Corrosion Behavior of Brass in Simulated Cooling Water Containing Sulphate-reducing Bacteria

The electrochemical corrosion behaviour of brass in simulated cooling water containing sulphate-reducing bacteria was investigated by electrochemical impedance spectroscopy, polarization curve, wire beam electrode measurement, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). SEM photographs and EDS analysis indicated that a slimy layer or biofilm formed on electrode surface in solution containing SRB, and the elements such as Cu and S were detected. According to the results of electrochemical measurements, the brass electrode impedance increased and the corrosion current density decreased with the immersion time in sterile solution. The impedance of brass electrode decreased and the corrosion current density significantly increased in solution with SRB. The results of wire beam electrode measurement showed that at the initial stage of immersion, the largest potential difference of the electrode surface was relatively high and then decreased with immersion time, indicating electrochemical inconsistency of the surface which may be caused by the uneven biofilm at that stage, and causing corrosion in local region.