Corrosion Behavior of Ni-Base Superalloys in a Hot Molten Salt

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 handling molten salt. In this study, corrosion behavior of Inconel 713LC, Inconel MA 754, Nimonic 80A and Nimonic 90 in the molten salt LiCl-Li2O under an oxidizing atmosphere was investigated at 650 degrees C for 72 similar to 216 hrs. Inconel 713LC alloy showed the highest corrosion resistance among the examined alloys. Corrosion products of Inconel 713LC were Cr2O3, NiCr2O4 and NiO, and those of Inconel MA 754 were Cr2O3 and Li2Ni8O10 while Cr2O3, LiFeO2, (CrTi)(2)O-3 and Li2Ni8O10 were produced from Nimonic 80A. Also, corrosion products of Nimonic 90 were found to be Cr2O3, (Cr,Ti)(2)O-3, LiAlO2 and CoCr2O4. Inconel 713LC showed local corrosion behavior and Inconel MA 754, Nimonic 80A, Nimonic 90 showed uniform corrosion behavior.