Effect of High Temperature Aging on Microstructure and Mechanical Properties of Environmental Barrier Coatings for CMC.

Abstract

In order to develop reliability of Environmental Barrier Coatings (EBCs) for ceramic matrix composite, effects of high temperature aging on pore structure and thermo-mechanical properties of an atmospheric plasma sprayed BSAS (BaO-SrO-Al₂O₃-2SiO₂) coating and Mullite (3Al₂O₃-SiO₂) coating were investigated. EBCs have an important role to protect substrate from environmental attacks. Free-standing coating specimens of BSAS and Mullite were prepared. The cross-sectional SEM observation was carried out on EBC coatings, and the microstructure of the coating was identified. The elastic modulus of the coating was measured by micro-indentation testing. The measurement of thermal expansion coefficient of the coating was also carried out in this study.