Methods of fabricating polycrystalline diamond, and cutting elements and earth-boring tools comprising polycrystalline diamond
Methods of fabricating polycrystalline diamond include functionalizing surfaces of carbon-free nanoparticles with one or more functional groups, combining the functionalized nanoparticles with diamond nanoparticles and diamond grit to form a particle mixture, and subjecting the particle mixture to high pressure and high temperature (HPHT) conditions to form inter-granular bonds between the diamond nanoparticles and the diamond grit. Cutting elements for use in an earth-boring tool include a polycrystalline diamond material formed by such processes. Earth-boring tools include such cutting elements.
1. A method of fabricating polycrystalline diamond, comprising:
functionalizing surfaces of carbon-free nanoparticles with one or more functional groups;
combining the functionalized nanoparticles with diamond nanoparticles and diamond grit to form a particle mixture; and
subjecting the particle mixture to high pressure and high temperature (HPHT) conditions to form inter-granular bonds between the diamond nanoparticles and the diamond grit.
2. The method of claim 1 , wherein functionalizing the surfaces of the carbon-free nanoparticles with one or more functional groups comprises functionalizing the surfaces of the carbon-free nanoparticles with methyl functional groups.
3. The method of claim 1 , wherein functionalizing the surfaces of the carbon-free nanoparticles with one or more functional groups comprises functionalizing the surfaces of the carbon-free nanoparticles with acetylene functional groups.
4. The method of claim 1 , further comprising selecting the carbon-free nanoparticles to comprise a metal or a metal alloy.
5. The method of claim 4 , further comprising selecting the carbon-free nanoparticles to comprise one or more of iron, cobalt, and nickel.
6. The method of claim 1 , further comprising selecting the carbon-free nanoparticles to comprise a ceramic material.
7. The method of claim 6 , further comprising selecting the carbon-free nanoparticles to comprise one or more of an oxide and a nitride.
8. The method of claim 6 , further comprising selecting the carbon-free nanoparticles to comprise alumina or magnesia.
9. The method of claim 1 , wherein combining the functionalized nanoparticles with the diamond nanoparticles and the diamond grit to form the particle mixture comprises:
suspending the functionalized nanoparticles and the diamond nanoparticles in a liquid to form a suspension; and
drying the suspension.
10. The method of claim 9 , wherein drying the suspension comprises one or more of spray drying, freeze drying, and flash drying the suspension.
11. The method of claim 9 , further comprising suspending the diamond grit in the liquid.
12. The method of claim 9 , wherein drying the suspension comprises drying the suspension to form a powder product.
13. The method of claim 12 , further comprising mixing the powder product with the diamond grit to form the particle mixture.
14. The method of claim 13 , further comprising milling the particle mixture prior to subjecting the particle mixture to the HPHT conditions.
15. The method of claim 12 , further comprising milling the powder product.
16. The method of claim 1 , wherein subjecting the particle mixture to the HPHT conditions comprises subjecting the particle mixture to a temperature of at least about 1400° C. and a pressure of at least about 5.0 GPa.
17. A cutting element for use in an earth-boring tool, the cutting element comprising a polycrystalline diamond material formed by a method comprising:
functionalizing surfaces of carbon-free nanoparticles with one or more functional groups;
combining the functionalized nanoparticles with diamond nanoparticles and diamond grit to form a particle mixture; and
subjecting the particle mixture to high pressure and high temperature (HPHT) conditions to form inter-granular bonds between the diamond nanoparticles and the diamond grit.
18. The cutting element of claim 17 , wherein functionalizing the surfaces of the carbon-free nanoparticles with one or more functional groups comprises functionalizing the surfaces of the carbon-free nanoparticles with methyl or acetylene functional groups.
19. An earth-boring tool comprising a cutting element, the cutting element comprising a polycrystalline diamond material formed by a method comprising:
functionalizing surfaces of carbon-free nanoparticles with one or more functional groups;
combining the functionalized nanoparticles with diamond nanoparticles and diamond grit to form a particle mixture; and
subjecting the particle mixture to high pressure and high temperature (HPHT) conditions to form inter-granular bonds between the diamond nanoparticles and the diamond grit.
20. The earth-boring tool of claim 19 , further comprising selecting the carbon-free nanoparticles to comprise a ceramic, a metal, or a metal alloy.
21. The earth-boring tool of claim 19 , wherein the earth-boring tool comprises an earth-boring rotary drill bit.