Corrosion behavior of Fe-Cr-Ni alloys in solid-liquid phase change energy storage medium NaCl-MgCl2

As a phase change energy storage medium, molten chloride salt will undergo high frequency melting and solidification state, which is highly corrosive for metal pipes and container materials. The corrosion behavior of three kinds of Fe-Cr-Ni alloys and a carbon steel in molten NaCl-MgCl2 were studied at constant (545℃) and circulating temperature (from melting to solidification). The results show that on one hand, a compact MgO shell is formed on the carbon steel surface under condition of the constant temperature, which improves the corrosion resistance. However, at the circulating temperature, the mass loss of the carbon steel is large. On the other hand, the three kinds of Fe-Cr-Ni alloys were corroded severely at constant temperature due to electrochemical corrosion. However, under condition of the circulating temperature, a compact oxide layer is formed on the three kinds of Fe-Cr-Ni alloys surface due to high oxygen party pressure, which can protect the sample matrix from corrosion in the eutectic chloride salt. © 2020, Editorial Board of Acta Energiae Solaris Sinica. All right reserved.