Influence of Nano-Al Concentrates on the Corrosion Resistance of Epoxy Coatings

A two-stage process was used to produce nano-composite epoxy coatings. The first step involved preparing nano-Al concentrates with high concentration and low viscosity, and the second step produced nano-composite epoxy coatings by mixing the nano-Al concentrates and epoxy resin. Later, the coating was examined with immersion and salt spray tests. The coatings were characterized by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that the 5% nano-Al significantly improves the corrosion resistance of the coatings. There are two effects of nano-Al on the coating. Nano-Al is corroded initially to protect the substrate from corrosion, and then the aluminum oxide and aluminum hydroxide were produced after corrosion of nano-Al, which hindered the transmission of corrosion fluid into the coatings.