The possibility of depositing copper powders with different apparent density by changing the shape of reversing current wave is shown. The morphology and crystallinity of powder particles can be varied considerably by changing shape of the reversing current wave and, hence, the apparent density of powders. The relation of apparent density with particle morphology and structure was illustrated.
The one of the main contributions of Belgrade Electrochemical School to the field of metal electrodeposition is investigation of a mechanism of formation and growth of the disperse deposits. Spongy-like, cauliflower-like, needle-like, carrot-like, dendrites of various shapes, etc In these publications all aspects of morphology of electrodeposited metal are discussed, from dendritic growth initiation and dendritic growth [2,3,11] to the bright deposits formation [2,3,8] and the effect of hydrogen co-deposition on morphology of electrodeposits [3,9,14]. One of the most important conclusion derived by BES is the mechanism of disperse deposits formation, based on different behaviour of the macroelectrodes and microelectrodes under the same conditions of electrodeposition. The aim of this article is to discuss this phenomenon in the way given in [11] for the growth of dendrites.
One of the most important properties of copper powder is its flow ability which depends on the shape and the structure of the powder particles. A procedure for the determination of a representative powder particle permitting the free flow of copper powder is proposed.
The processes of Pb electrodeposition under diffusion control were examined by scanning electron microscopy (SEM) of the formed crystals. The orientation of grains of hexagonal shape formed in the initial stage of electrodeposition strongly affected the final morphology of the Pb crystals. The formation of Pb crystals of the different shape from the same initial shape was discussed in terms of the effect of orientation of initially formed grains on the type of diffusion control. A spherical diffusion layer was formed around the tip of the hexagonal-shaped grain oriented with its tip towards the bulk solution that led to the formation of elongated crystals in the growth process. On the other hand, a cylindrical type of diffusion was responsible for the growth of hexagonal-shaped grains oriented with the lateral side towards the bulk solution. Pb crystals with well-defined sides parallel to the surface area of the macroelectrode were formed under this type of diffusion.
The structures of bright zinc coatings obtained from acid sulfate solutions
in the presence of dextrin/salicyl aldehyde mixture were examined. It was
shown by the STM technique that the surfaces of bright zinc coatings are
covered by hexagonal zinc crystals, the tops of planes of which are flat and
mutually parallel and which exhibit smoothness on the atomic level. X-Ray
diffraction (XRD) analysis of the bright zinc coatings showed that the zinc
crystallites are oriented in the (110) plane only.
A method for the determination of the critical apparent density, which permits the free flow of electrodeposited copper powder is discussed. It was found that powders the apparent density of which were larger than 2.3 g/cm3 exhibit free flow. This is in good agreement with the literature data.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.