?Electrons-siphoning? of sulfate reducing bacteria biofilm induced sharp depletion of Al--Zn--In--Mg--Si sacrificial anode in the galvanic corrosion coupled with carbon steel

The microbiologically influenced corrosion (MIC) of Al--Zn--In--Mg--Si sacrificial anode coupled with X80 carbon steel induced by sulfate reducing bacteria (SRB) was investigated. Results revealed that SRB strongly promoted the galvanic current density between the aluminum anode and carbon steel by facilitating the cathodic process of the galvanic corrosion on carbon steel. In the medium with SRB, 73.7% of the corrosion loss of aluminum anode coupled to carbon steel was caused by the enhanced galvanic corrosion. SRB biofilm on the carbon steel continuously obtained electrons from the aluminum anode, which was like an "electrons-siphoning" process in the galvanic corrosion.