球磨工艺调控碲化铋基材料微结构及热电性能研究

碲化铋基化合物是室温附近性能最佳的热电材料，在余热回收以及固态制冷领域具有重要的应用价值. 其主要的制备方式是球磨法，各类参数的细微变化都可能影响材料的微结构和热电性能. 球磨时间作为重要的球磨参数既能影响粉末粒径的细化，也对材料的热电性能有所调控，因此亟需逐步分析球磨时间对晶体结构、粒径尺寸及产物热电性能的影响. 本文采用恒定的球磨转速，调节不同球磨时间制备碲化铋基材料. 通过晶体结构及粉体粒径的分析发现了晶粒对球磨时间的响应. 后续热电性能测试结果表明，增加球磨时间后粒径发生变化并导致了电子、声子输运模式的协同改变. 最终，有效提升了n型与p型碲化铋的最大ZT值，分别达到了0.91和1.11. 本研究工作系统总结了球磨工艺中关键参数对碲化铋材料微结构及热电性能的影响，为粉末冶金及热电学的交叉融合及热电转换技术的商业化应用提供了实验和理论参考.

Synergistic tuning of microstructure and thermoelectric performance of bismuth telluride based materials by ball milling

Bismuth telluride compounds are thermoelectric materials with the best performance near room temperature, which have important application value in waste heat recovery and solid state refrigeration. The main preparation method is ball grind milling, and slight changes of various parameters may affect the microstructure and thermoelectric properties of materials. Ball milling time, as an important ball grinding parameter, can not only affect the refinement of powder particle size, but also regulate the thermoelectric properties of materials. Therefore, it is urgent to analyze the influence of ball milling time on the crystal structure, particle size and the thermoelectric performance of products. In this paper, bismuth telluride compounds were prepared by adjusting different ball milling time with constant ball grinding speed. The response of grains to ball milling time is found through the analysis of crystal structure and powder particle size. The result of subsequent thermoelectric performance tests shows that, with the increase of ball milling time, the change of particle size leads to the synergistic tuning of electron and phonon transport. Finally, the maximum ZT merit of n-type and p-type bismuth telluride were increased to 0.91 and 1.11, respectively. This study systematically summarizes the influence of ball milling time on the microstructure and the thermoelectric capability of bismuth telluride. Our work shows the significance in the mergence of powder metallurgy and thermoelectrics, which may play some roles in the commercial application of thermoelectric conversion technology.