Mechanisms of Al2O3 and Cr2O3 formation during FeCrAl alloy Oxidation: A First-Principles study

FeCrAl alloys are the best candidates for nuclear fuel cladding materials due to their excellent corrosion resistance and high-temperature oxidation resistance. However, the oxidation mechanisms of them have not been fully explained. In this study, we investigate the oxygen adsorption on the surface of FeCrAl alloys using density functional theory. Our results reveal that Cr are prone to interact with O. Furthermore, an increasing number of Cr atoms in the adsorption configuration leads to a higher absolute value of the adsorption energy, especially for three Cr (-4.48 eV). To gain further insights, we conduct an analysis of their charge and orbital interactions. We find that Al atoms transfer the most charge to O atoms, resulting in the most stable bonding. This finding explains the experimental phenomenon where Cr2O3 is primarily observed at low temperatures or in the initial oxidation stage, while Al2O3 is observed at high temperatures during prolonged oxidation. This study highlights the variations in the behavior of metal atoms during their interaction with oxygen at atomic level. These findings contribute to the understanding of FeCrAl alloys' exceptional oxidation resistance. Moreover, this research serves as a valuable scholarly reference for the advancement of FeCrAl alloys for their oxidization resistance.

Automated summary

In this study, the oxygen adsorption on the surface of FeCrAl alloys was investigated using density functional theory. The results showed that Cr atoms are prone to interact with O atoms, and Al atoms transfer the most charge to O atoms, resulting in stable bonding. These findings contribute to the understanding of the oxidation resistance of FeCrAl alloys.