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人工晶体学报 ›› 2023, Vol. 52 ›› Issue (3): 520-525.

• 研究论文 • 上一篇    下一篇

微氧条件下镁氧化过程原位观测及机制研究

卢竞涵1, 吴淑静1, 卢泽浩1, 杜雨萌1, 马永强1, 曹冲2   

  1. 1.华北理工大学理学院,唐山 063210;
    2.华北理工大学矿业工程学院,唐山 063210
  • 收稿日期:2022-12-12 出版日期:2023-03-15 发布日期:2023-04-06
  • 通信作者: 吴淑静,博士,副教授。E-mail:530002364@qq.com
  • 作者简介:卢竞涵(2003—),女,河北省人。E-mail:1397231400@qq.com
  • 基金资助:
    国家自然科学基金(42002098);河北省自然科学基金(E2019209283,D2020209017);大学生创新创业训练计划项目(X2022183)

In Situ Observation and Mechanism Study on the Oxidation Process of Magnesium under Trace Oxygen Condition

LU Jinghan1, WU Shujing1, LU Zehao1, DU Yumeng1, MA Yongqiang1, CAO Chong2   

  1. 1. College of Science, North China University of Science and Technology, Tangshan 063210, China;
    2. Institute of Mining Engineering, North China University of Science and Technology, Tangshan 063210, China
  • Received:2022-12-12 Online:2023-03-15 Published:2023-04-06

摘要: 原位实时观测镁合金氧化反应及生长过程,揭示其氧化过程与控制机理是目前镁表面处理领域的主流和热点。本文将纯镁薄膜样品在加热炉中400 ℃下保温10 h,采用聚焦电子束技术在透射电子显微镜(TEM)中制备了带边的镁纳米孔,并借助原位高分辨透射电子显微学技术,对镁纳米孔边缘表面晶格在微氧条件下缓慢氧化及生长动态进行了原位观测及机制研究。结果表明:通过原子吸附过程,Mg原子扩散到氧化物亚表层实现氧化,通过MgO的外延式层层生长实现氧化物生长,属于典型的各向异性生长,表现出由{200}晶面包围的带边形貌特点。对晶格缺陷在氧化生长过程中作用的研究发现:空位、位错带等缺陷促进氧化过程的进行;孪晶的大角晶界可抑制晶界的旋转或者迁移,有利于提高镁合金的耐腐蚀性。

关键词: 镁合金, 微氧条件, 氧化机制, 原位观测, 镁纳米孔, 原子吸附过程, 孪晶, 各向异性生长

Abstract: The study on the oxidation process of magnesium (Mg) alloy and corresponding control mechanism by in situ real-time observation has been a hotspot in the field of surface treatment for magnesium. In this study, magnesium film was kept for 10 h at 400 ℃ in a furnace, and the faceted Mg nanopores were prepared by focused electron beam technology under a transmission electron microscope (TEM). The slow oxidation and growth dynamics of the surface lattices at the vicinity of Mg nanopores under trace oxygen condition were observed using in situ high-resolution transmission electron microscopy techniques, while the corresponding mechanisms were also researched. The results show that the oxidation proceeds via an adatom process, resulting in the diffusion of Mg atoms from the substrate to the subsurface of oxides, and the oxidation growth process is mainly achieved via layer-by-layer epitaxial growth of MgO. The faceted morphology enclosed by {200} lattice planes attributes to the typical anisotropic growth. The study on the roles of defects in the process of oxidation growth shows that the defects, such as vacancies and dislocatios, promote the oxidation process, whereas the large-angle grain boundary of the twinning inhibits the rotation or migration of the grain boundary, which is conducive to improve the corrosion resistance of magnesium alloy.

Key words: magnesium alloy, trace oxygen condition, oxidation mechanism, in situ observation, magnesium nanopore, adatom process, twinning, anisotropic growth

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