【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．更多还原

【Abstract】 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 -173μV/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.更多还原