Sintering of cubic boron nitride under high pressures and temperatures in the presence of boron carbide as the binding material

Abstract

Sintering of cubic boron nitride (cBN) was carried out by subjecting fine powders of cBN to high pressures and temperatures (<i style="">P</i> = 50-60 kb, <i style="">T</i> = 1200-1500°C ) in the presence of boron carbide as the main binding material together with a small amount of aluminium nitride. The composites were characterized by X-ray diffraction, scanning electron microscopy, FTIR, Raman Spectroscopy and microhardness measurements. Best composites with a maximum microhardness of about 3700 kg/mm² were obtained at around 50 kb, 1450°C using 75 wt% of cBN in the mixture. No peaks due to hexagonal boron nitride were observed in the XRD patterns.