William F. Nelson
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Flash rusting is a corrosion process in which steel rapidly oxidizes upon contact with air at a high relative humidity. The ultimate goal of this research is to develop a bio-inspired corrosion inhibitor that is both water-soluble and environmentally friendly and will inhibit flash rust on high strength steel (HY80) as well as corrosion on the aluminum alloy AA 5083. Several proteins involved in the formation of the adhesive byssal threads by the blue mussel Mytilus edulis L have been identified for their potential as corrosion inhibitors. The most important feature of these biomolecules for corrosion prevention applications is the presence of a post-translationally modified amino acid L-3, 4 dihydroxyphenylalanine (L-dopa). L-dopa has a well characterized ability to form strong bonds with metal ions, thus stabilizing the metal surface and inhibiting corrosion. In addition, when enzymatically treated, L-dopa containing proteins and polypeptides can participate in crosslinking reactions, which have been shown to lead to a thicker and more durable protein layer when applied to surfaces. In this study, HY80 steel coupons were treated with varying amounts of MAP-1, the largest and most well-characterized of the five mussel proteins, in varying buffer and enzyme content and exposed in an accelerated atmospheric corrosion chamber maintained at 40'C and 100% relative humidity. For comparison, identical HY80 samples were treated with a commercially available flash rust corrosion inhibitor under identical exposure conditions. The results show that enzymatically crosslinked MAP-1 can last for as long as 272 hours, 200 hours longer than the average control sample. Electrochemical measurements including cyclic polarization scans and electrochemical impedance spectroscopy (EIS) data were collected for HY80 samples treated with MAP-1 immersed in seawater. The results of these measurements and exposure tests will be presented and discussed.
Douglas C. Hansen
Primary Advisor's Department
Materials Degradation and Electrochemical Engineering (Research Institute-Materials Engineering)
Stander Symposium project
"Investigation and Testing of Corrosion Inhibiting Polyphenolic Proteins" (2013). Stander Symposium Projects. 316.