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    在硝酸溶液中不锈钢表面钝化膜的电化学特性

    Electrochemical Properties of Passive Film on Stainless Steel Surface in Nitric Acid Solution

    • 摘要: 采用极化曲线、电化学阻抗谱(EIS)、Mott-Shottky曲线,研究了在不同温度、不同含量硝酸溶液中304不锈钢的耐蚀性与其表面钝化膜特性之间的相互关系。结果表明:随着温度和硝酸含量的升高,不锈钢表面钝化膜的保护性和稳定性降低;不锈钢在硝酸溶液中生成的钝化膜具有P型半导体特性;通过X射线光电子能谱(XPS)分析结果发现,不锈钢表面的钝化膜主要成分为铬和铁的氧化物,高温、高含量硝酸中生成的钝化膜中Cr (Ⅵ)含量明显较高。温度、硝酸含量的变化及钝化膜中强氧化性离子的产生会对304不锈钢表面钝化膜的生成与溶解速率产生不同程度的影响,进而影响不锈钢的耐蚀性。

       

      Abstract: The relationship between the corrosion resistance of 304 stainless steel and the properties of passive film on its surface at different temperatures and different concentrations of nitric acid solution was studied by polarization curve, electrochemical impedance spectrum (EIS) and Mott-Shottky curve. The results show that with the increase of temperature and nitric acid concentration, the protection and stability of the passive film on stainless steel surface reduced. The passive film forming in nitric acid solution was characterized by P-type semiconductor. XPS analysis show that the passive film was mainly composed of Cr and Fe oxides, besides high content of Cr(Ⅵ) was found in passive film generated at high temperature and high concentration of nitric acid. The changes of temperature, nitric acid concentration and the generation of some strong oxidizing ions in the passive film have different effects on the generation and dissolution rate of the passive film, which affect the corrosion resistance of the stainless steel.

       

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