(Mg2Si1- Sb 04-(Mg Sn) 固溶体合金的制备及热电输运特性

第27卷 第8期 无 机 材 料 学 报

Vol. 27

No. 8

2012年8月

Journal of Inorganic Materials Aug., 2012

收稿日期: 2011-08-30; 收到修改稿日期: 2011-10-18

基金项目: 国家自然科学基金(50801002); 北京市自然科学基金(2112007); 北京市属高校人才强教计划(PHR20110812) National Natural Science Foundation of China (50801002); Beijing Natural Science Foundation (2112007); Founding

Project for Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality (PHR20110812)

作者简介: 韩志明(1984−), 男, 硕士研究生. E-mail: 0402hzm@ 通讯作者: 张 忻, 副研究员. E-mail: zhxin@

文章编号: 1000-324X(2012)08-0822-05 DOI: 10.3724/SP.J.1077.2012.11550

(Mg 2Si 1-x Sb x )0.4-(Mg 2Sn)0.6固溶体合金的制备及热电输运特性

韩志明, 张 忻, 路清梅, 张久兴, 张飞鹏

(北京工业大学 材料学院, 新型功能材料教育部重点实验室, 北京 100124)

摘 要: 以Mg 、Si 、Sn 、Sb 块体为原料, 采用熔炼结合放电等离子烧结(SPS)技术制备了n 型(Mg 2Si 1-x Sb x )0.4-(Mg 2Sn)0.6(0≤x ≤0.0625)系列固溶体合金. 结构及热电输运特性分析结果表明: 当Mg 原料过量8wt%时, 可以弥补熔炼过程中Mg 的挥发损失, 形成单相(Mg 2Si 1-x Sb x )0.4-(Mg 2Sn)0.6固溶体. 烧结样品的晶胞随Sb 掺杂量的增加而增大; 电阻率随Sb 掺杂量的增加先减小后增大, 当样品中Sb 掺杂量x ≤0.025时, 样品电阻率呈现出半导体输运特性, Sb 掺杂量x >0.025时, 样品电阻率呈现为金属输运特性. Seebeck 系数的绝对值随Sb 掺杂量的增加先减小后增大; 热导率κ在Sb 掺杂量x ≤0.025时比未掺杂Sb 样品的热导率低, 在Sb 掺杂量x >0.025时高于未掺杂样品的热导率, 但所有样品的晶格热导率明显低于未掺杂样品的晶格热导率. 实验结果表明Sb 的掺杂有利于降低晶格热导率和电阻率, 提高中温区Seebeck 系数绝对值; 其中(Mg 2Si 0.95Sb 0.05)0.4-(Mg 2Sn)0.6合金具有最大ZT 值, 并在723 K 附近取得最大值约为1.22.

关 键 词: Mg 2Si 基热电材料; Sb 掺杂; 热电性能; 放电等离子烧结 中图分类号: TK9 文献标识码: A

Preparation and Thermoelectric Properties of (Mg 2Si 1-x Sb x )0.4-(Mg 2Sn)0.6 Alloys

HAN Zhi-Ming, ZHANG Xin, LU Qing-Mei, ZHANG Jiu-Xing, ZHANG Fei-Peng

(College of Materials Science and Engineering, Beijing University of Technology, The key Laboratory of Advanced Functional

Materials, Ministry of Education, Beijing 100124, China)

Abstract: n-type (Mg 2Si 1-x Sb x )0.4-(Mg 2Sn)0.6 (0≤x ≤0.0625) alloys were prepared by an induction melting and

spark plasma sintering method using bulks of Mn, Si, Sn, Sb as raw materials. The analyzing results of the structure and thermoelectric properties show that the single-phase (Mg 2Si 1-x Sb x )0.4-(Mg 2Sn)0.6 alloys can be obtained at 8wt% excess of Mg addition. The lattice constant increases linearly with the amount of Sb, the electrical resistivity ρ firstly increases and then decreases. The electrical resistivity ρ of samples (x ≤0.025) shows semi-conductor be-havior, while that of the samples (x >0.025) shows the metallic behavior. The Seebeck coefficient α firstly increases and then decreases with the increase of x value. Compared with the non-doped sample, the thermal conductivity κ for samples (x ≤0.025) decreases and that of the other samples (x >0.025) increases. The ZT value for (Mg 2Si 0.95Sb 0.05)0.4-(Mg 2Sn)0.6 sample reaches its highest value of 1.22 at 773 K, which is much higher than that of the non-doped sample.

Key words: Mg 2Si base thermoelectric materials; Sb doping; thermoelectric properties; spark plasma sintering