High Temperature Oxidation of CrAl-coated Zr–1 Nb Alloy in 1000 – 1300 °C Steam

The CrAl coating of 13 μm thick on Zr–1 Nb alloy prepared by filtered cathodic vacuum arc deposition with Cr70Al30 target exhibited excellent steam oxidation resistance below 1200 °C, but its protective properties were obviously weakened at 1300 °C. The mass gain of CrAl-coated alloy was 7.8%, 6.5%, 16.6% and 66.0% of that of bare alloy after 3600 s oxidation at 1000 °C, 1100 °C, 1200 °C and 1300 °C, respectively. The addition of a little Al in CrAl coating was beneficial to further suppress oxygen diffusion into alloy substrate due to the hindering effect of Al2O3 against oxygen atoms.