Papers by Keyword: Aerosol Process

Abstract: Ag and Ni spherical fine powders were continuously produced by carrying out an aerosol process in a mass nanopowder production apparatus. The particles size, particle morphology, crystal phases and crystallinity of the as-prepared powders were characterized by a scanning electron microscope (SEM) and X-ray diffraction (XRD). The particles were nonaggregated and they exhibited a spherical morphology with a narrow size distribution. The average sizes of Ag and Ni particles were 500 nm and 700 nm, respectively. The crystallinity of the as-prepared powders was high. The XRD patterns showed that the crystal phases of the as-prepared powders were the same as those of their respective metals.

Abstract: BaTiO3 nano-sized powders were successfully prepared by spray pyrolysis using multiphase plasma under the air atmosphere. The particles characteristics of BaTiO3 nano-sized powders were studied by SEM and XRD. The effect of volume of arc plasma and precursor solution on the formation of BaTiO3 nano-sized powders was investigated. The use of Ba-Ti complex precursor solution derived from lactic acid led to formation of tetragonal BaTiO3 nano-sized powders with 140 nm size. As for BaTiO3 ceramics, the effect of sintering temperature on relative density and the temperature dependence of dielectric properties were investigated.

Abstract: A pulsed spark-discharge aerosol generator using air as a carrier gas was successfully applied to the titania nanoparticle production. The titanium vapor evaporated by spark discharge was subsequently supersaturated and condensed to titania nanoparticles by nucleation and condensation. The size and concentration of the particles can be controlled easily using air as a carrier gas by altering the repetition frequency, capacitance, gap distance, and flow rate of the spark-discharge system. TEM observation shows that the generated particles were aggregates, which primary particle sizes are a few nanometers. The element composition of the nanoparticles was titanium and the crystal phase was amorphous. XPS analysis shows that oxidation state of generated particles corresponded to TiO2. These XPS data indicates that some fraction of the evaporated titanium vapor could be oxidized in an air atmosphere by the oxidation with oxygen. However, enough time for crystallization was lacked because of raid cooling.

Abstract: Homogeneous BaTiO3 nano-sized powders were successfully prepared by spray pyrolysis using multiphase plasma under the air atmosphere. Particle size, morphology, crystal phase and crystallinity of as-prepared powders were characterized by SEM and XRD. The effect of starting precursor solution on the formation of nanoparticles was investigated. The use of Ba/Ti aqueous solution derived from malic acid led to formation of cubic BaTiO3 nanoparticles with 50 nm size.

Abstract: Fe2O3 nano-particles coated with SiO2 are synthesized using H2/O2 co-axial diffusion flame with the state-of-the-art electro-spraying (e-spray) technique at atmospheric condition. Fe(CO)5 and TEOS (tetra-ethyl-ortho-silicate) mixture in liquid phase is injected directly into the center of the flame using the electro-spraying method. The synthesized particle characteristics are analyzed with HRTEM, XRD, SQUID. The core (iron oxide)-shell(silica) structured spherical particles are obtained. Most of the particles synthesized are magemite(
) regardless of the particles sampling positions inside the flame.