Comparative analysis of the polarization and morphological characteristics of electrochemically produced powder forms of the intermediate metals

Abstract

The polarization and morphological characteristics of powder forms of the group of the intermediate metals were examined by the analysis of silver and copper electrodeposition processes at high overpotentials. The pine-like dendrites constructed from the corncob-like forms, which are very similar to each other, were obtained by electrodeposition of these metals at the overpotential belonging to the plateaus of the limiting diffusion current density. A completely different situation was observed by the electrodeposition of silver and copper at the overpotential outside the plateaus of the limiting diffusion current density in the zone with the fast increase in current density with the overpotential. Silver dendrites, which were very similar to silver and copper dendrites obtained inside the plateaus of the limiting diffusion current density, were obtained at the overpotential outside the plateau. Due to the lower overpotential for hydrogen evolution for copper, hydrogen produced during the copper electrodeposition process strongly affected the surface morphology of copper. The same shape polarization curves with completely different surface morphologies of Cu and Ag electrodeposited at overpotentials after the inflection point clearly indicate the importance of morphological analysis in the investigation of polarization characteristics of the electrodeposition systems. The role of hydrogen as a crucial parameter in the continuous change of copper surface morphology from dendrites to honeycomb-like structures was investigated in detail. On the basis of this analysis, the transitional character of the intermediate metals between the normal and inert metals was considered. The typical powder forms characterising electrodeposition of the intermediate metals were also defined and systematized.