The environment within the advanced industrial gas turbine is highly oxidizing and contains the compounds, salts and oxides that accelerate the rate of oxidation of structural materials. Protective coatings which differ from each other and the superalloys in composition and phase morphology, enhance the oxidation and corrosion resistance of the superalloys. As temperatures increase, the relativity stability and long term effectiveness of the coatings is of concern. The interdiffusion of coating and alloy constituents can affect chemical and mechanical properties. Long term studies are appropriate. Thermal barrier coatings, introduced at the inception of the current program will further improve the thermal efficiency of industrial gas turbine engines. The interaction between state-of-the-art thermal barrier coatings (TBC) and oxidation and corrosion in the coal fired environment is of concern and should be critically examined. The superior performance of the overlay coating is related to thickness rather than chemistry. With respect to sodium sulfate corrosion, the life of the overlay coating is 2.7 times longer than that of the platinum aluminide which in turn is 2.2 times longer than that of the simple aluminide. The ranking of the coatings is unchanged with respect to eutectic soft corrosion, however the salt is more aggressive. The life of the overlay coating is 1.4 times longer than that of the platinum aluminide which is 1.9 times longer than that of the simple aluminide.