“Effect of Nano-zinc Oxide Particles on the ...

A nano-composite coating was formed by incorporating nano-ZnO pigments in a waterborne polyurethane dispersion (WPUD) to different loading levels (0.1% and 1.0% by weight). Corrosion performance of the nano-composite coatings were evaluated by applying these nano-composites coatings on mild steel substrate and exposing them to salt-spray, humidity and accelerated UV-weathering. Mechanical properties like scratch resistance, abrasion resistance and pencil hardness were also studied. The electrochemical performance and mechanical properties of the composite coatings were evaluated using various analytical techniques. FTIR technique was used to investigate the interaction between nano-ZnO particles and the polymer functionalities. SEM and AFM were used to investigate dispersion of nano-ZnO particles and the changes in the surface behavior of the modified coatings before and after exposure to the test environment. The optical property of the coating was evaluated using UV-Visible spectrophotometer. The results showed an improvement in the corrosion, UV and mechanical properties of the coatings at lower concentration (0.1% by wt), indicating the positive effect of addition of nano-ZnO particles in the coatings. It was found that the optical transparency of the coating was not altered at lower loading level of nano-ZnO particles.