Effect ofVibrio Neocaledonicus sp. on Corrosion Behavior of Copper in Artificial SeaWater postprint

Abstract: 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 mV/(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 images showed 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.