硫酸盐还原菌对两种不锈钢的腐蚀作用

CORROSION ACTION OF SULFATE-REDUCING BACTERIA ON TWO STAINLESS STEELS

采用电化学方法、微生物学方法和表面分析方法研究了在厌氧环境中硫酸盐还原菌(sulfate-reducing bacteria, SRB)溶液和电化学加速腐蚀协同作用下不锈钢1Cr18Ni9Ti和Cr17Ni2的腐蚀电化学行为.结果表明,未在菌液中浸泡的两种不锈钢电极在SRB菌液中的开路电位在第4天最大,分别为-0.409和-0.396 V;而在菌液中浸泡的两种电极开路电位在第6天最大,分别为-0.240和-0.303 V.未浸泡的两种不锈钢电极点蚀电位随细菌生长时间的增长而变化,但在6-10天变化不大;浸泡在菌液中的两种电极点蚀电位随浸泡时间的增加先负移然后正移再负移. 1Cr18Ni9Ti比Cr17Ni2更耐蚀.显微观察表明生物膜并不完整致密,在SRB和电化学加速腐蚀作用下不锈钢电极发生了严重的点蚀.

The corrosion behaviors of 1Cr18Ni9Ti and Cr17Ni2 in the synergistic action of sulfate-reducing bacteria (SRB) and electrochemically accelerated corrosion were studied by electrochemical, microbiology and surface analysis methods. The open circuit potential (E-oc) and pitting potential (E-b) of the electrodes were measured at the culture times of 0-10 days in non-immersion electrode way and immersion electrode way. It was found that E-oc for the non-immersion electrode way was the biggest on the fourth day while E-oc for the immersion electrode way was the biggest on the sixth day. E-b for the former decreased with the growth time. E-b for later shifted negatively at first, then positively, finally negatively. It was demonstrated that the corrosion resistance of 1Cr18Ni9Ti was much better than that of Cr17Ni2. The biofilm observed through the biology microscope was neither integrity nor compact. The serious pitting corrosion occurred on the electrode surface under the comprehensive action of electrochemically accelerated corrosion and SRB was observed by SEM.