EAGER: Spark Plasma Sintering of Bulk Nanostructured Thermoelectric Materials

热电材料可以直接将废热中可利用的热能转化为电能。这一早期的探索性研究概念补助金(AGER)为开发高性能纳米结构热电材料的块状结构提供了资金。一种新的放电等离子烧结(SPS)工艺将被用来将机械合金化的热电纳米结构粉末烧结成块状。SPS过程将包括同时对放置在石墨模具中的纳米结构粉末施加单轴压力和脉冲直流电流。这项提议的研究将集中在热电材料的碲化铋和碲化铅基组合物的块状纳米结构上。研究计划的重点将是研究纳米结构热电粉末在SPS过程中的基本致密化机理，以及在纳米范围内(50 Nm)热电性能与颗粒/特征尺寸的关系。该项目的成功完成将极大地推动块状热电材料纳米结构的发展，以提高这些材料的性能。这些研究将提供关于晶粒度对热电性能影响的有价值的信息，这对于优化这些材料的性能是很重要的。由于能量转换需要大量的材料，利用SPS制备块状纳米结构热电材料的可能性有望加速这些材料在现实世界热电设备中的应用。拟议的EARGER计划将为研究生和本科生提供研究经验和培训，并为他们未来在这个重要的能源材料领域的职业生涯做好准备。拟议的研究结果也将被纳入现代材料研究生课程，以实现更广泛的影响。

Thermoelectric materials can directly convert thermal energy available in waste heat into electrical energy. This EArly Concept Grant for Exploratory Research (EAGER) provides funding for the development of bulk shapes of high performance nanostructured thermoelectric materials. A novel spark plasma sintering (SPS) process will be used to sinter mechanically alloyed nanostructured powder of thermoelectric compositions into bulk shapes. The SPS process will involve simultaneous application of uniaxial pressure and pulsed direct current to nanostructured powder placed in the graphite dies. The investigations of this proposal will be focused on bulk nanostructuring of bismuth telluride- and lead telluride-based compositions of thermoelectric materials. Major emphasis of the research plan will be on investigating the fundamental densification mechanisms of nanostructured thermoelectric powder during SPS and the dependence of thermoelectric performance on grain/feature size in nano-scale range ( 50 nm). Successful completion of this project will significantly advance the state-of-the-art in nanostructuring of bulk thermoelectric materials for improving the performance of these materials. The proposed investigations will provide valuable information about the influence of grain size on the thermoelectric performance which is important for optimizing the performance these materials. Since large amounts of materials are needed for energy conversion, the possibilities of fabricating bulk shapes of the nanostructured thermoelectric materials using SPS is expected to accelerate utilization of these materials in real-world thermoelectric devices. The proposed EAGER plan will provide research experiences and training to graduate and undergraduate students, and prepare them for future career in this important field of energy materials. The results of the proposed research will also be incorporated in the graduate course on Modern Materials to achieve the broader impact.