Correlation between morphology and magnetic properties of electrochemically produced cobalt powder particles

Abstract

Cobalt 3D powder particles were successfully prepared by galvanostatic electrodeposition. The electrodeposited cobalt powders were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and SQUID magnetometry. It was shown that the morphology, structure and magnetic properties of cobalt particles were closely associated and could be easily controlled by adjusting the electrodeposition process parameters. The morphology of cobalt powder particles was strongly affected by the hydrogen evolution reaction as a parallel reaction to cobalt electrodeposition. Depending on the applied current density, two types of powder particles were formed: dendrites at lower and spongy-like particles at higher current densities. Morphologies and structures of powder particles were correlated with their magnetic properties, and compared with those of the bulk cobalt. In comparison with the properties of bulk cobalt, the obtained 3D structutes exhibited a decreased saturation magnetization (M-S), but an enhanced coercivity (H-C), which was explained by their peculiar morphology.