Improvement of sinterability of Al2O3-SiC ceramics

An Al2O3-SiC mixed powder with additional SiO2 powder and pre-oxidized Al2O3-SiC mixed powder containing SiO2 were hot-pressed in Ar. The sinterability was examined in comparison with Al2O3-SiC mixed powder free from SiO2. The structures and transverse rupture strength were also examined. Sinterability improved with powder containing over 2-3% SiO2. This is due to mullite formation and the appearance of mullite-SiO2 eutectic liquid during the period of rising temperature. With increasing SiO2 contents, the microstructure became locally coagulated and T.R.S. decreased slightly. As the fracture source, an area probably due to the coagulated structure was observed.