METHOD OF PRODUCTION OF POLYCRYSTALLINE CUBE BORON NITRIDE Russian patent published in 2000 - IPC

FIELD: production of superhard materials; manufacture of parts for high-pressure apparatus. SUBSTANCE: pressed mixture of wurtzite-like and cube boron nitride, mass ratio of (65- 35):(35:65) is placed in high-pressure apparatus, type toroid. Size of grain of cube boron nitride is 3 to 40 mkm. Pressure of 6.5 to 12.5 hPa and temperature of 165- to 2500 C correspond to field of thermodynamic stability of cube boron nitride. Mixture is held for 1 to 5 min, after which temperature is dropped to room level and pressure is reduced to atmospheric level at rate of 200 to 250 C per hPa. Yield of satisfactory POLYCRYSTALLINE cube boron nitride is 86 to 96 mass-%, wear resistance at turning is 75 to 90, abrasive wear resistance is 0.0170 to 0.0229 mm/km and compressive strength is 2.90 to 3.75 hPa. EFFECT: enhanced efficiency. 1 dwg, 1 tbl, 4 ex