Effect of Inorganic Content on the Performance of Anticorrosive Hybrid Sol-Gel Coated EN AW-6063 Alloy
authors Fontinha, IR; Salta, MM; Zheludkevich, M; Ferreira, MGS
editors Pinto, AMP; Pouzada, AS
nationality International
journal ADVANCED MATERIALS FORUM VI, PTS 1 AND 2
author keywords Hybrid coating; sol-gel; corrosion; aluminium
keywords CORROSION PROTECTIVE PROPERTIES; CERIUM NITRATE; COATINGS; AA2024; RESISTANCE; METALS; ZR
abstract The organic-inorganic hybrid sol-gel films have been reported as an effective anti-corrosion and environmentally friendly alternative to Cr(VI) pre-treatment for aluminium alloys. The sol-gel process used to obtain these coatings allows the variation of the different synthesis parameters to achieve coatings with optimized properties. In this work, hybrid films with different Zr/Si ratios were synthesized from glycidoxypropyltrimethoxysilane (GPTMS) and zirconium n-propoxide (TPOZ) precursors. Electrochemical Impedance Spectroscopy (EIS) was used to evaluate the corrosion behaviour of coated aluminium specimens in 0.5 M NaCl solution. The morphology and chemical structure of the hybrid coatings prepared were studied by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), Fourier Transformed Infrared Spectroscopy (FUR) and Thermo Gravimetric Analysis (TGA). It was found that increasing Zr/Si ratio leads to a more cross linked inorganic network, resulting in higher initial coatings resistance, but may turn coatings more hydrophilic, prone to rapid degradation in water, due to a less connected organic network. Consequently, the best anticorrosive performance derives from the balance between the two opposite trends and it was achieved with Zr/Si molar ratio of 0.25.
publisher TRANS TECH PUBLICATIONS LTD
issn 0255-5476
year published 2013
volume 730-732
beginning page 745
ending page +
digital object identifier (doi) 10.4028/www.scientific.net/MSF.730-732.745
web of science category Materials Science, Multidisciplinary
subject category Materials Science
unique article identifier WOS:000315545200123
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