Gravity-induced gradients in thermoelectric Mg2Si0.9925−xSnxSb0.0075
Gravity-induced gradients in thermoelectric Mg2Si0.9925−xSnxSb0.0075
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DOI：
10.1016/j.actamat.2012.06.050
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发表时间：
2012-09
期刊：
影响因子：
9.4
通讯作者：
M. Søndergaard;M. Christensen;K. Borup;H. Yin;B. Iversen
中科院分区：
文献类型：
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作者：
M. Søndergaard;M. Christensen;K. Borup;H. Yin;B. Iversen
采用感应熔炼、球磨和放电等离子烧结(SPS)工艺制备了10个名义成分为Mg2.2Si0.3925Sn0.6Sb0.0075和Mg2.2Si0.5925Sn0.4Sb0.0075的高效热电材料样品。在SPS处理后，通过空间分辨的Seebeck系数测量和X射线粉末衍射(包括随后的Rietveld精细化)，研究了所有球团的潜在的成分梯度。样品具有梯度，富镁锡相始终位于所有样品的底部。能量色散X射线光谱证实了这一结果。富镁锡相和富镁硅相密度的巨大差异是导致梯度产生的原因。研究结果为SPS工艺在功能梯度材料制备中的应用提供了一条新途径。此外，还测量了从室温到400°C的每批两个样品的Seebeck系数、导热系数、电阻率和霍尔载流子浓度。
Ten samples of high-efficiency thermoelectric materials with nominal compositions Mg2.2Si0.3925Sn0.6Sb0.0075and Mg2.2Si0.5925Sn0.4Sb0.0075were prepared by induction melting, ball milling and spark plasma sintering (SPS). After SPS processing, all pellets were investigated for a potential compositional gradient in Si/Sn content by employing spatially resolved Seebeck coefficient measurements and X-ray powder diffraction including subsequent Rietveld refinement. The samples have gradients, with the Mg2Sn-rich phase being consistently in the bottom of all samples. Energy dispersive X-ray spectroscopy confirmed the results. The large difference in densities between the Mg2Sn-rich and the Mg2Si-rich phases is responsible for the creation of the gradient. The results propose a new way to utilize SPS processing in fabrication of functionally graded materials. Additionally, the Seebeck coefficient, thermal conductivity, electrical resistivity, and Hall carrier concentration are measured on two samples from each batch from room temperature to 400°C.