| 摘要 |
60SD00455 CBN/CBN COMPOSITE MASSES AND THEIR PREPARATION Broadly, the present invention is directed to a high pressure/high temperature (HP/HT) process for making polycrystalline CBN composite masses from graphitic boron nitride (GBN) in the substantial absence of catalytically-active material. The present invention specifically comprises subjecting a mixture of different structural forms of GBN to simultaneous conversion of each for making a CBN/CBN composite mass. Pyrolytic boron nitride/hexagonal boron nitride (PBN/HBN) mixtures are ideally suited for conversion into the inventive CBN/CBN composite masses of the present invention.
|
