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International Journal of Electrochemistry
Volume 2016, Article ID 4318178, 11 pages
http://dx.doi.org/10.1155/2016/4318178
Research Article

Cyclic Voltammetric Study of High Speed Silver Electrodeposition and Dissolution in Low Cyanide Solutions

1School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
2MacDermid Enthone, Enthone Chemistry, A Division of Alent Singapore Pte. Ltd., 26 Tuas West Road, Singapore 638382
3Singapore Institute of Manufacturing Technology, 2 Fusionopolis Way, No. 08-04, Innovis, Singapore 138634

Received 7 March 2016; Revised 12 May 2016; Accepted 12 May 2016

Academic Editor: Sheng S. Zhang

Copyright © 2016 Bo Zheng et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The electrochemical processes in solutions with a much lower amount of free cyanide (<10 g/L KCN) than the conventional alkaline silver electrolytes were first explored by using cyclic voltammetry. The electrochemical behavior and the effect of KAg(CN)2, KCN, and KNO3 electrolytes and solution pH on the electrodeposition and dissolution processes were investigated. Moreover, suitable working conditions for high speed, low cyanide silver electrodeposition were also proposed. Both silver and cyanide ions concentration had significant effects on the electrode polarization and deposition rate. The onset potential of silver electrodeposition could be shifted to more positive values by using solutions containing higher silver and lower KCN concentration. Higher silver concentration also led to higher deposition rate. Besides maintaining high conductivity of the solution, KNO3 might help reduce the operating current density required for silver electrodeposition at high silver concentration albeit at the expense of slowing down the electrodeposition rate. The silver dissolution consists of a limiting step and the reaction rate depends on the amount of free cyanide ions. The surface and material characteristics of Ag films deposited by low cyanide solution are also compared with those deposited by conventional high cyanide solution.