Application of the differential impedance analysis on the microbiologically induced corrosion of bronze

In this work, the behavior of a binary Cu-Sn (12wt% Sn) alloy has been studied in presence and absence of bacteria in aqueous solution simulating stagnant fresh water. The corrosion processes have been investigated using the Electrochemical Impedance spectroscopy (EIS) technique. The application of the Differential Impedance Analysis (DIA) allowed identifying three processes attributed to the electrical double layer, electrical properties of the passive film and mass transfer processes at the metal/solution interface. Based on DIA structural analysis, equivalent circuit model was proposed and used for better parametric identification of the impedance data. The formation of a biofilm strongly influenced the passive layer behavior, promoting localized corrosion. Post-experiment characterization performed by Scanning electron microscopy (SEM) supported the electrochemical characterization.