添加剂对DMH体系电沉积金的影响

Effect of Additive on Electrodeposition of Gold in DMH System

在以5,5'-二甲基已内酰脲(DMH)为配位剂的镀液体系中研究了添加剂C_4H_6O_2、C_7H_4NNa O_3S和C_(12)H_(25)SO_4Na对金电沉积工艺和电结晶过程的影响。阴极极化曲线测试中,金电沉积的最佳电势区间是-0.60^-1.2V,添加剂浓度在研究的范围内对阴极极化电势的影响较小。循环伏安曲线结果表明,反应界面上添加剂的吸附能够影响成核生长超电势,对金还原过程表现出抑制作用。电化学阻抗谱研究表明,镀液中加入添加剂后,电荷转移过程变得更加困难。SEM观察表明,添加剂改善了镀层质量,晶粒变得细致、均匀。XRD分析证实,两种镀液体系中获得的镀金层都沿着Au(111)和(220)晶面择优生长。

Effect of additives composed of C4H6O2、C7H4NNaO3 S and C（12）H（25）SO4 Na on electrodeposition and electrocrystallization behavior of gold from a cyanide-free bath with DMH as complexing agent were investigated. The results of cathodic polarization curves show that the optimized deposition potential range is- 0. 60 -- 1. 2 V,and additive concentration had tiny effect on cathodic polarization potential. Cyclic voltammetry curves indicate that the adsorption behaviors of additives on reaction surface can affect nucleation growth potential, and had inhibitive effects on the process of cathode deposition.Electrochemical impedance spectroscopy results indicate that after addition of additives to the bath,charge transfer process is more difficult. The results of SEM show that the grains is smaller and exhibited better flattening capability than the grains obtained in basic bath. The XRD results indicate that the gold electrodeposits plated in the baths both has a preferential orientation along Au（111） and Au（220）direction.