Influence of Static Magnetic Field on Microbiologically Induced Corrosion of Cu-Zn Alloy in SRB Culture Medium

Abstract

Sulphate-reducing bacteria (SRB) have been known as one of the key microbes in the microbiologically influenced corrosion (MIC) process. In the paper, the corrosion behavior of Cu-Zn alloy in SRB culture media by SRB biofilms under a 200mT static magnetic field (SMF) was investigated using electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and x-ray photoelectron spectrum (XPS). The open circuit potential (OPC) was generally much more negative in the presence of SMF. After 14 days immersion, the number of SRB in biofilm with SMF were 4.5 ×103 cells/cm2 and without SMF were 1.0 ×108 cells/cm2, which showed that SMF decreased the sessile SRB and triggered SRB biofilm dispersion. SEM, EDAX and XPS demonstrated that in presence of SMF, the protect film was compact and the corrosion products were mainly Cu2O, Cu2S and very little Cu(II)X, which were very different from the corrosion products without SMF mainly Cu(II)X. The EIS of samples which were cultured in inoculated SRB media in the presence and absence of SMF were tested. At the same time, the applied SMF accumulating the compact protective products film that deposited on the surface of the Cu-Zn alloy. Thus, SMF mitigated both biofouling and MIC can be controlled.