Corrosion behavior of ZnNiAl 2 O 3 nanocomposite coatings obtained by electrodeposition from alkaline electrolytes

• Published in: Materials and corrosion Vol. 64; no. 5; pp. 433 - 438
• Main Authors: Blejan, D., Muresan, L. M.
• Format: Journal Article
• Language: English
• Published: 01.05.2013
• ISSN: 0947-5117; 1521-4176
• DOI: 10.1002/maco.201206522

Abstract The aim of this work was to investigate the anti‐corrosive properties of nanocomposite ZnNi coatings containing Al 2 O 3 nanoparticles, prepared from alkaline commercial electrolytes (pH 13), (PERFORMA 280.5, COVENTYA S.A.S, France), by electrodeposition on carbon steel (OL37). The corrosion resistance of the coatings prepared with different concentrations of Al 2 O 3 (5, 10, and 15 g/L) was evaluated in 0.2 g/L Na 2 SO 4 solution (pH 5) by open circuit potential (OCP) measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. The results of electrochemical measurements were corroborated with those obtained by using X‐ray diffraction analysis. The obtained results show that the introduction of Al 2 O 3 nanoparticles in the plating bath generally brings an increase in corrosion resistance of ZnNi layers and put in evidence the existence of an optimal Al 2 O 3 concentration. Under the examined conditions, the optimal concentration determined from polarization measurements was proven to be 5 g/L Al 2 O 3 . The highest value of the polarization resistance, R p , obtained from impedance measurements corresponds also to ZnNi with 5 g/L Al 2 O 3 , which is in agreement with the results obtained from polarization and XRD measurements.