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Vol. 29 No. 5 (2017): Vol 29 Issue 5

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Dealloying of Cu-Ag Alloys in Sodium Sulphate Solutions

https://doi.org/10.14233/ajchem.2017.20495
Mishael A. Al-Khaldi
Chemistry Department, College of Sciences, Dammam University, P.O. Box 1982, Dammam 31441, Saudi Arabia
Ayman M. Zaky
Chemistry Department, College of Sciences, Dammam University, P.O. Box 1982, Dammam 31441, Saudi Arabia; Chemistry Department, Faculty of Sciences, South Valley University, Qena 83523, Egypt
Nada K.M. AL-Eidan
Chemistry Department, College of Sciences, Dammam University, P.O. Box 1982, Dammam 31441, Saudi Arabia

Corresponding Author(s) : Ayman M. Zaky

azaky1@yahoo.com

Asian Journal of Chemistry, Vol. 29 No. 5 (2017): Vol 29 Issue 5

Abstract

The electrochemical behaviour of copper-silver system was studied in 0.1 M Na2SO4 using cyclic voltammetry, potentiodynamic anodic polarization and current-time transients techniques are used to study the electrochemical behaviour of copper-silver alloys was studied in 0.1 M Na2SO4. Microstructure characterization and surface morphology of the compounds formed on the electrodes surfaces during electrochemical processes are carried out using XRD and SEM and EDX analysis. The anodic portion of the voltammogram was characterized by the existence of two potential regions I and II separated by certain critical potential, Ecrit. In 1st potential region preferential dissolution of copper occurs and leads to the appearance of three anodic peaks A1, A2 and A3 which are related to the formation of soluble Cu+ species, Cu2O and [CuO-Cu(OH)2], respectively. As soon as the critical potential, Ecrit, was reached the current density raises sharply indicating surface enlargement and the onset of region II where copper and silver dissolve simultaneously. The preferential dissolution of copper was enhanced and the critical potential was decreased on increasing the silver content in the alloy. Potentiostatic current/time transients showed that the formation of Cu2O, CuO and Cu(OH)2 layers involves a nucleation and growth mechanism under diffusion control.

Keywords

Copper-silver alloys Surface enlargement Cyclic voltammetric Current/time transients
Al-Khaldi, M. A., Zaky, A. M., & AL-Eidan, N. K. (2017). Dealloying of Cu-Ag Alloys in Sodium Sulphate Solutions. Asian Journal of Chemistry, 29(5), 1161–1167. https://doi.org/10.14233/ajchem.2017.20495
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