新喀里多尼亚弧菌对Cu在人工海水中腐蚀行为的影响

Effect of Vibrio Neocaledonicus sp. on Corrosion Behavior of Copper in Artificial Sea Water

分离出了一种具有高度缓蚀作用的新喀里多尼亚弧菌,通过电化学测量方法和表面分析技术研究了该细菌对Cu在人工海水中腐蚀行为的影响。结果表明,新喀里多尼亚弧菌使Cu的开路电位明显负移;在有菌介质中,Cu表面的阻抗值显著增大;同时腐蚀电流密度明显降低,说明该细菌可以抑制Cu在人工海水中的腐蚀。CLSM结果显示,Cu表面吸附有大量的细菌,而SEM观察到Cu表面生物膜并不多,说明这种抑制作用是由吸附在Cu表面的细菌引起的,而与Cu表面的生物膜关系不大。

In our previous research, the corrosion inhibitory effect of marine Vibrio neocaledonicus sp. bacterium was introduced for the first time. EIS results showed that the corrosion resistance of carbon steel increased by more than sixty fold in the presence of this bacteria. The aim of this paper is the investigation of bacterial influence on the corrosion process of unalloyed copper. Different electrochemical measures（open circuit potential, electrochemical impedance spectroscopy（EIS）,and potentiodynamic polarization measurements） and surface analysis techniques（field emission scanning electron microscopy（FESEM） and confocal laser scanning microscopy（CLSM）） were used. The results showed that： in the presence of bacteria, EOCP（open circuit potential） of copper shifted to negative direction about 500 m V/（vs SCE）; while the charge transfer resistance（Rct） and the corrosion current density（Icorr） increased and decreased respectively. These results confirmed that the Vibrio neocaledonicus sp. could lessen the corrosion of unalloyed copper. CLSM imagesshowed bacteria could adsorbed on the copper easily, but no obvious biofilm were found on the copper surface. So, it seems the corrosion inhibition of the bacteria is due to bacterial attachment in the first hours of exposure. The mechanism has been discussed in this paper.