Advanced thermal and environmental barrier coatings for ceramic matrix composites

SiCf/SiC ceramic matrix composites (CMCs) are advanced high-temperature structural materials for gas turbine engines. Due to the extensive vapor corrosion of the CMCs at high-temperature combustion environments, environmental barrier coatings (EBCs) are required to apply on the surface of CMCs to improve service lifetime and performance. In some cases, EBCs are utilized in conjunction with thermal barrier coatings (TBCs). A concept of thermal and environmental barrier coatings (TEBCs) is also promoted. Recently, EBCs as key part of the engineering application of CMCs attracted intensive attention. This chapter generally summarizes the application background, development of TEBCs materials, and deposition technologies. The background of TEBCs includes application demand, key requirements, and continuous evolution. The materials of TEBCs can be divided into thermal barrier coatings and environmental barrier coatings, and several typical materials are selected for introduction. For several commonly used deposition techniques (including plasma spraying, electron beam physical vapor deposition, and plasma spraying physical vapor deposition), it describes the technical principles, characteristics of the as-deposited coatings, and some related literature reports. Finally, the existing shortcomings and challenge are discussed, and the development direction on the investigation is proposed.