Corrosion behavior study of AZ91 magnesium alloy coated with methyltriethoxysilane doped with cerium ions

Correa, Paulo S. P.; Malfatti, Célia de Fraga; Azambuja, Denise Schermann

doi:10.1016/j.porgcoat.2011.08.005

Cited by 70 publications

(30 citation statements)

References 27 publications

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“…The temperature and time of the heat treatment depend on the kind of precursors and solvents used to produce the coating, but economically it is more interesting to work at lower temperatures and shorter times. Many works report the production of sol-gel coatings with low-temperature heat treatments [19][20][21][22][23][24][25][26][27][28][29][30][31] . The objective of this work is to determine the effects of three different acids (acetic, hydrochloric and nitric acids) added to the formulation of the sol of the siloxane-PMMA hybrid films on the morphological and physical-chemical properties of these films and to evaluate their anti-corrosion performance when deposited on tinplate.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Siloxane-poly(methyl methacrylate) Hybrid Films Obtained on a Tinplate Substrate Modified by the Addition of Organic and Inorganic Acids

et al. 2015

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Tinplate is used to food packaging and other types of packages. The corrosion resistance of the tinplate has been study due the necessity of an alternative to high environmental impact of chromatization process. Therefore protective coatings as hybrid films base elaborations with different acids are studied to improve the barrier effect against corrosion. The objective of this work is characterize hybrid films deposited on a tinplate from a sol made up of the alkoxide precursors 3-(trimethoxysilylpropyl) methacrylate (TMSM), tetraethoxysilane (TEOS) and poly(methyl methacrylate) (PMMA) together with one of three acids (acetic, hydrochloric or nitric acid) and to verify their action against the corrosion of the substrate. The films were obtained by a dip-coating process and cured for 3 hours at 160 °C. The film hydrophobicity was determined by contact angle measurements, and the morphology was evaluated by SEM. FTIR measurements were performed to characterize the chemical structures of the films. The electrochemical behavior of the coatings was evaluated by techniques open circuit potential monitoring (OCP), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results demonstrate that the siloxane-PMMA films improve the protective properties of the tinplate, with the films obtained by acetic acid addition exhibiting the greatest improvement.

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Section: Introductionmentioning

confidence: 99%

Characterization of Siloxane-poly(methyl methacrylate) Hybrid Films Obtained on a Tinplate Substrate Modified by the Addition of Organic and Inorganic Acids

et al. 2015

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“…Higher or lower concentrations of cerium decrease the coating resistance and capacitance, which leads to a rapid loss of the protective properties. 10 The inhibiting properties of this element are strongly determined by the ion concentration inside the hybrid film, 11 showing the existence of the optimum cerium concentration. This is due to the formation of insoluble compounds such as CeO 2 and Ce(OH) 3 12 that temporally block the passage of the corrosive species through the hybrid coating to the metallic substrate.…”

Section: Electrochemical Characteristics Of the Hybrid Coatingsmentioning

confidence: 99%

Hybrid sol-gel coatings doped with cerium to protect magnesium alloys from corrosion

et al. 2015

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Hybrid coatings produced via the sol-gel route were deposited onto an Elektron 21 magnesium alloy. The sol consisted of tetraethyl-orthosilicate (TEOS) and 3-(trimethoxysilyl)propylmethacrylate (MAP) to which corrosion inhibitors were added. The influence of the cerium concentration on the anti-corrosion properties of the hybrid coating is presented. Furthermore, the morphology of the organic/inorganic coatings deposited on the magnesium alloy was determined with scanning electron microscopy (SEM). In parallel, the electrochemical behavior during the immersion in a 0.05 M NaCl corrosive solution was studied with electrochemical impedance spectroscopy (EIS). It was proven that the hybrid films exhibit a high impedance modulus during the first hours of the immersion and that an addition of cerium to the sol with a concentration of 0.01 M considerably increases the durability of the film, delaying its degradation during the immersion. In addition, this project especially focusses on determining the critical concentration of the cerium salt at which the impedance modulus of the hybrid coating strongly decreases during the immersion. Keywords: magnesium, coating, sol-gel, corrosion inhibitor, EIS Hibridni nanosi, pripravljeni s sol-gel-postopkom, so bili naneseni na magnezijevo zlitino Elektron 21. Osnova je bila tetraetil-ortosilikat (TEOS) in 3-(trimetoksisilil)propilmetakrilat (MAP), ki so ji bili dodani inhibitorji korozije. Predstavljen je vpliv koncentracije cerija na protikorozijske lastnosti hibridnega nanosa. Poleg tega je bila dolo~ena morfologija organskih/ neorganskih nanosov na magnezijevo zlitino z vrsti~nim elektronskim mikroskopom (SEM). Vzporedno je bilo preu~evano elektrokemijsko vedenje med potopitvijo v korozijsko raztopino 0,05 M NaCl, z uporabo elektrokemijske impedan~ne spektroskopije (EIS). Dokazano je bilo, da izkazujejo hibridni nanosi visok impedan~ni modul med prvimi urami namakanja in da dodatek cerija osnovi v koncentraciji 0,01 M mo~no pove~a zdr`ljivost nanosa z zadr`anjem njegove degradacije med namakanjem. Ta projekt je bil usmerjen v dolo~anje kriti~ne koncentracije cerijeve soli, pri kateri se impedan~ni modul hibridnega nanosa mo~no zmanj{a med namakanjem.

