Corrosion behavior of Ce-oxide/hydroxide coated AA7075-T6 prepared by dip immersion method

Abstract

In this study, cerium-based conversion coating was deposited on aluminum 7075-T6 by dip immersion method. Cerium oxide/hydroxide is an environmentally friendly conversion coating. Its corrosion resistance in 3.5 wt.% NaCl solution was investigated by means of electrochemical impedance spectroscopy, potentiodynamic polarization, and surface techniques. The coated samples showed a significant decrease in corrosion rate and the coating resistance increased with increasing immersion time up to 1200 s. In addition, electrochemical impedance data showed that in the presence of cerium oxide/hydroxide conversion coatings, the charge transfer resistance of aluminum increased. Surface morphology and its chemical composition were analyzed by means of scanning electron microscopy and energy dispersive spectroscopy.