High temperature molten salt corrosion of structural materials in UCl3-LiCl-KCl

High temperature corrosion behaviour of 2.25Cr-1Mo, 9Cr-1Mo and SS 410 in molten UCl3-LiCl-KCl salt at 500 and 600 degrees C under inert and reactive atmospheres for 24 h were studied by thermogravimetry. The results indicate marginal weight gains in all the alloys. In all conditions, except at 600 degrees C under reactive atmosphere, the weight gains were higher in initial period of exposure. The weight gain was continuous for samples studied at 600 degrees C under reactive atmosphere. The 2.25Cr-1Mo showed higher weight gain in an inert atmosphere, whereas SS 410 showed more weight gain at 500 degrees C and 9Cr-1Mo at 600 degrees C under reactive atmosphere. The weight gains were attributed to the formation of gamma-FeOOH, alpha-Fe2O3, Fe3O4, FeCr2O4 and Cr2O3 as confirmed by Raman spectra analysis. The oxide films formed are neither uniform as evidenced from SEM-EDS analysis nor protective, attributed to the corrosive and aggressive nature of molten chloride salts.