Electrocodeposition and characterization of cobalt lanthanide oxides composite coatings

Composite coatings were prepared by electrodeposition of cobalt and the following lanthanide oxides: CeO2, Nd2O3, La2O3 and Y2O3. The morphology and the particle content of the layers were characterized and their dependence on the deposition parameters is discussed. The highest particle incorporation achieved was 3 5 wt.% CeO2 within the cobalt matrix. The amount of incorporated particles (in wt.%) decreased in the order CeO2>Y2O3>Nd2O3>La2O3. In order to evaluate the improvement of the corrosion resistance of the Cobalt matrix due to the incorporation of lanthanide oxide particles, the electrochemical behaviour of the composite films was studied by linear sweep voltammetry and electrochemical impedance spectroscopy in chloride containing solutions. In comparison with pure Co, Co-Nd2O3, Co-La2O3 and CO-Y2O3 the Co-CeO2 composite coatings showed a superior corrosion resistance in 0.1 M NaCl. (C) 2007 Elsevier B.V. All rights reserved.