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Plasma Processing (plasma + processing)
Selected AbstractsSpheroidization of Titanium Carbide Powders by Induction Thermal Plasma ProcessingJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2001Ya-Li Li Highly spherical particles of titanium carbide (TiC) have been produced by in-flight heat processing of irregularly shaped TiC powders in an aerosol reactor under argon-hydrogen and argon-helium induction thermal plasma. The spherical powders obtained by the plasma treatment consist of unagglomerated and uniform particles with mean diameters between 25 and 28.5 ,m, which is smaller than the original TiC particle mean diameters (29.5 ,m) because of partial evaporation of the particles during the plasma treatment. The spheroidization ratio of the treated TiC powders increases with the increase of hydrogen flow rate in plasma gases and the reduction of powder feeding carrier gas flow rate. Under certain processing conditions, the TiC powders have been completely spheroidized. The morphology and structure of individual spherical particles were examined and their formation mechanism was discussed based on calculation of heat transfer kinetics of the particles in the thermal plasma. [source] Tailoring surface properties of cellulose acetate membranes by low-pressure plasma processingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Chun Huang Abstract The aim of this study was to tailor the surface properties of cellulose acetate membranes using low-pressure plasma processing. Argon (Ar) plasma and Difluoromethane (CH2F2) plasma were used to control the surface wettabilities of cellulose acetate membranes. Optical emission spectroscopy was used to examine the various chemical species of low-pressure plasma processing. In this investigation, the plasma-treated surfaces were analyzed by X-ray photoelectron spectroscopy, while changes in morphology and surface roughness were determined with confocal laser scanning microscopy. Ar plasma activation resulted in hydrophilic surface. CH2F2 plasma deposited hydrophobic layer onto the cellulose acetate membrane because of strong fluorination of the top layer. The results reveal low-pressure plasma processing is an effective method to control the surface properties of cellulose acetate membranes. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Energy Transfer Enables 1.53 ,m Photoluminescence from Erbium-Doped TiO2 Semiconductor Nanocrystals Synthesized by Ar/O2 Radio-Frequency Thermal PlasmaJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2008Ji-Guang Li Highly crystalline, highly luminescent nanopowders of Er3+ -doped TiO2 have been successfully synthesized via one-step Ar/O2 radio-frequency thermal plasma processing. Energy transfer from the TiO2 host to Er3+ activators has been confirmed by combined means of UV-vis, excitation, and photoluminescence spectroscopies. As a consequence, bright photoluminescence at ,1.53 ,m was observed from the nanopowders either by directly exciting the Er3+ activator or by exciting the TiO2 host lattice. A comparative study shows that the nanopowder of the same system made via coprecipitation lacks the energy transfer. The plasma-generated nanopowders may thus find applications in optoelectronic devices. [source] Modeling and Simulation of Fast Neutral Beam Sources for Materials ProcessingPLASMA PROCESSES AND POLYMERS, Issue 5 2009Demetre J. EconomouArticle first published online: 6 MAY 200 Abstract Fast (kinetic energy of 10 to some 100 eV) neutral beams can be used for etching, deposition or surface modification, without charging damage that may occur in conventional plasma processing of materials. This paper provides an overview of the modeling and simulation approaches applicable to neutral beam sources. Neutral beam sources based on both volume and surface neutralization of ions are discussed, with emphasis on the latter. [source] | ||||||||||