Morphology and internal structure of copper deposits electrodeposited by the pulsating current regime in the hydrogen co-deposition range

Abstract

The effect of the regime of pulsating current (PC) on copper electrodeposition in the hydrogen co-deposition range was examined by the techniques of scanning electron and optical microscopes. The quantities of evolved hydrogen and morphologies of electrodeposited copper strongly depended on the applied parameters of square waves PC, such as the current density amplitude (or the amplitude of the cathodic current density), deposition pulse, and pause duration. The increase of the current density amplitude led to intensification of hydrogen evolution reaction, and the change of morphology of electrodeposited copper from dendrites and shallow holes to dish-like holes was observed. For the constant pause duration, the prolonging deposition pulses intensify hydrogen evolution reaction leading to the formation of the honeycomb-like structures. The set of modified equations considering the effect of hydrogen generated during metal electrodeposition processes by the pulsating current regime is also presented. The concept of "effective overpotential amplitude" was proposed to explain the change of copper surface morphology with the intensification of hydrogen evolution reaction.