Corrosion behavior of Zn-TiO2 and Zn-ZnO Electrodeposited Coatings in 3.5% NaCl solution

Electrodeposition is a widely used method to protect metallic materials from corrosion. Electrodeposited coatings provide the metal substrate with both cathodic protection and a barrier effect. The corrosion resistance achieved with this type of zinc-electroplating process in increased by adding nanometric materials to the electrolytic bath. In the present research, coatings were obtained by electrodeposition of pure zinc, Zn-TiO2 and Zn-ZnO nanoparticles. The coatings were generated by immersion in a chloride acid bath applying a current density of 0.05 and 0.10 A/cm(2) for 1 min and adding 2 g/l of TiO2 or ZnO nanoparticles. Corrosion behaviour was evaluated with potentiodynamic polarization curves and the electrochemical impedance spectroscopy (EIS) technique using a 3.5% NaC test solution. After electrochemical testing, the coating surface morphology was analysed by scanning electron microscopy (SEM) and the atomic composition by energy dispersive X-ray spectroscopy (EDS). The electrodeposited coating thickness was measured using the ultrasound technique. The coating thickness was less than 2.5 mu m and its corrosion resistance increased with the addition of nanoparticles.