METHODS FOR FORMING POLYCRYSTALLINE MATERIALS INCLUDING PROVIDING MATERIAL WITH SUPERABRASIVE GRAINS PRIOR TO HPHT PROCESSING
Grains of superabrasive material may be infiltrated with a molten metal alloy at a relatively low temperature, and the molten metal alloy may be solidified within interstitial spaces between the grains of superabrasive material to form a solid metal alloy having the grains of superabrasive material embedded therein. The solid metal alloy with the grains of superabrasive material embedded therein may be subjected to a high pressure and high temperature process to form a polycrystalline superabrasive material. A polycrystalline superabrasive material also may be formed by depositing material on surfaces of grains of superabrasive material in a chemical vapor infiltration process to form a porous body, which then may be subjected to a high pressure and high temperature process. Polycrystalline compacts and cutting elements including such compacts may be formed using such methods.
1 . A method of forming a polycrystalline compact, comprising:
depositing a layer of catalyst material on grains of superabrasive material to form a three-dimensional solid porous body, the three-dimensional solid porous body comprising the grains of superabrasive material bonded to one another by the catalyst material deposited thereon and having a shape of the polycrystalline compact to be formed;
infiltrating pores of the three-dimensional solid porous body with a molten metal alloy at a temperature of about 1200° C. or less and cooling and solidifying the molten metal alloy within the pores of the three-dimensional solid porous body to form a solid metal alloy within the three-dimensional solid porous body, wherein the grains of superabrasive material within the three-dimensional solid porous body are free of inter-granular bonds directly between the grains of superabrasive material; and
subjecting the three-dimensional solid porous body having the solid metal alloy therein to a high pressure and high temperature process to form inter-granular bonds between the grains of superabrasive material.
2 . The method of claim 1 , wherein depositing the layer of catalyst material on the grains of superabrasive material comprises depositing the layer of catalyst material on grains of superabrasive material to form a three-dimensional solid porous body having a cylindrical disc shape.
3 . The method of claim 1 , wherein depositing the layer of catalyst material on the grains of superabrasive material to form the three-dimensional solid porous body comprises forming the three-dimensional solid porous body to have a substantially continuous open pore network between the grains of superabrasive material having the layer of catalyst material thereon.
4 . The method of claim 1 , wherein depositing the layer of catalyst material on the grains of superabrasive material comprises depositing a layer comprising at least one of a carbon based material, a carbide, a nitride, cobalt, iron, and nickel on the grains of superabrasive material.
5 . The method of claim 1 , wherein depositing the layer of catalyst material on grains of superabrasive material comprises depositing two layers of material on the grains of superabrasive material, the two layers of material having differing compositions.
6 . The method of claim 5 , wherein depositing at least two layers of materials on the grains of superabrasive material comprises depositing a first layer comprising a carbon based material on the grains of superabrasive material and depositing a second layer comprising at least one of cobalt, iron, and nickel on the grains of superabrasive material.
7 . The method of claim 1 , wherein depositing the layer of catalyst material on the grains of superabrasive material comprises depositing the layer of catalyst material on the grains of superabrasive material in a chemical vapor infiltration process.
8 . The method of claim 1 , wherein infiltrating pores of the three-dimensional solid porous body with the molten metal alloy comprises infiltrating the grains of superabrasive material and the particles with the molten metal alloy at a pressure of about 500 MPa or less.
9 . The method of claim 1 , wherein infiltrating pores of the three-dimensional solid porous body with the molten metal alloy at a temperature of about 1200° C. or less comprising infiltrating pores of the three-dimensional solid porous body with the molten metal alloy at a temperature of about 750° C. or less.
10 . The method of claim 1 , further comprising selecting the molten metal alloy to comprise a metal alloy of at least one of iron, cobalt, and nickel having a melting temperature of 1200° C. or less.
11 . The method of claim 1 , further comprising selecting the molten metal alloy to comprise a metal alloy of nickel, chromium, titanium, and silicon having a melting temperature of 1200° C. or less.
12 . The method of claim 1 , further comprising selecting the grains of superabrasive material to comprise at least one of diamond and cubic boron nitride.
13 . The method of claim 1 , wherein subjecting the three-dimensional solid porous body having the solid metal alloy therein to a high pressure and high temperature process comprises subjecting the solid metal alloy having the grains of superabrasive material and the particles embedded therein to a pressure of at least about 5.0 GPa and a temperature of at least about 1350° C.
14 . A method of forming a cutting element comprising a polycrystalline compact for an earth-boring tool, comprising:
depositing a layer of catalyst material on grains of superabrasive material to form a three-dimensional solid porous body, the three-dimensional solid porous body comprising the grains of superabrasive material bonded to one another by the catalyst material deposited thereon and having a shape of the polycrystalline compact to be formed;
disposing the three-dimensional solid porous body over a substrate;
infiltrating pores of the three-dimensional solid porous body with a molten metal alloy at a temperature of about 1200° C. or less and cooling and solidifying the molten metal alloy within the pores of the three-dimensional solid porous body to form a solid metal alloy within the three-dimensional solid porous body and to bond the three-dimensional solid porous body to the substrate, wherein the grains of superabrasive material within the three-dimensional solid porous body are free of inter-granular bonds directly between the grains of superabrasive material; and
subjecting the three-dimensional solid porous body having the solid metal alloy therein and the substrate to a high pressure and high temperature process to form inter-granular bonds between the grains of superabrasive material.
15 . The method of claim 14 , wherein infiltrating pores of the three-dimensional solid porous body with the molten metal alloy comprises infiltrating a portion of the substrate adjacent the three-dimensional solid porous body with the molten metal alloy.
16 . The method of claim 14 , further comprising:
disposing loose grains of superabrasive material between the three-dimensional solid porous body and the substrate; and
subjecting the three-dimensional solid porous body and the substrate to the high pressure and high temperature process.
17 . The method of claim 14 , wherein depositing the layer of catalyst material on the grains of superabrasive material comprises depositing the layer of catalyst material on grains of superabrasive material to form a three-dimensional solid porous body having a cylindrical disc shape
18 . A method of forming a cutting element comprising a polycrystalline compact for an earth-boring tool, comprising:
disposing a three-dimensional solid porous body over a substrate, the three-dimensional solid porous body comprising grains of superabrasive material bonded to one another by a catalyst material deposited thereon and having a shape of the polycrystalline compact to be formed, the grains of superabrasive material within the three-dimensional solid porous body being free of inter-granular bonds directly between the grains of superabrasive material;
infiltrating pores of the three-dimensional solid porous body with a molten metal alloy at a temperature of about 1200° C. or less and cooling and solidifying the molten metal alloy within the pores of the three-dimensional solid porous body to form a solid metal alloy within the three-dimensional solid porous body and to bond the three-dimensional solid porous body to the substrate; and
subjecting the three-dimensional solid porous body having the solid metal alloy therein and the substrate to a high pressure and high temperature process to form inter-granular bonds between the grains of superabrasive material.
19 . The method of claim 18 , wherein infiltrating pores of the three-dimensional solid porous body with the molten metal alloy comprises infiltrating a portion of the substrate adjacent the three-dimensional solid porous body with the molten metal alloy.
20 . The method of claim 18 , further comprising, prior to subjecting the three-dimensional solid porous body having the solid metal alloy therein and the substrate to the high pressure and high temperature process, removing the solid metal alloy from some of the pores of the three-dimensional solid porous body.