Improved oxide scale adherence of low-Pt/Hf co-doped β-NiAlCrSi coating on superalloy IC21 at 1200 °C

Low-Pt/Hf co-doped β-NiAlCrSi and Hf single-doped β-NiAlCrSi coatings were produced onto advanced single crystal (SC) superalloy IC21 containing Mo, respectively. The cyclic oxidation and interdiffusion behaviour of the coatings at 1200 °C were investigated. As compared to the single-doped coating, the co-doped coating revealed suppressed interdiffusion and delayed β-γ′ phase transformation. Simultaneously, the interfacial voids formation and scale rumpling were inhibited. As a result, the thermally grown oxide (TGO) grown on the co-doped coating exhibited improved adherence and the roles of Pt and Hf in low-Pt/Hf co-doped coating were discussed.