Preparation and microstructure of Ti3SiC2 bonded cubic boron nitride superhard composites

Ti3SiC2-cBN composite was prepared by a cubic high pressure apparatus under 4.5 GPa at 1050°C for 10 min with commercial cubic boron nitride (cBN) powders and Ti3SiC2 powders as starting materials. The Ti3SiC2 powders were prepared in a tube furnance under Ar atmosphere.The microstructrure was observed using scanning electron microscope. The phase and the composition were analyzed using X-ray diffraction and electron energy dispersive spectra. The results show that the cBN particles were homogenously distributed in Ti3SiC2 matrix. The cBN particles are bonded with the matrix during friction and are not removed. The main phase of the composites matrix is Ti3SiC2 with a little TiC as a second phase. However, the composites cannot be obtained in a tube furnace under normal pressure. The main reason is not the phase transformation of cBN at a high temperature under normal pressure. It is because that Ti3SiC2 reacts with BN and decomposes at a high temperature.