The ionic equilibrium in the CuSO4-H2SO4-H2O system and the formation of the honeycomb-like structure during copper electrodeposition

Abstract

The ionic equilibrium of the species in the CuSO4-H2SO4-H2O system was employed to systematize the conditions of copper electrodeposition leading to the formation of the honeycomb-like structure. The reason why CuSO4 concentrations higher than 0.15 M are unsuitable for the formation of honeycomb-like structures is shown. The range of H2SO4 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 CuSO4 and less) in a concentration range from 0.25 to 1.0 M H2SO4, at a temperature of 18.0±1.0°C and at overpotentials outside the plateau of the limiting diffusion current density at which hydrogen evolution is vigorous enough to change the hydrodynamic conditions in the near-electrode layer. .

Analizirana je jonska ravnoteža u sistemu CuSO4-H2SO4-H2O da bi se sistematizovali uslovi elektrohemijskog taloženja bakra koji dovode do formiranja strukture pčelinjeg saća. Pokazano je da su koncentracije CuSO4 veće od 0,15 M nepogodne za formiranje strukture pčelinjeg saća. Određen je i opseg koncentracija H2SO4 u kojem se formira ovakva struktura. Uslovi koji dovode do formiranja strukture pčelinjeg saća su: elektro- hemijsko taloženje iz rastvora sa koncentracijom Cu(II) od najviše 0,15 M i opsegom koncentracija H2SO4 od 0,25 do 1,0 M, temperature od 18,0±1,0°C, i na prenapetostima pozitivnijim od onih koji odgovaraju platou granične difuzione gustine struje, na kojima je izdvajanje vodonika dovoljno intenzivno da promeni hidrodinamičke uslove u prikatodnom sloju. .