Corrosiveness of CMAS and CMAS + salt (NaVO3, Na2SO4 and NaCl) to YSZ thermal barrier coating materials

Abstract

Calcium-magnesium-alumina-silicate (CMAS) is found to consist with many salts especially in marine environment, where thermal barrier coatings (TBCs) are widely used. In this study, the corrosiveness of CMAS + salt (NaVO3, Na2SO4 and NaCl) to a typical TBC material of Y2O3 partially stabilized ZrO2 (YSZ) was investigated. As compared to CMAS, CMAS + salt had lower melting temperature, viscosity and crystallization ability. This led to the CMAS + salt more aggressive to YSZ at relatively low temperature, and more permeable at 1250 ℃. Accordingly, the CMAS + salt had higher corrosiveness than CMAS to TBCs, which is worth special attention.