高压合成纳米晶Bi_(0．85)Sb_(0．15)的低温热电性能  

The low temperature thermoelectric properties of Bi_(0.85)Sb_(0.15) fabricated by high pressure

作　　者：宋春梅[1] 刘华军[2] 黄荣进[2] 蔡方硕[2] 李来风[2] 

机构地区：[1]遵义师范学院物理系,遵义563002 [2]中国科学院理化技术研究所

出　　处：《材料研究学报》2007年第2期126-130,共5页Chinese Journal of Materials Research

基　　金：国家自然科学基金50666001;50676101;贵州省科技基金20052088资助项目

摘　　要：通过机械合金化法获得Bi0．85Sb0．15纳米晶粉末材料,在常温下冷压成型并分别在不同温度下进行高压处理,制备出块状样品．X-ray衍射实验证实已形成了Bi0.85Sb0．15单相合金．测量了样品在80～300 K温区的Seebeck系数和电导率,计算出材料的功率因子与温度的关系．在523 K 6 GPa下压制30 min的样品,其Seebeck系数在150 K达到-173μV／K,比同温度下单晶材料样品的Seebeck高大约60％,功率因子在200 K达到3．27×10-3W／m·K2,表明高压处理可以有效改善材料热电性能．高分辨电镜分析发现材料中存在均匀分布的小于5 nm的“纳米点”,“纳米点”的存在导致材料Seebeck系数在低温显著提高．Nano crystallite Bi0.85Sb0.15 powders were prepared by mechanical alloying method. The powders were pressed into pellets and then pressed to form bulk samples under high pressure of 6 GPa at different pressing temperatures. The X-ray diffraction analysis indicated that single phase was formed. Seebeck coefficient and electrical conductivity were measured at the temperature range of 80-300 K. The Seebeck coefficient has a maximum value of-173 μV/K at about 150 K which is 60% higher than that of conventional single crystal materials. The power factor is calculated at the temperature range of 80- 300 K, and the maximum value is of 3.27×10^-3W/m.K2 at 200 K. It is indicated that high pressing treatment can effectively improve the thermoelectric properties. High-resolution transmission electron microscopy analysis showed that there were lots of homogeneously distributed nano-dots with the size less than 5 nm, and this shall be the reason to improve the Seebeck coefficient at cryogenic temperature.

关 键 词：无机非金属材料 热电材料 高压 SEEBECK系数 功率因子 

分 类 号：O513[理学—低温物理] O482[理学—物理]