Co-B纳米合金功能膜化学沉积和电沉积的比较

Impact of electroplate and electroless plating on nano-Co-B alloy functional film

以硫酸钴、硼氢化钠为主要原料,对电沉积和化学沉积Co-B纳米合金功能膜进行比较,发现尽管电沉积较化学沉积的速度快,但各影响因素和变化规律是一致的。pH值增大和温度的升高会加快沉积速率,络合剂浓度增大则会降低沉积速率,增加硫酸钴、硼氢化钠的浓度都会加快沉积速率,但用化学法沉积时,当硫酸钴、硼氢化钠的浓度超过最大值时,沉积速率反而下降。XRD结果表明,两种方法制备的Co-B纳米合金在镀态下都是非晶态,其结构并不受沉积方法的影响,SEM、STM和AFM观察发现,非晶膜镀层是由纳米相微粒构成微米级的二次颗粒,二次颗粒堆砌形成薄膜。化学沉积得到的颗粒相对电沉积得到的要小一些,两种方法得到的最大颗粒都不超过3μm。

Cobalt sulfate and sodium borohydride were used to prepare the nano-Co-B alloy functional film by electroplating or electroless plating. The deposition rate by electroplating was faster than by electroless plating, with the influence of affecting factors the same for both electroplating and electroless plating. The higher the pH value and temperature, the faster the deposition rate, the higher the concentration of complexing agent, the slower the deposition rate. Also, deposition rate increased with increasing concentrations of cobalt sulfate and sodium borohydride, but decreased when the concentrations of cobalt sulfate and sodium borohydride exceeded a maximum value for electroless plating. XRD results showed that the nano-Co-B alloy functional film prepared was amorphous. The structure was not affected by the kind of plating method. SEM, STM and AFM showed that the amorphous film was formed by the secondary micrometres particles that were constituted by the initial nano particles. The particles were smaller by electroless plating. All particles for both methods were not larger than 3 μm.