强磁场辅助碲化铋系热电材料的熔炼法制备、微结构调控及热电性能研究

项目名称： 强磁场辅助碲化铋系热电材料的熔炼法制备、微结构调控及热电性能研究

项目编号： No.51272080

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 一般工业技术

项目作者： 杨君友

作者单位： 华中科技大学

项目金额： 80万元

中文摘要： 碲化铋系单晶材料机械性能差、生产周期长，基于粉末冶金的一些多晶材料新工艺近年来取得了长足进展，但在规模化和单位成本方面仍难以和单晶材料抗衡。熔炼-凝固法是大规模制备传统材料的最有效方法之一，本项目将熔炼凝固法用于碲化铋系多晶块体材料的制备，在熔体中添加纳米形核剂以提高其形核率，并在凝固过程中引入强磁场，为体系引入除温度、压力之外的新变量 - 磁场强度，从而可以通过调节磁场参量，改变体系的热力学状态，实现对碲化铋系材料凝固过程和微结构的有效调控，进而优化其综合性能。本项目首次将强磁场与熔炼法结合用于碲化铋系多晶材料的制备，探索强磁场环境下碲化铋系材料凝固结晶的热力学、动力学规律及其微结构调控机理，这在国际国内都是一项有意义的探索和创新。对揭示强磁场条件下热电材料的形核结晶长大规律、丰富热电材料微结构和性能的调控优化途径，推动碲化铋系材料的高效规模化制备和应用推广具有重要的科学意义和应用价值。

中文关键词： 热电材料；碲化铋；赛贝克系数；热导率；强磁场

英文摘要： Single crystalline Bi2Te3-based thermoelectric materials are prone to cleave along the weak van der Waals bonding planes.Furthermore,the process of single crystal growth is quite energy-consuming and takes a very long time. Recently, some powder metallurgical (PM) methods, such as mechanical alloying (MA) combined with spark plasma sintering (SPS), melt spinning combined with spark plasma sintering (SPS), have been developed for preparing polycrystalline Bi2Te3-based materials, and some exciting progress has been reported. However, PM methods need more complicated facilities and are not suitable for large scale production yet. Melting -solidification (MS) method, which is one of the most traditional and efficient methods for large scale production of many metallic materials, is employed to prepare polycrystalline Bi2Te3-based thermoelectric materials in this project. To manipulate the solidification process, strong magnetic field is introduced during the process of solidification, and some refractory intermetallic nanoparticles are added into the melt of Bi2Te3-based materials. Thermodynamics and kinetics of nucleation and growth of Bi2Te3-based materials are supposed to be altered, and the microstructure of the solidified Bi2Te3-based materials will be adjusted accordingly, therefore their comprehensive propert

英文关键词： thermoelectric materials；Bi2Te3；Seebeck coefficient；thermal conductivity；high magnetic field