Impact of the Dopant Species on the Thermomechanical Material Properties of Thermoelectric Mg<sub>2</sub>Si<sub>0.3</sub>Sn<sub>0.7</sub>

Thermoelectric generators are an excellent option for waste heat reuse. Materials for such devices have seen their thermoelectric properties improving constantly. The functioning of a generator, however, does not only depend on thermoelectric properties. Thermal and mechanical properties play a deci...

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Main Authors: Gustavo Castillo-Hernández, Eckhard Müller, Johannes de Boor
Format: Article
Language:English
Published: MDPI AG 2022-01-01
Series:Materials
Subjects:
Online Access:https://www.mdpi.com/1996-1944/15/3/779
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author Gustavo Castillo-Hernández
Eckhard Müller
Johannes de Boor
author_facet Gustavo Castillo-Hernández
Eckhard Müller
Johannes de Boor
author_sort Gustavo Castillo-Hernández
collection DOAJ
description Thermoelectric generators are an excellent option for waste heat reuse. Materials for such devices have seen their thermoelectric properties improving constantly. The functioning of a generator, however, does not only depend on thermoelectric properties. Thermal and mechanical properties play a decisive role in the feasibility of any thermoelectric generator. To shed light on the properties exhibited by thermoelectric materials, we present the temperature dependent characterization of Young’s modulus and coefficient of thermal expansion for Mg<sub>2</sub>Si<sub>0.3</sub>Sn<sub>0.7</sub>. Comparing undoped to Bi-doped n-type and Li-doped p-type material, we investigated the influence of doping in the relevant temperature regime and found the influences to be minor, proving similar properties for n- and p-type. We found a Young’s modulus of 84 GPa for the p-type and 83 GPa for the n-type, similar to that of the undoped compound with 85 GPa. The thermal expansion coefficients of undoped, as well as n- and p-type were equally similar with values ranging from 16.5 to 17.5 × 10<sup>−6</sup> 1/K. A phase analysis was performed to further compare the two materials, finding a similar phase distribution and microstructure. Finally, using the gathered data, estimations on the possible thermally induced stresses under a temperature difference are provided to evaluate the relevance of knowing temperature dependent thermal and mechanical properties.
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spelling doaj.art-856cefaa9c9c4ff794f6110804362f372023-11-23T16:57:00ZengMDPI AGMaterials1996-19442022-01-0115377910.3390/ma15030779Impact of the Dopant Species on the Thermomechanical Material Properties of Thermoelectric Mg<sub>2</sub>Si<sub>0.3</sub>Sn<sub>0.7</sub>Gustavo Castillo-Hernández0Eckhard Müller1Johannes de Boor2Institute of Materials Research, German Aerospace Center, 51170 Cologne, GermanyInstitute of Materials Research, German Aerospace Center, 51170 Cologne, GermanyInstitute of Materials Research, German Aerospace Center, 51170 Cologne, GermanyThermoelectric generators are an excellent option for waste heat reuse. Materials for such devices have seen their thermoelectric properties improving constantly. The functioning of a generator, however, does not only depend on thermoelectric properties. Thermal and mechanical properties play a decisive role in the feasibility of any thermoelectric generator. To shed light on the properties exhibited by thermoelectric materials, we present the temperature dependent characterization of Young’s modulus and coefficient of thermal expansion for Mg<sub>2</sub>Si<sub>0.3</sub>Sn<sub>0.7</sub>. Comparing undoped to Bi-doped n-type and Li-doped p-type material, we investigated the influence of doping in the relevant temperature regime and found the influences to be minor, proving similar properties for n- and p-type. We found a Young’s modulus of 84 GPa for the p-type and 83 GPa for the n-type, similar to that of the undoped compound with 85 GPa. The thermal expansion coefficients of undoped, as well as n- and p-type were equally similar with values ranging from 16.5 to 17.5 × 10<sup>−6</sup> 1/K. A phase analysis was performed to further compare the two materials, finding a similar phase distribution and microstructure. Finally, using the gathered data, estimations on the possible thermally induced stresses under a temperature difference are provided to evaluate the relevance of knowing temperature dependent thermal and mechanical properties.https://www.mdpi.com/1996-1944/15/3/779mechanical propertiesthermoelectricMg<sub>2</sub>SiMg<sub>2</sub>Snthermal expansion
spellingShingle Gustavo Castillo-Hernández
Eckhard Müller
Johannes de Boor
Impact of the Dopant Species on the Thermomechanical Material Properties of Thermoelectric Mg<sub>2</sub>Si<sub>0.3</sub>Sn<sub>0.7</sub>
Materials
mechanical properties
thermoelectric
Mg<sub>2</sub>Si
Mg<sub>2</sub>Sn
thermal expansion
title Impact of the Dopant Species on the Thermomechanical Material Properties of Thermoelectric Mg<sub>2</sub>Si<sub>0.3</sub>Sn<sub>0.7</sub>
title_full Impact of the Dopant Species on the Thermomechanical Material Properties of Thermoelectric Mg<sub>2</sub>Si<sub>0.3</sub>Sn<sub>0.7</sub>
title_fullStr Impact of the Dopant Species on the Thermomechanical Material Properties of Thermoelectric Mg<sub>2</sub>Si<sub>0.3</sub>Sn<sub>0.7</sub>
title_full_unstemmed Impact of the Dopant Species on the Thermomechanical Material Properties of Thermoelectric Mg<sub>2</sub>Si<sub>0.3</sub>Sn<sub>0.7</sub>
title_short Impact of the Dopant Species on the Thermomechanical Material Properties of Thermoelectric Mg<sub>2</sub>Si<sub>0.3</sub>Sn<sub>0.7</sub>
title_sort impact of the dopant species on the thermomechanical material properties of thermoelectric mg sub 2 sub si sub 0 3 sub sn sub 0 7 sub
topic mechanical properties
thermoelectric
Mg<sub>2</sub>Si
Mg<sub>2</sub>Sn
thermal expansion
url https://www.mdpi.com/1996-1944/15/3/779
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AT eckhardmuller impactofthedopantspeciesonthethermomechanicalmaterialpropertiesofthermoelectricmgsub2subsisub03subsnsub07sub
AT johannesdeboor impactofthedopantspeciesonthethermomechanicalmaterialpropertiesofthermoelectricmgsub2subsisub03subsnsub07sub