Chronovoltammetry of the Anodic Dissolution of AgAu Alloys in Nitrate Environments O. A. Kozaderov, V. V. Lozovskii, and A. V. Vvedenskii Voronezh State University, Universitetskaya pl. 1, Voronezh, 394006 Russia E-mail:
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Received April 4, 2007 Abstract — A theory of quasi-reversible anodic chronovoltammetry of the selective dissolution of a homogeneous A–B alloy controlled by the solid-phase diffusion is proposed. The effects of the equilibrium solid-phase adsorption of the components and the roughness of the electrode surface with either homogeneously or statistically normally distributed microscopic irregularities of diverse kind on the shape of chronovoltammogram (the IA current dependence on the (t) overpotential) are successively taken into account. An expression for the IA,m current at the voltammogram maximum, which is a generalization of the Randles–Sevcik formula, is derived. A technique of estimating the recording-time boundaries of voltammograms, within which the surface roughness effect may be taken into account by simply multiplying the current by the roughness factor fr, is founded. Outside the time interval, the IA,m 1/2 dependence ( is the potential scanning rate), which is criterion for the diffusion kinetics, is shown to be substantially nonlinear. The diffusion-zone parameters ( thickness and DAg heterodiffusion coefficient) obtained by processing the experimental data for Ag–Au alloys with a gold content of 15 or 20 at. % with the use of three models discussed are compared. PACS numbers: 82.45.Qr DOI: 10.1134/S0033173208040036
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