The ionic equilibrium in the CuSO_4-H_2SO_4-H_2O system and the formation of the honeycomb-like structure during copper electrodeposition

摘要

The ionic equilibrium of the species in the CuSO_4-H_2SO_4-H_2O system was employed to systematize the conditions of copper electrodeposition leading to the formation of the honeycomb-like structure. The reason why CuSO_4 concentrations higher than 0.15 M are unsuitable for the formation of honeycomb-like structures is shown. The range of H_2SO_4 concentrations enabling the formation of this type of structure was also determined. The conditions leading to the formation of the honeycomb-like structures are: electrodeposition from solutions with lower concentrations of Cu(II) ions (0.15 M CuSO_4 and less) in a concentration range from 0.25 to 1.0 M H_2SO_4, at a temperature of 18.0±1.0 ℃ and at overpotentials outside the plateau of the limiting diffusion current density at which hydrogen evolution is vigorous enough to change the hydrodyna-mic conditions in the near-electrode layer.