Methods for preparing cubic boron nitride sintered body and cubic boron nitride, and method for preparing boron nitride for use in the same

摘要

There are disclosed methods for preparing cubic boron nitride sintered body. One method involves pyrolyzing borazine and/or a borazine derivative to obtain a boron nitride; mixing said boron nitride and a catalyst composed of a metal and/or metallic compound; and reacting the mixture at a pressure of 3 GPa or more and at a temperature of 700° C. or more. Another method comprises the step of pyrolyzing borazine and/or a borazine derivative to obtain a boron nitride; mixing said boron nitride and a catalyst composed of a metal and/or metallic compound; reacting the mixture at a pressure of 3 GPa or more and at a temperature of 700° C. or more; and removing the catalyst from a formed product. The conversion rate into cubic boron nitride achieved with these methods is as high as 100%, and the obtained cubic boron nitride is highly pure and fine. Also disclosed is a method for preparing boron nitride by pyrolyzing at least one compound selected from the group consisting of borazine and/or a borazine derivative at a temperature of 150° to 700° C. and a pressure of 10 MPa or more.