摘要钢筋锈蚀是导致混凝土结构劣化失效的主要原因之一。近年来随着大型工程对 结构长寿命周期需求的增加，不锈钢混凝土结构得到了大量推广应用。而由于孔蚀 具有随机性大、隐蔽性强和破坏性大等特点，成为很多钢材腐蚀失效的主要原因之 一，因此研究孔蚀的早期行为——亚稳态孔蚀对于孔蚀的预测及控制具有重要的理 论和现实意义。本论文利用交流阻抗、Mott-Schottky 曲线、动电位扫描极化曲线、 恒电位极化等方法研究了 304 奥氏体不锈钢在模拟混凝土孔隙溶液中的亚稳态小孔 腐蚀行为与特征，探讨了溶液 pH 值、Cl-离子浓度对 304 不锈钢小孔腐蚀的影响， 并统计分析了与亚稳态小孔腐蚀相关的一些参数之间的关系。所得主要结论如下：79862

（1）随着孔隙溶液中 Cl-离子浓度的增加，不锈钢在溶液中的阻抗值逐渐降低， 其钝化膜中载流子浓度逐渐增加，平带电位也显著提高，表明不锈钢的钝化性能逐 渐降低。

（2）Em、Eb 以及（Eb-Em）值均在逐渐降低，且与溶液中 Cl-离子浓度的对数呈 现良好的线性关系。在含不同 Cl-离子浓度溶液中，亚稳孔的生长速率和再钝化速率 均随峰值电流的增大而增大。Cl-离子浓度越高，小孔越容易生长成为稳定孔。

（3）随着孔隙溶液 pH 值的增加，不锈钢在溶液中的阻抗值逐渐增大，其钝化 膜中载流子浓度逐渐降低，平带电位也有所降低但幅度不明显，表明不锈钢的钝化 性能逐渐提高。

（4）Em、Eb 以及（Eb-Em）值均在逐渐增大，且与溶液 pH 值呈现良好的线性关 系。在不同 pH 值溶液中，亚稳孔的生长速率和再钝化速率均随峰值电流的增大而增 大。pH 值越高，小孔越难生长成为稳定孔。

毕业论文关键词：不锈钢、亚稳态孔蚀、氯离子浓度、pH、电化学

Abstract Corrosion of steel bars is one of the main causes of deterioration of concrete structures。 In recent years, with the increasing of the demand for the long life cycle of the structure, the stainless steel concrete structure has been widely used。 Due to the concealment, random and failure characteristics of pitting corrosions, it has become one of the main reasons for the deterioration of many steels。 Therefore, the study of early pitting behavior, metastable pitting, has both theoretical and practical significance in the prediction and protection of pitting corrosion。 The methods of EIS, Mott Schottky curve, dynamic potential scanning polarization curve and constant potential polarization were used to study metastable pitting corrosion behavior and characteristics of 304 austenitic stainless steel in simulated concrete pore solution。 We discussesed the effect of pH value and chloride ion concentration on the metastable pitting corrosion of 304 stainless steel。 And the relationship between some electrochemical parameters related to the metastable pitting corrosion was analyzed。 The main conclusions are set as follows:

(1)With the increasing of the chloride ion concentration in the pore solution, the impedance value of the stainless steel decreased gradually。 The carrier concentration and the flat band potential of its passive film increased gradually。 This indicated that the passivation property of the stainless steel was gradually decreased。

(2)The values of Em, Eb and (Eb-Em) were gradually decreased, and a good linear relationship was showed between them and the logarithm of the chloride ion concentrations。 In the solution of different chloride ion concentrations, the rates of growth and repassivation of the metastable pores increased with the increasing of the peak current。 The higher the chloride ion concentration, the more easily the metastable pittings grew to be stable pittings。

(3)With the increasing of the pH value of the pore solution, the impedance value of the stainless steel increased gradually。 The carrier concentration and the flat band potential of its passive film decreased gradually。 This indicated that the passivation property of the stainless steel was gradually increased。 碱性溶液中304奥氏体不锈钢的亚稳态孔蚀特征研究:http://www.youerw.com/cailiao/lunwen_92574.html