Cubic boron nitride (CBN) compact and direct conversion process for making same from pyrolytic boron nitride (PBN)

摘要

A process for making a sintered polycrystalline cubic boron nitride (CBN) compact by direct conversion of a pyrolytic, preferably substrate nucleated, boron nitride (PBN) comprises subjecting the PBN to temperatures and pressures within the CBN stable region. The crystallites of the compact produced by this process are preferentially oriented. Also, such compacts have a high thermal conductivity between about 2 watts/cm DEG K and 9 watts/cm DEG K and thus are useful as a heat sink for electronic devices. The size of the CBN crystallites of the compact may be between about 1 x 103 ANGSTROM to 1 x 105 ANGSTROM .