The effect of nanoporous silica aerogel on corrosion protection properties of epoxy coatings on carbon steel

In this paper, due to special properties of aerogels such as ultra-low density and hydrophobic nature of aerogels, this nanomaterial was used as anticorrosive pigments. Silica aerogel was dispersed in epoxy resin by using sonication method. The dispersion of nanoparticles were characterized by transmission electron microscopy. The anticorrosive properties of these coatings were investigated by salt-spray and electrochemical impedance spectroscopy methods in a 3.5 wt % NaCl solution. Impedance parameters showed a decrease in coating resistance over immersion time. Results indicated that epoxy coatings containing nano silica aerogel could significantly increase the corrosion resistance of composite coatings compared to those of pure epoxy and the highest value was obtained for 0.5% aerogel nanocomposite coatings after 160 days immersion. Pull off adhesion test showed the highest value of adhesion was related to coating containing 0.5% aerogel. According to salt-spray methods, it was found that the best results were obtained with coatings containing 0.5 and 1 wt % of silica aerogel.