Artigo de peri??dico
On the corrosion mechanism of Mg investigated by electrochemical impedance spectroscopy
Registro en:
0013-4686
306
10.1016/j.electacta.2019.03.080
0000-0002-8304-9939
0000-0002-4987-3334
83.333
94.50
Autor
GOMES, MAURILIO P.
COSTA, ISOLDA
PEBERE, NADINE
ROSSI, JESUALDO L.
TRIBOLLET, BERNARD
VIVIER, VINCENT
Resumen
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. Funda????o de Amparo ?? Pesquisa do Estado de S??o Paulo (FAPESP) Coordena????o de Aperfei??oamento de Pessoal de N??vel Superior (CAPES) FAPESP: 13/13235-6 CAPES: Cofecub 806-14; 88881.154406/2017-01