J. Mater. Sci. Technol. ›› 2024, Vol. 175: 10-21.DOI: 10.1016/j.jmst.2023.07.046

• Research article • Previous Articles     Next Articles

TEM comparative study on oxide films of 316L and T91 steel exposed to 350-500 °C steam

Chao Liua,b,*, Le Qia,c, Tielong Shena,b,*, Peng Jina,b, Zhiguang Wanga,b   

  1. aInstitute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China;
    bSchool of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China;
    cKey Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000, China
  • Received:2023-04-04 Revised:2023-07-10 Accepted:2023-07-19 Published:2024-03-10 Online:2023-09-07
  • Contact: *E-mail addresses: chaoliu@impcas.ac.cn (C. Liu), shentielong@impcas.ac.cn (T. Shen).

Abstract: The oxide films of 316L and T91 exposed to 350-500 °C steam were investigated using transmission electron microscopy (TEM). Independent of the exposure temperature, a triplex oxide structure with outer magnetite, inner Cr-rich (Fe1.4Cr1.6O4), and Ni-rich layer formed on 316L, while only a duplex layer with outer magnetite and inner Cr-rich (Fe2.2Cr0.8O4) layer formed on T91. As the fast channels for oxidant and the obstacles for solid-state diffusion, nanopores are distributed evenly in the Cr-rich inner layer and are more abundant in 316L than in T91. The oxidation behavior of the materials was understood based on the microscopic characteristics of the oxide films.

Key words: Austenitic steel, Ferritic-martensitic steel, Steam oxidation, Oxide film, TEM