Microbiologically influenced corrosion of metals and alloys

In aquatic environments, microorganisms attach to metals and colonise the surface to form biofilms producing an environment at the biofilm/metal interface that is radically different from that of the bulk medium in terms of pH, dissolved oxygen, and organic and inorganic species and leading to electrochemical reactions that control corrosion rates. The term microbiologically influenced corrosion is used to designate corrosion resulting from the presence and activities of microorganisms within biofilms at metal surfaces. Microorganisms can accelerate rates of partial reactions in corrosion processes and shift the mechanism for corrosion. Microbiologically influenced corrosion has received increased attention by corrosion scientists and engineers in recent years with the development of surface analytical and electrochemical techniques that can quantify the impact of microbes on electrochemical phenomena and provide details of corrosion mechanisms. Microbiologically influenced corrosion has been documented for metals exposed to sea water, fresh water, demineralised water, process chemicals, food stuffs, soils, aircraft fuels, human plasma, and sewage.