Water permeability of organic/inorganic hybrid coatings prepared by sol–gel method: a comparison between gravimetric and capacitance measurements and evaluation of non-Fickian sorption models

Nguyen, Van Nhan; Perrin, F.X.; Vernet, Jean

doi:10.1016/j.corsci.2004.06.028

Cited by 111 publications

(58 citation statements)

References 23 publications

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“…The term (SC c ) is the capacitance 'swelling' term 11 in F/s. Other fitting of the materials properties has been based on short-term linear region of the capacitance or mass with time, 13,20,23 though the approximations based on the early time linear capacitive changes still require an accurate estimate of the saturated and dry mass or capacitance.…”

Section: Resultsmentioning

confidence: 99%

“…[2][3][4][5][6][7][8][9] EIS single frequency spectra in the capacitive region have been used to calculate the diffusion coefficient of water into a coating and saturated water concentration, 10 among other properties. Gravimetry has also been used to measure the water uptake 11,12 or loss 13 of coatings and in some cases is unsatisfactorily compared to EIS measurements of water uptake or loss. 5,11 The low frequency EIS spectrum has also been used to rank the coating corrosion protection effectiveness.…”

Section: Introductionmentioning

confidence: 99%

“…Gravimetry has also been used to measure the water uptake 11,12 or loss 13 of coatings and in some cases is unsatisfactorily compared to EIS measurements of water uptake or loss. 5,11 The low frequency EIS spectrum has also been used to rank the coating corrosion protection effectiveness. [14][15][16][17] Electrochemical impedance spectroscopy consists of generating electromagnetic waves (EM) at fixed, small amplitude, and measuring the amplitude and phase after the EM wave transits the material of interest.…”

Section: Introductionmentioning

confidence: 99%

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Water sorption and diffusional properties of a cured epoxy resin measured using alternating ionic liquids/aqueous electrolytes in electrochemical impedance spectroscopy

et al. 2008

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The protective quality of a coating is often measured by how long it delays the arrival of water to the substrate. The transport of water in, redistribution within, and eventually through a coating to the substrate has long been investigated through electrochemical impedance spectroscopy (EIS). EIS measurements employing alternating nonaqueous (room temperature ionic liquids, RTIL) and aqueous electrolytes elucidated the behavior of water within the coating. Diffusion coefficients could be measured and the redistribution of water into percolating paths identified. The use of RTIL alternating with aqueous electrolytes allows determination of intrinsic properties (water volume fraction at saturation and relative dielectric) and kinetic properties predicted by the Brasher Kingsbury formulation. This article focuses on the sensitivity of these intrinsic and kinetic properties to test duration in an unique experimental method.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Water sorption and diffusional properties of a cured epoxy resin measured using alternating ionic liquids/aqueous electrolytes in electrochemical impedance spectroscopy

et al. 2008

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“…6), which denotes the entry of electrolyte into the coating. This means that the initial decrease in R c and increase in C c during the first few periods are intimately associated with the diffusion of water molecules in the micropores of the polymer net, which are caused during further days of immersion by the development of the conductive macropores in the coating due to the diffusion of Cl À , Na þ , and oxygen [22][23][24][25][26].…”

Section: Water Absorption Analysis With Gravimetric and Capacitive Tementioning

confidence: 99%

Corrosion performance of epoxy coatings modified by nanoparticulate SiO₂

Tian

Hou

2010

Materials & Corrosion

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Electrochemical impedance spectroscopy (EIS) was employed to investigate the corrosion performance of nanoparticulate SiO 2 modified epoxy coatings on carbon steel in 3.5 wt% NaCl solution, coupled with salt spray test. Capacitancegravimetric methods and delamination tests were performed to analyze the water uptake behavior and interface stability against delamination of modified coatings, respectively. Four systems were studied, including a clear coating and three pigmented coatings (with 1, 2, and 3 wt% nanoparticulate SiO 2 ). The experimental results showed that nanoparticulate SiO 2 particles can improve the anti-corrosion performance of the coatings and the optimal addition content is 2 wt%. The results obtained with capacitance-gravimetric measurements showed that the diffusion process of water through epoxy coatings with different pigment volume concentration (PVC) obeyed the second Fick's diffusion law in the initial period. Adding nanoparticulate SiO 2 into epoxy coatings can act effectively. The positive influence is attributed to the reaction between nanoparticles and epoxy resin which is confirmed by FTIR, improving the barrier and dispersion effectiveness of coatings. The negative one is increasing the number of pores in the coatings when the adding amount is beyond the critical PVC.

