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On the corrosion mechanism of Mg investigated by electrochemical impedance spectroscopy

Gomes, Maurilio Pereira and Costa, Isolda and Pébère, Nadine and Rossi, Jesualdo Luiz and Tribollet, Bernard and Vivier, Vincent On the corrosion mechanism of Mg investigated by electrochemical impedance spectroscopy. (2019) Electrochimica Acta, 306. 61-70. ISSN 0013-4686

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Official URL: https://doi.org/10.1016/j.electacta.2019.03.080

Abstract

This work reported a detailed analysis of the electrochemical impedance spectra obtained for the Mg electrode during immersion in a sodium sulfate solution. A model was proposed which took into account the presence of: (i) a thin oxide film (MgO) which progressively covered the Mg electrode surface, (ii) film-free areas where the Mg dissolution occurs in two consecutive steps, (iii) a thick layer of corrosion products (Mg(OH)2), (iv) an adsorbed intermediate (Mg+ads) which is responsible for the chemical reaction allowing the negative difference effect to be explained. From the impedance data analysis, various parameters were extracted such as the thin oxide film thickness, the resistivity at the metal/oxide film interface and at the oxide film/electrolyte interface, the active surface area as a function of the exposure time to the electrolyte, the thickness of the thick Mg(OH)2 layer and the kinetic constants of the electrochemical reaction.

Item Type:Article
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Other partners > Sorbonne Université (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Other partners > Centro de Ciência e Tecnologia de Materiais - CCTM (IPEN) (BRAZIL)
Laboratory name:
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Deposited By: cirimat webmestre
Deposited On:26 Mar 2019 16:01

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