Effect of reaction temperature on the corrosion behaviour of Inconel alloys in lithium molten salt under an oxidising atmosphere

Abstract

The effect of temperature on the corrosion behaviour of Inconel alloys employed for the electroreduction of metal oxides to metals in a lithium molten salt was investigated. The ratio of the weight loss of Inconel 601 and 690 to that of Inconel 600, Inconel 601 and 690 was approximately four and six at 650 °C, and five and eight times higher than that of Inconel 600 above 750 °C for 72 h, respectively. The corrosion products of all the alloys tested at 650 °C and 750 °C for 72 h were mainly Cr2O3 and FeCr2O4; however, only Cr2O3 was obtained when Inconel 690 was corroded at 750 °C or higher. Additionally, an alloy with a composition of max. 16.3 wt.% Cr, min. 73.66 wt.% Ni and well below 8.15 wt.% Fe was expected to exhibit excellent corrosion resistance in a lithium molten salt system at 650–850 °C.