Corrosion of CVD Silicon Carbide in 500°C Supercritical Water

Abstract

A high‐purity CVD β‐SiC showed a relatively low corrosion rate in deoxygenated supercritical water at 500°C. The corrosion rate was lower than that previously reported for CVD SiC in 360°C water and much lower than that reported for sintered and reaction‐bonded SiC. The present study confirmed that CVD SiC was preferentially attacked at the grain boundaries. Analytical examinations did not reveal the presence of a measurable oxide scale. As a result, it is believed that corrosion of the high‐purity SiC occurred via hydrolysis to hydrated silica species at the surface that were rapidly dissolved into the supercritical water.