Corrosion behaviors of Ni-based GH3625 alloy in molten solar salt

作者：Shanwu Yang, Hokeun Sun, Youping Fan, Hongyu Zhang, Yong Yang, Xiaolong Zhou, Si Cheng, W.Y. Zhang, Lili Jiang, Lilong Zhu, Nobufumi Ueshima, Katsunari Oikawa, Jingjing Ruan · 发表于：Journal of Materials Research and Technology · 年份：2024 · DOI：10.1016/j.jmrt.2024.11.164 · 被引用次数：9 · 研究领域：Solar Thermal and Photovoltaic Systems、Phase Change Materials Research、Radiative Heat Transfer Studies

The high-temperature corrosion behavior of GH3625 alloy was investigated in molten solar salt (NaNO 3 /KNO 3 (60/40 mass %)) under an argon atmosphere. The dynamic corrosion rate increased with rising temperature, from 4.3 to 21.6 μm/y. Through the sophisticated sample preparation on the oxidation layer using FIB technology, and the fine characterization using TEM analysis, the corrosion type shows no influence on the oxide types. Meanwhile, the oxidation layers were discovered to be constituted by the Cr 2 O 3 particles in the matrix, a depleted region of Cr, a Cr 2 O 3 layer, a layer consisting of NiO and Cr 2 O 3 particles, and a dense NiO layer from the matrix to the outer layer. The Cr 2 O 3 was found to form before NiO. The NiO was confirmed to protect the alloy during the corrosion process. A narrow depletion zone of Cr was discovered. The silicon was indicated to be harmful to the corrosion resistance. This work provides insight into the corrosion mechanism of GH3625 in molten solar salt. • The Cr 2 O 3 was found to form prior to NiO in molten solar salt. • The NiO rather than Cr 2 O 3 was discovered to provide the pretection of the alloy. • Thin TEM sample from fragile oxide layer was prepared by FIB technology.