METHOD FOR PRODUCING CUBIC BORON NITRIDE CRYSTALS Russian patent published in 1997 - IPC

FIELD: production of abrasive materials, precursors of cubic boron nitride (c-BN). SUBSTANCE: mixture of powders of r-BN, 7-16 wt.% having particle size <150 mcm, and 1.5-5 wt.% Zn(BH₄)₂•4NH₃ or NaBH₄•2NH₃ having particle size <150 mcm is pressed, placed into high-pressure chamber, kept under static pressure 30-50 kbar, heated at heating rate 5-15 C/s up to 1000-1300 C, followed by holding at this temperature for 30-120 s. Yield of c-BN with dispersity 80-240 mcm is 40-57 wt.%. Impurities are easily washed out water. EFFECT: simplified method for producing c-BN. 1 tbl