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

The CrAl coating of 13 mu m thick on Zr-1 Nb alloy prepared by filtered cathodic vacuum arc deposition with Cr70Al30 target exhibited excellent steam oxidation resistance below 1200 degrees C, but its protective properties were obviously weakened at 1300 degrees 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 degrees C, 1100 degrees C, 1200 degrees C and 1300 degrees 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.