Abstract:The superalloy-based hot components in gas turbines (combustion and turbine sections) work at 1000oC or even higher temperatures in long term, resulting in some critical problems occurred in the component materials such as high-temperature oxidation, hot corrosion, loading and mechanical property changes. MCrAlY coatings play an important role in protecting those hot components. However, the elemental diffusion and microstructure development take place in the superalloy-MCrAlY coating systems at high temperatures, which influences the properties and service lifetime of the components. In this study, ThermoCalc and DICTRA software were used with considering the surface oxidation of MCrAlY coatings, so that "oxidation-diffusion" models were set up in the superalloy-coating systems. The models were successfully applied in the optimization of coating composition and the prediction of the coating life. We also summarized the other applications of the thermodynamic calculations in the superalloys and coatings