Methods of forming hardfacing materials including PCD particles, and welding rods including such PCD particles

1. A method of forming a hardfacing material, comprising:

subjecting diamond grains to a temperature greater than about 1,500° C. and a pressure greater than about 5.0 GPa to form diamond-to-diamond bonds between the diamond grains and form a polycrystalline diamond material; and

breaking down the polycrystalline diamond material to form particles of polycrystalline diamond material, the particles of polycrystalline diamond material comprising a plurality of inter-bonded diamond grains.

2. The method of claim 1 , wherein breaking down the polycrystalline diamond material comprises crushing the polycrystalline diamond material.

3. The method of claim 1 , further comprising catalyzing formation of the diamond-to-diamond bonds between the diamond grains using a catalyst material.

4. The method of claim 3 , further comprising removing the catalyst material from interstitial spaces between the inter-bonded diamond grains within the particles of polycrystalline diamond material.

5. The method of claim 1 , further comprising encapsulating the particles of polycrystalline diamond material with an encapsulant material comprising a metal.

6. The method of claim 5 , further comprising forming the encapsulant to further comprise at least one of a carbide material, a boride material, a nitride material, and non-polycrystalline diamond grit.

7. The method of claim 1 , further comprising embedding the particles of polycrystalline diamond material within a matrix material.

8. The method of claim 7 , further comprising forming the matrix material to comprise a metal.

9. The method of claim 8 , further comprising forming the matrix material to comprise at least one of a carbide material, a boride material, a nitride material, and non-polycrystalline diamond grit.

10. The method of claim 7 , wherein embedding the particles of polycrystalline diamond material within the matrix material comprises embedding the particles of polycrystalline diamond material within the matrix material on a surface of an earth-boring tool.

11. The method of claim 10 , wherein embedding the particles of polycrystalline diamond material within the matrix material on the surface of the earth-boring tool comprises embedding the particles of polycrystalline diamond material within the matrix material on a surface of an earth-boring rotary drill bit.

12. The method of claim 10 , wherein embedding the particles of polycrystalline diamond material within the matrix material on the surface of the earth-boring tool comprises:

using a welding torch to at least partially melt the matrix material;

applying the at least partially molten matrix material and the particles of polycrystalline diamond material to the surface of the earth-boring tool; and

allowing the at least partially molten matrix material to cool and solidify on the surface of the earth-boring tool.

13. The method of claim 1 , wherein subjecting the diamond grains to the temperature greater than about 1,500° C. and the pressure greater than about 5.0 GPa to form diamond-to-diamond bonds between the diamond grains and faun, the polycrystalline diamond material comprises forming a layer of the polycrystalline diamond material.

14. The method of claim 13 , wherein breaking down the polycrystalline diamond material to form particles of polycrystalline diamond material comprises forming at least substantially planar fragments of the layer of polycrystalline diamond material.

15. The method of claim 14 , further comprising forming the at least substantially planar fragments of the layer of polycrystalline diamond material to have an average particle diameter between about 0.25 millimeter and about 7.0 millimeters, and an average particle thickness between about 0.1 millimeter and about 5.0 millimeters.