In:
Canadian Journal of Chemistry, Canadian Science Publishing, Vol. 65, No. 9 ( 1987-09-01), p. 2109-2113
Abstract:
The influence of F − ions on the anodic dissolution of copper in aqueous acidic solutions (pH 1.6–6), mainly at pH 5 with 0.1 M KF, has been studied. The nature of the changes that occur on the electrode during the oxidation has been examined by cyclic voltamperometry as well as by different techniques of surface analysis (SEM, XPS, AES). To determine the mechanism of the electrochemical oxidation of copper at pH 5, studies with rotating disk electrodes have been carried out under conditions giving rise to a general dissolution of copper. At pH 1.6–6, the copper electrode dissolves uniformly, i.e., without preferential zones on the surface, when it is submitted to a potentiodynamic polarization (10 mV s −1 ) at potentials above 0 V ECS . At slightly acidic pH (pH 5, KF0.1 M), with a sweep of potential up to +0.5 V, the oxidation of copper begins with a generalized corrosion of the electrode and it is followed by the formation of a film of Cu 2 O that is not passivating; as the oxidation proceeds, the current drops and the electrode becomes passivated. One model for the anodic dissolution is presented for the results obtained at pH 5. When a uniform corrosion develops on the rotating electrode, the copper is oxidized to Cu 2+ ions. When ω → 0, the rate of dissolution of the electrode is limited by the diffusion of the Cu 2+ ions from the electrode to the solution, whereas when ω → ∞ the process of charge transfer is the limiting factor to the kinetics of the dissolution. [Journal translation]
Type of Medium:
Online Resource
ISSN:
0008-4042
,
1480-3291
Language:
English
Publisher:
Canadian Science Publishing
Publication Date:
1987
detail.hit.zdb_id:
1482256-8
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