Improve the Corrosion Behavior of Galvanized Coating by Incorporation of ZrO 2 Particles Using a Hot-Dip Method

The effect of ZrO 2 particles with 0.1, 0.2 and 0.3 wt % was studied on the corrosion behavior of zinc coating with nano and micro sizes. In this case, the specimens were immersed in a zinc bath for 6 s. The mechanical, structural properties and corrosion behavior of coatings were determined by Vickers’s hardness, bending, porosity and thickness measurement tests, SEM and FE-SEM, Open circuit potential, Salt spray, Polarization and Impedance test. The obtained results showed that the reduced of thickness, surface porosity and roughness of coating, increased the adhesion of coating due to the incorporation of oxide particles and increased the hardness of coating. Additionally, increase in the polarization resistance and reduction of corrosion current density and reduced the corrosion rate of the galvanized coating, which confirmed with impedance test. Also, the addition of oxide particle, decreased the thickness of brittle phases such as gamma and delta in the coating. Because, the formation of fine grain and distribution of oxide particle in the coating, prevented the accumulation and changed the coating texture, improved the corrosion resistance and mechanical properties of coating. Consequently, the electrochemical analysis revealed the desirable amount of corrosion resistance for the coating containing 0.3 wt % of nano ZrO 2 , which showed about 99/89% reduction in corrosion rate.