Morphology of lead dendrites electrodeposited by square-wave pulsating overpotential

A mechanism for copper powder formation in potentiostatic deposition is proposed, and the critical overpotential of copper powder formation is determined. A good agreement between theoretical and experimental results has been obtained.

The mechanism of copper powder formation in potentiostatic deposition

It has been known for a relatively long time that the application of a periodically changing current in plating practice leads to improvements in the quality of electrodeposits. Three types of current variation have been found useful: reversing current (RC); pulsating current (PC); and sinusoidal, alternating current superimposed on a direct current (AC).1–12 In recent years, the beneficial effects of pulsating overpotential (PO) have also been discussed.4 Even though this kind of electrodeposition at a periodically changing rate (EPCR) is important from a theoretical point of view and offers a variety of experimental possibilities, it is as yet not frequently used in plating practice.

Theory of the Effect of Electrodeposition at a Periodically Changing Rate on the Morphology of Metal Deposits

We investigated the influence of pulse current density on a crystallographic microstructure of twin Cu films through x-ray diffraction and electron backscatter diffraction (EBSD). With an increase in the pulse current density, the intensity of the preferred orientation (texture), grain size and the fraction of the twins decreased. The high-density twin copper films, including the nanotwins observed from the orientation image maps, were achieved using a pulsed electrodeposition technique at the current density of 0.5 A cm−2, with an average grain size of 818 nm. The crystallographic microstructure of the high-density twin copper films shows a 0 1 1 preferred orientation associated with the 60°1 1 1 twin having a {1 1 1} twin plane.

https://iopscience.iop.org/article/10.1088/0022-3727/42/21/215410/pdf

EBSD characterization of twinned copper using pulsed electrodeposition

Experiments have been carried out on copper powder electrodeposition by constant overpotential and constant current on aluminium, graphite, platinum and copper electrodes. It is shown that for one and the same quantity of electricity, electrode material, electrode surface area, electrolyte, temperature and time of deposition, different particle size distribution curves, current efficiency and specific energy consumption are obtained in galvanostatic and potentiostatic deposition.

The comparison of galvanostatic and potentiostatic copper powder deposition on platinum and aluminium electrodes

The possibility of electrodepositing copper powder by pulsating overpotential is shown. These powders are compared to the powders obtained by constant overpotential electrodeposition. It is also shown that the grain size and the morphology of deposited powder is a function of overpotential, and of amplitude and frequency of pulsation in constant and pulsating overpotential deposition respectively.

M. D. Maksimović

Papers

Formation of powdered copper deposits by constant and pulsating overpotential electrolysis