Synergistic Effect of Additives on the Surface Roughness and Throwing Power of Copper Deposited from Electrorefining Solution

Abstract

To elucidate the synergistic effect of gelatin, thiourea and chloride ions on the surface roughness, throwing power and polarization curves for Cu deposition from electrorefining solution, Cu electrodeposition was performed at a current density of 200 A·m -2 and 5×105 C·m -2 of charge in an unagitated sulfate solution containing 0.708 mol・dm -3 of CuSO 4 and 2.04 mol・dm -3 of H 2 SO 4 at a temperature of 60℃. In solutions containing three kinds of additives such as gelatin, thiourea and chloride ions, the surface roughness of deposited Cu decreased with increasing the concentration of thiouea and gelatin and decreasing the chloride ions. On the other hand, the throwing power of deposited Cu was improved with decrease in thiourea and increase in gelatin in solutions containing three kinds of additives. The throwing power of deposited Cu was significantly improved in solution containing both gelatin and chloride ions. The polarization resistance dE/di for Cu deposition increased in solution containing both gelatin and chloride ions, which resulting in improvement of throwing power of Cu deposition. As small amounts of thiourea have a depolarization effect on Cu deposition, a leveling effect is expected owing to the promotion of deposition at recesses.

Patterning Cu nanostructures tailored for CO2 reduction to electrooxidizable fuels and oxygen reduction in alkaline media

“…The inuence of facet-dependent conductivity on chemical kinetics cannot be excluded. 86 The increase of roughness of Cu deposits in the presence of Cl À anions was recently reported by Suzuki et al 87 The electrodeposition of Cu on glassy carbon (GC) from a solution containing Cu-Cl complexes also produces CuNSs with numerous edges and corners (Fig. 3g).…”

Synergistic Effects of Additives on the Deposition Behavior, Throwing Power and Surface Roughness of Cu Obtained from Electrorefining Solution

“…The throwing power of Cu deposited in solution containing thiourea, chloride ions and gelatin of standard concentrations is reported to be identical with that in solution containing two kinds additives of chloride ions and gelatin of standard concentrations. 22,23) Since the thiourea added to one-tenth of the standard concentration improved the throwing power of deposited Cu (Fig. 1), the optimum concentration of thiourea seems to exist from the perspective of throwing power.…”