The wetting behaviour and reaction kinetics in diamond–silicon carbide systems

The wetting behaviour of silicon on diamond and the interaction of diamond with molten silicon were investigated. It was found that diamond is well wetted by molten silicon reaching a contact angle of about 20° after melting. The wetting is caused by the rapid formation of a SiC interlayer by nucleation of silicon carbide grains on the surface of the diamond. Investigations of the interaction of silicon with CVD diamond, using SEM, showed that the initial rate of SiC formation is very fast and is significantly reduced after the formation of a 4–6 μm thick dense SiC interlayer. At that stage further growth is likely to be controlled by the diffusion of Si and C through the grain boundaries of the silicon carbide interlayer. The results were compared with the interaction of silicon with glassy carbon.