Electrochemical Study on Microbiologically Influenced Corrosion of Carbon Steel in Seawater

Samples of carbon steel with microbes were prepared by exposing to seawater on site. The influence of microbes on corrosion rate and corrosion mechanism of carbon steel in seawater was studied by electrochemical measurement techniques. The corrosion rate of carbon steel in seawater showed a trend of falling-steadying-rising. Microbes, especially sulfate-reducing bacteria (SRB) in internal rust layer, could accelerate the corrosion rate. The corrosion rate of the steel showed a rising trend when accelerating effect of SRB in the internal rust layer exceeded the corrosion inhibition of the rust layer. The carbon steel corrosion in seawater could be divided into 3 stages including oxygen diffusion control, transition and SRB activation control.