铁氧化菌作用下316L不锈钢点蚀电化学特性的研究

Electrochemical Characteristic on Iron-oxidizing Bacteria Inducing Pitting Corrosion of 316L Stainless Steel

采用电化学测量、交流阻抗技术、扫描电镜观察和能谱分析等实验方法,研究了316L不锈钢在铁氧化菌(IOB)溶液中的腐蚀电化学行为,分析了炼油厂冷却水系统微生物腐蚀的特征及机制,结果表明,在含有IOB溶液中的自腐蚀电位(Ecorr)、点蚀电位(Epit)和极化电阻(Rp)均随浸泡时间的增加呈现出降-升-降的变化趋势;在含有IOB溶液中的腐蚀速率均大于在无菌溶液中;IOB的生长代谢活动及其生物膜的完整性和致密性影响了316L不锈钢表面的腐蚀过程,使不锈钢表面的钝化膜层腐蚀破坏程度增加,加速了316L不锈钢的点蚀。

Pitting corrosion behavior of 316L stainless steel（SS） was investigated in the presence of aerobic IOB isolated from cooling water system in oil refinery by using polarization measurement. electrochemical impedance spectrum （EIS）, scanning electron microscopy（SEM） and energy disper sive spectrum（EDS） analysis. The results showed that the corrosion potential（Ecorr）, pitting potential （Epit） and polarization resistance （Rp） of 316L SS presented the variational trend of decrease-increase decrease with the increase of immersion time; the corrosion rate of 316L SS in lOB solution was larger than that in sterile medium. The metabolic activity of IOB as well as the integrality and compactness of biofilm influenced pitting corrosion process, increased the corrosion damage of the passive film, accelerated the pitting corrosion of 316L SS. It is suggested from the present study that the effect of aer obic lOB on the pitting corrosion of 316L SS is highlighted.