Initial corrosion behavior of composite coatings obtained by co-electrodeposition of zinc with nanoparticles of Ti and Ce oxides

The present work reports the results obtained for the electrodeposition of composite Zn coatings on steel by using Ti and Ce oxides nanopowders, separately or in mixture, and a TiO₂·CeO₂ binary oxide. In an attempt to correlate the effects of nanoparticles on corrosion behavior of the composite deposits, the properties of Zn–TiO₂·CeO₂ layers were compared with those referring to similar coatings prepared by using a simple mixture of the two oxides or individual oxides. Corrosion measurements were performed in 0.2 g?L^?1 Na₂SO₄ solution (pH?=?5). The results of electrochemical measurements (open circuit potential measurements, polarization curves, and electrochemical impedance spectroscopy) were corroborated with those obtained by using X-ray diffraction, atomic force microscopy, scanning electron microscopy, and salt spray tests. The results indicate that the composite Zn–(TiO₂?+?CeO₂) coatings exhibit the highest corrosion resistance from all investigated Zn coatings.