Dresden 2009 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 35: Poster Session II
MM 35.34: Poster
Mittwoch, 25. März 2009, 16:30–18:30, P4
On the quality of electrical contacts between carbon nano-fibers in composite-materials — •Michael Konter1, Pablo Carballera2, Frank Haupert2, Bernd Wetzel2, and Rolf Pelster1 — 1Fachrichtung 7.2 Experimentalphysik, Universität des Saarlandes, Saarbrücken, Germany — 2Institut für Verbundwerkstoffe GmbH, Kaiserslautern, Germany
We have investigated the electric transport properties of composite materials using temperature dependent dielectric spectroscopy (10 Hz - 2 GHz, 40 K - 290 K). The samples consist of epoxy-resin containing up to 2 vol.% carbon nano-fibers. We observe percolation above a threshold of about 0.05vol.%. The dc-conductivity is associated with a polarization process at high frequencies. The latter one stems from an interfacial polarization process at the contacts between the fibers, which act as barriers. The analysis of the data reveals microscopic information on the quality of these contacts. It is poor close to the percolation threshold and improves with increasing concentration of nano-fibres.