氯离子对典型不锈钢材料腐蚀的EIS分析

以Alloy 690、Alloy 600和X80 3种典型的不锈钢材料为研究对象,利用电化学阻抗谱实验得到了3种材料在不同浓度的KCl溶液中的阻抗谱特性。实验表明Alloy 690、Alloy 600和X80的抗氯离子腐蚀性能依次降低,当氯离子含量比较少时,随着氯离子浓度的增加,腐蚀的倾向性逐步增加;但当氯离子含量超过一定值时,继续增加氯离子,腐蚀的倾向性反而会减小。R(QR)(QR)电路能够在各种情况下较好地拟合阻抗谱数据,等效电路拟合后的数据表明:外层氧化膜的电阻相对较小,可能会含有可供溶液离子扩散的通道,具有非理想电容器特征;内层氧化膜的结构对材料的抗腐蚀性能影响明显,内层氧化膜阻值突然变小是由于电子通过费米能级从金属向氧化膜渗透。

EIS Analysis of Chloride Ion Corrosion Effect on Typical Stainless Steel

Based on the research of Alloy 690,Alloy 600 and X 80 stainless steel,the electrochemical impedance spectroscopy technology was applied to obtain their impedance spectra in KCl solution with different concentrations.Analyzing experimental results shows that,as to the properties of corrosion resistance to chloride the ion,Alloy 690 is the best and both Alloy 600 and X 80 are on Alloy 690＇ s heels ; and the corrosion tendency rises gradually with the increase of ion concentration; and when chloride ion concentration exceeds a certain value,increasing the ion concentration sometimes can reduce corrosion tendency.R （QR） （QR） circuit can fit impedance spectral data in all circumstances ; analyzing the equivalent circuit fitting data shows that,the relatively-small resistance of outer layer oxide film has a non-ideal capacitor characteristics and possibly contains ionic diffusion channels; and the structure of inner oxide film influences the material＇ s corrosion properties obviously.The electrons going through Fermi level and permeating into oxide film can make resistance of the inner oxide film smaller suddenly.