A Comparative Study of Mussel Adhesive Proteins As Flash Rust Inhibitors on High Strength Low Alloy Steel

Abstract

Several proteins found in the adhesive system of the common blue mussel Mytilus edulis have chemical properties which might enable them to inhibit the flash rusting of steels. In this work, Mytilus edulis foot proteins (MAPs) 1, 3, and 5 were purified and applied to HY80 steel in a number of buffer systems containing various amounts of borate, acetate, and phosphate at pH 5.5-7.0. Treated HY80 samples were then monitored in an exposure chamber at 40°C and 100% relative humidity for 7 days. The MAP treatments were also evaluated electrochemically via electrochemical impedance spectroscopy (EIS). The effect of enzymatic crosslinking of the applied proteins using mushroom tyrosinase was also investigated. HY80 samples treated with MAP-1 failed to inhibit corrosion when the protein was dissolved in deionized water, and the effect of MAP-1 on the corrosion on HY80 in buffers containing acetate was not significantly different from the control samples. However, in 0.05M phosphate buffer solution at pH 5.5, enzyme treated MAP-3 and MAP 5 were capable of significantly increasing the time to corrosion and significantly reducing the mass loss of HY80 in the exposure chamber compared to relevant buffer-only controls. The performance of the crosslinked MAP-5 was similar to a commercial temporary corrosion inhibitor applied at the same mass concentration as the protein, suggesting that MAP-5 and similar proteins or polymers may be capable of inhibiting corrosion under certain conditions.