Abstract: Effect of additives composed of C4 H6 O2、C7 H4 NNaO3 S and C12 H25 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.

Key words: Effect of additives composed of C4 H6 O2、C7 H4 NNaO3 S and C12 H25 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.