High temperature corrosion of superalloys in a molten salt under an oxidizing atmosphere

The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which results in 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 behavior of Inconel 713LC, Nimonic 80A and Nimonic 90 in a molten LiCl–Li2O salt under an oxidizing atmosphere was investigated at 675 °C for 72–216 h. Inconel 713LC alloy showed the highest corrosion resistance among the examined alloys. Corrosion products of Inconel 713LC were Cr2O3, NiCr2O4, Ni and NiO, and those of Nimonic 80A were Cr2O3, LiFeO2, (Cr, Ti)2O3 and Li2Ni8O10 while Cr2O3, (Cr, Ti)2O3, LiAlO2 and CoCr2O4 were produced from Nimonic 90. Inconel 713LC showed a local corrosion behavior and Nimonic 80A, Nimonic 90 showed a uniform corrosion behavior.