High temperature thermoelectric properties evolution of Pb1-xSnxTe based alloys
High temperature thermoelectric properties evolution of Pb1-xSnxTe based alloys
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DOI：
10.1016/j.jallcom.2017.06.075
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发表时间：
2017-10-25
影响因子：
6.2
通讯作者：
Gelbstein, Yaniv
中科院分区：
文献类型：
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作者：
Ben-Ayoun, Dana;Sadia, Yatir;Gelbstein, Yaniv
在诸如热电（TE）转换器的热力发动机中，需要通过应用大的温差来最大化卡诺效率，以最大化热能到电能的转换。这一要求是尽可能最大化TE转换器热端温度的关键因素。然而，实际的稳定性考虑，如挥发性物质的升华，构成许多目前可用的TE材料，限制热侧温度到一定的水平，这取决于具体的组成。已知基于Pb 1-xSnxTe的TE组合物在高达约500摄氏度的温度下高效且稳定。为了更好地理解这种组合物的降解机制，目前的研究集中在热压后在520摄氏度的稍高温度下长达900小时的加速降解研究。据发现，在这类TE材料中，除了已经报道的perferial表面升华之外，挥发性物质从晶界的升华也是明显的，使TE品质因数ZT降低高达44%。这种性能下降的机制进行了详细讨论。此外，ZT增强高达40%，目前正在报道使用热压合成，而不是以前报道的冷压和烧结。(C)2017爱思唯尔B. V.保留所有权利。
In thermodynamic engines, such as thermoelectric (TE) converters, maximizing the Carnot efficiency, by applying large temperature differences, is required for maximizing the heat to electricity energy conversion. This requirement is a key factor for the desire to maximize the hot side temperature of TE converters as much as possible. Yet, practical stability considerations, such as sublimation of volatile species, composing many of the currently available TE materials, limit the hot side temperature to a certain level, depending on the specific composition. Pb1-xSnxTe based TE compositions are known as highly efficient and stable up to a temperature of around 500 degrees C. For a better understanding of the degradation mechanisms in such compositions, the current research is focused on accelerated degradation studies at a slightly higher temperature of 520 degrees C for periods of up to 900 h, following hot pressing. It was found that in this class of TE materials, besides of the already reported perferial surface sublimation, sublimation of volatile species from grain boundaries is also apparent, degrading the TE figure of merit, ZT, by up to 44%. The mechanisms for this performance degradation are discussed in details. Furthermore, ZT enhancement of up to 40% is currently being reported by using hot-pressing synthesis rather than the previously reported cold pressing and sintering. (C) 2017 Elsevier B.V. All rights reserved.