Improving the corrosion performance of hybrid sol-gel matrix by modification with phosphonic acid
Sol-gel films were prepared using different ratios of two silica precursors, vinyltrimethoxysilane (VTMS) and tetraethylorthosilicate (TEOS), targeting the anticorrosion treatment of aluminum alloy 2024-T3. The electrochemical behavior of the alloy coated with such films, which was studied in a 0.05...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2015 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/76981 |
| Acceso en línea: | https://hdl.handle.net/2117/76981 https://dx.doi.org/10.1016/j.porgcoat.2014.11.018 |
| Access Level: | acceso abierto |
| Palabra clave: | Aluminum alloys Corrosion and anti-corrosives Surface modification Corrosion resistance Silane aluminum-alloy magnesium alloy infrared-spectroscopy phenylphosphonic acid resistance properties silane films protection coatings silica 2024-t3 Corrosió i anticorrosius Revestiments protectors Alumini -- Aliatges Àrees temàtiques de la UPC::Enginyeria química |
| Sumario: | Sol-gel films were prepared using different ratios of two silica precursors, vinyltrimethoxysilane (VTMS) and tetraethylorthosilicate (TEOS), targeting the anticorrosion treatment of aluminum alloy 2024-T3. The electrochemical behavior of the alloy coated with such films, which was studied in a 0.05 mol L-1 NaCI solution, revealed that the VTMS/TEOS ratio drastically affects the anticorrosion performance. Electrochemical impedance spectroscopy (EIS) results provided evidences that the best anticorrosive response occurs with the films prepared from 50% (v/v) ethanol, 46% (v/v) water, 3% (v/v) VTMS and 1% (v/v) TEOS. Moreover, the effects of the addition of ethylenediamine tetra(methylene phosphonic acid) (EDTPO) to a hybrid sol-gel matrix were examined. The corrosion resistance was considerably improved when the concentration of added phosphonic acid was 3.75 x 10(-5) mol L-1. Scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy analyses revealed that EDTPO-containing films provide a more uniform coverage. Results evidenced the formation of S-O-Al linkages in the VTMS/TEOS and VTMS/TEOS/EDTPO systems and that the VTMS/TEOS/EDTPO system contained P-O-Al linkages. The P-O-Al bonds, combined with the modified silica network action, may be responsible for the good anticorrosive behavior of the VTMS/TEOS/EDTPO films. (C) 2014 Published by Elsevier B.V. |
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