SRB-biofilm growth and influence in corrosion monitoring by electrochemical impedance spectroscopy

2005 by NACE International. A mixed culture of D. gabonensis and D. capillatus, in synthetic seawater supplemented with nutrients formed a biofilm combined with ferrous sulfide corrosion products that largely covered carbon steel electrodes (SAE-1020). Electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP) measurements were carried out for this study. Electrochemical impedance results indicated the formation of three films: an inner corrosion products film, an outer corrosion products film and the biofilm or organic film in abiotic media. After one month of batch culture, it was observed that during biofilm formation there are two different controlled processes. During the first period activation-diffusion controlled corrosion was observed. The second period showed diffusion controlled corrosion due to biofilm establishment. Impedance spectra denote an increase in Rct(charge transfer resistance) with time in the presence of biofilm. Magnitudes of the phase angle contributions are indicative of biofilm and corrosion products interphases heterogeneity during primary formation stages.

SRB-biofilm growth and influence in corrosion monitoring by electrochemical impedance spectroscopy Conference Paper