材料期刊网

进行了氨性溶液中Cu置换Ag的热力学分析,计算结果表明,该置换反应在热力学上是可能的。用Cu的旋转圆盘研究了氨性溶液中Cu置换Ag的动力学,观察到有两段反应速率,即初始段反应速率慢和第二段反应速率增快。发现沉积物的形态明显影响置换速率。初始阶段的反应对应于Ag沉积于较光滑的表面,置换动力学受传质控制;第二阶段反应速率增快,是由于形成粗糙结构的表面沉积物,使适于该置换反应进行的表面积有效增加。

A thermodynamic analysis of cementation of Ag with Cu in ammoniacal solution has been carried out. The calculated results indicated that this cementation reaction is possible thermodynamically. The rotating disc of Cu has been used to study the kinetics of Ag cementation on metallic Cu in ammoniacal solution. Two stages of reaction rate were found in this cementation process, i.e., an initial slow rate and a second enhanced rate. The deposit morphology influences the cementation rate significantly. The initial stage of reaction corresponds to deposition on a relatively smooth surface and the reaction kinetics is controlled by mass transfer. The increased rate of the second stage reaction is due to the development of a structured surface deposit which effectively increases the surface area available for the cementation reaction.