Abstract As a thermal energy storage medium (TESM) at moderate-high temperature of concentrating solar power (CSP), the molten NaCl-MgCl2 has sharp corrosive action on a metal container. The influence of MgCl2 content on a metal corrosion behavior is not clear. The corrosion behavior of a Fe based alloy (GH1140) in molten NaCl-MgCl2 (at 1123 K) with different content of MgCl2 (wt%：0.0，48.9，61.0，93.6) were studied by the submergence corrosion experience. Results show that: after corrosion for 5 h, there is a negative correlation between the weight loss of samples and the content of MgCl2. In the molten salt without MgCl2, the sample was corroded according to the mechanism of “dissolution as anode- oxidizing- peeling off of oxide film”. After adding a little MgCl2 in the molten salt, an unprotected MgO shell was formed on the sample surface. The samples weight decreased and obeyed a line law. The elements of Fe and Cr deplete in the corrosion layer. Corrosion mechanism is “dissolution as anode- oxidizing- reduction- chlorination”. When the content of MgCl2 is very high in the molten salt, partial pressure of Cl2 increases. The corrosion mechanism is similar to what in the molten salt with a little MgCl2, but the chlorination reaction is more severe.

中文翻译：

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MgCl 2 含量对GH1140在熔融NaCl-MgCl 2 中作为蓄热介质腐蚀行为的影响

摘要 作为聚光太阳能（CSP）中高温的热能储存介质（TESM），熔融的NaCl-MgCl2对金属容器具有强烈的腐蚀作用。MgCl2 含量对金属腐蚀行为的影响尚不清楚。通过浸没腐蚀实验研究了Fe基合金（GH1140）在不同MgCl2含量（wt%：0.0，48.9，61.0，93.6）的NaCl-MgCl2（1123 K）熔液中的腐蚀行为。结果表明：腐蚀5 h后，试样失重与MgCl2含量呈负相关。在不含MgCl2的熔盐中，试样按照“溶解为阳极-氧化-氧化膜剥落”的机理被腐蚀。在熔盐中加入少量 MgCl2 后，样品表面形成了无保护的 MgO 壳层。样品重量减少并遵循线性规律。Fe和Cr元素在腐蚀层中耗尽。腐蚀机理为“阳极溶解-氧化-还原-氯化”。当熔盐中 MgCl2 的含量非常高时，Cl2 的分压会增加。腐蚀机理与含少量MgCl2的熔盐中的腐蚀机理相似，但氯化反应更为剧烈。