Synthesis of Nanosized Copper Powder by an Aqueous Route (original) (raw)
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Three different forms of Cu powder particles obtained by either galvanostatic electrolysis or a non-electrolytic method were analyzed by a scanning electron microscope (SEM), X-ray diffraction (XRD) and particle size distribution (PSD). Electrolytic procedures were performed under different hydrogen evolution conditions, leading to the formation of either 3D branched dendrites or disperse cauliflower-like particles. The third type of particles were compact agglomerates of the Cu grains, whose structural characteristics indicated that they were formed by a non-electrolytic method. Unlike the sharp tips that characterize the usual form of Cu dendrites, the ends of both the trunk and branches were globules in the formed dendrites, indicating that a novel type of Cu dendrites was formed in this investigation. Although the macro structures of the particles were extremely varied, they had very similar micro structures because they were constructed by spherical grains. The Cu crystallites ...
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Materials Science and Engineering: A, 1996
Nanocrystalline copper powders were produced by the cryogenic melting technique. The molten metal is overheated while maintained in levitation by r.f. induction in a flux of liquid nitrogen. A calefaction layer is produced at the interface between the two phases, and it is believed that the nanoparticies are formed by rapid condensation of supersaturated metal vapour. Nanocrystalline copper powders were obtained with a production rate of 60 g h-r and a yield of 75%. The structure and the composition of the powder specimens were investigated by transmission electron microscopy. The particles with an average size of 35 nm are nearly spherical and partially aggregated. It was found that the particles had the structure and lattice parameter of bulk copper, and that the Cu,O oxide phase was also present. This oxide appears as a strained 2.5 nm layer surrounding a metallic copper kernel. Additionally, many twin boundaries are seen crossing the particles. Keywords: Nanocrystals; Copper + Corresponding author, Tel: 33 {l) 46 87 35 95; Fax: 33 (1) 46 75 04 33. ' Present address:
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This paper describes an investigation into the effects of copper concentration, current density, and time of electrolysis on the particle size distribution and morphology of synthesized copper powder via electrodeposition. Characterization of copper powder was performed using Particle Size Analyzer to determine the size distribution, Scanning Electron Microscope to confirm particle size and shape, and X-Ray Diffraction to determine the phase and structure of copper powder. The result shows that copper powder has a singlephase, specifically Cu with purity of 98.42%, face-centred cubic (FCC) crystal lattice, and dendritic structure with cauliflower-like and corn-like shape particles. Electrolysis experiment at a condition of 0.2 A/cm 2 current density and 0.02 M Cu concentration results in the smallest particle size comprising 0.499 μm at 3 seconds, and the size distribution resembles a normal distribution at 15 minutes.
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Atomistic Simulation of Sintering Mechanism for Copper Nano-Powders
Journal of Korean Powder Metallurgy Institute, 2015
The sintering mechanisms of nanoscale copper powders have been investigated. A molecular dynamics (MD) simulation with the embedded-atom method (EAM) was employed for these simulations. The dimensional changes for initial-stage sintering such as characteristic lengths, neck growth, and neck angle were calculated to understand the densification behavior of copper nano-powders. Factors affecting sintering such as the temperature, powder size, and crystalline misalignment between adjacent powders have also been studied. These results could provide information of setting the processing cycles and material designs applicable to nano-powders. In addition, it is expected that MD simulation will be a foundation for the multi-scale modeling in sintering process.
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