Heterogeneous corrosion of mild steel under SRB-biofilm characterised by electrochemical mapping technique

Heterogeneous corrosion of mild steel under sulphate reducing bacteria (SRB)-biofilm was characterised by wire beam electrode (WBE) technique and electrochemical impedance spectrum. The potential/current distributions of the WBE under SRB-biofilm showed that the potential maps could not indicate the localised corrosion of steels beneath biofilm due to the fact that all wire electrodes were short-circuited by the highly conductive sulphide precipitates embedded in SRB-biofilm. Instead, the galvanic current maps may give a good indication. The characteristic of super-capacitance (0.21 F/cm(2)) of SRB-biofilm was attributed to the huge specific surface area of conductive pore walls inside biofilm. (C) 2011 Elsevier Ltd. All rights reserved.