Characterization and corrosion resistance of organically modified silicate/MO2 (M = Zr, Ti, or Ce) hybrid coatings on a 6061‐T6 aluminum alloy

Abstract

AbstractHybrid coatings based on organically modified silicate (Ormosil)/ZrO2 (0–1.0 wt %) and Ormosil/MO2 (M = Ti or Ce) were synthesized through a sol–gel technique. Tetraethylenepentamine, 3‐glycidoxypropyltrimethoxysilane, tetraethoxysilane, and MO2 (M = Zr, Ti, or Ce) metallic particle were used as precursors for the hybrid coatings. These hybrid films were deposited via spin coating onto an aluminum alloy to improve the corrosion protection. The effects induced by the ZrO2 content and the metallic particle type on the chain dynamics, thermal stability, and corrosion performance of the coated samples were investigated. The rotating‐frame spin–lattice relaxation times and scale of the spin–diffusion path length indicated that the configuration of the hybrid films was highly crosslinked and dense and adhered to the aluminum alloy substrates. The thermal stability and the apparent activation energy, evaluated by van Krevelen's method, of the hybrid coatings depended on the ZrO2 content and on the metallic particle type. Potentiodynamic and salt‐spray analysis revealed that the hybrid films provided exceptional barrier and corrosion protection in comparison with untreated aluminum alloy substrates. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 335–342, 2006