Interaction protection cathodique et biofilm en milieu marin

IFREMER. Plouzane

Abstract

In marine environments cathodic protection using sacrificial anodes or impressed current is widely used. In aerated seawater a cathodic potential of – 800 mV/SCE is generally accepted as efficient against marine corrosion. Biofilms formed on the metallic surfaces exposed to seawater can promote localized corrosion and interfere with the cathodic polarization process.

Experiments were conducted both in natural environments and with a monoculture of a marine bacterium in order to understand the relationship between cathodic protection and biofilm formation. Results indicated that, in the former case, there was no evidence that biofilms significantly affect the cathodic current demand. Conversely, in sterilized seawater inoculated with a single bacterial species, biofilm on the surface seriously affected the current demand. Furthermore, cathodic polarisation does not appear to influence bacterial attachment to the surfaces.