Microbiologically influenced corrosion (MIC) is very severe corrosion for the constructions buried in sea mud environment Therefore it is of great importance to carry out the investigation of the corrosion behavior of marine steel in sea mud. In mis paper, the effect of sulfate-reducing bacteria(SRB) on corrosion behavior of mild steel in sea mud was studied by weight loss, dual compartment-cell, electronic probe microanalyzer(EPMA), transmission electron microscope(TEM) combined with energy dispersive X-ray detector (EDX) and electrochemical impedance spectroscopy(EIS). The results showed that free corrosion rate and galvanic current were influenced by the metabolic activity of SRB. In the environment of sea mud containing SRB, the original corrosion products, ferric (oxyhydr)oxide, transformed to ferrous sulfide. With the increase of the dissolved H_2S the component of the protective layer formed of FeS transformed to Fe_(1-x)S, and FeS_(1-x) later, which changed the state of the former layer and accelerated the corrosion process.
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