关键词: IIb金刚石, 高温高压, 热冲击韧性, 静压强度, 热稳定性

Abstract: The IIb type diamond was synthesized at high temperature and high pressure (HTHP) by using the technique of adding BN in Febased catalyst. The appearance of the IIb type and the Ib type diamond was studied under opticsmicroscope. Static compressive strength measurement, impact toughness measurement and DTA and TG analysis were used to research thermal stability of these two types of diamond in atmosphere. The results demonstrate that the IIb type diamond possesses not only fine static compressive strength and thermal impact toughness, but also owns excellent thermal stability. In addition, an available way is put forward to improve the thermal stability of diamond. Thermal decompose and mass loss of diamond happened at the same time shows that it is graphitization and oxidation of diamond causes the mass loss.

Key words: the IIb type diamond, high temperature and high pressure, thermal impact toughness, static compressive strength, thermal stability