海泥中硫酸盐还原菌对Zn-Al-Cd牺牲阳极腐蚀的影响

来源期刊：金属学报2010年第10期

论文作者：张杰 刘奉令 李伟华 段继周 侯保荣

文章页码：1250 - 1257

关键词：硫酸盐还原菌； Zn-Al-Cd； 海泥； 电化学阻抗谱

Key words：sulfate reducing bacteria； Zn-Al-Cd； marine sediment； electrochemical impedance spectroscopy

摘    要：采用EIS,PC,SEM和EDS等方法,通过在硫酸盐还原菌(SRB)的一个生长周期内测试Zn-Al-Cd牺牲阳极在不含和含SRB海泥中的腐蚀行为,以对比研究海泥中SRB对其腐蚀行为的影响.EIS和PC测试结果显示,实验初期,试样在2种海泥中的腐蚀速率都快速增大,但由于SRB的大量增长,其对试样的腐蚀作用不断增强,所以在含SRB海泥中的腐蚀速率一直大于在不含SRB海泥的腐蚀速率;实验后期,由于SRB的大量死亡,其对试样的腐蚀作用已经十分微弱,因此2者的腐蚀速率逐渐变得比较接近.SEM分析显示,2种海泥中的试样表面都出现大量的腐蚀坑,但含SRB试样表面的腐蚀程度更为严重.EDS结果显示含SRB试样表面的Zn和Al含量明显低于无SRB试样,说明了试样在含SRB海泥中的腐蚀溶解速度相对较大.

Abstract: With the development of marine industry,the corrosion of metal structures in marine sediment has received increasing attention.Marine sediment is a very complex marine corrosion environment.The corrosion of sulfate-reducing bacteria (SRB) in the marine sediment is thought as one of major corrosion factors.Sacrificial anodes are widely used for protection of steel structures in the marine environment due to their high theoretical current efficiency,low active potential and low cost.However,in the marine environment,the sacrificial anodes may be attacked by microbial activity, which leads to serious failure and energy loss.Some researchers have investigated the biocidal activity of sacrificial anode,but work about the influence of microbes on the performance of sacrificial anode has been rarely reported. In this paper,a comparative study of the corrosion behavior of Zn-Al-Cd sacrificial anode in marine sediment without and with SRB was carried out using electrochemical impedance spectroscopy (EIS),polarization curve (PC),scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).The results of EIS and PC showed that the corrosion of the sample was enhanced sharply in the presence of SRB at the beginning,while the corrosion performance of the sample in marine sediment with and without SRB gradually became similar with each other due to the decreasing SRB populations. SEM images revealed that the damage of the sample in the SRB-containing medium was severer than that in the sterile medium.EDS analysis showed that the concentration of Al and Zn in the surface film of the sample with SRB was much lower than that for the sample without SRB,which suggests that the corrosion rate of the sacrificial anode is accelerated by SRB.