Improved interfacial interactions and corrosion resistance of epoxy coated reinforcement by pre-electrodeposited silane layer

Epoxy coating is one of the most useful measures for corrosion protection of steel bar due to the facile operation and excellent barrier property. However, the high brittleness and porosity of epoxy coating as well as the weak interface bonding properties between epoxy and steel bar greatly limited its protective performances. In this work, a uniform silane layer was prefabricated on the surface of steel bar by electrodeposition to enhance the interfacial interactions between steel bar and epoxy, and thus enhance the protective properties of the coating. The surface features and corrosion resistance of the prepared silane-epoxy composite coatings were studied by means of scanning electron microscope, Fourier transform infrared spectroscopy, Raman analyses, electrochemical and Machu tests. The results show that the presence of the electrodeposited silane layer significantly increases the chemical bond between carbon steel and epoxy resin, thereby enhance the adhesion between epoxy resin and carbon steel. In addition, the network structure formed by silane acts as a physical barrier to the corrosive medium, improving the corrosion resistance of single epoxy coating, thereby delaying the corrosion of carbon steel. • Silane film using electrodeposition method improves the protective effect of silane on carbon steel. • The use of silanes as adhesion promoters between epoxy and carbon steel enhances the corrosion resistance of epoxy coatings. • The adhesion of silane to carbon steel inhibits the diffusion of corrosion products, and the filling of pores by passivation products enhances the short-term corrosion resistance of the coating and delays the corrosion of carbon steel.