METHOD OF MANUFACTURE OF POLYCRYSTAL SUPERHARD MATERIAL Russian patent published in 2005 - IPC

FIELD: manufacture of polycrystal superhard materials on base of dense modifications of borazon and wurtzite-like boron.

SUBSTANCE: borazon and wurtzite-like boron may be used as materials for parts of high-pressure apparatus and tools in treatment of wear-resistant materials, first in sharpening heat-treated steels, gray and high-strength cast irons, tungsten-containing hard alloys, reinforced concrete, stone and plastics. Proposed method includes subjecting boron nitride to action of pressure from 6.5 to 9 Gpa at high temperature for 2-3 min, after which temperature is reduced to room magnitude and pressure is reduced to atmospheric level at rate of 200°C per Gpa to 250°C per Gpa. Used as borazon is wurtzite-like boron or mixture of wurtzite-like boron and borazon at its content 0f from 0 to 50 mass-%; process is performed at temperature of from 1500°C to 2200°C in field of their stability under isothermal conditions; temperature gradient of from 20°C/mm to 70°C/mm may be additionally created in direction of reaction cell axis. Borazon and wurtzite-like boron are placed in reaction cell layer-by-layer perpendicularly to cell axis; composition of one layer differs from that of adjacent layer in content of wurtzite-like boron and borazon; graininess of borazon ranges from 3/2 mcm to 200/160 mcm.

EFFECT: enhanced efficiency; possibility of producing flaw-free material possessing high strength.

3 cl, 11 dwg, 1 tbl, 11 ex