Superhard Composite Containing Boron Nitride and Silicon Nitride

摘要

As a superhard material, next to diamond, the cubic boron nitride (cBN) is of great interest owing to its efficiency in machining ferrous alloys. In nature, only the hexagonal, hBN allotropic form is found. In practice, high pressure and high temperature (HPHT) synthesis has to be used to produce small cBN crystals. For larger size machining inserts, the powder-like cBN crystals need to be sintered at specific HPHT conditions using a metallic binder. The present work investigates the sintering of cBN inserts using a Si_3N_4 binder agent. The results disclosed relatively high hardness for the inserts and revealed their effectiveness in machining high strength steels.