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.

热电材料基体中分散有多种细颗粒，如绝缘导电细颗粒和/或金属导电细颗粒，本研究中使用的热电材料为β-FeSi_2、CoSb_3和几种热电氧化物，并研究了它们的影响。在β-FeSi_2的情况下，通过添加细颗粒可以提高热电性能，特别是热导率，可以合成具有高品质因数的致密烧结体。 SiC细颗粒分散和Cu粉的添加具有较低的热导率和良好的化学稳定性，对降低热导率和提高塞贝克系数有显着效果，特别是当添加Y_2O_3粉末时，塞贝克系数的提高。霍尔系数测量结果表明，在CoSb_3的情况下，少量稀土元素溶解到β-FeSi_2基体的Fe位中，发生了金属的弥散。 FeSb_2和NiSb细颗粒对降低电阻率和热导率非常有效，从而通过聚合复合方法（PCM）合成了热电氧化物ZnO和Na_xCo_2O_4。研究发现，与传统的固相反应方法相比，可以促进掺杂元素的溶解，扩大了通过掺杂提高热电性能的可能性。沉淀后，它们精细地分散在基体中，表明相变材料也能有效降低导热系数。