Dielectric Properties of W-SiO2 Nanocomposites

  1. Prof. Dr. M. Rühle2 and
  2. Prof. Dr. H. Gleiter3
  1. Shlomo Berger and
  2. Tamar Tepper

Published Online: 23 DEC 2005

DOI: 10.1002/352760622X.ch23

Interface Controlled Materials, Volume 9

Interface Controlled Materials, Volume 9

How to Cite

Berger, S. and Tepper, T. (2000) Dielectric Properties of W-SiO2 Nanocomposites, in Interface Controlled Materials, Volume 9 (eds M. Rühle and H. Gleiter), Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, FRG. doi: 10.1002/352760622X.ch23

Editor Information

  1. 2

    Max-Planck-Institut für Metallforschung, Seestraße 92, 70174 Stuttgart, Germany

  2. 3

    Forschungszentrum Karlsruhe, Postfach 3640, 76021 Karlsruhe, Germany

Author Information

  1. Department of Materials Engineering, Technion, Haifa 32000, Israel

Publication History

  1. Published Online: 23 DEC 2005
  2. Published Print: 27 JUN 2000

Book Series:

  1. EUROMAT 99

ISBN Information

Print ISBN: 9783527301911

Online ISBN: 9783527606221

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Keywords:

  • interface controlled materials;
  • nanocomposite materials;
  • W-SiO2 nanocomposites;
  • dielectric properties

Summary

The dielectric properties of nanocomposite materials composed of nano-sized amorphous silica powder and micron-sized tungsten powder were studied as a function of composition and heat treatment temperature. The dielectric constant of the nanocomposites, at all compositions, is higher than that of a pure silica powder. The percolation threshold of this system is at about 20 % vol. W. Above this composition a sharp increase in the dielectric constant occurs, which becomes even sharper after a heat treatment at 950....C for 1 hour. The dielectric constant of pure silica specimens, on the other hand, decreases after the heat treatments. ESR measurements show peaks associated with dangling bonds at the surfaces of the particles. The change of the intensity and location of the ESR peaks is correlated with the change of the dielectric constant of the powders due to the heat treatments.