Electrodeposition of Cu2+ in presence of Ni2+ in sulfuric acid system

Abstract

The electrodeposition of Cu2+ in the presence of Ni2+ in a sulfuric acid system was investigated using conventional electrochemical techniques and scanning electron microscopy. The Ni2+ had a hindering effect on the mass transfer of Cu2+, while increasing the temperature and H2SO4 concentration weakened this negative effect. The “S2−” could be hydrolyzated from thiourea and reacted with “Cu2+” and “Ni2+” to form copper sulfide and nickel sulfide, respectively, which obviously increased the charge transfer resistance and refined the particle size of the copper deposit. In addition, the nucleation model of the Cu deposition was changed from instantaneous nucleation and mixed nucleation to progressive nucleation in the presence of thiourea at 4\xa0mg/L.