Microstructural understanding of the oxidation and inter-diffusion behavior of Cr-coated Alloy 800H in supercritical water. (February 2023)

• Record Type: Journal Article
• Authors: Yang, Jianqiao; Bai, Shuyuan; Sun, Jiyuan; Wu, Hao; Sun, Shenghan; Wang, Shuzhong; Li, Yanhui; Ma, Wenhao; Tang, Xingying; Xu, Donghai
• Is Part Of: Corrosion science. Volume 211(2023)
• Publication Date: 2023-02
• Subjects: Cr coatings -- Alloy 800H -- Supercritical water -- Corrosion -- Magnetron sputtering; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2022.110910
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: In this study, corrosion tests were performed on Cr-coated Alloy 800 H in 500 °C supercritical water, containing 6000 mg∙L −1 oxygen, for 500 h. After exposure, the structure of the sample can be divided into a Cr2 O3 layer with a nanocrystal structure, a residual Cr coating with columnar or equiaxed Cr grains, an inter-diffusion layer including Fe-Ni-rich and Cr-O-rich zones, and an alloy substrate. Transmission electron microscopy was employed for the high-resolution analysis of atom diffusion in the sample. The outward diffusion of Fe and Ni was restrained by the coating, and no oxide exfoliation was observed. Highlights: A 15 µm Cr coating was prepared on a Alloy 800 H alloy. Cr2 O3 nanocrystal structure formed on the sample surface. Outward diffusion of Fe and Ni was restrained by the coating. Grain boundary diffusion of Fe observed by TEM.