Study on the performance of liquid phase sintered SiC ceramics

The SiC ceramics has been prepared by the hot pressing of 30 MPa with Al₂O₃ and Y₂O₃(weight ratio of 2:3) as sintering aids under the nitraogen or argon atmosphere at 1900~1970°C. The densification and the open porosity has been measured by Archimedes method. The phase, microstructure and the thermal conductivity have been characterized by using XRD, SEM(EDS) and the thermal conductivity tester respectively. The effects of the sintering temperature, sintering atmosphere and the thermal conductivity have been investigated. The results showed that the dense SiC ceramic with the porosity less than 0.30% and the thermal conductivity up to 182.50 W/(m·K) could be obtained when the amount of sintering aids was 10%. The densification and the thermal conductivity of the SiC cermic were decreased obviously with the amount of sintering aids decreased to 6%. In the argon atmosphere, the aids of Al₂O₃-Y₂O₃ had better wettability with SiC matrix.