Development of an ecofriendly silane sol-gel coating with zinc acetylacetonate corrosion inhibitor for active protection of mild steel in sodium chloride solution

Abstract

This work intends to develop an ecofriendly silane sol-gel coating with zinc acetylacetonate for active protection of mild steel. This water-based silane coating was composed of γ-glycidoxypropyltrimethoxysilane, tetraethoxysilane and methyltriethoxysilane. The optimum inhibitor concentration was determined using electrochemical impedance spectroscopy. The electrochemical impedance spectroscopy data indicated no effect of zinc acetylacetonate on the coating barrier properties, which was confirmed by field emission scanning electron microscope (field emission scanning electron microscope), energy dispersive X-ray spectroscopy and fourier transform infrared spectroscopy surface analysis. From the charge transfer resistance, the superiority of inhibitor-doped films was associated with the function of zinc acetylacetonate at the interface. The electrochemical measurements showed an increase in the corrosion resistance of bare metal in sodium chloride solution with zinc acetylacetonate. From the results of field emission scanning electron microscope, energy dispersive X-ray spectroscopy, and atomic-force microscopy surface analysis, the corrosion control was suggested to be attributed to formation of a protective layer on the surface with contribution of zinc acetylacetonate.