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The quantitative microstructural analysis and the sieve analysis of copper powder as well as the scanning electron microscopy analysis of the copper powders particles were performed. It was found that the structure of the copper powder particles determines the apparent density of copper powder. The powder particles from the same fractions of different powders occupy approximately the same volume, but the structure of metallic copper is very different. This causes the difference in apparent densities of copper powder obtained under different conditions. The more dendritic is the structure of powder particles the smaller is the apparent density of copper powder.

Production of copper powders by the potentiostatic electrolysis under different hydrogen evolution conditions has been investigated. Copper powders were characterized by the scanning electron microscope (SEM), X-ray diffraction (XRD), particle size distribution (PSD), and by determination of the specific surface area (SSA) of the formed powders. Depending on quantity of hydrogen generated during electrolysis, the two types of particles were formed: dendrites and cauliflower-like particles. The dendrites were formed without, while cauliflower-like particles with the quantity of evolved hydrogen enough to achieve strong effect on hydrodynamic conditions in the near-electrode layer. Although macro structure of the particles was very different, they showed similar micro structure. Namely, the both types of the particles consisted of small agglomerates of approximately spherical Cu grains at the micro level. The existence of the spherical morphology was just responsible for random orientation of Cu crystallites in the both types of particles. The SSA of cauliflowerlike particles was more than three times larger than the dendrites, while their size was considerably smaller than the dendritic particles. In this way, the useful benefit of Cu powder formation in the conditions of vigorous hydrogen evolution is shown.

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Detailed defect structure of dendrite formation was studied in order to connect the mesoscopic with the atomistic structure. It was demonstrated that twinning and stacking fault formation play a central role in the growth of electrodeposited Ag dendrites. The broad faces of Ag dendrites and the main trunk growth direction were found to be (1̅11) and [1̅12̅], respectively. Dendrite branches also formed and grew from the main trunk parallel to the [121̅] and [2̅1̅1̅] crystallographic directions. Twins and stacking faults were found to reside on the {111} crystallographic planes, as expected for a face centered cubic (FCC) Ag crystal. Using electron back scattered diffraction (EBSD) we found two variants of in-plane 60° rotational twin domains in the (1̅11) broad dendrite surface plane. The intersections of twins and stacking faults with dendrite arm surfaces are perpendicular to the ⟨112⟩ arm growth directions. However, occasionally twins on the {111} planes parallel to the ⟨112⟩ arm growth directions were also observed. Although defect assisted dendrite growth is facilitated by twinning and stacking fault formation on {111} planes, the growth directions of the trunk and branches are not of the ⟨111⟩ type, but rather close to ⟨112⟩. The ⟨112⟩ growth directions are maintained by breaking dendrite facets into thermodynamically stable 111 and 200 steps and structural ledges of different length.