As-prepared Copper Research Articles

Synthesis of oleic acid capped copper nano-particles via reduction of copper salt by SFS

Synthesis of oleic acid capped copper nano-particles has been carried out by use of sodium formaldehyde sulfoxylate (SFS) in aqueous medium. Nano-copper can be effectively coated with polyvinyl alcohol (PVA). Phase-pure nano-Cu can be obtained when water/acetone was used as aqueous medium. It is observed that the surface plasmon resonance (SPR) phenomena can be controlled during synthesis by the use of suitable reagent system, e.g. absorption band in presence of PVA can be blue shifted. As-prepared copper nano-particles were characterized by X-ray diffraction measurements (XRD), Scanning electron microscopy (SEM), energy dispersive analysis of X-rays (EDAX), thermo gravimetric analysis (TGA) and Fourier transform infra-red spectroscopy (FTIR). XRD analysis revealed broad pattern for fcc crystal structure of copper metal. The particle size by use of Scherrer's equation was calculated to be about 20 nm. TGA revealed ∼10% weight loss due to the presence of surfactant. FTIR spectroscopy confirmed the presence of oleic acid around the particles.

Preparation of fine copper powder using ascorbic acid as reducing agent and its application in MLCC

The preparation of ultrafine copper powder with chemical reduction method was investigated. Ascorbic acid was employed as reducing agent. Reaction of CuSO 4·5H 2O with ascorbic acid at 70 °C gives polyhedron monodispersed ultrafine copper powder. The copper powder having excellent dispersibility was prepared when the pH value was controlled at 6 with aqueous ammonia. Influences of reaction temperature on the efficiency of copper powders were also studied. TG/DTG/DTA of copper powder was discussed with thermal analyzer. As-prepared copper powder was applied in BME-MLCC. The micro-structures of end termination and interface were discussed with SEM and polarized light microscope. The copper end termination has high adhesion force, excellent solderibility behavior and resistance behavior to soldering.

Preparation of micron size copper powder with chemical reduction method

The preparation of micron size copper powder with chemical reduction method was investigated. The copper powder having excellent dispersibility was prepared when sodium metaphosphate was employed as dispersion agent. Reaction of CuSO 4·5H 2O with hydrazine hydrate at 80 °C gives spherical monodispersed micron size copper powder. The influences of dosage of dispersion agent on the size and dispersibility of powder particles were obvious. The appropriate conditions were NH 4Cl/Copper (W/W) 15% and five times calculated value of hydration hydrazine. TG/DTA/DTG of the as-prepared copper powder was investigated with thermal analyzer.

Seed-mediated growth and properties of copper nanoparticles, nanoparticle 1D arrays and nanorods

Copper nanorods were simply prepared by a method of seed-mediated growth in solution. In this method, poly( N-vinyl-2-pyrrolidone) (PVP) was used as a surface modified reagent as well as a soft template. By adjusting the concentration of copper ion and PVP and the refluxing time, the copper nanoparticles, copper 1D array nanoparticles wrapped in PVP and nanorods were obtained successively. Transmission electron microscopy, ultraviolet-visible spectrum and fluorescence spectroscopy were used to characterize the as-prepared copper nanoparticles and nanorods. X-ray absorption near edge structure (XANES) spectrum was carried out to investigate the microstructure. Obvious UV luminescence was observed for the copper nanorods. The mechanism of the growth process of copper nanomaterials was discussed.