Preparation and corrosion protective properties of nanostructured titania-containing hybrid sol–gel coatings on AA2024

Poznyak, S.K.; Zheludkevich, Mikhail L.; Raps, D.; Gammel, F.; Yasakau, K.A.; Ferreira, M.G.S.

doi:10.1016/j.porgcoat.2007.12.004

Cited by 74 publications

(43 citation statements)

References 29 publications

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“…Further published data suggests that the route of zirconium inclusion is important, as the choice of chelating ligand may have an effect of the final coating performance [28]. This would be in agreement with previous studies which found that hydrolysis of zirconium alkoxides can be controlled to deliver nanoparticles of varying sizes [29,30].…”

Section: Introductionsupporting

confidence: 89%

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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Section: Introductionsupporting

confidence: 89%

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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“…This hypothesis can be confirmed by the presence of another phenomenon, noted at low frequencies (%10 À1 Hz) on the phase angle evolution for the two higher cerium concentrations (0.05 and 0.1 M). Indeed, this new time constant can be correlated to the presence of the corrosion activity on the substrate [4,5,36,13,[39][40][41]. It is possible to note that the phenomenon is more important for the higher values of cerium concentration (0.1 M).…”

Section: Morphological Characterization Of the Filmmentioning

confidence: 84%

Effect of cerium on structure modifications of a hybrid sol–gel coating, its mechanical properties and anti-corrosion behavior

Cambon

Esteban

Ansart

et al. 2012

Materials Research Bulletin

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“…Similar approaches were investigated by Ferreira's group in Portugal which concentrated on epoxy functionalised silane-zirconium systems by adding cerium [24], azole based organic inhibitors in host molecules [25,26] and bis-silanes [27]. This group has also published data which suggests the route of zirconium inclusion is important, as the choice of chelating ligand may have an effect of the final coating performance [28]. This would be in agreement with the previous studies which found that hydrolysis of zirconium alkoxides can be controlled to deliver nanoparticles of varying sizes [29,30].…”

Section: Introductionmentioning

confidence: 90%

Effect of organic chelates on the performance of hybrid sol–gel coated AA 2024-T3 aluminium alloys

Varma

Colreavy

Cassidy³

et al. 2009

Progress in Organic Coatings

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a b s t r a c tSol-gels are organic-inorganic polymers formed by hydrolysis/condensation reactions of alkoxide precursors, primarily silanes, which have found applications as electronic, optical and protective coatings. These coatings possess important characteristics such as chemical stability, physical strength and scratch resistance. Further performance improvement is achieved through the incorporation of zirconium and titanium based nanoparticles, also formed through the sol-gel process. However due to the inherent difference in the reactivity of the precursors, the hydrolysis of each precursor must be carried out separately before being combined for final condensation. Zirconium precursors are commonly chelated using acetic acids, prior to hydrolysis, to lower the hydrolysis rate.In this body of work various ligands such as organic acids, acetyl acetone (AcAc) and 2,2 -bipyridine (Bipy) were used to control the zirconium hydrolysis reaction and form nanoparticles within the silane sol matrix.Nanoparticle modified coatings formed from the silane sol on AA 2024-T3 aluminium were characterised spectroscopically, electrochemically and calorimetrically to evaluate the potential effect of the different chelates on the final film properties while neutral salt spray tests were performed to study their anti-corrosion performance. Results indicate that the acid ligand modified coatings provided the best performance followed by AcAc, while Bipy was the poorest. In all cases the zirconium nanoparticle improved the protective properties of the sol-gel coating.

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Preparation and corrosion protective properties of nanostructured titania-containing hybrid sol–gel coatings on AA2024

Cited by 74 publications

References 29 publications

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

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

Effect of cerium on structure modifications of a hybrid sol–gel coating, its mechanical properties and anti-corrosion behavior

Effect of organic chelates on the performance of hybrid sol–gel coated AA 2024-T3 aluminium alloys

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