酸性土壤环境中Q235钢的微生物腐蚀行为

Microbial Corrosion of Q235 Steel in Acidic Red Soil Environment

采用电化学阻抗谱(EIS)、极化电位扫描等电化学技术和微观形貌观察方法研究含硫酸盐还原菌(SRB)的酸性红壤环境中Q235钢的微生物腐蚀(MIC)行为及对应电化学过程特征。结果表明:酸性红壤环境中,前4 d为环境适应期,期间SRB细菌数量减少,SRB对腐蚀电化学过程没有显著影响;生长期中SRB促使Q235钢的自腐蚀电位和极化电阻降低,腐蚀速率增大;EIS极化电阻测试结果表明,有菌红壤中腐蚀速率约为无菌红壤中的2倍。SRB呼吸代谢活动可与红壤颗粒表层Fe OOH等铁氧化物作用,引起Fe OOH的微生物异化还原,促进Q235钢的腐蚀电化学过程。

Microbial corrosion induced by sulphate-reducing bacteria（SRB） for carbon steel Q235 beneath coating defects was studied by means of electrochemical impedance spectroscopy（EIS）, polarization measurement and microscopic surface observation. Results showed that, in acid red soil environment, SRB have no significant effect on the electrochemical process during the initial environmental adaptation period. Then in the next period, the respiratory metabolic activities of the growing SRB lead to decrease of the free corrosion potential of Q235 steel and accelerate corrosion process of the carbon steel.Bacteria can react with iron oxides in the red soil, causing microbial dissimilatory reduction of iron oxides,which promotes electrochemical corrosion process of the carbon steel.