316L不锈钢在硫酸盐还原菌和铁氧化菌共同作用下的腐蚀行为

采用微生物分析、电化学测试、扫描电镜观察及表面能谱分析等方法，研究了316L不锈钢在硫酸盐还原菌（Sulfate—Reducing Bacteria，SRB）与铁氧化菌（Iron—Oxidizing Bacteria，IOB）共同作用的溶液中的腐蚀电化学行为，分析了炼油厂冷却水系统中微生物腐蚀的特征及机制。结果表明，不锈钢电极在SRB与IOB相结合的溶液中的自腐蚀电位、点蚀电位和再钝化电位均随浸泡时间的增加而负移，其滞后环增大；在SRB与IOB共同作用的溶液中的腐蚀速率大于在无菌溶液中；显微观察表明生物膜疏松多孔，生物膜内细菌的生长代谢活动促使不锈钢表面的钝化膜层腐蚀破坏程度增加，在SRB与IOB共同作用下316L不锈钢电极发生了严重的点蚀。

Corrosion behavior of 316L stainless steel in the combination action of sulfate-reducing and iron-oxidizing bacterias

The corrosion behavior of 316L SS in the combination action of aerobic IOB and anaerobic SRB isolated from cooling water system in oil refinery was investigated using bacterial analyses,electrochemical measurement,scanning electron microscopy(SEM) and energy dispersive spectrum(EDS).The results show that the E_(corr),E_(pit) and E_(rp) of 316L SS decrease significantly for the presence of SRB and IOB,in comparison with those observed in the sterile medium for the same exposure time interval.E_(corr) of 316L SS in the sterile medium remained virtually unchanged with exposure time,indicating that pitting attack did not occur.However,micrometer-scale pitting is observed on the 316L SS surface in the combination action of SRB and IOB.The combination action of SRB and IOB demonstrates higher corrosion rates than that in the sterile medium.The biofilm observed by biology microscope is neither integrity nor compact.The metabolic activity of bacteria under biofilms increases the corrosion damage degree of the passive film,and accelerates the pitting corrosion.It is suggested from the present study that SRB and IOB in influencing pitting corrosion of 316L SS is highlighted.