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Application of Silicon Carbide-Boron Carbide Composite Ceramics for Functionally Graded Thermoelectric Conversion Materials

碳化硅-碳化硼复合陶瓷在功能梯度热电转换材料中的应用

基本信息

批准号：
06453081
负责人：
GOTO Takashi
金额：
$ 3.07万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06453081/
关键词：
Boron Carbide Titanium Boride Silicon Carbide Eutectic Reaction Boron-rich Borides Functionally Graded Material Microstructure Thermoelectric Figure of Merit 熱電性能性能指数

项目摘要

Boron carbide (B_4C) is a good candidate material for high-temperature thermoelectric conversion at more than 1200K.In the present study, we tried to improve the thermoelectric performance of B_4C by controlling microstructure making B_4C-based composites. Firstly, we prepared SiC-B_4C composites by arc-melting., since SiC has good oxidation resistance and superior thermoelectric properties. A typical lamella texture was observed at SiC content of 40 to 50 mol%, and we confirmed that SiC-B_4C composites are a quasi-binary system. The optimum SiC content was 40 mol%, and its thermoelectric figure of merit value (ZT) was about 0.1 at T=1100K.Secondary, we found that the dispersed phase in the B_4C should be highly electrically conductive in order to improve the thermoelectric performance. Then we prepared TiB_2-B_4C composites. The TiB_2-B_4C composites are also a quasi-binary system. The lamella texture was observed at TiB_2 content of 15 to 25 mol%. The highest ZT values was attained at TiB_2 content of 6 mol%, and its ZT value was 0.5 at T=1100K.This value is almost equivalent to the required level for practical thermoelectric devises.The next issue which we should try is to develop a functionally graded thermoelectric materials which consist of the TiB_2-B_4C composites, Si-Ge alloys, PbTe and Bi_2Te_3.

碳化硼(B4C)是一种在1200K以上进行高温热电转换的理想候选材料，本研究试图通过控制B4C基复合材料的微观结构来改善其热电性能。首先，由于碳化硅具有良好的抗氧化性和优异的热电性能，我们采用电弧炉熔炼的方法制备了碳化硅-碳化硼复合材料。当碳化硅含量在40~50摩尔%时，观察到典型的片层织构，证实了碳化硅-B_4C复合材料为准二元系。最佳的碳化硅含量为40mol%，在T=1100K时，其热电优值ZT约为0.1。其次，我们发现B4C中的分散相必须具有较高的导电性才能改善其热电性能。然后制备了TiB_2-B_4C复合材料。TiB_2-B_4C复合材料也是准二元系。当TiB_2含量为15~25mol%时，可观察到层状织构。当TiB_2含量为6mol%时，ZT值达到最大值，T=1100K时，ZT值为0.5，几乎相当于实际热电器件所要求的水平。下一步，我们应该努力开发一种由TiB_2-B_4C复合材料、Si-Ge合金、PbTe和Bi2Te_3组成的功能梯度热电材料。