Electrochemical Evaluation of Microbiologically Induced Corrosion by Two Iron-Oxidizing Bacteria

摘要

The anodic corrosion current resulting from the colonization of carbon steel and nickel electrodes by an heterotrophic iron-oxidizing bacterium was 10.4 microangstrom/sq cm and 0.1 microangstrom/sq cm, respectively, indicating that oxidation reactions controlled the overall corrosion. Both metals were shown to be electrochemically active in the presence of differential aeration and acidic metabolites. Accumulations of ferric hydroxide on the surface of the carbon steel resulted in an anodic current of 8.6 microangstrom/sq cm that persisted after the colonizing microorganisms had been heat-killed. Attempts were made to measure the electrochemical impact of an autotrophic iron-oxidizing bacterium on the corrosion of stainless and carbon steels in the presence and absence of added soluble Fe(++). Under the experimental conditions described, it was impossible to demonstrate microbiologically induced corrosion with these microorganism/substrata combinations.