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Aluminum Particles (aluminum + particle)
Selected AbstractsSelection of injection conditions for aluminum particles as a raw material by numerical analysis in the synthesis of ultrafine particles with transferred type arc plasmaELECTRICAL ENGINEERING IN JAPAN, Issue 2 2010Shizue Furukawa Abstract We investigated by numerical analysis the dependence of vaporization behavior of aluminum particles injected into transferred type arc plasma on injection conditions in synthesis of aluminum nitride ultra fine particles. On the basis of calculation results, we chose one proper injection condition where aluminum particles vaporized more. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(2): 46,52, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20852 [source] Preparation and evaluation of composite electromagnetic wave absorbers made of aluminum fine particles dispersed in polystyrene mediumELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 1 2010Norizumi Asano Abstract We developed composite electromagnetic wave absorbers consisting of dispersed aluminum fine particles in a polystyrene medium and evaluated their properties in order to realize single-layer electromagnetic wave absorbers with good absorption in the gigahertz region. Polystyrene particles with two diameters (approximately 200 ,m and 1 ,m) and fine aluminum particles were mixed by mechanical milling. The mixture was heated above the melting point of polystyrene and then cooled naturally in air. The frequency characteristics of the complex relative permeability and the complex relative permittivity were calculated from the values of the scattering parameters of a coaxial line loaded with a sample of a toroidal-core shape. Both the diamagnetism and the magnetic loss increased in proportion to the volume mixing ratios of aluminum particles up to approximately 34 vol for samples made of polystyrene particles with approximately 200 ,m or 1,m diameter. The diamagnetism was almost frequency-independent and the magnetic loss decreased with increasing frequency for all samples. These results were in agreement with qualitative theoretical prediction. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 93(1): 30, 40, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10169 [source] Encapsulation of nanoparticles by polymerization compounding in a gas/solid fluidized bed reactorAICHE JOURNAL, Issue 9 2009Babak Esmaeili Abstract For the first time, a fluidized bed reactor was used for encapsulating nanoparticles by the polymerization compounding approach using Ziegler,Natta catalysts. The polymerization reaction was carried out using a solvent-free process in a gas-phase reactor. This direct gas,solid reaction greatly simplified collecting the particles of interest after polymerization because none of the extra steps often found in encapsulation processes, such as filtering and drying, were performed in this work. The grafting of the catalyst to the original surface of particles was confirmed by X-ray photoelectron spectroscopy. Micrographs obtained by transmission electron microscopy confirmed the presence of a thin layer of polymer, in the order of a few nanometers, around the particles. The thickness of this coating was affected by the operating conditions of the process. The characterization of the modified particles with electron microscopy also revealed that zirconia nanoparticles tend to be coated in an agglomerated state, whereas aluminum particles were mostly individually encapsulated by the polymer. In addition, the effects of temperature and pressure were studied on the encapsulation process and a kinetic analysis was presented based on the available models in the literature. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] The Reaction-Bonded Aluminum Oxide (RBAO) Process: II, The Solid-State Oxidation of RBAO CompactsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2000Ender Suvaci The oxidation kinetics and the fraction of aluminum that is oxidized via solid,gas reaction in reaction-bonded aluminum oxide (RBAO) compacts are shown to be strongly dependent on the oxidation temperature and the characteristics (size and green density) of the RBAO compact. Based on the Biot number, the oxidation process of RBAO compacts is controlled by convective heat transfer. Low heat transfer from the surface of the compact results in too-rapid oxidation, thermal gradients, and core,shell oxidation of the compacts. Uniform oxidation of RBAO compacts is possible by oxidizing at low temperatures (400°,470°C), where slow surface reaction of the aluminum particles controls the oxidation of the compact. A grain model is presented to cover both linear and nonlinear oxidation regimes during the oxidation of a RBAO compact, and this model predicts the experimental results when surface reaction of the aluminum particles is the rate-controlling mechanism and oxidation of the compact occurs uniformly. [source] | ||||||||||