Enhanced oxidation resistance and adhesion performance of Cr–Mo-coated Zry-4 by a thin Cr layer in steam up to 1600 °C

In this study, Cr–Mo–Cr tri-layer coating with Cr inner layer is designed and compared with the pure Cr coating and Cr–Mo bi-layer coating in steam up to 1600 °C. The Cr–Zr interdiffusion is mitigated effectively by Mo layer. The outer Cr2O3 layer of Cr–Mo coating peels off, and Mo–Zr eutectic reaction occurs above 1500 °C. Cr–Mo–Cr coating maintains the integrity and protects the Zr substrate from being oxidized. The bond performance is improved by forming Mo–Zr–Cr solid solution. Finite element simulation indicates that the stress in the coating is reduced by 6 GPa in the presence of the inner Cr layer.