High-pressure sintering of cubic boron nitride

Abstract

Cubic boron nitride (cBN) powder was compacted at high pressure and high temperature using a solid solution of titanium carbide and titanium nitride (TiC _x N_1−x ) as binding material in the presence of a small amount of aluminium. Different compositions of (TiC _x N_1−x ), 0<x<1 were used as binders. The weight percentage of cBN, TiC _x N_1−x and aluminium were optimized and found to be critical; any marked deviation from these optimized values deteriorated the quality of compacts. Various high-pressure sintering parameters such as pressure, temperature and sintering time, etc, were optimized for this binder. The compacts were also characterized using X-ray diffraction, scanning electron microscopy and microhardness measurements. The microstructural and X-ray diffraction observations indicated no marked changes in the compacts as the value ofx in TiC _x N_1−x was varied, but the microhardness was found to depend on the value ofx.