Improved corrosion protection of aluminium alloy AA 2024 by sol–gel hybrid coatings after surface pretreatment by silanisation

Basu, Bharathibai J.; Srinivasan, Ananda Kumar; Manasa, J.; Grips, V.K. William

doi:10.1179/1743294411y.0000000074

Cited by 14 publications

(13 citation statements)

References 23 publications

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“…The chromate salt passivation treatment method [13] is an effective chemical conversion technology. In spite of a good corrosion prevention effect, its use is limited by environmental regulations, due to high toxicity and carcinogenicity of hexavalent chromium [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Interactions between Phosphoric/Tannic Acid and Different Forms of FeOOH

Mei

Liao

Wang

et al. 2015

Advances in Materials Science and Engineering

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Alpha, beta, gamma, and delta hydroxyl ferric oxides (FeOOH), as the most common rust layers on iron surface, play different roles in iron preservation. Using modern surface analysis technologies such as X-ray diffraction (XRD), infrared spectra (IR), Xray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), we studied the interactions between these four types of synthetic FeOOH and phosphoric and tannic acid of different concentrations and proportions. A 3% tannic acid + 10% phosphoric acid + FeOOH was the most suitable formula for rust stabilizer and its reaction products were made up of iron phosphate and chelate of iron and tannin. This research provided technical basis in distinguishing FeOOH and selecting rust layer stabilizer for the preservation of iron, especially iron cultural relics.

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Section: Introductionmentioning

confidence: 99%

Interactions between Phosphoric/Tannic Acid and Different Forms of FeOOH

Mei

Liao

Wang

et al. 2015

Advances in Materials Science and Engineering

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“…However, the alloy is extremely apt to be corroded due to the presence of intermetallic compounds containing copper, which could act either as anodic or cathodic regions. [4][5][6][7] After the alloy was immersed into a chloride solution, an electrochemical displacement reaction would occur on the relatively electropositive aluminum substrate. In this case, the S-phase particles (Al 2 CuMg) exhibit severe dealloying behavior.…”

Section: Introductionmentioning

confidence: 99%

“…17 As a kind of significant rare-earth oxide, ceria has been investigated in many aspects, including catalytic converter, oxygen storage, fuel cell, and anticorrosion coatings. 5,11,[18][19][20][21][22] Schem et al 16 prepared the coating by adding CeO 2 nanoparticles into the solution of tetraethoxysilane, methyltriethoxysilane, hydrochloric acid, SiO 2 particles, etc. Shi et al 23 studied the corrosion behavior of the coatings with addition of cerium salts on AA2024-T3 substrates.…”

Section: Introductionmentioning

confidence: 99%

Sol–gel route to ceria coatings on AA2024-T3 aluminum alloy

Zuo

et al. 2014

J Coat Technol Res

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The ceria coating was studied as an efficient alternative to the chromate protective coating of aluminum alloys. The environmentally friendly inhibitor of cerium ion was incorporated into the surface coating using Ce(NO 3 ) 3 as precursor via a sol-gel route. The coatings were analyzed with FESEM and EDS. The anticorrosion performance evaluation of the coatings was carried out using electrochemical methods and full immersion experiments. Under the conditions of surface pretreatment with 15 wt% NaOH solution for 20 s, a sol reaction time of 2 h and 3-5 times of dip-coating, the uniform ceria coatings with low defect and barrier were successfully synthesized. After the full immersion process, pitting holes containing copper-rich phases were detected on the surface of the uncoated sample. In contrast, such holes were not observed on the coated sample. Furthermore, the I corr values of the coated samples were smaller than that of the uncoated one, which confirms that the coatings provide a considerable protection barrier and promote the anticorrosion performance of aluminum alloys.

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“…In this context, numerous researchers are making a considerable effort to look for alternatives to chromate conversion coatings (CCCs) due to the carcinogenic effect of the hexavalent chromium used on these formulations [6,7]. One promising technique to develop eco-friendly and non-toxic coatings consists of applying films based on hybrid organopolysiloxane precursors as surface chemical conversion coatings [8][9][10][11]. The hybrid sol-gel method consists of a combination of hydrolysis and condensation processes of mixtures of organic and inorganic constituents, which makes possible the production of coatings with good flexibility, reduced defects and hydrophobic in nature, keeping the adhesion to the metal substrate and improving the compatibility with polymeric top-coatings [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Enhancing the Corrosion Protection of AA2024-T3 Alloy by Surface Treatments Based on Piperazine-Modified Hybrid Sol–Gel Films

Carbonell

Montoya

Gelling

et al. 2020

Metals

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The aim of this study was to develop new chrome-free surface pretreatments for AA2024-T3 aluminum alloy. These pretreatments were based on hybrid organic–inorganic sol–gel thin films prepared from mixtures of γ-methacryloxypropyltrimethoxysilane (MAPTMS) and tetramethylorthosilicate (TMOS). Different MAPTMS/TMOS molar ratios were used for optimizing the physical–chemical characteristics of the sol–gel films. The formulation of a set of these sols was modified by incorporating piperazine (1,4-diazacyclohexane) as a corrosion inhibitor. The resulting sol–gel films were characterized by using Fourier transform infrared spectroscopy (FTIR), liquid-state 29Si nuclear magnetic resonance spectroscopy (29Si-NMR) and viscosity measurements. The corrosion performance of the sol–gel films was analyzed by using electrochemical impedance spectroscopy (EIS) and local electrochemical impedance mapping (LEIM). The characterization techniques indicated that piperazine behaved as a catalyst for the condensation reaction during the formation of the MAPTMS/TMOS organopolysiloxane network and produces an increase of the crosslinking degree of the sol–gel films. EIS and LEIM results showed that piperazine is an effective corrosion inhibitor, which can be used to enhance the active corrosion protection performance of sol–gel films.

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Improved corrosion protection of aluminium alloy AA 2024 by sol–gel hybrid coatings after surface pretreatment by silanisation

Cited by 14 publications

References 23 publications

Interactions between Phosphoric/Tannic Acid and Different Forms of FeOOH

Interactions between Phosphoric/Tannic Acid and Different Forms of FeOOH

Sol–gel route to ceria coatings on AA2024-T3 aluminum alloy

Enhancing the Corrosion Protection of AA2024-T3 Alloy by Surface Treatments Based on Piperazine-Modified Hybrid Sol–Gel Films

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