Patent ID: 7938997

Claim:
A process for preparing a bulk, superhard, nanocomposite compact, comprising: (a) ball milling a mixture consisting essentially of graphite and hexagonal boron nitride to produce a ball-milled mixture comprising amorphous boron nitride, nanocrystalline boron nitride, or mixtures thereof, the ball-milled mixture further comprising amorphous carbon, nanocrystalline graphitic carbon, or mixtures thereof; (b) encapsulating the ball-milled mixture; and thereafter (c) subjecting the now encapsulated ball-milled mixture to a pressure in a range of from about 15 GPa to about 25 GPa; and thereafter (d) sintering the pressurized, encapsulated ball-milled mixture at a temperature in a range of from about 1800 K to about 2500 K for a period of time sufficient to convert the pressurized encapsulated ball-milled mixture into a bulk, superhard nanocomposite compact consisting essentially of nanocrystalline grains of at least one ternary phase of B—C—N surrounded by amorphous diamond-like carbon grain boundaries.