Anti-Corrosion Behaviour of Silver-Cobalt Oxide-Titanium Dioxide Nanocomposites Coated Mild Steel in Sea water

Abstract

The research work investigates the corrosion resistance of Silver-Cobalt Oxide-Titanium Dioxode (Ag/Co3O4/TiO2) nanocomposites coated mild steel (AISI 1020) in seawater environment. The coatings were carried out by dipping method. The nanoparticles were individually produced by mixing the salt precursors with extract of Piptadeniastrum africana leaf under the optimized synthesis conditions. The Ag/Co3O4/TiO2 nanocomposite was produced by mixing Ag, Co3O4 and TiO2 NPs in equal proportions to constitute 75 wt% of the composite. 10 wt % epoxy resin and its hardener in the ratio (1:1) were added to serve as the binder, while 15 wt% of CNT was introduced to serve as support. Phase and Microstructural examination of the coatings was carried out by XRD and HRSEM. The corrosion protection properties were determined by using computer- controlled EGG 273A Potentiostat with three- electrode cell system under static laboratory conditions using the linear potentio-dynamic polarization method. The coated sample was dried at temperatures of 100oC to enhance adherence of the coating on the steel substrate. The result of Tafel polarization plots revealed improved corrosion resistance of the coated specimen as compared to as-received sample. Corrosion rate and corrosion resistance of 0.201 m/y and 195.12 Ω were recorded against the coated sample while 0.261 m/y and 71.42 Ω were recorded for the as-received sample respectively. The coated sample exhibited higher potential shift in the positive direction and showed better corrosion resistance properties.