Evolution of Cr/Cr2O3 interface in Cr-coated zirconium alloy in high temperature steam. (June 2023)

• Record Type: Journal Article
• Authors: Wang, Yao; Chen, Bo; Wang, Xian-Zong; Chen, Mingju; Li, Shilei; Bai, Guanghai; Li, Jinshan; Gong, Weijia
• Is Part Of: Corrosion science. Volume 217(2023)
• Publication Date: 2023-06
• Subjects: ATF cladding -- Cr-coating -- High temperature oxidation -- Interface -- Reduction -- EBSD; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2023.111099
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: <100> textured Cr-coating was deposited on Zr-based nuclear fuel cladding and went through steam oxidation at 1200 °C. The formed Cr2 O3 layer exhibited thickening-thinning transition characteristic accompanying undulation of the Cr/Cr2 O3 interface with oxidation progress. Electron microscopy characterization revealed that the convex tips of Cr/Cr2 O3 interface invariably linked to grain boundaries of residual Cr-coating, which channeled the outward diffusion of Zr atoms consequently reducing Cr2 O3 -grains into Cr-grains. The reduction reaction at the Cr/Cr2 O3 interface accounts for the interface undulation and consumption of protective oxides. This study is expected to shed light on failure mechanism of protective oxides on ATF Cr-coatings. Highlights: Evolution of Cr/Cr2 O3 interface on Cr-coated Zr alloys during oxidation is studied. Thickness transition of Cr2 O3 layer is identified with oxide interface undulation. Nano-scale Cr-grains in Cr2 O3 layer are induced by outward diffusion of Zr atoms. The reduction reaction at the interface account for failure of oxide protection.