循环冷却水中硫酸盐还原菌对不锈钢腐蚀行为影响

Influence of Sulfate-reducing Bacteria in Circulating Cooling Water on Corrosion Behavior of Stainless Steel

利用扫描电镜(SEM)、金属表面元素分析、交流阻抗以及极化曲线等分析方法,研究了循环冷却水中SRB对SS316L和SS317L两种不锈钢的腐蚀行为。结果表明:试验前期,SRB较易吸附在SS317L表面,钝化膜被破坏,SS316L与SS317L腐蚀速率增大且在10 d达到最大;浸泡中期,SS316L成膜速度较快于SS317L,生物膜对不锈钢表面起到保护作用,阻塞了导电通路,使腐蚀速率减小;浸泡后期,不锈钢表面生物膜被破坏,腐蚀速率增大。SS317L极化电阻较大,Mo和Cr含量较多,钝化膜不易被破坏,耐蚀性较强。

By using the scanning electron microscopy （SEM） , metal surface elemental analysis, AC impedance and polarization curve analysis method, this paper studied the corrosion behavior of SRB in the circulating cooling water to SS316L and SS317L stainless steel. The results show that in testing prophase, SRB is easily absorbed in SS317L surface,passive film is damaged,SS316L and SS317L corrosion rate increases and reaches the maximum in 10 d;in the soaking medium-term ,SS316L film-forming is faster than SS317L ,biofilm on stainless steel plays a protective role on the surface, blocking the conductive path, so that the corrosion rate is reduced;in the soaking late-term stainless steel biofilm is destroyed,and the corrosion rate increases. SS317L has larger polarization resistance with more contents of Mo and Cr,the passive film with strong corrosion resistance is not easy to be destroyed.