摘要
Corrosion caused by sulfate-reducing prokaryotes(SRP)is an important cause of magnesium alloy anode failure in oil pipeline.In this study,the effects of Desulfovibrio sp.HQM3 on the corrosion behavior of AZ31B magnesium alloy anode in organic carbon sources with different contents in simulated tidal flat environment were analyzed using weight loss test,surface analysis and electrochemical analysis technologies.The results showed that the weight loss rate of coupons in low carbon sources contents(0%,1%,10%)was higher than that in 100%carbon sources.Electrochemical analyses showed that the corrosion current density(J_(corr))under low carbon sources contents was larger,while the charge transfer resistance(R_(ct))was lower,leading to a higher corrosion rate compared to those under 100%carbon sources content.Observations from scanning electron microscopy(SEM)and confocal laser scanning microscopy(CLSM)revealed more severe pitting corrosion on the alloy surface in the absence of carbon sources.In addition,a large number of nanowires were observed between bacteria on the alloy surface using SEM.Combined with thermodynamic calculations,it was demonstrated that the corrosion of coupons by Desulfovibrio sp.HQM3 in the absence of carbon sources was achieved through extracellular electron transfer.
滩涂环境是一个泥水气混合的相对封闭的独特环境,硫酸盐还原原核生物(SRP)引起的腐蚀是滩涂环境石油管道中管线破坏失效的重要原因。目前,国内外关于滩涂环境中埋地油气管线腐蚀的研究通常侧重于管线钢本身的腐蚀情况,对于为管线钢提供阴极保护的镁阳极的研究涉及不多。但在实际工况下镁阳极的异常腐蚀失效严重威胁着输油管线的安全运行。此外,滩涂环境中物质交换的困难和镁阳极周围化学填充物的包裹而导致SRP缺乏充足的碳源供应。在碳源饥饿条件下SRP是否会导致镁阳极腐蚀以及如何影响镁阳极腐蚀尚不清楚。因此,本研究通过失重测试、表面分析和电化学分析等方法,研究了菌株Desulfovibrio sp. HQM3在模拟滩涂环境下不同含量的有机碳源(柠檬酸三钠和乳酸钠)对埋地油气管线中AZ31B镁阳极腐蚀行为的影响。失重结果表明,在Postgate C(PGC)培养基中添加低含量有机碳源(0%,1%,10%)时合金试样的失重率高于添加100%碳源时的。电化学分析表明,合金试样在低有机碳源含量时的腐蚀电流密度(J_(corr))比100%有机碳源情况下的J_(corr)大,电荷转移电阻(R_(ct))小,腐蚀速率快。扫描电子显微镜(SEM)和激光扫描共聚焦显微镜(CLSM)观察也表明,在缺乏有机碳源时,Desulfovibrio sp. HQM3引起的合金表面的点蚀更严重。此外,利用SEM在镁阳极试样表面细菌之间观察到大量的纳米线,结合热力学计算证明了缺乏有机碳源时菌株Desulfovibrio sp. HQM3对AZ31B镁阳极的腐蚀是通过胞外电子转移而实现的。
作者
LI Jin-rong
ZHANG Jie
KRISHNAMURTHY Mathivanan
ZHU Qing-jun
XING Shao-hua
ZHANG Rui-yong
SAND Wolfgang
DUAN Ji-zhou
HOU Bao-rong
李金融;张杰;KRISHNAMURTHY Mathivanan;朱庆军;邢少华;张瑞永;SAND Wolfgang;段继周;侯保荣(Key Laboratory of Advanced Marine Materials,Key Laboratory of Marine Environmental Corrosion and Bio-fouling,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China;Institute of Marine Corrosion Protection,Guangxi Academy of Sciences,Nanning 530007,China;College of Materials Science and Engineering,Qingdao University of Science and Technology,Qingdao 266042,China;Open Studio for Marine Corrosion and Protection,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China;State Key Laboratory for Marine Corrosion and Protection,Luoyang Ship Material Research Institute,Qingdao 266101,China;Institute of Biosciences,University of Mining and Technology,09599 Freiberg,Germany;Aquatic Biotechnology,Faculty for Chemistry,University of Duisburg-Essen,45141 Essen,Germany©Central South University 2024)
基金
Project(42076043) supported by the National Natural Science Foundation of China
Project(ZR2023ZD31) supported by the Major Basic Research Project of Natural Science Foundation of Shandong Province,China
Project(2023VEA0007) supported by the Chinese Academy of Sciences President’s International Fellowship Initiative。
