Effect of AA2024‐T3 surface pretreatment on the physicochemical properties and the anticorrosion performance of poly(γ‐glycidoxypropyltrimethoxysilane) sol‐gel coating. (27th December 2017)

• Record Type: Journal Article
• Authors: Mrad, M.; Ben Amor, Y.; Dhouibi, L.; Montemor, M. F.
• Is Part Of: Surface and interface analysis. Volume 50:Number 3(2018)
• Page Start: 335
• Page End: 345
• Publication Date: 2017-12-27
• Subjects: AA2024‐T3 -- coating -- corrosion -- pretreatment -- γ‐GPTMS; Surfaces (Physics) -- Periodicals; Surface chemistry -- Periodicals; Thin films -- Periodicals; 541.33
• DOI: 10.1002/sia.6373
• Languages: English
• ISSNs: 0142-2421

Abstract

Abstract : This study investigated the dependence of the anticorrosion performance of a poly(γ‐glycidoxypropyltrimethoxysilane) (poly(γ‐GPTMS)) sol‐gel coating on AA2024‐T3 aluminum alloy surface state. Two different AA2024‐T3 surface pretreatment procedures were tested: a degreasing with acetone and a chemical multistep etching process (industrial chemical etching pretreatment). Poly(γ‐GPTMS) coatings were deposited onto both pretreated surfaces using the dip‐coating technique. Surfaces were characterized principally by scanning electron microscopy, X‐ray photoelectron spectroscopy, Fourier transform infrared attenuated total reflectance, contact angles, and roughness measurements. Moreover, for the coated AA2024‐T3 surfaces, a pull‐off test was used to evaluate the poly(γ‐GPTMS) adhesion to the pretreated surface. Bare surface properties depended on the applied pretreatment. The chemically etched surface was the roughest and the most concentrated in hydroxyl groups. In addition, comparatively to the degreased surface, it has a more hydrophobic character. Poly(γ‐GPTMS) coating revealed an uneven nature and a poor adhesion once it was deposited onto the degreased surface. Coatings anticorrosion performances were evaluated using electrochemical impedance spectroscopy measurements (EIS). Electrochemical impedance spectroscopy data proved that the sol‐gel coating applied onto the chemically etched surface had better anticorrosion performance.