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“…The protection against active corrosion obtained in the presence of an inhibiting component in this pretreatment allows the corrosion rate to be minimized, preventing the degradation of the metal. Thus, a synergistic effect is obtained by using a silane layer modified with an inhibitor [7,8,9,10] Recent studies have been carried out with the use of silanes in combination with inhibitors [11], bilayer systems where a silane coating precedes the epoxy paint [12] and epoxy coating systems which are modified with silanes [13].…”

Section: Introducionmentioning

confidence: 99%

Revestimentos a base de TEOS/ácido fosfônico como tratamento anticorrosivo para a liga AA2024-T3

Cendron

Azambuja

2016

Matéria (Rio J.)

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RESUMOO objetivo deste estudo foi investigar o comportamento corrosivo da liga de alumínio AA2024-T3 tratada com filmes obtidos pela combinação de tetraetilortossilicato (TEOS) com ODPA (ácido octadecilfosfônico) em solução de NaCl 0,05 mol L -1 . As razões volumétricas de TEOS/etanol/água utilizadas foram 4:90:6 e 4:80:16, e os filmes formados foram denotados como 90TEOS e 80TEOS respectivamente. A adição de áci-do fosfônico nos filmes TEOS foi testada como uma maneira de se obter um efeito cooperativo, a fim de melhorar as características de proteção do revestimento. Análises de espectroscopia de impedância electroquí-mica (EIE) e polarização potenciodinâmica mostraram que os filmes 90TEOS na presença de ODPA apresentaram um maior módulo de impedância após 168 horas de imersão em solução de cloreto. Os resultados obtidos indicam que os filmes obtidos apenas com TEOS não fornecem uma proteção adequada contra a corrosão, evidenciando a existência de sinergismo entre o ácido fosfônico e TEOS. Essa melhora foi relacionada à maior hidrofobicidade dos revestimentos.Palavras chaves: Liga de Alumínio, Silano, Ácido fosfônico, EIE. ABSTRACTThe aim of this study was to investigate the corrosion behavior of aluminum alloy AA2024-T3 substrates treated with self-assembled films obtained by combining tetraethylorthosilicate (TEOS) with ODPA (octadecylphosphonic acid)in a 0.05 mol L-1 NaCl solution. The volumetric ratios of TEOS/ethanol/water used were 4:90:6 and 4:80:16, and the corresponding films formed were denoted as 90TEOS and 80TEOS, respectively. The addition of phosphonic acid to TEOS films was tested as a way to obtain a cooperative effect in order to improve the protective characteristics of the coating. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization data showed that the 90 TEOS films in the presence of ODPA had the highest impedance modulus after 168h of immersion in chloride solution. The results obtained indicate that undoped sol-gel coatings do not provide adequate protection against corrosion, evidenced by the existence of synergism between phosphonic acid and TEOS, improving the hydrophobicity of the films.

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Corrosion behavior study of AZ91 magnesium alloy coated with methyltriethoxysilane doped with cerium ions

Cited by 70 publications

References 27 publications

Characterization of Siloxane-poly(methyl methacrylate) Hybrid Films Obtained on a Tinplate Substrate Modified by the Addition of Organic and Inorganic Acids

Characterization of Siloxane-poly(methyl methacrylate) Hybrid Films Obtained on a Tinplate Substrate Modified by the Addition of Organic and Inorganic Acids

Hybrid sol-gel coatings doped with cerium to protect magnesium alloys from corrosion

Revestimentos a base de TEOS/ácido fosfônico como tratamento anticorrosivo para a liga AA2024-T3

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