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

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 KNO3electrolytes 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, KNO3might 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.

Identifying Key Factors towards Highly Reflective Silver Coatings

“…These additives are proprietary information by the suppliers. Besides the plating chemistry, the operating conditions such as pH, temperature, current density, and agitation will also greatly affect the quality of the Ag coating [15].…”

A Kinetic Study of Silver Electrodeposition Onto Pt Ultramicroelectrodes From Amoniacal Solutions

“…[1] Ag coatings can be obtained by electrodeposition, since this technique allows obtaining uniform coatings with excellent quality at low-cost, and easily scalable at the industrial level. [2] Silver has been electrodeposited on Pt, [4][5][6][7][8][9][10][11][12] Cu, [1,2,[13][14][15][16][17] GCE, [5,16,[18][19][20][21] Au, [5,22] Si, [19,23] HOPG, [21,24] and graphene, [4] among others substrates. Plating baths based on nitrates, [7][8][9][10][11][12][13]20,23,24] cyanides, [1,4,9,[15][16][17][18]22] chloride, [5,<...>…”

“…Moreover, a change in nitrates concentration in the solution allows to control the roughness of the deposit. [10,12,13,15,23] In cyanide silver plating baths, a higher concentration of these anions causes a major energy requirement to electrodeposit silver. However, if the silver ions concentration is increased, the silver electrodeposition potential value moves to potentials that are more positive.…”

“…However, if the silver ions concentration is increased, the silver electrodeposition potential value moves to potentials that are more positive. [1,12,14,16] For a low silver concentration it has been reported a transition 2D-2D and 2D-3D on GCE substrates, while that at higher concentration it is possible to get a 3D growth. Also, Nevers and others have reported that the use of ultrasound during silver plating can change significantly the microstructure and morphology of the silver deposits without the use of chemical additives.…”

Highly reflective metallic thin films for high brightness LEDs

“…These additives are proprietary information by the suppliers. Besides the plating chemistry, the operating conditions such as pH, temperature, current density and agitation will also greatly affect the quality of the Ag coating [134].…”