Corrosion Behavior of Superalloys in a Hot Lithium Molten Salt

The electrolytic reduction of a spent oxide fuel involves a liberation of the oxygen in a molten LiCl electrolyte, which is a chemically aggressive environment that is too corrosive for typical structural materials. So, it is essential to choose the optimum material for the process equipment for handling a molten salt. In this study, corrosion behaviors of Haynes 263, Inconel 718, Nimonic 80 A and Incoloy 800 H in a molten LiCl-Li2O salt under an oxidizing atmosphere were investigated at 650 oC for 72∼216 h. Haynes 263 alloy showed the highest corrosion resistance among the examined alloys. Corrosion products of Haynes 263 were Li(Ni,Co)O2 and Li((Cr,Al)TiO4), and those of Inconel 718 were Cr2O3, NiFe2O4, and CrNbO4, while Cr2O3, LiFeO2, (Cr,Ti)2O3, and Li2Ni8O10 were identified as the corrosion products of Nimonic 80 A. Incoloy 800 H showed Cr2O3 and FeCr2O4 as its corrosion products. Haynes 263 showed a localized corrosion behavior while Inconel 718, Nimonic 80 A and Incoloy 800 H showed a uniform corrosion behavior. KCI Citation Count: 4