Morphological characterization of copper deposited by electrolysis influenced by presence of chloride ions

Abstract

In the present work, the effect of current density on the morphology of copper deposited by electrolysis from an acidic solution of copper sulfate in the presence and absence of chloride ions as impurities is studied. For this purpose, chronopotentiometry and scanning electron microscopy techniques are used. The study reveals that, for both situations, in the presence and absence of chloride ions, the time profiles of the cathodic poten-tial are shifted in cathodic direction with the increase of the current density. These time profiles are associated with the simultaneous occurrence of cathodic reactions during copper electrolysis. The morphological results demonstrate a direct influence of the current density represented by transitions in the electrocrystalli-zation mechanisms associated with nucleation and growth stages of the deposited particles. Changes in the morphological patterns are corroborated by a dendritic and granular type copper deposit in the electrolyte solution without chloride ions, in contrast to the copper deposit observed in the electrolyte solution with the presence of chloride ions, where a dendritic and laminar morphology is observed. These results clearly demonstrate the mechanistic aspects on copper electrolysis.