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“…to water uptake which may lead to coating destruction. 21,37,38 An advantage of PMMA blocks is its hydrophobicity and low swelling (small water uptake). 32 Chelating agents play an important role in forming or promoting bonding between organic and inorganic phases, 33 thus influencing the corrosion properties of hybrid coatings.…”

mentioning

confidence: 99%

Corrosion Properties of UV Cured Hybrid Sol-Gel Coatings on AA7075-T6 Determined under Simulated Aircraft Conditions

Rodič

Milošev

2014

J. Electrochem. Soc.

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Novel hybrid sol-gel coatings have been developed for aluminum alloys as an alternative to the restricted use of chromate conversion coatings. They were prepared from two individual sols: zirconium tetrapropoxide (ZTP) and methacrylic acid (MAA) were added to siloxane sol prepared by mixing tetraethyl orthosilicate (TEOS) and organically modified silica 3-methacryloxypropyl trimethoxysilane (MAPTMS). The mixtures were deposited on alloy AA7075-T6 substrate and cured in air under daylight at room temperature or at 100 • C without the addition of photo-initiator. Different molar ratios of ZTP and MAA were investigated, as well as the effects of curing temperature and aging time. The corrosion behavior of the coated alloy was examined by electrochemical potentiodynamic measurements and six-month immersion tests in Harrison's solution, which simulates aircraft conditions. The coatings provided excellent corrosion protection in the atmospheric region and at high anodic potentials up to 7 V, as well as effective protection during long-term immersion. Curing under daylight improved the corrosion properties compared to curing in the dark. The corrosion behavior of synthesized coatings was compared to standard chromate coatings, including primer and topcoat. The morphology of the coatings was analyzed by scanning electron microscopy, and their adhesion to aluminum alloy surface measured using the X-cross cut test. Chromate conversion coatings (CCCs) have been used successfully for corrosion protection of aluminum alloys.1-3 The formation of CCCs involves the reduction of the oxy chromium species and consequent oxidation of aluminum. Stable, hydrophobic Cr(III) oxide/hydroxide film thus formed contains residual, releasable hexavalent chromium which maintains the active inhibition of the film. Due to rapid adsorption and passivation at the intermetallic sites, the main role of the inhibition process by Cr 6+ is to limit the oxygen reduction on intermetallics, which are the main initiation sites for localized corrosion of aluminum alloys.2,3 Further, the susceptibility to pit initiation is reduced, because the Cr 6+ compounds are adsorbed to aluminum oxide, minimizing the susceptibility to adsorption of chloride. Despite these excellent characteristics, the use of CCCs is restricted because of their hazards for the environment and humans. New alternatives include a broad spectrum of possibilities -from various cerium, molybdenum and organic inhibitors, barrier coatings including plasma deposited, sol-gel and electrodeposited coatings, to conducting polymers.3-6 An alternative yielding highly effective and long lasting protection that is fully comparable to CCCs is still to be found.Over the last decade, inorganic-organic (hybrid) sol-gel coatings have been studied as important alternatives to CCCs.7-13 They combine the properties of inorganic (scratch resistance, durability, adhesion, chemical and thermal stability) and organic (density, flexibility and functional capability) components. Of the one-component hybrid coatings...

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Water permeability of organic/inorganic hybrid coatings prepared by sol–gel method: a comparison between gravimetric and capacitance measurements and evaluation of non-Fickian sorption models

Cited by 111 publications

References 23 publications

Water sorption and diffusional properties of a cured epoxy resin measured using alternating ionic liquids/aqueous electrolytes in electrochemical impedance spectroscopy

Water sorption and diffusional properties of a cured epoxy resin measured using alternating ionic liquids/aqueous electrolytes in electrochemical impedance spectroscopy

Corrosion performance of epoxy coatings modified by nanoparticulate SiO₂

Corrosion Properties of UV Cured Hybrid Sol-Gel Coatings on AA7075-T6 Determined under Simulated Aircraft Conditions

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Water permeability of organic/inorganic hybrid coatings prepared by sol–gel method: a comparison between gravimetric and capacitance measurements and evaluation of non-Fickian sorption models

Cited by 111 publications

References 23 publications

Water sorption and diffusional properties of a cured epoxy resin measured using alternating ionic liquids/aqueous electrolytes in electrochemical impedance spectroscopy

Water sorption and diffusional properties of a cured epoxy resin measured using alternating ionic liquids/aqueous electrolytes in electrochemical impedance spectroscopy

Corrosion performance of epoxy coatings modified by nanoparticulate SiO2

Corrosion Properties of UV Cured Hybrid Sol-Gel Coatings on AA7075-T6 Determined under Simulated Aircraft Conditions

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Corrosion performance of epoxy coatings modified by nanoparticulate SiO₂