Electrochemical noise analysis applied to srb-induced corrosion of carbon steel

Corrosion of carbon steel in the presence of a sulfate-reducing bacteria biofilm was investigated by electrochemical noise (EN) measurements on a specific sensor on which localized corrosion processes had been artificially initiated by modifying the electrode surface electrochemically or mechanically. EN has been analyzed in the time domain by considering the occurrence and the peak amplitude of the potential and current transients that characterize a localized corrosion on the central disk of the sensor. These parameters have been shown to be linked to the biological activity of the biofilm. On the contrary, measurements of the fluctuations of the only corrosion potential of a single carbon steel coupon on which a biocorrosion process had been initiated did not allow detection of this localized process. This is due to the large difference in the surface areas of the corrosion site and of the coupon.