Impact mechanism of nano-sized TiO2 and SiO2 on corrosion resistance of electric arc spraying sealing coat

In this paper, the corrosion resistance of organic coatings addition with nano-sized TiO2 and SiO2 was studied based on influencing factors of protection with coatings. The corrosion protection performances of coatings were further discussed such as adhesion between the coatings and the metal substrate; barrier property of coatings to penetration of water and ions; the coatings microstructure and the galvano-chemistry performance with the SEM and IM6EX electrochemical active station. The results indicate that homogeneous nano fillers can improve the fluidity and permeability of the epoxy, stiffen the adhesion between the coatings and the metal substrate. In the electrochemical impedance spectroscopy (EIS) experiments, the impedance diagram showed the Warburg characteristic impedance. It means that nano-sized grains impede the diffusion of electrolyte in the coatings, which improves the corrosion resistance of the metal substrate. As the soak time increases, the structure of the organic coating involved, the obstructive of the nano-particles lessened, and the characteristic of the EIS was also changed.