Investigation of carbon steel corrosion influenced by in-situ microbial communities can provide reliable information about microbiologically influenced corrosion (MIC) in the oil and gas field. Here, we investigated the 90-day corrosion behavior of Q235 carbon steel influenced by interior deposit microflora of an in-service pipeline using open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS). Linear sweep voltammetry (LSV), 16S rRNA gene sequencing, and surface analysis were used to comprehensively analyze the corrosion mechanisms. The results indicated that OCP was decreased while the charge transfer resistance (Rct) was increased, and that steel corrosion was inhibited during the first 45 days. Subsequently, OCP was significantly increased while Rct was rapidly decreased, and steel corrosion was enhanced. After 90-day immersion, severe pitting corrosion with a maximum pit depth of 89.6 μm occurred on the steel surface. Viable microbes in the final biofilm significantly increased the cathodic current. Iron carbonate, chukanovite and cementite were identified as the main corrosion products on the steel surface. Methanobacterium dominated the final biofilm community. These observations indicate that the corrosion mechanism of the final biofilm can be explained by extracellular electron transfer MIC in which microbes corrode steel by direct electron uptake.

中文翻译：

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在役管道内部沉积物菌群对碳钢的腐蚀行为及机理的影响。

对原位微生物群落影响的碳钢腐蚀的研究可以提供有关油气田中受微生物影响的腐蚀（MIC）的可靠信息。在这里，我们使用开路电势（OCP）和电化学阻抗谱（EIS）研究了在役管道内部沉积物菌群对Q235碳钢90天腐蚀行为的影响。线性扫描伏安法（LSV），16S rRNA基因测序和表面分析被用来全面分析腐蚀机理。结果表明，OCP降低而电荷转移电阻（Rct）升高，并且在开始的45天内抑制了钢的腐蚀。随后，OCP显着增加，而Rct迅速减小，并且钢腐蚀增强。浸入90天后，钢表面发生严重的点蚀，最大点蚀深度为89.6μm。最终生物膜中的活菌显着增加了阴极电流。碳酸铁，楚卡诺夫岩和渗碳体被确定为钢表面上的主要腐蚀产物。甲烷杆菌主导了最终的生物膜群落。这些观察结果表明，最终的生物膜的腐蚀机理可以通过细胞外电子转移MIC来解释，其中微生物通过直接电子吸收腐蚀了钢。甲烷杆菌主导了最终的生物膜群落。这些观察结果表明，最终的生物膜的腐蚀机理可以通过细胞外电子转移MIC来解释，其中微生物通过直接电子吸收腐蚀了钢。甲烷杆菌主导了最终的生物膜群落。这些观察结果表明，最终的生物膜的腐蚀机理可以通过细胞外电子转移MIC来解释，其中微生物通过直接电子吸收腐蚀了钢。