Enhanced high-temperature oxidation resistance of a zirconium alloy cladding by high-temperature preformed oxide on the cladding

Using a zirconium alloy, pre-oxidation was conducted at 1200 °C in a steam environment, and the pre-oxidised specimens were oxidised at 1012, 1100, and 1200 °C. The preformed oxide enhanced the oxidation resistance significantly during the subsequent oxidation at 1012 and 1100 °C. In addition, the preformed oxide enhanced the breakaway oxidation resistance greatly at 1012 °C. The microstructures of the preformed oxide were analysed using TEM and EPMA. The oxidation resistance enhancement may be related to the large columnar grain width of the preformed oxide and Zr-Sn type precipitates formed at the grain boundaries.