Enhancement of high temperature steam oxidation resistance of Zr–1Nb alloy with ZrO2/Cr bilayer coating

Abstract The ZrO2/Cr bilayer coating on Zr–1Nb alloy fabricated by plasma electrolytic oxidation and filtered cathodic vacuum arc deposition duplex treatments had good steam oxidation resistance. The mass gain of ZrO2/Cr-coated alloy was about 36 %, 44 % and 59 % of that of Cr-coated one after 3600 s steam oxidation at 900 °C, 1000 °C and 1100 °C, respectively. The top Cr layer for Cr-coated and ZrO2/Cr-coated alloys was oxidized into a Cr2O3 layer, and then a part of Cr2O3 was reduced by Zr to form metallic Cr layer again after the as-prepared Cr layer was completely consumed.