Electrochemical measurements (EIS and DC-polarisation curves) have been conducted on carbon steel coupons exposed in SRB-active environments. Results from EIS measurements show that very large interfacial capacities are found in such systems, and consequently high capacitive currents are to be expected when conducting d.c. polarisation scans. Further, it is indicated that the interfacial capacitance correlates with the concentration of dissolved sulfide, which in turn, to some degree, correlates with hydrogenase activity. It is suggested that the large and increasing interfacial capacitance is responsible for the large potential hysteresis generally found in d.c. scans obtained in these environments. By comparing polarisation curves obtained using different scan rates in an inorganic control environment, it is suggested that an ever increasing interfacial capacitance may be responsible for a misleading conclusion that increasing corrosion rates are caused by cathodic depolarisation in SRB-active environments.
|Title of host publication||Aspects of microbially induced corrosion|
|Place of Publication||London|
|Publisher||The Institute of Materials|
|Publication status||Published - 1997|