Effect of electrolysis parameters on the morphologies of copper powders obtained at high current densities

Abstract

The effects of copper ion concentrations and electrolyte temperature on the morphologies and on the apparent densities of electrolytic copper powders deposited at high current densities under galvanostatic control were examined. These parameters were evaluated by the current efficiency of hydrogen evolution. In addition, scanning electron microscopy was employed for analyzing the morphology of the copper powders. It was found that the morphology was dependent on the copper ion concentration and electrolyte temperature under same current density (CD) conditions. At 150 mA cm(-2) and a potential of 1000 +/- 20 mV (vs. SCE), porous and disperse copper powders were obtained at low concentrations of Cu ions (0.120 M Cu2+ in 0.50 M H2SO4). Under these conditions, a high rate of hydrogen evolution occurred parallel to copper electrodeposition. The morphology was changed from porous, disperse and cauliflower-like to coral-like, shrub-like and stalk stock-like morphology with increasing Cu ion concentrations from 0.120, through 0.155, 0.315 and 0.475 to 0.630 M Cu2+ in 0.5 M H2SO4, respectively, at the same CD. Similarly, with increasing temperature, the powder morphology and the apparent density changed. The apparent density values of the copper powders were suitable for many powder metallurgy applications.