Interfacial strength and oxidation resistance of the NiCrAlYSi coating with a diffusion barrier and/or buffer layer on DSM11 deposited by continuous arc ion plating

The NiCrAlYSi coating with a diffusion barrier (DB) and/or buffer layer (BL) on DSM11 substrates was deposited by continuous arc ion plating (AIP) method. The interfacial strength, oxidation resistance and diffusion-barrier effectiveness were investigated. The tensile adhesion test result showed that the interfacial adhesive strength was stronger than that in the coating system with a diffusion barrier deposited by the conventional two-step AIP. The pre-deposition of the buffer layer into the DB/DSM11 interface could improve the interfacial strength further. The oxidation test results indicated that the multilayer could provide more effective protection for the DSM11 substrate than the single coating system. During thermal exposure, continuous and adhered Al2O3 scales were presented to the coating surface and the interdiffusion of alloying elements between the overlayer and the substrate was suppressed markedly. After thermal exposure or thermal cycle, the diffusion barrier was stable and kept efficient.