Morphological analysis and corrosion performance of zirconium based conversion coating on the aluminum alloy 1050

An aluminum alloy 1050 was treated by zirconium-based conversion coatings at different pHs, immersion times, temperatures and Zr concentrations. Corrosion resistance and morphological properties of samples were investigated by potentiostatic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), energy dispersive X-ray spectrum (EDS) and atomic force microscope (AFM). The results showed that surface treatment of aluminum by zirconium conversion coating caused decrease in corrosion current density and increase in corrosion resistance even at long immersion times. The Zr conversion layer enhanced the adhesion of the epoxy coating to the aluminum alloy surface.