微波辅助MgH_2固相反应法制备Mg_2Si_(1-x)Sn_x基热电材料及性能  

Fabrication of Mg_2Si_(1-x)Sn_x from MgH_2 by Microwave-Assisted Solid State Reaction and Its Thermoelectric Performance

作　　者：王彦坤[1] 陈少平[1] 樊文浩[1] 张华[1] 孟庆森[1] 杨江峰[1] 崔教林[2] 

机构地区：[1]太原理工大学,山西太原030024 [2]宁波工程学院,浙江宁波315016

出　　处：《稀有金属材料与工程》2016年第3期755-759,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51101111);山西省回国留学人员科研资助项目(2012-031)

摘　　要：在微波作用下利用MgH2、纳米Si粉、Sn粉和Bi粉进行固相反应,结合电场激活压力辅助合成法（FAPAS）制备了高纯Bi掺杂的Mg2Si（1-x）Snx（0.4≤x≤0.6）基固溶体热电材料,并对其微观结构和热电性能进行了表征。结果表明,MgH2替代传统原料Mg粉显著降低了固相反应温度且防止了Mg的挥发和氧化,同时微波快速低温加热有效抑制晶粒长大,可获得平均晶粒尺寸为200 nm的高纯产物。在300-750 K的温度区间对样品热电性能进行测试。结果表明,细小的片层固溶体组织和Bi的掺杂有效降低了样品热导率,同时改善了其电性能,在600 K时,含1.5%Bi（原子分数）的Mg2Si（0.4/0Sn（0.6）热电材料具有最大ZT值0.91。The Bi doped Mg2Si（1-x）Snx（0.4≤x≤0.6）solid solution thermoelectric material with high purity was synthesized by microwave-assisted solid state reaction followed by field activated and pressure assisted synthesis（FAPAS）,and its microstructure and transport properties were characterized.Results show that the replacement of Mg used in traditional processes by MgH2 powder significantly reduces the temperature of the solid state reaction and further inhibits the oxidation and volatilization of magnesium.Meanwhile,the low-temperature and rapid heating from microwave restrains the grain growth effectively;as a result,the pure product with an average grain size of 200 nm has been obtained.Thermoelectric performance was tested in the temperature range of 300-750 K.It is indicated that the solid solution with fine lamellar structure and the doping of Bi significantly lower the thermal conductivity and improve the electric properties simultaneously.The 1.5 at% Bi doped Mg2Si（0.4/0Sn（0.6） gets the maximum ZT of 0.91 at 600 K.

关 键 词：微波 MgH2 Mg2Si1-xSnx 热电材料 

分 类 号：TB34[一般工业技术—材料科学与工程]