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Title: Plasma column and nano-powder generation from solid titanium by localized microwaves in air

This paper studies the effect of a plasma column ejected from solid titanium by localized microwaves in an ambient air atmosphere. Nanoparticles of titanium dioxide (titania) are found to be directly synthesized in this plasma column maintained by the microwave energy in the cavity. The process is initiated by a hotspot induced by localized microwaves, which melts the titanium substrate locally. The molten hotspot emits ionized titanium vapors continuously into the stable plasma column, which may last for more than a minute duration. The characterization of the dusty plasma obtained is performed in-situ by small-angle X-ray scattering (SAXS), optical spectroscopy, and microwave reflection analyses. The deposited titania nanoparticles are structurally and morphologically analyzed by ex-situ optical and scanning-electron microscope observations, and also by X-ray diffraction. Using the Boltzmann plot method combined with the SAXS results, the electron temperature and density in the dusty plasma are estimated as ∼0.4 eV and ∼10{sup 19 }m{sup −3}, respectively. The analysis of the plasma product reveals nanoparticles of titania in crystalline phases of anatase, brookite, and rutile. These are spatially arranged in various spherical, cubic, lamellar, and network forms. Several applications are considered for this process of titania nano-powder production.
Authors:
; ; ;  [1] ;  [2] ; ;  [3] ;  [4]
  1. Faculty of Engineering, Tel Aviv University, Ramat Aviv 6997801 (Israel)
  2. Wolfson Applied Materials Research Center, Tel Aviv Univ., Ramat Aviv 6997801 (Israel)
  3. IPR., U.M.R. No. 6251 du C.N.R.S., Université de Rennes I, 35042 Rennes (France)
  4. European Synchrotron Radiation Facility, 38043 Grenoble (France)
Publication Date:
OSTI Identifier:
22490771
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AIR; MICROWAVE RADIATION; NANOPARTICLES; PLASMA; POWDERS; RUTILE; SCANNING ELECTRON MICROSCOPY; SMALL ANGLE SCATTERING; SOLIDS; SPECTROSCOPY; SUBSTRATES; TITANIUM; TITANIUM OXIDES; VAPORS; X-RAY DIFFRACTION