Oxidation behavior of a glass-based composite coating with a low expansion cermet bond-coat and an AlN diffusion barrier on K417G superalloy

A ceramic particle reinforced glass matrix composite coating with a novel Ni + CrAlYSiN cermet bond-coat and an AlN diffusion barrier was prepared on K417G superalloy, and its oxidation behavior at 1000 °C was investigated. The oxidation rate of the coating was significantly reduced compared with the Ni + CrAlYSiN coating, because the glass-based top-coat promoted selective oxidation of Al within the bond-coat due to the oxygen barrier effect. Furthermore, cyclic oxidation resistance of the coating was improved by the low expansion bond-coat while weakened by the microstructure degradation of the top-coat. Additionally, the AlN diffusion barrier effectively restrained interdiffusion between bond-coat and substrate.