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Solid solution formation in Mg2(Si,Sn) and shape of the miscibility gap

Yasseri, Mohammad and Sankhla, Aryan and Kamila, Hasbuna and Orenstein, Rachel and Truong, Dao Y Nhi and Farahi, Nader and de Boor, Johannes and Müller, Eckhard (2020) Solid solution formation in Mg2(Si,Sn) and shape of the miscibility gap. Acta Materialia. Elsevier. doi: 10.1016/j.actamat.2019.11.054. ISSN 1359-6454.

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Abstract

Investigation of the thermochemical stability of Mg2(Si,Sn) thermoelectric materials is crucial for further development of thermoelectric modules. There is a miscibility gap reported for the quasibinary Mg2Si–Mg2Sn series, though the exact compositions of its limits are disputed. Gaining a better understanding of intersolubility limits in Mg2(Si,Sn) is important for further optimization of material performance by exploiting the gap-induced phase segregation. For a better understanding on the boundaries of the miscibility gap below 700 °C, two approaches were taken to provide evidence of thermodynamic stable phases and, hereby, monitor the borders of the miscibility gap. The approaches cover the homogenization of Mg2SixSn1-x at 700 °C and diffusion couple experiments at 600 °C, 525 °C, and 450 °C. For 600 °C we find two ranges where Mg2Si and Mg2Sn are not miscible, namely x = 0.35 ± 0.05 and x = 0.75 ± 0.05 for miscibility gap I and 0.85 ± 0.05 < x < 0.95 ± 0.05 for the second gap. The deduced complex temperature dependence of the mixing / demixing behavior helps to understand the previously observed, apparently contradicting experimental results. We also show that there is no demixing for the compositions with the best thermoelectric properties at temperatures above 700 °C.

Item URL in elib:https://elib.dlr.de/135082/
Document Type:Article
Title:Solid solution formation in Mg2(Si,Sn) and shape of the miscibility gap
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Yasseri, MohammadGerman aerospace center, Institute of materials research, Köln, Germany and Justus Liebig university Giessen, Institute of inorganic and analytical chemistry, 35392 Giessen, GermanyUNSPECIFIED
Sankhla, Aryangerman aerospace center, institute of materials research, köln, germanyhttps://orcid.org/0000-0002-1527-6902
Kamila, HasbunaGerman aerospace center, Institute of materials research, Köln, GermanyUNSPECIFIED
Orenstein, RachelGerman aerospace center, Institute of materials research, Köln, Germany and Justus Liebig university Giessen, Institute of inorganic and analytical chemistry, 35392 Giessen, GermanyUNSPECIFIED
Truong, Dao Y NhiGerman Aerospace Center, Institute of Materials Research, Köln, GermanyUNSPECIFIED
Farahi, NaderGerman aerospace center, Institute of materials research, Köln, GermanyUNSPECIFIED
de Boor, Johannesgerman aerospace center, institute of materials research, köln, germanyhttps://orcid.org/0000-0002-1868-3167
Müller, EckhardGerman Aerospace Center, Institute of Materials Research, Köln, Germany and Institute for Inorganic and Analytical Chemistry, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 58, 35392 Gießen, GermanyUNSPECIFIED
Date:15 February 2020
Journal or Publication Title:Acta Materialia
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
DOI :10.1016/j.actamat.2019.11.054
Publisher:Elsevier
ISSN:1359-6454
Status:Published
Keywords:Magnesium tin silicide, Thermoelectric, Miscibility gap, Solubility limit, Interdiffusion
HGF - Research field:Energy
HGF - Program:Storage and Cross-linked Infrastructures
HGF - Program Themes:Thermal Energy Storage
DLR - Research area:Energy
DLR - Program:E SP - Energy Storage
DLR - Research theme (Project):E - Thermochemical Processes (Storage) (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Research > Thermoelectric Materials and Systems
Deposited By: Yasseri, Mohammad
Deposited On:19 Oct 2020 09:44
Last Modified:15 Feb 2021 03:00

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