Table of Contents
ISRN Corrosion
Volume 2012, Article ID 506560, 9 pages
http://dx.doi.org/10.5402/2012/506560
Research Article

Effect of Plasma Surface Pretreatment on Ce3+-Doped GPTMS-ZrO2 Self-Healing Coatings on Aluminum Alloy

1Centre for Sol-Gel Coatings, International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur, Andhra Pradesh, Hyderabad 500005, India
2Centre for Mechanical and Chemical Characterization, International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur, Andhra Pradesh, Hyderabad 500005, India

Received 7 October 2012; Accepted 12 November 2012

Academic Editors: G. Bereket, C. Du, C.-H. Hsu, and S. Umoren

Copyright © 2012 N. Kumar et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A hybrid sol synthesized from an acid-catalyzed hydrolysis and condensation reaction of 3-glycidoxypropyltrimethoxysilane (GPTMS) and zirconium n-propoxide was used as a matrix nanocomposite sol. To this sol, 0.01 M Ce3+ was added as an inhibitor to provide a self-healing coating system. The effect of an atmospheric air plasma surface pretreatment of aluminum alloy substrates prior to coating deposition of Ce3+-doped/undoped GPTMS-ZrO2 sol was studied with respect to corrosion protection. Coatings were generated by a dip coating technique employing a withdrawal speed of 5 mm/s and thermally cured at 130° C for 1 h. The coated Al surfaces were characterized using potentiodynamic polarization studies and electrochemical impedance spectroscopy. They were also subjected to accelerated corrosion testing using neutral salt spray test with 5% NaCl solution after creating an artificial scratch for more than 200 hours to assess the self-healing ability of coatings. It was observed that cerium (III) doping was effective for corrosion protection during long-term exposure to the electrolyte solution, and a plasma surface pretreatment of substrates prior to coating deposition of Ce3+-doped coatings improved the adhesion of coatings that provides enhanced corrosion protection along with self-healing ability exhibited in case of damages/scratches caused in the coating.