关键词: 2205双相不锈钢, 成膜电位, 钝化膜, 电化学行为

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