Abstract
Corrosion resistance of sintered SiC ceramics, which were prepared using defferent sintering methods, crystal structures and sintering aids, were tested in pure water, 0.1kmol·m-3 H2SO4, and 0.1kmol·m-3 LiOH at 300°C for 50h. It was found that the corrosion resistance of SiC ceramics prepared using pressureless sintering, β-SiC powder, and sintering aids of B and C is better than those prepared using reaction sintering, α-SiC powder, and the aids of Al2O3. The corrosion rate of SiC ceramics in high temperature solutions increased with increasing concentration of oxidizing reagents in the solutions, and this suggests the corrosion proceeds in electrochemical reactions. The XPS analysis of specimen surfaces before and after the corrosion tests revealed that SiO2 films formed on SiC ceramics in air dissolved in high temperature solutions and no films grew in such solutions.
