METHOD OF PRODUCING POLYCRYSTALLINE CUBIC BORON NITRIDE Russian patent published in 2011 - IPC C01B21/64 C04B35/5831 B82B3/00 C30B28/00 B01J3/06 C30B29/38 

FIELD: process engineering.

SUBSTANCE: invention relates to production of synthetic superhard materials, particularly, polycrystalline cubic boron at high pressure and temperature to be sued in chemical, electronic and other industries. Proposed method comprises preparing mix of wurtzite-like and cubic modifications in relation of 1:4 to 2:1, respectively, processing it in planet mill for mechanical activation and crushing to grain size not exceeding 1 mcm, forming and annealing the mix at 1400-1800°C and 7.0-9.0 GPa, keeping at annealing temperature for time defined by conditions of transition on boron nitride wurtzite modification into cubic one without recrystallisation, equal to 5-30 s. Accurate time of keeping at preset temperature and pressure is defined proceeding from necessity of preservation of 5 to 15% of wurtzite boron nitride amount in initial mix.

EFFECT: lower temperature, pressure and duration of synthesis, improved mechanical and physical properties.

2 cl, 5 ex, 1 tbl