Kinetics and mechanism of PbSO<sub>4</sub> electroformation on Pb electrodes in H<sub>2</sub>SO<sub>4</sub> aqueous solutions

The electrochemical processes related to the passivation of Pb in 5 M H<sub>2</sub>SO<sub>4</sub> at 25°C, have been investigated combining a rotating ring-disk electrode, linear potential sweep voltammetry and potentiostatic pulse techniques complemented with scanning elec...

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Detalles Bibliográficos
Autores principales: Varela, Francisco Eduardo, Vela, María Elena, Vilche, Jorge Roberto, Arvia, Alejandro Jorge
Formato: Articulo
Lenguaje:Inglés
Publicado: 1993
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Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/121653
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Sumario:The electrochemical processes related to the passivation of Pb in 5 M H<sub>2</sub>SO<sub>4</sub> at 25°C, have been investigated combining a rotating ring-disk electrode, linear potential sweep voltammetry and potentiostatic pulse techniques complemented with scanning electron microscopic imaging. The kinetics of PbSO<sub>4</sub> anodic layer growth can be explained through the initial formation of a barrier layer acting as an ionic conductor, and the transference of Pb<sup>2+</sup> cations from the substrate the conducting layer yielding Pb<sup>2+</sup> ion in the solution. These ions further contribute to passivation through the precipitation of a PbSO<sub>4</sub> passivating layer.