Effect of vinyl resin addition on the adhesion strength of anti-corrosion zinc-rich epoxy coating on A283 steel

Abstract

The objective of this study is to improve the adhesive properties of anticorrosion zinc-rich coatings. This was achieved by introducing modifications, specifically by incorporating vinyl resin into the base formulation which consisting of epoxy resin and zinc powder. The efficacy of the newly modified coating (ZRC-M) was assessed in comparison to a commercially available zinc-rich epoxy coating (ZRC-C). Coatings with both formulations (ZRC-C and ZRC-M) were applied to the carbon steel panels. The main methods employed to investigate the corrosion protection efficacy and adhesion of the two variants of zinc-rich epoxy coatings included DC linear polarization, electrochemical impedance spectroscopy (EIS), salt spray exposure, and the pull-off test. The results revealed that the adhesion improved in ZRC-M compared to ZRC-C, while maintaining an equivalent level of anticorrosion protection. With the decrease in coating density and viscosity, the electrochemical impedance spectroscopy results obtained at the open circuit corrosion potential indicated that the addition of vinyl resin enhanced the effective zinc content and the barrier effect of the coating after a forty-day immersion period, attributable to the reduce of electrical conductivity of the coating.