A study of the corrosion resistance of a waterborne acrylic coating modified with nano-sized titanium dioxide

► Nano sized titanium dioxide particles were added to an organic primer coating. ► Particle dispersion was examined using scanning electron microscopy. ► Corrosion protection of galvanized steel substrates by the coatings was assessed. ► 3% (w/w) titanium dioxide gave greatest improvement in corrosion resistance. The incorporation of nano-sized inorganic pigment particles into organic coatings may offer the potential for improving many of their properties, including corrosion resistance, at relatively low loadings. In the present research, titanium dioxide with a crystallite size of 5–10 nm was added to a waterborne organic primer formulation at loadings from 0.1 to 5% (w/w) and applied to hot-dip galvanized steel (HDG) panels. The corrosion resistance of the modified coatings was measured by neutral salt spray corrosion testing and electrochemical impedance spectroscopy (EIS), with an unpigmented film tested for comparison. 3% (w/w) TiO 2 appeared to produce an optimum improvement in the corrosion resistance.