Investigation on failure mechanism and interfacial diffusion behavior of NiCoCrAlYTa coating at high temperature

The isothermal oxidation behavior of NiCoCrAlYTa coating deposited by arc ion plating (AIP) technology on DZ22B substrate was systematically investigated at 1050 degrees C and 1100 degrees C for 200 h. The results revealed a transition in oxide scale composition, which of undulation degree was also increased. The growth process of oxide scale involved additional control mechanisms except internal diffusion of oxygen. Interdiffusion at coating/substrate interface transformed gamma into gamma' phase in substrate, precipitating MC carbides. MC carbide underwent progressive disintegration, transforming into M6C carbide. The results could provide experimental data and theoretical support for the design of long-life protective coatings at ultra-high temperatures.