Effect of solvent dilution on corrosion protective properties of Ormosil coatings on 2024-T3 aluminum alloy
By Na, Eun-Young; Ko, Jae-Yong & Baik, Shin-Young
Published in Progress in Organic Coatings
2004
Abstract
The effects of solvent dilution on corrosion resistance characteristics of sol–gel derived organically-modified silicate (Ormosil) thin films on 2024-T3 aluminum alloy substrates were investigated. Solvents were introduced into the sol immediately prior to spray application of the coating and were found to have a significant effect on film structure, thickness, and corrosion resistance properties. Various concentrations (28.5–66.5 vol.%) of non-polar solvents (hexane, heptane), aprotic polar solvents (acetone, MEK), primary alcohols (methanol, ethanol, isopropanol, 2-methoxyethanol, 2-ethoxyethanol, 2-methyl-1-butanol, 3-methyl-1-butanol), secondary alcohols (1-methoxy-2-propanol), and tertiary alcohols (t-amyl alcohol) were investigated. Corrosion resistance properties were found to depend on the Ormosil network structure and on the stability of solvent-induced reesterification products. Selection of the appropriate solvent was found to allow preparation of significantly thinner Ormosil films exhibiting enhanced corrosion resistance characteristics.