Effect of spark plasma sintering temperature on microstructure and thermoelectric properties of the cermet composites consisting of Bi2Te2.1Se0.9 matrix and Co@CoTe2 inclusions
| Autor: | Alexei Vasil'ev, Marina Zhezhu, Vseslav Novikov, Maxim Yaprintsev, Oleg Ivanov |
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| Rok vydání: | 2022 |
| Předmět: |
Materials science
Composite number Sintering Spark plasma sintering Cermet Condensed Matter Physics Microstructure Electronic Optical and Magnetic Materials Inorganic Chemistry Electrical resistivity and conductivity Seebeck coefficient Thermoelectric effect Materials Chemistry Ceramics and Composites Physical and Theoretical Chemistry Composite material |
| Zdroj: | Journal of Solid State Chemistry. 305:122696 |
| ISSN: | 0022-4596 |
| Popis: | Novel cermet Bi2Te2.1Se0.9+0.33 wt% Co composite has been prepared via spark plasma sintering (SPS) the starting Bi2Te2.1Se0.9 and Co powders at different SPS-temperatures (TS = 598, 623, 648 and 673 K). During the sintering, initial Co inclusions transform into final filler Co@CoTe2 (“core”-“shell”) inclusions, randomly distributed inside textured grained Bi2Te2.1Se0.9 matrix. Forming these inclusions is originated from high-temperature chemical interaction between Bi2Te2.1Se0.9 and Co. Main features in microstructure and thermoelectric properties of the cermet composite found with increasing TS are: (i) a texturing degree of grained Bi2Te2.1Se0.9 matrix gradually decreases that is attributed to reducing in ability of initial nanometer Co particles to act as lubricant; (ii) a fraction of the Co core decreases, and a fraction of the CoTe2 shell increases that is related to acceleration of Co→CoTe2 reaction at higher temperatures; (iii) the specific electrical resistivity and the Seebeck coefficient reduce, whereas the total thermal conductivity increases that can be originated from growth of electron concentration due to local Co doping. Highest value of the thermoelectric figure-of-merit equal to ∼0.8 was observed for the composite, SPS-treated at 673 K. |
| Databáze: | OpenAIRE |
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