Title:
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Silica-based hybrid coatings for corrosion protection of carbon steel. Part I: Effect of pretreatment with phosphoric acid
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Author:
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Santana, Ianina; Pepe, Andrés; Jiménez Piqué, Emilio; Pellice, Sergio; Ceré, Silvia
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Other authors:
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Universitat Politècnica de Catalunya. Departament de Ciència dels Materials i Enginyeria Metal·lúrgica; Universitat Politècnica de Catalunya. CIEFMA - Centre d'Integritat Estructural, Micromecànica i Fiabilitat dels Materials |
Abstract:
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This work studies the synthesis and characterization of hybrid organic–inorganic coatings based on silica to
improve the corrosion resistance of carbon steel. Hybrid organic–inorganic silica sol–gel coatings were
obtained by dipping in an organically modified silica sol synthesized through hydrolysis and condensation
of 3-glicidoxipropyl-trimetoxisilano (GPTMS) and tetraethoxysilane (TEOS) in acidic catalysis. The coatings
were doped with a cerium salt (Ce(NO3)3·6H2O) and loaded with silica nanoparticles in order to improve
both barrier effect and the anticorrosive behavior of the coatings by the inhibitory effect of cerium. Prior to
the application of the coating, some samples were treated with a phosphoric acid 2% v/v in order to improve
coating adherence. A two layered coating was applied onto AISI 1010 carbon steel, the outer containing with
a cerium salt and the inner one with silica nanoparticles without the cerium salt, producing homogeneous
and cracks-free films. Raman spectroscopy was used to characterize the compounds present in the surface
of steel after pretreatment with phosphoric acid. Microstructural characterization of coatings was performed
by means of scanning electron microscopy (SEM).
The evolution with time of the protective properties of films was studied by electrochemical impedance spectroscopy
(EIS), providing quantitative information of the role of the pre-treatment. Electrochemical behavior
in each stage of the corrosion processes was modeled by equivalent circuits. Additionally, films adhesion was
evaluated by nano-scratch demonstrating that the phosphate treatment improves adhesion of the hybrid
coating. |
Subject(s):
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-Àrees temàtiques de la UPC::Enginyeria dels materials::Assaig de materials -Àrees temàtiques de la UPC::Enginyeria química::Química orgànica::Compostos orgànics -Phosphoric acid -Metals Corrosion fatigue -Corrosió i anticorrosius -Àcid fosfòric |
Rights:
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Attribution-NonCommercial-NoDerivs 3.0 Spain
http://creativecommons.org/licenses/by-nc-nd/3.0/es/ |
Document type:
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Article - Published version Article |
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