Fanciulli C, Coduri M, Boldrini S, Abedi H, Tomasi C, Famengo A, Ferrario A, Fabrizio M, Passaretti F
J Nanosci Nanotechnol. 2017 Mar;17(3):1571-578. doi: 10.1166/jnn.2017.13735.
Outstanding ZT values registered on single crystals recently renewed the interest of thermoelectric community for SeSn compound. Owing to the strong anisotropy of the phenomenon, so far only single crystals proved to be the suitable for its application. Here we present the production and the characterization of bulk polycrystalline materials processed by open die pressing, aimed at reducing the gap with single crystal materials by taking advantage from the highly texture degree derived by the processing and by the improved phonon scattering promoted by grain boundaries. The resulting bulks display good compaction, improved mechanical properties and strong texture of the phase. Structural and morphological analyses confirmed the successful orientation according to the (400) cleavage plane. The structural transition responsible for the ultra-low thermal conductivity has been investigated and possible irreversible effects on the starting phase due to thermal cycling have been evaluated. Preliminary measurements of thermal conductivity are reported.
最近在单晶上测得的出色ZT值，重新唤起了热电领域对SeSn化合物的兴趣。由于该现象具有很强的各向异性，到目前为止，仅单晶被证明适用于其应用。在此，我们展示了通过开模压制工艺制备的块状多晶材料及其表征，旨在利用加工过程中产生的高度织构化以及晶界促进的声子散射改善效果，缩小与单晶材料的差距。所得块体显示出良好的压实度、改善的机械性能以及该相的强织构。结构和形态分析证实了沿(400)解理面的成功取向。对导致超低热导率的结构转变进行了研究，并评估了热循环对起始相可能产生的不可逆影响。报告了热导率的初步测量结果。
