论文部分内容阅读
以硼氢化物为还原剂化学镀金的槽液用周期地加入其组分进行操作。由于硼氢化物离子产生水解,主要生成了过量的偏硼酸盐,所以槽液使用的总的操作时间是有限的,大约20小时。高浓度的偏硼酸盐离子使沉积反应变慢,而且在槽液中产生金属金的颗粒沉淀。由沉积反应放出的大量氰化物离子也会使沉积速度下降,但其影响相当小,而且用 AuCN 代替KAu(CN)_2作为金补充源能够消除这种影响。指出了所补充的硼氢化物量能够用简单的分析或是用水解反应速度常数的计算来测定。
A bath of electroless gold plating with borohydride as a reducing agent is operated by periodically adding its components. Due to the hydrolysis of borohydride ions, an excess of metaborate is predominantly produced, so the total operating time for bath use is limited to about 20 hours. High concentration of metaborate ions slows the deposition reaction and results in precipitation of metal gold particles in the bath. The large amount of cyanide ions released by the deposition reaction also decreases the deposition rate, but the effect is quite small, and the effect can be eliminated by using AuCN instead of KAu (CN) 2 as a gold replenishment source. It is pointed out that the amount of borohydride added can be determined either by simple analysis or by calculation of the rate constant of the hydrolysis reaction.