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Article Dans Une Revue Journal of Electroanalytical Chemistry Année : 2015

Electrochemical behavior of zinc in KOH media at high voltage: Micro-arc oxidation of zinc

Résumé

Electrochemical behavior of pure zinc was studied in alkaline KOH-based media over a large range of voltage (0-300 V) in order to investigate the occurrence of the micro-arc phenomenon, responsible for the formation of ``ceramic-like'' oxide layer. According to electrolyte composition, three anodizing steps can be observed, first, a classical anodizing process at low voltage, a voltage range of micro-arc phenomenon with a more or less intense water oxidation, and a sharp current rise corresponding to an increase of electronic conductivity of ``metal/oxide/electrolyte'' interface. Both KOH concentration and presence of additives in the electrolytic bath control the micro-arc voltage range, and the composition of anodized layer. Nevertheless, the internal layer of the coating remains mainly constituted by crystallized ZnO, formed by a mechanism of solid-state diffusion of O2- under electric field. Despite the significant coating thickness (several microns), the electrochemical characterization of the corrosion behavior in NaCl electrolyte only shows a slight improvement of the performances of the zinc anodized in presence of additives in KOH electrolyte, compared to an untreated one.
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Dates et versions

hal-01295121 , version 1 (30-03-2016)

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Emmanuel Rocca, Delphine Veys-Renaux, Khadoudj Guessoum. Electrochemical behavior of zinc in KOH media at high voltage: Micro-arc oxidation of zinc. Journal of Electroanalytical Chemistry, 2015, 754, pp.125-132. ⟨10.1016/j.jelechem.2015.06.021⟩. ⟨hal-01295121⟩
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