Study of microbiologically induced corrosion of 5052 aluminum alloy by sulfate-reducing bacteria in seawater

This study evaluated the biocorrosion on 5052 aluminum alloy caused by sulfate-reducing bacteria (SRB) inoculated in sterile seawater. Specimens were immersed in two reactors, one containing only sterile seawater and other containing sterile seawater with inoculum of sulfate reducing bacteria (SRB). The biofilm formation was assessed by periodic analyses of microbial quantification and Scanning Electron Microscopy (SEM) over 48 days of immersion. The Open Circuit Potential (OCP) was monitored for a period of 15 days. To evaluate the corrosion, morphology images were obtained using SEM and optical microscopy. The results demonstrated that the SRB showed high adhesion to the metal substrate. Localized corrosion morphology was identified for the two conditions studied. Better results of mass loss, OCP, polarization and EIS were observed for aluminum alloy exposed to seawater with SRB, evidencing the protective effect of the formed biofilm.