CUTTING ELEMENTS AND TOOLS COMPRISING INTERBONDED GRAINS OF DIAMOND AND RELATED METHODS
Methods of forming a polycrystalline compact using at least one metal salt as a sintering aid. Such methods may include forming a mixture of the at least one metal salt and a plurality of grains of hard material and sintering the mixture to form a hard polycrystalline material. During sintering, the metal salt may melt or react with another compound to form a liquid that acts as a lubricant to promote rearrangement and packing of the grains of hard material. The metal salt may, thus, enable formation of hard polycrystalline material having increased density, abrasion resistance, or strength. The metal salt may also act as a getter to remove impurities (e.g., catalyst material) during sintering. The methods may also be employed to form cutting elements and earth-boring tools.
1 . A method of forming a cutting element, the method comprising:
subjecting a mixture of diamond grains and lithium fluoride to high temperature high pressure conditions to form a sintered diamond table comprising interbonded grains of diamond and lithium fluoride within interstitial spaces in the sintered diamond table.
2 . The method of claim 1 , further comprising, prior to subjecting the mixture of diamond grains and lithium fluoride to high temperature high pressure conditions, combining the diamond particles with the lithium fluoride to form a powder mixture comprising the diamond particles and the lithium fluoride substantially homogeneously dispersed on the diamond particles, and wherein subjecting the mixture of diamond grains and lithium fluoride to high temperature high pressure conditions comprises subjecting the powder mixture to high temperature high pressure conditions.
3 . The method of claim 2 , wherein combining the diamond particles with the lithium fluoride comprises dispersing the lithium fluoride in an organic solvent.
4 . The method of claim 1 , further comprising:
prior to subjecting the mixture of diamond grains and lithium fluoride to high temperature high pressure conditions, combining the diamond particles with the lithium fluoride in at least one solvent to form a slurry; and
subjecting the slurry to a spray-drying process to form a powder mixture, and wherein subjecting the mixture of diamond grains and lithium fluoride to high temperature high pressure conditions comprises subjecting the powder mixture to high temperature high pressure conditions.
5 . The method of claim 1 , wherein subjecting a mixture of diamond grains and lithium fluoride to high temperature high pressure conditions comprises subjecting a mixture of diamond grains, lithium fluoride, and at least one catalyst material to high temperature high pressure conditions.
6 . The method of claim 5 , further comprising removing a portion of the lithium fluoride from interstitial spaces between the diamond grains.
7 . The method of claim 6 , wherein removing a portion of the lithium fluoride from interstitial spaces between the diamond grains comprises reacting fluorine of the lithium fluoride with at least one catalyst material in the mixture.
8 . The method of claim 1 , wherein subjecting a mixture of diamond grains and lithium fluoride to high temperature high pressure conditions comprises subjecting a mixture of diamond grains, lithium fluoride, and silicon to high temperature high pressure conditions.
9 . The method of claim 1 , wherein subjecting a mixture of diamond grains and lithium fluoride to high temperature high pressure conditions comprises subjecting the mixture to a temperature greater than about 1,500.degree. C. and a pressure greater than about 5.0 GPa.