Preparation of a chromium carbon coating on 316L by a disproportionation reaction in molten salts and its corrosion resistance in molten fluorides

Abstract

Molten fluorides have been widely used in specific nuclear reprocessing and molten salt reactors due to their unique pyrophysical and pyrochemical properties. However, the severe corrosion of structural materials in highly corrosive molten fluorides at high temperatures limits their commercial use. In view of the high thermodynamic stability of chromium carbides in molten fluoride salts, and their good Cr-diffusion-blocking ability, it is proposed to develop a CrxCy coating, by electrodeposition coupled with a disproportionation reaction in molten salts, for application in molten fluorides A carbon coating is first prepared on 316L stainless steel by electrodeposition in molten LiCl-KCl-K2CO3, followed by a disproportionation reaction of Cr2+ on the carbon coating to obtain a CrxCy coating. Furthermore, the growth mechanism of the CrxCy coating and its corrosion resistance in molten fluorides are also investigated.