tool. The cutting element may be at least partially made from a composite material including a carbide material, a binder material, and a plurality of diamond particles. The carbide material may be from 55 wt % to 97 wt % of a total weight of the composite material. The binder material may be from 3 wt % to 20 wt % of the total weight of the composite material. The plurality of diamond particles may be from 0.1% to 25% of the total weight of the composite material. The carbide material and the binder material may be combined and sintered together prior to being combined with the plurality of diamond particles, such that the carbide material and the binder material form a plurality of pellets having an average cross-sectional length from 10 m to 250 m.

A polycrystalline diamond compact includes a polycrystalline diamond material having a plurality of grains of diamond bonded to one another by inter-granular bonds and an intermetallic gamma prime () or -carbide phase disposed within interstitial spaces between the inter-bonded diamond grains. The ordered intermetallic gamma prime () or -carbide phase includes a Group VIII metal, aluminum, and a stabilizer. An earth-boring tool includes a bit body and a polycrystalline diamond compact secured to the bit body. A method of forming polycrystalline diamond includes subjecting diamond particles in the presence of a metal material comprising a Group VIII metal and aluminum to a pressure of at least 4.5 GPa and a temperature of at least 1,000 C. to form inter-granular bonds between adjacent diamond particles, cooling the diamond particles and the metal material to a temperature below 500 C., and forming an intermetallic gamma prime () or -carbide phase adjacent the diamond particles.

A polycrystalline compact comprises a plurality of grains of hard material and a plurality of nanoparticles disposed in interstitial spaces between the plurality of grains of hard material. The nanoparticles have cores of a first material and at least one oxide material on the cores. An earth-boring tool comprises such a polycrystalline compact. A method of forming a polycrystalline compact comprises combining a plurality of hard particles with a plurality of nanoparticles to form a mixture and sintering the mixture to form a polycrystalline hard material comprising a plurality of interbonded grains of hard material. A method of forming a cutting element comprises infiltrating interstitial spaces between interbonded grains of hard material in a polycrystalline material with a plurality of nanoparticles.