Effect of nickel on the FeCrAl alloy oxidation resistance in steam environment at high temperature (1000 °C)

Despite their widespread application, FeCrAl alloys face several challenges in maintaining performance under high thermal cycling and extreme oxidation conditions. Following the 2011 Fukushima Daiichi accident, there has been a growing interest on developing of accident tolerant fuel (ATF) cladding materials, as well as modifications to existing ones, for advanced nuclear reactors. This study investigates the role of nickel in enhancing the high-temperature oxidation resistance of FeCrAl alloys, which are being considered as potential replacements for zirconium alloys. Specifically, the oxidation behavior of FeCrAl alloys with 17 wt% chromium and varying nickel contents Fe-17Cr-5.5Al, Fe-17Cr-5.5Al-1Ni, and Fe-17Cr-5.5Al-3Ni were examined under steam environment at 1000 °C for 5000 s. The oxide layer thickness and compositional changes were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM-EDX) and transmission electron microscopy (TEM). The results indicate that low nickel concentrations significantly improve the oxidation resistance of FeCrAl alloys, making them more suitable for accident-tolerant fuel cladding applications in advanced nuclear reactors. This study provides valuable insights in optimizing FeCrAl alloy compositions to improve their oxidation resistance under extreme conditions.