AM355不锈钢在酸性溶液中的腐蚀电化学行为  

Electrochemical Corrosion Behavior of AM355 Stainless Steel in Acid Solution

作　　者：范春华 李国祥 李雪莹 刘伯洋 吴钱林 尹衍升 

机构地区：[1]上海海事大学海洋科学与工程学院,上海201306

出　　处：《材料科学与工程学报》2018年第1期121-124,157,共5页Journal of Materials Science and Engineering

基　　金：973项目资助项目(2014CB643306)

摘　　要：结合腐蚀形貌,通过极化曲线、交流阻抗谱(EIS)和莫特肖特基(MS)曲线的测定,分析了溶液pH值对AM355不锈钢腐蚀电化学行为的影响。结果表明:随溶液pH值的减小,腐蚀电位正移,腐蚀电流密度增大,致钝电位发生了正移,致钝电流密度、维钝电流密度增大。钝化膜由铬氧化物和铁氧化物组成,酸性增加使得铁氧化物施主浓度增大,钝化膜表面吸附氢离子电荷密度增加。钝化膜的厚度及其电阻随pH值的减小而减小,钝化膜更容易被破坏,酸性达到一定程度,钝化膜局部区域优先腐蚀。溶液pH值减小,AM355在溶液中保持自钝化性能降低,材料的腐蚀速率增加。Effect of pH value on the electrochemical corrosion behaviors of AM355 stainless steel was investigated by means of polarization,electrochemical impedance spectroscopy（EIS）,Mott-Schottky（MS）and scanning electron microscope（SEM）.Results show that both of the corrosion potential and the initiating passive potential move toward positive direction as pH decreases.Additionally,the current densities of corrosion,passivity-initiating and passivity-maintaining increase simultaneously.The passive film is composed of Cr and Fe oxides.The decrease of pH leads to the increment of both donor density of Fe oxide and the H＋absorption density on the film surface.The thickness and the resistance of passive film reduce as pH declines.The passive film will be locally destroyed when the pH decrease to a certain extent.In the high concentration acid solution,the passive film is more easily destroyed and the self-passivation ability is weakened,thereby the steel corrosion rate accelerates.

关 键 词：AM355不锈钢 PH 腐蚀电化学 

分 类 号：TG172.5[金属学及工艺—金属表面处理]