| 研究実績の概要 |
In this research proposal, we are aiming to develop high performance half-Heusler thermoelectric materials that are also environmental friendly, low cost and stable at medium-high operating temperature range (i.e. 300-600 degree Celcius). In order to achieve the goal, firstly, we have fabricated a series of slightly off-stoichimetric quinary (Ti,Zr,M)Ni1.1Sn alloys,where M=V, Nb and Ta. The selection of the alloy composition is intended to maximise the introduction of multiscale microstructure, which includes microstructral features of different sizes, such as (a) the Ti-, Zr-, M- and vacancy point defects, (b) the nanoscopic clusters of point defect domains, (c) the various size of Ni-rich Heusler nanoprecipitates, and (d) planar defects created by the microscopic half-Heusler-half-Heusler phase domains. At this moment, we are trying to characterize the multiscale microstrucure with various microscopic techniques, such as SEM, EPMA, X-ray diffraction, TEM, HRTEM and STEM. Next, their thermoelectric properties will be measured with increasig temperature. This enables us to evaluate how to better control formation of the microstrutcure and eventually leads to the development of the best thermoelectric performance of half-Heusler alloys.
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| 次年度使用額が生じた理由 |
The main reason was due to the cancelling of a domestic and an international conferences. Therefore, in the next fiscal year, we plan to publish our research findings in high impact factor journals, and several well-recognised international and domestic conferences of thermoelectricity.
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