Magnèli phase Ti O2-1 bulks prepared by SPS followed by carbon reduction and their thermoelectric performance
| Autor: | Hiroyuki Yoshida, Yun Lu, Yingrong Jin, Liang Hao, Yuta Kikuchi |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
Scanning electron microscope Mechanical Engineering Metallurgy Metals and Alloys Analytical chemistry Spark plasma sintering 02 engineering and technology Power factor 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Thermal conductivity Mechanics of Materials Electrical resistivity and conductivity Rutile Seebeck coefficient Thermoelectric effect Materials Chemistry 0210 nano-technology |
| Zdroj: | Journal of Alloys and Compounds. 722:846-851 |
| ISSN: | 0925-8388 |
| DOI: | 10.1016/j.jallcom.2017.06.096 |
| Popis: | We fabricated Magneli phase TinO2n-1 compacts from nano-sized rutile TiO2 powder by spark plasma sintering (SPS) followed by carbon reduction at elevated temperatures. These compacts were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results showed that the n value in Magneli phase TinO2n-1 mainly depended on the reduction temperature and holding time. Higher reduction temperature or longer holding time favored to smaller n value through withdrawing more oxygen atoms from the lattice of TiO2. Meanwhile, the thermoelectric properties including electrical resistivity, thermal conductivity, Seebeck coefficient, power factor and ZT value of these compacts were measured or calculated. The electrical conductivity was greatly improved while Seebeck coefficient still kept rather large values, which resulted in an extremely high value of power factor at elevated temperature. The highest power factor reached 6.5 × 10−4 W m−1 K−2 at 973 K and the greatest ZT value ran up to 0.1 at 873 K. |
| Databáze: | OpenAIRE |
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