Oxidation and hot corrosion of thermal barrier coatings (TBCs)

Thermal barrier coatings (TBCs) with a two-layered structure consisting of an oxidation protective bond coat and a thermally insulating yttria stabilized zirconia (YSZ) top coat are used to provide thermal insulation and oxidation resistance to metallic components from the hot gas stream in gas turbine engines used for aircraft propulsion, power generation and marine propulsion. The oxidation behavior of the bond coat, including both MCrAlY and Pt aluminide coating, has a major impact on the life of the TBCs. The oxidation behavior and failure mechanisms of TBC systems are summarized. In addition, the degradation mechanisms experienced by TBC systems exposed to deposits are also discussed.