亚硒酸在氰化物镀银中的催化作用

Catalytic Behavior of Selenious Acid on Silver Electroplating in Cyanide Bath

本文采用旋转圆盘电极技术与交流阻抗技术对亚硒酸在氰化物镀液中银电沉积过程时的行为进行了研究。结果表明不发生亚硒酸中的硒与银的共同电沉积,但能增大交换电流密度,减小电化学极化电阻,并使交流阻抗谱出现吸附环。据此提出了亚硒酸根离子的吸附催化作用,能形成较易在阴极还原的活性中间物Ag_2SeO_3。

An investigation of the behavior of selenious acid during the process of silver electrodeposition from a cyanide bath was carried out using several techniques including RDE and AC impedance. The results show that selenious acid can accelerate casthodic reduction of silver, increase exchange current density, decrease charge transfer resistance and add adsorption loops to the AC impedance diagrams while selenium does not coelectrodeposit with silver. Therefore an adsorption-catalysis effect of selenite ion through the formation of easier redution intermediate Ag_2SeO_3 is suggested.