Electrochemical corrosion behavior of carbon steel exposed to low concentration agar with and without nutrients

摘要

A novel technique for the study of microbial corrosion in soil is currently being developed.rnThis technique uses microbiologically graded agar to simulate more closely thernconditions experienced in soil than is possible with an aqueous solution. Traditionally,rnmost soil based corrosion testing is conducted in the laboratory with solutions madernto mimic the chemical composition of soil. This does not take into account the physicalrnstructure of soil and resultant electrochemical interactions between the soil, steelrnand microbes. Agar is commonly used as a solidly setting gelling agent. However, inrnlower concentrations it forms a sludge like consistency, similar to the consistency ofrnsaturated soil.rnUtilizing low concentration agar in an electrochemical cell, the corrosion behavior ofrncarbon steel has been investigated under varying nutrient conditions.rnPotentiodynamic scans, potential hold measurements, optical microscopy and SEMrnimaging were used to monitor the steel surface both during and after exposure of thernsteel to the agar. These measurements will make the basis of a control for later experimentsrnwhen the response of Pseudomonas to nutrient changes under a range ofrnpotentials when in an electrochemical set up will be investigated.rnThis work is part of a continuing investigation into the mechanisms of microbial corrosionrnat the soil-steel interface of buried potable water pipes.