The high-temperature corrosion of Hastelloy N alloy (UNS N10003) in molten fluoride salts analysed by STXM, XAS, XRD, SEM, EPMA, TEM/EDS

The effect of Fe ion impurity on the corrosion behavior of Hastelloy N (UNS N10003) alloy in molten FLiNaK salts at 850 °C has been investigated by combined synchrotron radiation and other characterization techniques. Results showed that Mo and Cr were depleted from the alloy surface, where Fe-rich layer formed. The corrosion process was mainly controlled by the redox reaction between Fe ion and Cr, and no new compound with high valence state formed in the alloy surface. The loss of Mo and Cr in M12C carbide occurred due to the presence of a concentration-gradient between M12C carbide and matrix.