Structural and electrochemical behavior of sol-gel ZrO2 ceramic film on chemically pre-treated AZ91D magnesium alloy

In the present investigation sol-gel-based ZrO2 ceramic film was obtained using zirconium acetate as the precursor material. The film was deposited on AZ91D magnesium alloy by a dip-coating technique. An uniform stannate conversion coating as chemical pretreatment was employed as an intermediate layer prior to deposition of the ZrO2 film in order to provide advantage for the formation of sol-gel-based ZrO2 layer. The corrosion properties, structure, composition and morphology of these coatings on AZ91D magnesium alloy were studied by potentiodynamic polarization tests, EIS, XRD, SEM, respectively. According to the electrochemical tests, the corrosion resistance of AZ91D magnesium alloy was found to be greatly improved by means of this new environment-friendly surface treatment. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.