Sintering of silicon carbide with rare-earth oxide additions

This paper reports that rare-earth oxide additions, such as yttrium oxide, in silicon carbide can promote sintering to densities above 95% of theoretical density when sintered in surroundings of coarse aluminum oxide and silicon carbide packed within a carbon crucible. Aluminum oxide is transported into the SiC body where it reacts to form a reactive liquid phase. Aluminum oxide is believed to be transported by a gas species. Densification occurs by reactive liquid sintering. Microstructural analysis shows that the liquid phase is eliminated from the microstructure by prolonged heating above 2050 degrees C. Scanning Auger microscopy was used to analyze the Al:Y:O ratios associated with the second phase