The effect of ceria and zirconia nanoparticles on the corrosion behaviour of cataphoretic epoxy coatings on AA6060 alloy

Abstract

In this work an attempt was made to produce epoxy coating doped with ceria (CeO2) and/or zirconia (ZrO2) nanoparticles, in single step electrophoretric deposition process. Deposition was carried out on AA6060 cataforetically from epoxy resin suspension containing synthesized stable aqueous colloidal dispersions (sols) of CeO2 and ZrO2. The influence of ceria and zirconia nanoparticles on the physicochemical characteristics of epoxy coatings was evaluated by energy dispersive X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis and adhesion measurements, while their corrosion stability during immersion in 0.5 M NaCl solution was monitored by electrochemical impedance spectroscopy. All ceria and/or zirconia containing coatings showed better corrosion stability and adhesion than pure epoxy coating, while between doped epoxy coatings one with CeO2/ZrO2 exhhibited the greatest values of charge-transfer resistance due to synergetic effect of both types of added nanoparticles.