Abstract: Corrosion resistance of stainless steel is closely related to the formation conditions of passivation film. The effects of film⁃formation potentials on the characteristics and electronic structure of passivation films on 2205 duplex stainless steel surface in 3.5% NaCl solution were explored by potentiodynamic polarization technique, electrochemical impedance spectroscope, and Mott⁃Schottky methods. The results show that with the increase in film⁃formation potential, the passivation film is first porous and then becomes dense. However, under the film⁃formation potential of 0.90 V, the passivation film finally underwent an additional porous structure process. With the increase of film⁃formation potential, donor density and acceptor density in passivation film increase, and the formation rate of passivation film increase. However, the adsorption of erosive anion is also promoted by the increase of film⁃formation potential. The defects and porosity of the outer layer of passivation film increase with the increase of potential, which led to the increase of passivation film thickness. The compactness of the inner layer of the passivation film is the best under the film⁃forming potential of 0.60 V(SCE). With the increase of the potential to 0.90 V(SCE), the inner layer oxide becomes porous, the compactness of the passivation film degraded, and the rupture risk of the passivated film is the highest.

Key words: 2205 duplex stainless steel, Film?formation potentials, Passivation film, Electrochemical behavior

摘要： 不锈钢耐蚀性与钝化膜形成条件密切相关。采用动电位极化法、电化学阻抗谱和Mott⁃Schottky方法，研究了成膜电位（相对于饱和甘汞电极（SCE）的电位）对2205双相不锈钢（2205DSS）钝化膜在质量分数为3.5%的 NaCl溶液中的电化学行为。结果表明，2205DSS在25 ℃下质量分数为3.5%的NaCl溶液中具有良好的耐蚀性能；在0.10 V和0.60 V的成膜电位下，钝化膜形成过程为先多孔后致密，而成膜电位为0.90 V时，钝化膜最后还额外经历了一个疏松多孔的形成过程；随着成膜电位的增加，钝化膜中施主密度与受主密度均增加，钝化膜生成速率增加，但也促进了侵蚀性阴离子吸附性的增加；钝化膜外层缺陷和多孔性随成膜电位的增加而增加，导致钝化膜厚度增加；钝化膜内层膜在0.60 V的成膜电位下致密性最好，随着成膜电位增加至0.90 V，内层氧化物变为多孔，钝化膜致密性退化，钝化膜破裂倾向最大。

关键词: 2205双相不锈钢, 成膜电位, 钝化膜, 电化学行为