Yin Hao, Blichfeld Anders Bank, Christensen Mogens, Iversen Bo Brummerstedt
Centre for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University , Langelandsgade 140, DK-8000 Aarhus C, Denmark.
ACS Appl Mater Interfaces. 2014 Jul 9;6(13):10542-8. doi: 10.1021/am502089a. Epub 2014 Jun 16.
Zn4Sb3 is among the cheapest high performance thermoelectric materials, and it is made of relatively nontoxic elements. Strong activities are aimed at developing commercial power generation modules based on Zn4Sb3 making it vital to develop fast reliable synthesis processes for high-quality material. Here direct synthesis and compaction of homogeneous phase-pure thermoelectric Zn4Sb3 by spark plasma sintering (SPS) has been developed. Compared with the traditional quench and press method, the complexity and process time of the new method is very significantly reduced (order of magnitude), making large-scale production feasible. A composition gradient is observed in the pellet along the axis of applied pressure and current. The homogeneity of the pressed pellets is studied as a function of the SPS parameters: sintering time, applied current, sintering temperature and applied pressure, and the mechanism behind the formation of the gradient is discussed. The key finding is that pure and homogeneous Zn4Sb3 pellets can be produced by adding an extra layer of elemental Zn foil to compensate the Zn migration.
Zn4Sb3是最便宜的高性能热电材料之一，且由相对无毒的元素制成。目前正积极开展基于Zn4Sb3的商业发电模块开发活动，因此开发快速可靠的高质量材料合成工艺至关重要。在此，通过放电等离子烧结（SPS）直接合成并压实了单相纯热电材料Zn4Sb3。与传统的淬火压制方法相比，新方法的复杂性和工艺时间大幅减少（数量级），使得大规模生产成为可能。在沿施加压力和电流轴的颗粒中观察到成分梯度。研究了压制颗粒的均匀性与SPS参数（烧结时间、施加电流、烧结温度和施加压力）的关系，并讨论了梯度形成背后的机制。关键发现是，通过添加额外的一层元素锌箔来补偿锌迁移，可以生产出纯净且均匀的Zn4Sb3颗粒。
