Microstructural evolution of the Cr/FeCrAl coated Zircaloy-4 under simulated PWR and high-temperature steam oxidation environments

A dual-layer Cr/FeCrAl coating was deposited on zircaloy-4 using magnetron sputtering, and its corrosion performance was investigated under simulated pressurized water reactor (PWR) and high-temperature steam environments. Despite experiencing weight loss in high-temperature and high-pressure water (360 degrees C/18.6 MPa), the coating developed a durable Fe/Cr composite oxide layer on its surface, effectively mitigating corrosion. In high-temperature steam conditions, a continuous Al2O3 coating formed, providing protection up to 1200 degrees C for 30 min. Microstructure analysis unveiled the formation of Zr (Fe, Cr)2 layer, which played a crucial role in preventing Fe indiffusion and the formation of Fe-Zr low melting point eutectic. These findings provide valuable insights into enhancing the corrosion and oxidation resistance of zirconium alloy cladding in extreme environments.