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

摘要

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-Li_2O under an oxidizing atmosphere was investigated at 650 deg C for 72 approx 216 hrs. Inconel 713LC alloy showed the highest corrosion resistance among the examined alloys. Corrosion products of Inconel 713LC were Cr_2O_3, NiCr_2O_4 and NiO, and those of Inconel MA 754 were Cr_2O_3 and Li_2Ni_8O_(10) while Cr_2O_3, LiFeO_2, (Cr,Ti)_2O_3 and Li_2Ni_8O_(10) were produced from Nimonic 80A. Also, corrosion products of Nimonic 90 were found to be Cr_2O_3, (Cr,Ti)_2O_3, LiAlO_2 and CoCr_2O_4 Inconel 713LC showed local corrosion behavior and Inconel MA 754, Nimonic 80A, Nimonic 90 showed uniform corrosion behavior.