Effect of Shaping Method and Heat Treatment on Microstructure and Thermoelectric Properties of Titanium Dioxide

The TiO2 samples were obtained by two different shaping methods: cold isostatic pressing and cold extrusion, sintered in air at 1373 K, 1573 K, 1773 K and annealed under vacuum at 1373 K. Differences in density, microstructure and thermoelectric properties were observed between the samples depending on the shaping method used. With increase in sintering temperature the electrical conductivity of all samples increased while the Seebeck coefficient decreased. Great microstructural differences were observed between the surface and bulk of the samples made by each of the shaping techniques. It was found that microstructural differences between surface and bulk of the samples affect their thermoelectric properties.