High-Temperature Corrosion Behavior Of Al-Coated Ni-Base Alloys In Lithium Molten Salt For Electroreduction

The electrolytic reduction of a spent oxide fuel involves the liberation of oxygen in a molten salt LiCl-Li2O electrolyte, which creates a corrosive environment for typical structural materials. In this study, the corrosion behaviors of Al-Y-coated specimens in a Li molten salt kept under an oxidizing atmosphere at 650 degrees C for 72 and 168 h were investigated. The weight loss fraction of the coated specimen to bare specimen was approximately 60% for 3% Li2O and 54% for 8% Li2O at 72 h, and approximately 38% for 3% Li2O and 30% for 8% Li2O at 168 h. Corrosion was induced in the LiCl-Li2O molten salt by the basic oxide ion O2- via the basic flux mechanism, and the corrosion product was found to be dependent on the activity of the O2- ion. The increase in weight loss may have been caused by the increase in the O2- concentration due to the increase in the Li2O concentration rather than being because of the increased reaction time. The Al-Y coating was found to be beneficial for hot corrosion resistance, which can be useful for handling high-temperature lithium molten salt under an oxidizing atmosphere.