活化液中稀土离子Ce^(3+)对铜粉化学法镀银的促进作用

The Promotion of Ce^(3+) in the Activation Solution to Electroless Plating of Ag on Cu Powers

通过化学镀活化液中添加微量稀土元素Ce3+,在Cu粉表面化学镀银,用电化学法和扫描电子显微镜测试技术分别研究了含稀土活化液的极化曲线、镀银层的表面形貌、银包覆率。结果表明,稀土以适宜比例添加到Pd2+活化液中,能使静止电极电位正移,极化度减小,过电位绝对值增大,活化液中的反应易于进行。适量稀土介入活化液中有助于提高银在铜粉表面的沉积速度和包覆率,增加稀土含量,可使镀层晶粒和组织逐渐细化且致密。最佳加入值为0.32

A trace amount of rare earth metal cation,e.g.Ce3＋ was added to the activation solutions to enhance the electroless plating of Ag on Cu powder.Polarization curves of activation solutions,micromorphology and the clad ratio of silver on copper powder surface were studied through electrochemistry and scanning electron microscopy.The results show that the Ce3＋ added to the Pd2＋ activation solutions with an appropriate amount enables the decrease of polarizability,the increase of static potential and plating potential.Therefore,the reaction of activation solution became easier.A suitable amount of rare earth element can increase the deposition speed of silver on copper powder surface.With the further increase of rare earth element content,the particle size of silver plating on copper powder tend to dcrease and the coatings became clease gradually.The optimal addition value of Ce3＋ is 0.32 g/L.