Study of the Efficiency of Ag-SiO2 Nanoparticles as Additives in Anticorrosion Coatings

In this work, Ag-SiO2 nanoparticles were used as additives in an epoxy paint to evaluate their efficiency to protect SAE 1020 carbon steel from corrosion. Ag-SiO2 particles were characterized using X-ray diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM). Samples of ABNT 1020 steel were coated with an industrial epoxy based paint added with Ag-SiO2 nanoparticles. Electrochemical tests of open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) were conducted to evaluate the anticorrosive behavior of the investigated coatings when exposed to saline solution. DLS data show that Ag-SiO2 particles have average diameters of around 223.4 nm. TEM images highlight the presence of Ag-SiO2 particles agglomeration. EIS and OCP measurements show that addition of 0.5% w/w Ag-SiO2 to the epoxy paint could improve the efficiency of the anticorrosive coating, when compared to the epoxy paint without any corrosion inhibitor. Results also show the importance of developing efficient dispersion techniques to avoid the agglomeration of the particles that may increase the porosity of the coating and thus affect its corrosion protection efficiency.