Corrosion resistance properties of Ormosil coatings on 2024-T3 aluminum alloy

Metroke, Tammy L.; Gandhi, Jarel K.; Apblett, Allen W.

doi:10.1016/j.porgcoat.2004.03.001

Cited by 116 publications

(48 citation statements)

References 40 publications

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“…The vinyl groups presumably disrupt the integrity of the hydroxylated surface (i.e., the concentration of SiOH groups on the surface decreases) [35], enhancing the hydrophobicity and the barrier properties of the with a lower concentration of VTMS (e.g. 2V panels).…”

Section: Electrochemical Measurementsmentioning

confidence: 99%

Improving the corrosion performance of hybrid sol–gel matrix by modification with phosphonic acid

Dalmoro

Santos

Baibich

et al. 2015

Progress in Organic Coatings

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Sol-gel films were prepared using different ratios of two silica precursors, vinyltrimethoxysilane (VTMS) and tetraethylorthosilicate (TEOS), targeting the anticorrosion treatment of aluminum alloy 2024-T3. The electrochemical behavior of the alloy coated with such films, which was studied in a 0.05 mol L -1 NaCl solution, revealed that the VTMS/TEOS ratio drastically affects the anticorrosion performance. Electrochemical impedance spectroscopy (EIS) results provided evidences that the best anticorrosive response occurs with the films prepared from 50% v/v ethanol, 46% v/v water, 3% v/v VTMS and 1% v/v TEOS. Moreover, the effects of the addition of ethylenediamine tetra(methylene phosphonic acid) (EDTPO) to a hybrid sol-gel matrix were examined. The corrosion resistance was considerably improved when the concentration of added phosphonic acid was 3.7510 -5 mol·L -1 . Scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy analyses revealed that EDTPO-containing films provide a more uniform coverage. Results evidenced the formation of Si-O-Al linkages in the VTMS/TEOS and VTMS/TEOS/EDTPO systems and that the VTMS/TEOS/EDTPO system contained P-O-Al linkages. The P-O-Al bonds, combined with the silica network action, may be responsible for the good anticorrosive behavior of the VTMS/TEOS/EDTPO films.

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Section: Electrochemical Measurementsmentioning

confidence: 99%

Improving the corrosion performance of hybrid sol–gel matrix by modification with phosphonic acid

Dalmoro

Santos

Baibich

et al. 2015

Progress in Organic Coatings

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“…The current state of the art for protecting aluminium alloys involves the use of hexavalent chromium technology in the form of conversion coatings and pigmented anticorrosion primers [1]. However in the interest of human health [2,3] and environmental concerns, alternative solutions are being pursued. For engineering applications organic polymers (polyesters, polyamides, alkyds, and polyurethane) [4], conductive polymers (polyaniline and polypyrrole) [5] and sol-gel derived organicinorganic hybrid materials have emerged as promising Cr 6+ alternatives [6].…”

Section: Introductionmentioning

confidence: 99%

Corrosion protection of AA 2024-T3 aluminium alloys using 3, 4-diaminobenzoic acid chelated zirconium–silane hybrid sol–gels

Varma

Colreavy

Cassidy³

et al. 2010

Thin Solid Films

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Organic-inorganic polymers formed by hydrolysis/condensation reactions of alkoxide precursors, such as organically modified silanes (Ormosils) are used for several industrial applications such as electronic, optical and protective anticorrosion coatings. Such materials possess superior chemical stability, physical strength and scratch resistance characteristics when compared to organic polymers. Further performance improvement can be achieved through the incorporation of zirconium and titanium based nanoparticles, also formed through from precursors via the sol-gel process. However due to the inherent reactivity differences of the above precursors, they must be hydrolysed separately before being combined for final condensation. Zirconium precursors are commonly chelated using acetic acid or acetyl acetonate prior to hydrolysis, to lower the hydrolysis rate. In this body of work, 3,4-diaminobenzoic acid (DABA) and acetyl acetonate (acac) were compared as chelating ligands for controlling the hydrolysis reactions of zirconium n-propoxide to form nanoparticles within a silane sol matrix. The sols were applied as coatings on aerospace grade aluminium alloy AA 2024-T3 and characterised by physical, spectroscopical, microscopical, electrochemical and calorimetric techniques. The electrochemical properties of the coatings, as characterised by EIS and PDS, correlated with neutral salt spray evaluations confirming that the use of DABA as a chelating ligand significantly improved the coating performance when compared to the traditional diketone ligand. The data indicates the anticorrosion properties of the nitrogen rich chelate have a key role in protecting the alloy through the formation of smaller zirconium nanoparticles, thus improving the polymer network stability.

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“…Metroke et al [13] showed that impedance of organically modified silane thin films on 2024-T3 aluminum alloy in 0.05% NaCl or 0.5 M K 2 SO 4 was sensitive to water and electrolyte uptake as well as to degradation of coating properties. Kittel et al [14,15] used embedded electrodes to demonstrate marked variations in the impedance of organic coatings as a function of depth, concluding that accurate models for coated electrodes should integrate gradients of properties over the thickness of the coatings.…”

Section: Introductionmentioning

confidence: 99%

Identification of Resistivity Distributions in Dielectric Layers by Measurement Model Analysis of Impedance Spectroscopy

Chen

Nguyen

Orazem

et al. 2016

Electrochimica Acta

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The Voigt measurement model, developed in the 1990s for identification of the error structure of impedance measurements, is shown here to have utility in identifying resistivity distributions that give rise to frequency dispersion. The analysis was validated by application to synthetic data derived from a constant-phase-element model, a power-law distribution of resistivity, and an exponential distribution corresponding to a Young impedance. The application to experimental data obtained from coated aluminum demonstrates its utility for interpretation of impedance measurements.

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Corrosion resistance properties of Ormosil coatings on 2024-T3 aluminum alloy

Cited by 116 publications

References 40 publications

Improving the corrosion performance of hybrid sol–gel matrix by modification with phosphonic acid

Improving the corrosion performance of hybrid sol–gel matrix by modification with phosphonic acid

Corrosion protection of AA 2024-T3 aluminium alloys using 3, 4-diaminobenzoic acid chelated zirconium–silane hybrid sol–gels

Identification of Resistivity Distributions in Dielectric Layers by Measurement Model Analysis of Impedance Spectroscopy

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