304不锈钢晶间腐蚀过程中的电化学阻抗谱特征  

EIS CHARACTERISTICS OF 304 STAINLESS STEEL DURING INTERGRANULAR CORROSION

作　　者：秦丽雁[1] 宋诗哲[1] 卢玉琢[1] 

机构地区：[1]天津大学材料科学与工程学院

出　　处：《中国腐蚀与防护学报》2007年第2期74-79,共6页Journal of Chinese Society For Corrosion and Protection

基　　金：国家自然科学基金重大项目资助(50499335)

摘　　要：用电化学阻抗谱(EIS)方法研究了固溶态、敏化态304不锈钢在0.5mol/L H2SO4+0.01mol/L KSCN溶液中的阻抗谱特征.研究表明,不锈钢在不同极化电位下的阻抗谱呈现活性溶解、活化-钝化、钝化及再活化的特征.达到再活化之前,固溶态和敏化态的不锈钢在0.5mol/L H2SO4+0.01mol/L KSCN溶液中呈现相同的EIS特征;而在再活化区,钝化膜局部溶解,EIS图有两个容抗弧,低频容抗弧延伸到第二象限,呈现负电阻特征,低频下敏化态比固溶态不锈钢阻抗模值小一个数量级.Electrochemical impedance spectroscopy （EIS） measurements were performed on sensitized and solutioned 304 stainless steels respectively in the process of Electrochemical potentiodynamic reactivation （EPR） polarization in 0.5molfL H2SO4 ＋0.01molfL KSCN solution. The variation rules of impedance resistance in process of EPR polarization were analyzed. It was found that the EIS spectra of the stainless steels during EPR polarization ex- hibited features of active dissolution, activation - passivation, passivation and reactivation. Before reactivation, the two kinds of stainless steels had the same EIS characteristics. In the reactivating region the passivated film dissolved partially and the impedance modulus of the sensitized stainless steel was one magnitude order smaller than that of the solution - treated stainless steel, indicating that intergranular corrosion had occurred on the surface of the sensitized stainless steel. In addition two capacitive loops appeared in the EIS of the sensitized stainless steel and it was quite interesting that the second arc at the low frequency range was actually a negative resistance capacitive loop. These results may provide essential basis for detecting intergranular corrosion susceptibility of stainless steel by electrochemical impedance spectroscopy.

关 键 词：不锈钢 晶间腐蚀 电化学阻抗谱 

分 类 号：TG174.3[金属学及工艺—金属表面处理]