Oxidation of a NiCrAlYSi overlayer with or without a diffusion barrier deposited by one-step arc ion plating

The coating systems of a NiCrAlYSi overlayer with or without a diffusion barrier (DB) were deposited by one-step arc ion plating (AIP). Isothermal and cyclic oxidations were performed at 1050 °C for 100 h and 100 cycles, respectively. The results indicate that the duplex coating system exhibits a more effective protection for the substrate, where thin and continuous scales are adhered to the overlayer surface, and very limited oxidation and interdiffusion attacks are detected. After exposure for 100 h or 100 cycles, the DB is stable and efficient. The oxidation resistance mechanism for the two coating systems is discussed.