Oxidation behavior of CoNiCrAlY bond coatings with single/double layer structure in water vapor environment at 1100 °C

A comparative study was conducted on the oxidation behavior of four different bond coat structures: single-layer air plasma spraying (APS), single-layer high-velocity oxygen fuel (HVOF), double-layer APS + HVOF, and double-layer HVOF + HVOF in a high-temperature and high-water vapor environment. The oxidation resistance and surface mixed oxide (MO) growth behavior and formation mechanisms of different structures in this environment were analyzed. The results indicate that CoNiCrAlY bond coats with different structures exhibit distinct oxidation behaviors in a high-temperature, high-water vapor environment. The growth of the MO phase is significantly influenced by the bond coat structure, and the high-water vapor environment promotes the nucleation and growth of bulk MO phase, resulting in a multilayer internal structure. Among these, the double-layer HVOF bond coat structure demonstrates superior resistance to water vapor corrosion, with fewer surface MO formations. These findings suggest that proper structural design can enhance the water vapor corrosion resistance of MCrAlY bond coats, providing theoretical foundations and technical support for optimizing their applications in high-temperature, high-water vapor environments.