PRODUCTION OF CUBIC BORON NITRIDE

摘要

PURPOSE:To prolong the life of an apparatus and to obtain cubic boron nitride in a high yield by adding the boronitride of an alkali metal to pyrolytic boron nitride and holding them under conditions of high temp. and pressure within ranges in which cubic boron nitride is thermodynamically stable. CONSTITUTION:The boronitride of an alkali metal is added as a catalyst to pyrolytic boron nitride and they are held under conditions of high temp. and pressure within ranges in which cubic boron nitride is thermodynamically stable to convert the pyrolytic boron nitride into polycrystalline cubic boron nitride. The pyrolytic boron nitride used is highly oriented boron nitride synthesized by a special production method called a chemical vapor deposition method (CVD method). Lithium boronitride is preferably used as the boronitride of the alkali metal. It is necessary to add the catalyst by >=0.1mol% of the amount of the pyrolytic boron nitride as starting material.