Study on Electrochemical Behavior of Nano-ZnO Modified Alkyd-Based Waterborne Coatings

A nano-composite coating was formed using nano-ZnO as pigment in different concentrations, to a specially developed alkyd-based waterborne coating. The nano-ZnO modified composite coatings were applied on mild steel substrate by dipping. The dispersion of nano-ZnO particles in coating system was investigated by scanning electron microscopic and atomic force microscopic techniques. The effect of the addition of these nanopigments on the electrochemical behavior of the coating was investigated in 3.5% NaCl solution, using electrochemical impedance spectroscopy. Coating modified with higher concentration of nano-ZnO particles showed comparatively better performance as was evident from the pore resistance (R(po)) and coating capacitance (C(c)) values after 30 days of exposure. In general, the study showed an improvement in the corrosion resistance of the nano-particle modified coatings as compared with the neat coating, confirming the positive effect of nano-particle addition in coatings. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 2232-2237, 2009