Acoustic spectroscopy of aerogel precursors

Conference paper
Part of the Progress in Colloid and Polymer Science book series (PROGCOLLOID, volume 115)


We investigate the acoustical properties of silica gels, which are precursors in the aerogel production process. These gels exhibit a strong “ringing gel” behavior, that is they emit a characteristic sound if one knocks against the container. We study this sound emission with a very simple spectroscopic technique and observe resonances which are characteristic for natural frequencies of a cylindrical body. From a fit of the experimental frequency positions to calculated values, we determine a sound velocity of c T = 4 m/s for a gel sample with porosity φ = 97.5%. This low sound velocity can only be interpreted as the transverse sound mode predicted by Biot’s theory for sound propagation in porous media.

Key words

Acoustic properties Porous materials Silica gels Aerogels 


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Copyright information

© Springer-Verlag 2000

Authors and Affiliations

  • C. Sinn
    • 1
    • 2
  1. 1.Institut für Physik derJohannes-Gutenberg-UniversitätMainzGermany
  2. 2.Institut für Angewandte Physik derUniversität BernBernSwitzerland

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