Progress in Novel Composite Thermal Barrier Coating

Abstract

Improved structure design has been acknowledged as an effective approach to obtain thermal barrier coating (TBC) with excellent resistance to high-temperature oxidation and spallation. Since ceramic composites can effectively enhance the strength and durability of ceramic components and improve their fracture toughness, it is reasonable to propose that composite structure of TBC should possess improved mechanical properties than its traditional structure with single phase in bond coat and top coat. In this paper, the progress in novel composite TBC developed by the authors’ research group has been summarized, including TBCs with bond coat of ceramic/ceramic and ceramic/noble metal composite coatings which replace the traditional alloy bond coat, and also TBCs with novel composite structure have been studied. It has been investigated that these TBCs exhibit not only excellent high-temperature oxidation resistance, but also excellent resistance to cracking, spallation and buckling under thermal cycling. Such beneficial effects can be attributed to the sealing mechanism of these coatings on oxygen diffusion, the improvement of thermal expansion mismatch and the toughening effects of these composite structures. It would be a growing trend in introducing various composite modes into the traditional thermal barrier coating or developing new composite structure of thermal barrier coating.