2021 Fiscal Year Final Research Report
Development of thermoelectric borides by powder metallurgy method using metal boride interphases
| Project/Area Number |
18K14030
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 26050:Material processing and microstructure control-related
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| Research Institution | Tokyo City University |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2022-03-31
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| Keywords | 粉末冶金 / 熱電変換 / ホウ化物 / 焼結 |
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| Outline of Final Research Achievements |
Boron-based composite thermoelectric materials for high-temperature applications were fabricated using a liquid-phase sintering based on the eutectic reaction between boride and metals.Metals such as Ni, Co, Fe and Mn, which form eutectic liquid phases with boron, were added to the raw powder mixture of boron-based materials. All samples were sintered by powder metallurgy method using SPS.
Due to the introduction of the eutectic liquid phase, the reaction of the boride phase was accelerated, and the densification of the boron-based composite material was achieved.The electrical conductivity was improved while maintaining the Seebeck coefficient around 200 μV/K, depending on the metal additives. Furthermore, it was observed that the thermal conductivity can be reduced due to the microstructural differences caused by the formation of the eutectic liquid phase and the difference in the wettability between the liquid phase and boride phase.
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| Free Research Field |
材料工学
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| Academic Significance and Societal Importance of the Research Achievements |
粉末冶金的手法という簡便な手法でホウ素系複合型熱電材料を作製した。ホウ素―金属間の共晶反応を利用することで、高密度化が困難であった炭化ホウ素の焼結温度の低下と反応の促進を同時に達成した。複合化に伴い熱電性能も向上しており、ホウ素系材料は高温用熱電材料として有望である。また、共晶液相を利用したホウ素系焼結技術は硬質材料分野にも適用可能であり、高温構造材料などにも応用可能な技術である
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