Corrosion behavior of SS316L in ternary Li2CO3–Na2CO3–K2CO3 eutectic mixture salt for concentrated solar power plants

Abstract

This paper elaborates the compatibility of SS316L alloy with LiNaK carbonate for concentrated solar power plant applications. In this study, corrosion behavior and corrosion mechanism of SS316L in the eutectic LiNaK carbonate molten salt, at 600 °C and 700 °C, were investigated in detail. The results revealed that the corrosion process of stainless steel 316L in the LiNaK carbonate molten salt is mainly divided into four successive steps: (i) selective oxidation process of metals → (ii) lithiation reaction of the oxide → (iii) formation of a dual-structured corrosion scale → (iv) separation and spalling of corrosion products. Moreover, increasing temperature to 700 °C results in a severe corrosion of SS316L in the molten carbonate salt. Therefore, it is imperative to explore a suitable protective coating for SS316L to use it as a structural material in concentrated solar power plant.