1. Contribution to a better understanding of different behaviour patterns observed with organic coatings evaluated by electrochemical impedance spectroscopy
- Author
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Oscar R. Mattos, Nadine Pébère, Jean-Baptiste Jorcin, Fernando de Loureiro Fragata, Marcelo Camargo Severo Macedo, Isabel C.P. Margarit-Mattos, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Universidade Federal do Rio de Janeiro - UFRJ (BRAZIL), and Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
- Subjects
Materials science ,EIS ,General Chemical Engineering ,Matériaux ,Alkyd ,Organic coatings ,General Chemistry ,Epoxy ,engineering.material ,Electrochemistry ,Corrosion ,Dielectric spectroscopy ,Anomalous behaviour ,chemistry.chemical_compound ,Coating ,chemistry ,visual_art ,visual_art.visual_art_medium ,engineering ,General Materials Science ,LEIS ,Composite material ,Electrical impedance ,Polyurethane - Abstract
In the present paper, three different coatings (epoxy, alkyd, polyurethane paints) were characterized by electrochemical impedance measurements, permeability tests, free-standing film impedance and local impedance measurements. The increase in resistance with immersion time of alkyd paint was linked to the nature of the polymeric network and not to phenomena occurring at the metal/paint interface. For polyurethane paint, local impedance was not able to detect defects in the paint, which was attributed to the fact that the defects are smaller than those observed in alkyd paint and also that they are less active and homogeneously distributed through the coating. Although electrochemical impedance methods (global and local) are excellent tools to monitor the behaviour of organic coatings, these techniques alone are not sufficient to screen different paints.
- Published
- 2009