Electrochemical Noise Analysis of Anaerobic (Bacterial) Corrosion of Steel

Corrosion of structural steel in an SRB containing environment for as long as 9 months, is studied using the Electrochemical Noise Analysis technique. The results show that the activity of the system, which was very low initially, started to increase after 6 months exposure to the environment. The power spectral density curves of the Electrochemical Potential Noise of the system, using the maximum entropy method (MEM), indicate the existence of a characteristic pattern in the spectra. The effect of the yeast extract in the culture media, added periodically to support the growth of the bacteria was shown to suppress the signals, which is related to the corrosion inhibition effect of the yeast extract. After feeding, it usually took 3 weeks before the corrosion activities, as manifested by the values of electrochemical potential noise of the system, reached the values prior to the addition of the culture media to the system. These preliminary results indicate that analysis of electrochemical noise may offer promise in detection and monitoring of bacterial corrosion.