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Synthesis of thermoelectric materials by simultaneous addition of several kinds of fine particles and improvement of their thermoelectric properties

同时添加多种细颗粒合成热电材料并改善其热电性能

基本信息

批准号：
12305049
负责人：
ITO Mikio
金额：
$ 21.77万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

Several kinds of fine particles, such as insulating conductive and/or metallic conductive fine particles, were dispersed in the matrix of thermoelectric materials. The thermoelectric materials used in this study were β-FeSi_2, CoSb_3 and several thermoelectric oxides, and the effects of these fine particles addition of the thermoelectric performance, especially the thermal conductivity. In the case of the β-FeSi_2, it was found that a densely sintered body with the high figure of merit could be synthesized by SiC fine particle dispersion and Cu powder addition. The addition of rare earth oxides, which have low thermal conductivity and good chemical stability, was significantly effective on reducing thermal conductivity and increasing Seebeck coefficient, especially when Y_2O_3 powder was added. The improvement of Seebeck coefficient and the results of the Hall coefficient measurement suggest that the solution of a small amount of the rare earth element into the Fe site of the β-FeSi_2 matrix occurs. In the case of the CoSb_3, the dispersion of the metallic FeSb_2 and NiSb fine particles was quite effective on reducing the electrical resistivity, as well as the thermal conductivity, resulting in the significant improvement of the thermoelectric performance. The thermoelectric oxides, ZnO and Na_xCo_2O_4 were synthesized by the polymerized complex method (PCM). The PCM was found to promote the solution of doping element compared to the conventional solid state reaction method, expanding the possibility of enhancement of thermoelectric properties by doping. When the impurity phases precipitated, they were finely dispersed in the matrix, indicating that the PCM is also effective on reducing the thermal conductivity.

在热电材料的基质中分散着多种细小颗粒，如绝缘导电和/或金属导电的细颗粒。本研究使用的热电材料是β-FeSi2、CoSb3和几种热电氧化物，以及这些细颗粒的加入对热电性能，特别是热导率的影响。以β-FeSi_2为例，研究发现，通过碳化硅微粉的分散和铜粉的加入，可以制备出高优值的致密烧结体。添加导热系数低、化学稳定性好的稀土氧化物对降低导热系数、提高塞贝克系数有显著效果，尤其是添加Y_2O_3粉末时效果更明显。塞贝克系数的提高和霍尔系数的测量结果表明，少量稀土元素固溶到β-FeSi2基质的Fe位中。在CoSb_3的情况下，金属FeSb_2和NiSb微粒的分散可以有效地降低材料的电阻率和热导率，从而显著提高材料的热电性能。采用聚合络合法制备了热电氧化物：氧化锌和碳酸氢钠。与传统的固相反应方法相比，相变材料促进了掺杂元素的溶解，扩大了通过掺杂提高热电性能的可能性。当杂质相析出时，它们在基体中分散得很好，表明PCM也具有降低导热系数的作用。