Electric current activated sintering of hard silicon carbide at lower temperatures with aid of carbon onion

Silicon carbide bodies are prepared by electric current activated sintering at lower temperatures with the aid of carbon onion. Sintering process is monitored in terms of compaction rate of silicon carbide particles. The variations of relative density and hardness of sintered bodies are related to carbon onion content. As a result, the addition of 8 mass% of carbon onion provides silicon carbide sintered body with 94% of relative density and 2800HV at as low sintering temperature as l850°C. Carbon onion is found to contribute to smaller void formation caused by inhibition of grain growth and to peak shift of the highest compaction rate to lower sintering temperatures. Furthermore, the inclusion of carbon onion influences little effect on hot hardness and improves lubricity and electrical conductivity of silicon carbide sintered bodies.