Corrosion susceptibility and chromium loss in Austenitic steels and Nickel-based alloys in molten FLiNaK at 700 °C

IF 3.2 2区工程技术 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Nuclear Materials Pub Date : 2025-08-25 DOI:10.1016/j.jnucmat.2025.156123

Kyle Williams, Lavanya Upadhyaya, Nathaniel Thomas, Michenna Allen, Lin Shao

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Abstract

A comparative study was conducted to evaluate the corrosion susceptibility of 316L, 316H, Ni 200, Inconel 625, and Hastelloy N in molten FLiNaK at 700 °C for 100 h. Top-view and cross-sectional scanning electron microscopy (SEM) imaging, combined with energy-dispersive X-ray spectroscopy (EDS) mapping, was performed to investigate microstructural and compositional changes. SEM images were further processed by introducing a contrast threshold to map cavity distribution. Using EDS mapping, intergranular and intragranular Cr loss were separately characterized. The ranking of mass loss after corrosion, from highest to lowest, is as follows: 316H > 316L > Inconel 625 > Hastelloy N > Ni 200. Cr loss was found to be correlated with Mo concentration, in agreement with many previous studies, with higher Mo content resulting in reduced Cr loss. On the other hand, there is no evidence that the high carbon content in 316H enhances corrosion resistance. The relatively low solubility of carbon in austenite at the testing temperature limits the amount of dissolved carbon. Therefore, the carbon-retarded vacancy diffusion, and consequently the reduced Cr diffusion, were not observed.

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奥氏体钢和镍基合金在700°C熔融熔融熔融熔液中的腐蚀敏感性和铬损失

对比研究了316L、316H、Ni 200、Inconel 625和Hastelloy N在熔融FLiNaK中700°C、100 h的腐蚀敏感性。采用俯视图和横断面扫描电子显微镜（SEM）成像，结合能量色散x射线能谱（EDS）成像，研究了显微组织和成分的变化。通过引入对比度阈值对扫描电镜图像进行进一步处理，绘制空腔分布。利用能谱图分别表征了晶间和粒内Cr的损失。腐蚀后质量损失由高到低依次为：316H >； 316L >；英科乃尔625 >；哈氏合金N >； Ni 200。Cr损失与Mo浓度相关，Mo含量越高，Cr损失越小，这与之前的许多研究结果一致。另一方面，没有证据表明高碳含量的316H提高了耐蚀性。在测试温度下，碳在奥氏体中的溶解度较低，限制了溶解碳的数量。因此，没有观察到碳阻滞的空位扩散，从而没有观察到还原的Cr扩散。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Nuclear Materials 工程技术-材料科学：综合

CiteScore

5.70

自引率

25.80%

发文量

601

审稿时长

63 days

期刊介绍： The Journal of Nuclear Materials publishes high quality papers in materials research for nuclear applications, primarily fission reactors, fusion reactors, and similar environments including radiation areas of charged particle accelerators. Both original research and critical review papers covering experimental, theoretical, and computational aspects of either fundamental or applied nature are welcome. The breadth of the field is such that a wide range of processes and properties in the field of materials science and engineering is of interest to the readership, spanning atom-scale processes, microstructures, thermodynamics, mechanical properties, physical properties, and corrosion, for example. Topics covered by JNM Fission reactor materials, including fuels, cladding, core structures, pressure vessels, coolant interactions with materials, moderator and control components, fission product behavior. Materials aspects of the entire fuel cycle. Materials aspects of the actinides and their compounds. Performance of nuclear waste materials; materials aspects of the immobilization of wastes. Fusion reactor materials, including first walls, blankets, insulators and magnets. Neutron and charged particle radiation effects in materials, including defects, transmutations, microstructures, phase changes and macroscopic properties. Interaction of plasmas, ion beams, electron beams and electromagnetic radiation with materials relevant to nuclear systems.