22Cr双相不锈钢钝化膜组成及其半导体性能研究

借助于Mott-Schottky方程分析了成膜电位、成膜时间、成膜温度以及氯离子等因素对22Cr双相不锈钢在碳酸氢钠/碳酸钠缓冲溶液中所成钝化膜半导体性能的影响, 同时借助于X射线光电子能谱(XPS)技术分析了所成钝化膜的组成. 结果表明: 22Cr双相不锈钢在碳酸氢钠/碳酸钠缓冲溶液中所成钝化膜呈n-p型半导体结构, 钝化膜内施主/受主密度随成膜电位增加、成膜时间延长、成膜温度降低、以及介质中氯离子浓度的降低而减小, 同时膜对基体保护作用随这些因素变化而增强. 钝化膜的XPS分析表明, 钝化膜呈现双层结构, 外层膜主要由三价铁的氧化物(Fe2O3)组成, 内层膜主要由三价铬氧化物(Cr2O3)以及少量二价铁氧化物(FeO)组成.

Investigation on the Composition and Semi-conductive Property of the Passive Film on 22Cr Duplex Stainless Steel

The semi-conductive performance of the passive film formed on 22Cr duplex stainless steel in bicarbonate/carbonate buffer solution was investigated by Mott-Schottky analysis, and the factors, including formation potential, formation time, formation temperature and chloride ions, etc., which affect the film semi-conductive property, were also examined. The film compositions were analyzed by the X-ray photoelectron spectra (XPS). The results showed that the passive film formed on 22Cr duplex stainless steel in bicarbonate/carbonate buffer solution displayed an n-p semi-conductive character, and the donor density ND and the acceptor density NA decreased with increasing the formation potential, prolonging the formation time, decreasing the formation temperature, and decreasing the chloride ion concentration. In addition, the protective effect of the passive film on 22Cr alloy was enhanced with the variation of these factors. XPS analysis revealed that the passive film had a double-layer structure, i.e., the outer trivalent iron oxide, and the inner chromium oxide with a little content of divalent iron oxide.