Role of microchannels in breakaway oxidation of Zr alloy under high-temperature steam oxidation at 1000 ℃. (1st May 2022)

• Record Type: Journal Article
• Authors: Cui, Zhexin; Liu, Junkai; Hu, Pengfei; Qiu, Jie; Xie, Shijing; Meng, Ruizhi; Liu, Wenbo; Lu, Junqiang; Cui, Yanguang; Li, Chong; Bai, Guanghai; He, Dan; Yun, Di
• Is Part Of: Corrosion science. Volume 199(2022)
• Publication Date: 2022-05-01
• Subjects: Zirconium alloy -- High-temperature steam oxidation -- Breakaway oxidation -- Microchannels; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2022.110204
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: In the present study, to determine the mechanism of the breakaway phenomenon, high-temperature steam oxidation of zirconium alloys was carried out at 1000 ℃. Additionally, the oxide microstructures of samples were characterized using multiple techniques. The results show that the microchannels caused an undulated structure of the oxide/metal (O-M) interface, which is a function of time. Meanwhile, after breakaway oxidation, a formation mechanism of cracks, based on vacancies, was proposed according to the crack morphologies. Finally, taking the microchannels as the center, a mechanism is established to explain the high-temperature oxidation behavior of the Zr alloy. Highlights: The undulation structure of oxide/metal (O-M) interface is caused by the formation of microchannels at different stages. Raman spectroscopy shows that zirconia phase distributions correspond to the local curvature of the O-M interface. Two different mechanisms on cracks formation before and after breakaway oxidation are established. A breakaway oxidation mechanism focusing on formation of microchannels vertical to the O-M interface is proposed.