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Thermal stability of Mg2Si0.55Sn0.45 for thermoelectric applications

Mejri, Mahdi and Malard, Benoît and Thimont, Yohann and Romanjek, Krunoslav and Ihou Mouko, Hilaire and Estournès, Claude Thermal stability of Mg2Si0.55Sn0.45 for thermoelectric applications. (2020) Journal of Alloys and Compounds, 846. 156413. ISSN 0925-8388

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Official URL: https://doi.org/10.1016/j.jallcom.2020.156413

Abstract

Understanding the thermal stability of the Mg2(Si,Sn) system is essential to define their safe tempera- tures of service. Despite its good thermoelectric performance, Mg2(Si,Sn) is subject to a phase separation during thermal cycling due to the miscibility gap, which leads to a degradation of its thermoelectric properties and affects its performance during device operation. Isothermal annealing at 500 !C and 750 !C were performed with different annealing time to investigate thermal stability of Mg2(Si,Sn). During the heat treatment, two phases were formed associated with porosity in the matrix. In addition, thickness of specimen was tracked and a significant expansion was detected. This phenomenon is attributed to the Kirkendall effect. The composition and the structure of the two forming phases were investigated by electron probe microanalysis and X-ray diffraction. Finally, the optimized thermal treatment allowed to stabilize the Mg2(Si,Sn) without porosity and the presence of two thermody- namically stabilized phase (Mg2Si0.41Sn0.59 and Mg2Si0.58Sn0.42) leading to a better reliability of the silicide thermoelectric modules.

Item Type:Article
HAL Id:hal-03040584
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Commissariat à l'Energie Atomique et aux énergies alternatives - CEA (FRANCE)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Other partners > Université Grenoble Alpes - UGA (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Laboratory name:
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Deposited On:04 Dec 2020 13:09

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