Molten NaCl–KCl–MgCl2 is becoming a potential heat transfer fluid (HTF) and thermal energy storage (TES) material in the third generation of concentrated solar energy power (CSP) stations due to its excellent heat storage-capacity and thermal stability. However, the strong corrosion of the molten chloride salt at high temperature limits its industrial application. In this study, the corrosion behaviour of FeCoNiCrAl HEA with BCC + FCC phase structure in molten NaCl–KCl–MgCl2 (24.5–20.55–54.95 wt-%) at 650 °C under argon was investigated by a combination of weight loss and electrochemical methods. The results show that, the corrosion of FeCoNiCrAl HEA in molten chloride salt mainly manifests as the selective dissolution of Fe and Cr. With the further increase of immersion time, oxides gradually crack and slightly flake, resulting in large weight loss of FeCoNiCrAl HEA.
GongQShiHChaiY, et al.Molten chloride salt technology for next-generation CSP plants: compatibility of Fe-based alloys with purified molten MgCl2-KCl-NaCl salt at 700°C. Appl Energy2022; 324: 119708.
2.
Al KindiAASapinPPantaleoAM, et al.Thermo-economic analysis of steam accumulation and solid thermal energy storage in direct steam generation concentrated solar power plants. Energy Convers Manage2022; 274: 116222.
3.
GrégoireBOskayCMeißnerTM, et al.Corrosion mechanisms of ferritic-martensitic P91 steel and inconel 600 nickel-based alloy in molten chlorides. Part II: NaCl–KCl–MgCl2 ternary system. Sol Energy Mater Sol Cells2020; 216: 110675.
4.
FernándezÁGCabezaLF. Molten salt corrosion mechanisms of nitrate based thermal energy storage materials for concentrated solar power plants: a review. Sol Energy Mater Sol Cells2019; 194: 160–165.
5.
GongQHankeAKesselF, et al.Molten chloride salt technology for next-generation CSP plants: selection of cold tank structural material utilizing corrosion control at 500°C. Sol Energy Mater Sol Cells2023; 253: 112233.
6.
DingWBauerT. Progress in research and development of molten chloride salt technology for next generation concentrated solar power plants. Engineering2021; 7: 334–347.
7.
DunhamMTIversonBD. High-efficiency thermodynamic power cycles for concentrated solar power systems. Renewable Sustainable Energy Rev2014; 30: 758–770.
8.
Gomez-VidalJCTirawatR. Corrosion of alloys in a chloride molten salt (NaCl-LiCl) for solar thermal technologies. Sol Energy Mater Sol Cells2016; 157: 234–244.
9.
YehJWChenSKLinS, et al.Nanostructured high-entropy alloys with multiple principal elements: novel alloy design concepts and outcomes. Adv Eng Mater2004; 6: 299–303.
10.
MiracleDBSenkovON. A critical review of high entropy alloys and related concepts. Acta Mater2017; 122: 448–511.
11.
YeYFWangQLuJ, et al.High-entropy alloy: challenges and prospects. Mater Today2016; 19: 349–362.
12.
XiongWGuoAXYZhanS, et al.Refractory high-entropy alloys: a focused review of preparation methods and properties. J Mater Sci Technol2023; 142: 196–215.
13.
PatelKSadeghilaridjaniMPoleM, et al.Hot corrosion behavior of refractory high entropy alloys in molten chloride salt for concentrating solar power systems. Sol Energy Mater Sol Cells2021; 230: 111222.
14.
PatelKHasannaeimiVSadeghilaridjaniM, et al.Molten salt corrosion behavior of dual-phase high entropy alloy for concentrating solar power systems. Entropy2023; 25: 96.
15.
FernándezAGPérezFJ. Improvement of the corrosion properties in ternary molten nitrate salts for direct energy storage in CSP plants. Solar Energy2016; 134: 468–478.
16.
YeXAiHGuoZ, et al.The high-temperature corrosion of Hastelloy N alloy (UNS N10003) in molten fluoride salts analysed by STXM, XAS, XRD, SEM, EPMA, TEM/EDS. Corros Sci2016; 106: 249–259.
17.
LIYNiuYWuW. Chlorination of metallic materials at high temperature. Corros Sci Prot Technol2000; 12: 41–44.
18.
LambrechtMde MiguelMTLasantaMI, et al.Past research and future strategies for molten chlorides application in concentrated solar power technology. Sol Energy Mater Sol Cells2022; 237: 111557.
19.
ZhuMYiHLuJ, et al.Corrosion of Ni–Fe based alloy in chloride molten salts for concentrating solar power containing aluminum as corrosion inhibitor. Sol Energy Mater Sol Cells2022; 241: 111737.
20.
ZhuMZengSZhangH, et al.Electrochemical study on the corrosion behaviors of 316 SS in HITEC molten salt at different temperatures. Sol Energy Mater Sol Cells2018; 186: 200–207.
21.
IbrahimAPengHRiazA, et al.Molten salts in the light of corrosion mitigation strategies and embedded with nanoparticles to enhance the thermophysical properties for CSP plants. Sol Energy Mater Sol Cells2021; 219: 110768.
22.
VidalJCKlammerN. Molten chloride technology pathway to meet the U.S. DOE sunshot initiative with Gen3 CSP. AIP Conf Proc2019; 2126: 080006.
ZahsASpiegelMGrabkeHJ. Chloridation and oxidation of iron, chromium, nickel and their alloys in chloridizing and oxidizing atmospheres at 400–700°C. Corros Sci2000; 42: 1093–1122.
25.
DingWShiHJianuA, et al.Molten chloride salts for next generation concentrated solar power plants: mitigation strategies against corrosion of structural materials. Sol Energy Mater Sol Cells2019; 193: 298–313.
26.
LiuQWangZLiuW, et al.Ni-Mo-Cr alloy corrosion in molten NaCl–KCl–MgCl2 salt and vapour. Corros Sci2021; 180: 109183.
