High temperature oxidation and interdiffusion behavior of the single-phase (Ni,Pt)Al coating on the high generation single crystal superalloy with and without Re diffusion barrier

The high-temperature oxidation and interfacial elemental interdiffusion behavior of single-phase (Ni,Pt)Al coatings with and without a Re-based diffusion barrier (DB) on the third- and fourth- generation single‑crystal superalloys at 1150 °C and 1200 °C were investigated. Microstructure evolution, oxidation behavior, interfacial elemental interdiffusion behavior, and the effect of the Re‑based DB were systematically characterized. The results show that the Re‑based DB effectively suppresses elemental interdiffusion between the coating and the substrate, significantly reducing the formation of secondary reaction zones (SRZ) and needle‑like topologically close‑packed (TCP) phases, retarding the phase transformation from β to γ′, and improving the oxidation resistance of the coating. The Re‑based DB exhibits superior diffusion‑blocking capability and higher thermal stability on the fourth generation superalloy (containing 3% Ru) than on the third generation. The role of Ru in suppressing Al diffusion and enhancing the thermal stability of the Re‑based DB is discussed.