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Electrical conductivity of TiC and (Ti,W)C ceramic samples
|Nikos Guskos 1,2, Janusz Typek 1, Anna Biedunkiewicz 3, Stamatis Patapis 2, Konstantinos A. Kanekas 2, Michał Maryniak 1|
1. Technical University of Szczecin, Institute of Physics (TUS), al. Piastów 48, Szczecin 70-311, Poland
Three samples: crystalline titanium carbide TiC (sample I), titanium-tungsten carbide (Ti,W)C (sample II), and nanocrystalline TiC dispersed in a carbon matrix (sample III) have been selected for electrical conductivity measurements. The first two samples consisted of macron-size grains, while the third was a nanocrystalline TiC/C composite and was synthesized by a nonhydrolytic sol-gel process. All samples have been characterized by the X-ray diffraction (XRD), scanning microscopy, microanalysis (WDS and EDS), transmission electron microscopy (TEM) and electron diffraction techniques. In sample II the ratio of W:Ti was equal to 0.3. The grain sizes in sample I and II were measured by the Fisher method and the mean diameter of the grains was calculated to be below 10 m. The TEM investigation of the TiC particles in the sample III has showed that they were formed with an average grain size around 20 nm. XRD measurements of sample III has revealed that the lattice constant is smaller than observed for other titanium carbides TiCx. The dc electrical conductivity studies have been made in the 80-330 K temperature range. Samples I and II have shown a metallic behavior but with different slopes of the conductance vs. temperature dependence. Sample III displayed at higher temperatures a pronounced thermal hysteresis in dc conductivity. The ac conductivity measurements have not shown any frequency dependence in the 1 kHz -100 MHz range.
Presentation: poster at E-MRS Fall Meeting 2004, Symposium I, by Michał Maryniak
See On-line Journal of E-MRS Fall Meeting 2004
Submitted: 2004-07-23 12:50 Revised: 2009-06-08 12:55