METHOD OF PRODUCTION OF SUPERHARD MATERIAL BASED ON DENSE FORMS OF BORON NITRIDE Russian patent published in 1994 - IPC

FIELD: powder metallurgy. SUBSTANCE: for widening the manufacturing potentialities due to the increase of yield of applicable specimens, improvement of material cutting properties powder of wurtzite boron nitride with a particle size of less than 1 u or its mix with powder of cubic boron nitride with a particle size of not more than 3 u, cubic boron nitride making up 3 to 80 per cent by mass is placed in contact with the metallic component made in the form of a plate, ampule or shell of Mg and/or Al and their alloy with addition of metal from series Mo, Si, Cu, Ge and subsequent hot compaction at a pressure of 5 to 25 kbars. The relation between boron nitride and metallic component is (10-50):(90-50) percent by mass, and the amount of addition in the metallic component is 5 to 20% of the total mass of metal. Heating at compaction is conducted by two isothermic holdings: the first - at 700 to 900 C during 30 to 60 s, the second - at 950 to 1500 C during 70 to 120 s. Additionally introduced in the sintered bar of dense forms of boron nitride before compaction is a metallic component in the form of powder with a submicron size of particles, its amount being 5% of the sintered bar mass. The yield of applicable specimens is 94 to 98%. EFFECT: widened manufacturing potentialities. 1 tbl