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Stainless steel coated with multilayers of Ti oxide/butoxide was prepared via a layer-by-layer sol-gel deposition process. The successful buildup of the Ti oxide/butoxide coatings was ascertained by X-ray photoelectron spectroscopy and static water Contact angle measurements. The differences in corrosion behavior between the Ti oxide/butoxide-coated and the uncoated coupons in a simulated seawater-based modified Baar's medium inoculated with Desulfovibrio desulfuricans under anaerobic conditions were investigated by electrochemical analyses, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). Electrochemical analyses and SEM results revealed that the pristine, the hydroxylated, and the nitric acid-passivated coupons were all vulnerable to biocorrosion due to localized breakdown of the passive film under synergistic attack of Desulfovibrio desulfuri- cans and biogenic sulfide ions, leading to destructive pitting and crevice corrosion. However, the Ti oxide/butoxide-coated coupons exhibited desirable resistance in the biocorrosion environment and the coating remained relatively stable throughout the exposure period. EDX analysis revealed that the bioactive properties of the Ti oxide/butoxide coating arose from the concomitant deposition of calcium and phosphorous compounds. The increase in resistance of the Ti oxide/butoxide coatings with time was correlated with the increase in nucleation of calcium anatite in electrochemical studies. [ABSTRACT FROM AUTHOR]

Microbiologically influenced corrosion (MIC) is extremely harmful to maritime industries and to the environment. A surface modification technique was developed in this work to impart antibacterial and corrosion-inhibition properties Onto the surface- oxidized Cu-Ni alloy to inhibit MIC. Thus, 4-(chloromethyl)phenyl tricholorosilane was first immobilized on the oxidized metal surface to allow the coupling of 4,4′-bipyridine to the methyl-chloride groups. Subsequently quaternization by benzyl chloride converted the terminal pyridine groups into pyridinium groups. The success of each functionalization step was ascertained by X-ray photoelectron spectroscopy, atomic force microscopy, and Static water contact angle measurement. The quaternized viologen moieties exhibited good bacterial inhibition efficiency at the initial stages of exposure to a seawater-based medium containing aerobic bacteria belonging to the genera Pseudomonas, as revealed by scanning electron microscopy images. The corrosion- inhibition properties of the organic layer were verified by Tafel polarization curves, cyclic polarization curves, and electrochemical impedance spectroscopy. In comparison; the pristine Cu-Ni alloy was readily susceptible to MIC in the same medium and under the same conditions. [ABSTRACT FROM AUTHOR]