Microbiologically Influenced Corrosion of Copper Alloys in Saline WatersContaining Sulfate-Reducing Bacteria

摘要

Sections of CDA 706 piping and Monel 400 tubing were severely pitted afterexposure to marine and estuarine waters. Pits developed under surface deposits of mixed bacterial communities containing 100,000-1,000,000 sulfate-reducing bacteria (SRB). Localized corrosion was attributed to a combination of differential aeration cells, a large cathode: small anode surface area, concentration of chlorides, development of acidity within the pits and the specific reactions of the base metals with sulfides produced by the SRB. Chlorine and sulfur reacted selectively with the iron and nickel in the alloys. Nickel had been removed from the pitted areas leaving a copper-rich, spongy pit interior.