ELEVATED-STRENGTH CUBIC BORON NITRIDE PREPARATION METHOD Russian patent published in 2004 - IPC

FIELD: inorganic synthesis. SUBSTANCE: invention relates to manufacture of abrasive and blade tools. Hexagonal boron nitride is supplemented by cubic boron nitride and catalyst to form initial blend. In another embodiment, blend is prepared from hexagonal boron nitride, boron, and lithium nitride at weight ratio 90:3:7. Blend is briquetted and placed into heat- and electro-insulated container. Between the blend and heater, an element with mass representing 30% of the mass of blend is placed. Element is made from product recovered after catalytic synthesis of cubic boron nitride. This product contains up to 97% hexagonal boron nitride and up to 3% graphite, the rest being cubic boron nitride. As said element, initial hexagonal boron nitride in mixture with graphite and cubic boron nitride as well as group II metal oxides or carbonates can be used. Element is compacted with binder to give stable form, which is then dried. Blend is affected by pressure 4-5 GPa and temperature 1500-1600^(r)' for at least 4 min. Invention allows reducing consumption of hexagonal boron nitride to 1.4-1.5 carat per 1 carat of cubic boron nitride. EFFECT: reduced consumption of raw material, improved quality of product, and enabled controlled distribution of graininess in the powder. 4 cl, 5 tbl, 5 ex