Electrical and thermal conductivity of liquid phase sintered SiC

Commercial silicon carbide ceramics are semi-conductors. To obtain SiC ceramics with insulating properties, a synthesised SiC powder which was doped with vanadium and boron to get insulating behaviour due to compensating mechanism, and in addition a commercial powder was used. Both powders were pressureless sintered by liquid phase sintering. Different packing powders were used to influence the electrical behaviour of the dense SiC ceramics. The influence of these conditions on the electrical and thermal conductivity are described. Densification of SiC by a solution-precipitation mechanism in the temperature range around 1900°C results in a decrease of resistivity. The resistivity of the commercial powder could be improved by using a vanadium based packing powder.