Superior oxidation resistant MCrAlY bond coats prepared by controlled atmosphere heat treatment

Long-life thermal barrier coatings for high-performance gas turbines require MCrAlY bond coats with high oxidation resistance. In this study, the oxidation resistance of bond coats was significantly improved by a novel controlled atmosphere heat treatment (CAHT). Results show that large alpha-Al2O3 grains with a grain size up to micron were formed on the surface of heat-treated MCrAlY bond coats. These large alpha-Al2O3 grains significantly improved the oxidation resistance of bond coats. We found that the grain size of alpha-Al2O3 and the surface microstructure changes of bond coats can be controlled by the oxygen partial pressure of CAHT.