海洋环境中的模拟微生物腐蚀研究

The Study on Simulated Microbiologically Influenced Corrosion of Mild Carbon Steel in Sea Condition

近来，海洋环境中的微生物腐蚀受到广泛的重视。为了更好地理解微生物腐蚀的机理，试验采用腐蚀电位、极化曲线法、交流阻抗法、扫描电镜法对低碳钢Q235在灭菌海水中和黏附有模拟生物膜状态下的海水中的不同腐蚀行为进行了研究分析。实验结果表明，在涂有模拟生物膜的试样表面，碳钢的自腐蚀电位有较大的负移，稳定后自腐蚀电位比空白试样低，相对在无菌海水中的腐蚀而言，腐蚀电流密度变大，极化电阻减小，加速了低碳钢的腐蚀速度。涂膜试样经14d腐蚀后，低碳钢表面出现大量的腐蚀孔，发生了严重的孔蚀行为。总的来说低碳钢在海水中有很强的腐蚀性，尤其是在试样表面存在生物膜的情况下会加速金属的腐蚀速度。

Microbiologically influence corrosion（MIC） in marine condition is attentive increasingly. In order to understand the mechanism of MIC, corrosive behaviors of mild carbon steel with film in sterile marine condition were investigated by using open- circuit potential of electrode, polarization curve, the electrochemical impedance spectrometry （ EIS） and the environmental scanning electronic microscope（ESEM）. The results showed that the corrosion potential of mild carbon steel with film removed to negative potential largely..The corrosion potential of mild carbon steel with film is lower than it of mild carbon steel without film. Otherwise, the corrosive current density had become bigger in film condition than it in sterile marine condition. And the galvanic current impedance had become litter in film condition than it in sterile marine condition. By the MIC, the surface of mild carbon steel appeared a large amount of holes, which were the results of heavily pitting corrosion. All in all, the corrosion of mild carbon steel in marine condition is very strong. Especially in the film marine condition, biomembrane could promote the corrosive speed of mild carbon steel in marine condition.