{"title":"Comparative study on high-temperature air and steam oxidation of Cr-coated Zr-4 alloy through experimental and DFT calculation","authors":"","doi":"10.1016/j.jnucmat.2024.155382","DOIUrl":null,"url":null,"abstract":"<div><p>The high-temperature oxidation performance of Cr-coated Zr-4 alloy in air and steam atmosphere is comparatively studied and the mechanism of steam promoted oxidation is revealed by density functional theory (DFT) calculation. The experimental results show that there are significant differences in surface and cross-sectional microstructures after oxidation in the two atmospheres. Dense irregular polyhedral oxides accompanied by randomly occurring micro-cracks are developed after high-temperature air oxidation. While mackerel scale-like or worm-like particles with whisker-like structures accompanied by defects such as pores and micro-cracks are developed after high-temperature steam oxidation. In the high-temperature steam atmosphere, the more vigorous atomic diffusion leads to a thicker Cr-Zr diffusion layer and higher O content, so that after exposure at 1100 °C for 3 and 4 h, the Zr-4 alloy adjacent to the Cr-Zr diffusion layer is oxidized to ZrO<sub>2</sub>. All the experimental results demonstrate that Cr-coated Zr-4 alloy experiences more severe oxidation in high-temperature steam atmosphere. The DFT calculation results reveal the main reason of steam promoted oxidation is that the interstitial H protons boost the formation of Cr and O vacancies and vacancy pairs in the Cr<sub>2</sub>O<sub>3</sub> oxide scale.</p></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":null,"pages":null},"PeriodicalIF":2.8000,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Nuclear Materials","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022311524004835","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
The high-temperature oxidation performance of Cr-coated Zr-4 alloy in air and steam atmosphere is comparatively studied and the mechanism of steam promoted oxidation is revealed by density functional theory (DFT) calculation. The experimental results show that there are significant differences in surface and cross-sectional microstructures after oxidation in the two atmospheres. Dense irregular polyhedral oxides accompanied by randomly occurring micro-cracks are developed after high-temperature air oxidation. While mackerel scale-like or worm-like particles with whisker-like structures accompanied by defects such as pores and micro-cracks are developed after high-temperature steam oxidation. In the high-temperature steam atmosphere, the more vigorous atomic diffusion leads to a thicker Cr-Zr diffusion layer and higher O content, so that after exposure at 1100 °C for 3 and 4 h, the Zr-4 alloy adjacent to the Cr-Zr diffusion layer is oxidized to ZrO2. All the experimental results demonstrate that Cr-coated Zr-4 alloy experiences more severe oxidation in high-temperature steam atmosphere. The DFT calculation results reveal the main reason of steam promoted oxidation is that the interstitial H protons boost the formation of Cr and O vacancies and vacancy pairs in the Cr2O3 oxide scale.
期刊介绍:
The Journal of Nuclear Materials publishes high quality papers in materials research for nuclear applications, primarily fission reactors, fusion reactors, and similar environments including radiation areas of charged particle accelerators. Both original research and critical review papers covering experimental, theoretical, and computational aspects of either fundamental or applied nature are welcome.
The breadth of the field is such that a wide range of processes and properties in the field of materials science and engineering is of interest to the readership, spanning atom-scale processes, microstructures, thermodynamics, mechanical properties, physical properties, and corrosion, for example.
Topics covered by JNM
Fission reactor materials, including fuels, cladding, core structures, pressure vessels, coolant interactions with materials, moderator and control components, fission product behavior.
Materials aspects of the entire fuel cycle.
Materials aspects of the actinides and their compounds.
Performance of nuclear waste materials; materials aspects of the immobilization of wastes.
Fusion reactor materials, including first walls, blankets, insulators and magnets.
Neutron and charged particle radiation effects in materials, including defects, transmutations, microstructures, phase changes and macroscopic properties.
Interaction of plasmas, ion beams, electron beams and electromagnetic radiation with materials relevant to nuclear systems.