Effect of Mg Addition on Molten Chloride Salt Corrosion Resistance of 310S Stainless Steel with Aluminum

As concentrated solar power (CSP) systems evolve, the new generation of CSP systems will utilize chloride molten salts, which are cost-effective and have high operating temperatures, but are highly corrosive. In order to reduce the corrosiveness of chloride salts, we investigated the addition of different levels of Mg to chloride salts to study the effect on corrosion. In this paper, the corrosion behavior of 310S stainless steel with aluminum in high-temperature molten salt NaCl-KCl-MgCl2 was studied. By adding different contents of magnesium corrosion inhibitor, the corrosion mechanism and the effect of the corrosion inhibitor were explored. The results show that the lowest corrosion rate of 6.623 mm/y was obtained for the aluminum-formed 310S with 0.05 wt.% Mg. However, the corrosion rate rises when the Mg content exceeds 0.05 wt.% compared to the corrosion rate of corroded specimens without Mg. Changing the added Mg content does not affect the corrosion products. For 310S stainless steel with aluminum, its corrosion inhibition was best achieved by adding 0.05 wt.% Mg to the chloride molten salt.