Corrosion behavior of steel A3 influenced by Bacillus

Surface analysis, mass loss and electrochemical mesurements were used to investigate the corrosion behavior of steel A3 under the effect of Bacillus. Scanning electron microscopy (SEM) indicated that the presence of Bacillus resulted in a compact biofilm after 7 days of exposure, which effectively protected the coupon from being corroded by the solution. Electrochemical impedance spectroscopy (EIS) showed that the number of time constants changed from 2 to 3 and returned to 2 in the Bacillus system. The mass loss and polarization curve results showed that the activity of the bacteria determined the effectiveness of the biofilm. The protective ability of the biofilm decreased when the activity of the bacteria decreased.