Improvement of anti-corrosion performance (surface and near the cut edge) and mechanical properties of epoxy coatings modified with nano, micro and hybrid ZnO particles

Composites were formed by incorporating nano, micro and hybrid-ZnO particles into the epoxy matrix at the same loading levels (3%) and applied at 90 μm thickness on the galvanized steel substrate using a film applicator in this study. The improvement in anti-corrosion performance and mechanical and physical properties of the composite coatings were evaluated using various tests and techniques such as salt-spray, electrochemical impedance spectroscopy, nanohardness, microscratch, cross-cut, bending, Fourier transform infrared spectroscopy, thermogravimetric and Scanning electron microscopy. The corrosion performance of the composite coatings near the cut edge is discussed in detail as well as on the surface of galvanized steel. The results show that the addition of all ZnO particles has a positive effect on the corrosion resistance and mechanical properties of the coatings. The addition of nano, micro and hybrid ZnO particles increased the hardness of the composites by 52, 37 and 56%, respectively, compared to the neat epoxy. Although the cathodic protection performance is weakened near the cut edge due to the loss of Zn after thermal cutting, high barrier protection was provided with composite coatings, especially micro ZnO/Epoxy composite coating.