70 巻 (2006) 2 号 p. 188-191
A new and stable bond coat system, EQ coating, which is in equilibrium thermodynamically with γ/γ′ substrate, suppresses the diffusion of alloying elements between the substrate and coating, and the formation of SRZ. In this study, β phase is proposed as the candidate for oxidation-resistant EQ coating material because of its high Al content. Combinations of γ/γ′ alloy for the substrate material and β alloy for the coating material which are in equilibrium were developed in Ni-Al-Cr ternary system and Ni-base multi-component system. Diffusion couples were made for each combination and were heat treated at 1100°C for 300 h. The concentration profiles of the alloying elements at the interfaces between the β alloy and γ/γ′ alloy in the diffusion couples were analyzed to investigate the existence of the diffusion zone. Cyclic oxidation examination was performed and oxidation properties were discussed.