Preparation and characterization of nanocrystalline copper powders (original) (raw)
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Characterization of nanocrystalline copper powders prepared by melting in a cryogenic liquid
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:
Production and Examination of Nanocrystalline Copper
2006
325-mesh copper powder was ball milled under various conditions to produce copper samples of different grain sizes. One well-milled sample was annealed at varying temperatures and for different times to promote grain growth. These two procedures provide a range of grain sizes for study. Crystallite size was determined by analyzing x-ray diffraction peak broadening. Continuing research would include equal channel
Synthesis of Nanosized Copper Powder by an Aqueous Route
1999
Nanostructured, crystalline copper powder was produced at ambient temperature by aqueous reduction of a copper salt by sodium borohydride. Conditions were optimized to produce boron-free copper powder with an average particle diameter of 200 nm, surface area of 5.48 m * m/g, and oxygent content of 0.155%. The effects of different experimental conditions on average particle size of the powder were also studied. The sintering phenomenon exhibited by produced copper particles at 100°C may be attributed to the low oxygen content of the powder along with other size variation-dependent factors.
Metals, 2019
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 ...
Materials Science and Engineering: A, 2001
Bulk copper samples were prepared by consolidating ultrafine-grained copper powders using the technique of Plasma Pressure Compaction. The microstructure and hardness are compared with a sample made from consolidating micron-sized powders using identical processing conditions. Samples made by consolidating nanometer powders revealed evidence of grain coarsening and a higher density than the sample made from consolidating micron-sized powders. Both nanohardness and microhardness measurements revealed an increase in hardness of the bulk sample obtained by consolidating the smaller sized powders. Influence of powder particle size and processing variables on microstructure, to include the presence and distribution of artifacts, density, and microhardness are discussed.
Synthesis and Thermal Properties of Copper Nanoparticles
Asian Journal of Chemistry
Nanomaterial is a mesmerizing material that is found in many applications in the field of basic and applied research. Copper nanoparticles with high specific surface to volume area have been widely studied. The copper nanoparticles have special physico-chemical characteristic which include catalytic activity, electronic properties and antimicrobial activity [1]. Nanoparticles have received considerable interest due to their good thermal, optical and electrical properties. Copper oxide is a semiconducting compound and its structure is a monoclinic. Copper compounds exhibit a range of potentially useful physical properties such as high temperature superconductivity and spin dynamic [2,3]. As in important p-type semiconductor copper oxide has found many diverse applications. Copper nanoparticles have been assumed cost effective as compared to noble metals like Ag, Au and Pt. They are potentially applied in the fields of catalysis [4], conductive inks [5] and fluids [6]. The synthesis of mono disperse, ultrafine metal nanoparticles have been potential application in photonics, catalysis, nanofluides, cooling fluids for electronic systems, Plasmonic photovoltaic and composite food packaging [7-14]. There are different methods of synthesis of copper nanoparticles including thermal decomposition [15], solid liquid discharge [16], quick precipitation [17] metal vapour synthesis [18], chemical reduction [19], vacuumed vapour deposition [20], radiation