The Influence of Air and Subsequent Vacuum Thermal Treatment on the Thermoelectric Properties of Extruded TiO2 Ceramics
Abstract
The thermoelectric properties of air sintered and
vacuum annealed TiO2 samples consolidated by the extrusion
process have been studied. The samples were sintered in air at
1100, 1175, 1250 and 1350 °C and subsequently annealed under
vacuum at 1075 °C. After both thermal treatments oxygen
deficient phases were not observed and only a single rutile TiO2
phase was present in the samples. The density and grain size of
the samples increased with an increase in air sintering
temperature, while the total porosity decreased. Electrical
conductivity of the samples increased with an increase in air
sintering temperature. The highest Seebeck coefficient (~410
μV/K) and thermoelectric power factor (3,25 × 10-6 W/m-1K-2) at
280 °C were obtained for the sample that was sintered in air at
1175 °C before the following annealing under vacuum.
vacuum annealed TiO2 samples consolidated by the extrusion
process have been studied. The samples were sintered in air at
1100, 1175, 1250 and 1350 °C and subsequently annealed under
vacuum at 1075 °C. After both thermal treatments oxygen
deficient phases were not observed and only a single rutile TiO2
phase was present in the samples. The density and grain size of
the samples increased with an increase in air sintering
temperature, while the total porosity decreased. Electrical
conductivity of the samples increased with an increase in air
sintering temperature. The highest Seebeck coefficient (~410
μV/K) and thermoelectric power factor (3,25 × 10-6 W/m-1K-2) at
280 °C were obtained for the sample that was sintered in air at
1175 °C before the following annealing under vacuum.
Keywords: |
TiO2, ceramics, microstructure, thermoelectric properties
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Full Text: |
DOI: 10.7250/msac.2013.006
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