Solar salt (60 wt% NaNO₃ + 40 wt% KNO₃) is widely used in the storage system of concentrated solar power plant. However, the chloride within the molten solar salt can affect the corrosion kinetics of stainless steels and hence affect the overall structural integrity. In this work, the corrosion behavior of 304 and 316L stainless steel (SS) in molten solar salt mixtures with different chloride impurities were investigated by immersion tests at 565 °C. Results show that as the content of chloride in the solar salt increases (up to 1.4 wt%), both 304 and 316L SS keep parabolic corrosion kinetics, and the rate constants increase. In comparison with 304 SS, the better corrosion resistance of 316L SS is ascribed to the higher thickness ratio of FeCr₂O₄ spinel to oxide scale. In addition, to quantitatively describe the effect of chloride impurity on corrosion kinetics of stainless steels, a novel theoretical model based on Fick’s first law is proposed and validated by the experiments.

太阳能盐（60 wt％NaNO ₃  + 40 wt％KNO ₃）被广泛用于集中式太阳能发电厂的存储系统中。但是，熔融太阳盐中的氯化物会影响不锈钢的腐蚀动力学，从而影响整体结构的完整性。在这项工作中，通过在565°C下的浸没试验研究了304和316L不锈钢（SS）在具有不同氯化物杂质的熔融太阳能盐混合物中的腐蚀行为。结果表明，随着太阳盐中氯化物含量的增加（最高1.4 wt％），304和316L SS均保持抛物线腐蚀动力学，并且速率常数增加。与304 SS相比，316L SS的更好的耐腐蚀性归因于FeCr ₂ O ₄的较高的厚度比尖晶石至氧化皮。此外，为了定量描述氯化物杂质对不锈钢腐蚀动力学的影响，提出了一种基于菲克第一定律的新型理论模型，并通过实验进行了验证。