Investigation of oxidation behaviors of coated Zircaloy as accident-tolerant fuel with CrAlN and CrAlSiN coatings in high-temperature steam

• Published in: Corrosion science 2020-10, Vol.175, p.108896, Article 108896
• Main Authors: Liu, Junkai, Cui, Zhexin, Ma, Dayan, Lu, Junqiang, Cui, Yanguang, Li, Chong, Liu, Wenbo, Hao, Zhe, Hu, Pengfei, Yao, Meiyi, Huang, Ping, Bai, Guanghai, Yun, Di
• Format: Article
• Language: English
• Subjects: Arc deposition; Coatings; CrAlN coating; CrAlSiN coating; Diffusion layers; High temperature; Ion plating; Microstructure; Nitrogen bubble; Oxidation; Oxidation resistance; Substrates; Zircaloys (trademark)
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2020.108896

•The dense CrAlN and CrAlSiN coatings with Cr interlayer were deposited on the Zircaloy samples by multi-arc ion plating.•The oxidation resistance of Zircaloy samples in high-temperature steam was effectively improved by surface coating.•The oxidation behaviors and mechanisms of two types of coatings in 1000 °C and 1200 °C steam were studied and discussed.•The distribution and diffusion behaviors of nitrogen bubbles in two types of coatings during oxidation were studied.•The added silicon in the CrAlSiN coating can improve the corrosion resistance but impact the structural integrity of coating. CrAlN and CrAlSiN coatings were deposited on Zircaloy samples by multi-arc ion plating (MAIP) and the microstructure, hardness, and oxidation resistance of the two types of coatings in high-temperature steams were investigated. The coatings can effectively protect the substrate from oxidation during exposure in 1000 °C steam for 2 h and can delay the oxidation of substrate for more than 15 min in 1200 °C steam. Mixed oxide layers formed and suppressed the elemental diffusion during oxidation. Nitrogen bubbles were found inside the mixed oxide. The CrAlSiN coatings showed better oxidation resistance but they cracked more easily.