Papers by Keyword: Electrolytic Copper Powder

Abstract: Because of distinctive properties, such as dendritic structure, high green strength, and low oxygen content, electrolytic copper powder has been widely used in aviation, aerospace, national defense industry and other domains. But at present, energy consumption of the electrolysis process in copper powder production is high, and the current efficiency is only about 90%. Therefore,the decrease in energy consumption of the electrolysis process has become the major bottlenecks in the development of the enterprises. In this paper, a new electrolysis cell with different electrolyte inlet arranged on the cell was manufactured. Then, the effect of flow pattern of electrolyte on the current efficiency, energy consumption and properties of copper powder was investigated. The experimental results showed that the electrolytic process had the higher current efficiency, lower energy consumption and smaller copper powders when the flow rate is 0.5l/min in the paralleled inlet and 1.5 l/min in the traditional inlet. Under the optimal conditions, the current efficiency, energy consumption and copper powder size were 99.10%, 712.90kw∙h/t and 47.80um respectively. This means an obvious rise in current efficiency and decrease in energy consumption compared to traditional feeding method.

Abstract: The principles of pulse electrolysis modes selection and their effect on the size distribution of the powder electrolytic copper in electrolyte with additions of water-soluble polymers, polyvinylpyrrolidone (PVP) and polyacrylamide (PAA) are considered in the paper. The research conducted with use of chronopotentiometry and potential transients as well as a simulation model of the electrocrystallisation process showed that the values of pulse duration were greater than the transient time of electroactive species and the pause duration equal to the linear part of potential transient was optimum to obtain a powder with a predominant fraction of nanoscale particles . PVP and PAA additives help to reduce the average particle size in the nanoscale fraction copper powder particles to 25-40 nm. Selected current pulse mode effect corresponds to the reduction of the emergence of new centers of crystallization probability and the adatoms on the surface of the cathode movement probability.

Abstract: This article presents the research on the effect of substrate nature and electrolysis modes on ultramicron and nanosized electrolytic powders formation regularities. It was found that the preliminarily electropolishing of titanium cathode in combination with impulse electrolysis mode for nickel and copper powders obtaining provides for the predomination of nanosized fraction. The presence of water soluble polymers in the electrolyte for copper powder obtaining, polyvinylpyrrolidone (PVP) and polyacrilamide (PAA) allows forming stable dendritic powders with low agglomeration. Using of powders stabilized by polymers allows obtaining compositions with uniform particle distribution across the whole volume of the sample which provides for heightened wear resistance of composition materials.

Abstract: The surface structure of powder particles, which allows free flow of copper powder, was examined. It has been shown that a sufficiently dense surface structure which permits free flow will be obtained if apparent density is higher than 2.2 – 2.3 g/cm3. Such a surface structure can be obtained by reversing current electrodeposition of powder at considerably lower apparent densities of powder due to selective dissolution of subparticles during anodic time of reversing current wave. The surface structure of copper powder particles is discussed and correlated with the lowest apparent density at which the copper powder can still flow.