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Mechanical Alloying of Optimized Mg2(Si,Sn) Solid Solutions: Understanding Phase Evolution and Tuning Synthesis Parameters for Thermoelectric Applications

Sankhla, Aryan and Patil, Akash and Kamila, Hasbuna and Yasseri, Mohammad and Farahi, Nader and Müller, Eckhard and de Boor, Johannes (2018) Mechanical Alloying of Optimized Mg2(Si,Sn) Solid Solutions: Understanding Phase Evolution and Tuning Synthesis Parameters for Thermoelectric Applications. ACS Applied Energy Materials. American Chemical Society (ACS). DOI: 10.1021/acsaem.7b00128 ISSN 2574-0962

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Abstract

Mechanical alloying by high energy ball milling is an attractive solid-state technique for synthesizing a diverse range of stable and metastable materials. We have studied the synthesis of n-type thermoelectric Mg2Si0.4Sn0.6 solid solution, aiming for a fundamental understanding of the mechanisms underlying this synthesis technique. The investigations on powders by XRD and SEM show that milling leads to welding of Mg and Sn but fracturing of Si. This fractured Si diffuses into the ductile matrix on longer milling times resulting in a phase mixture close to the nominal starting composition after 35 h of milling. However, phase pure material was only achievable after sintering; hence, the synthesis of Mg2(Si,Sn) is a two-step process. Furthermore, a thorough study on the effect of varying synthesis parameters on the thermoelectric properties was performed. This was done by systematically varying the milling and consolidation parameters. No strong influence of milling time on the thermoelectric properties was observed, and just 2 h of milling followed by compaction was sufficient to obtain a pellet with optimal thermoelectric properties. Moreover, increasing sinter temperature/time deteriorated carrier concentration, hence degrading the electronic properties. Thus, optimized thermoelectric properties were obtained for the powder consolidated at 973 K/20 min. Mg2Si0.4Sn0.6 synthesized by mechanical alloying achieved a thermoelectric figure-of-merit zTmax ∼ 1.4.

Item URL in elib:https://elib.dlr.de/122776/
Document Type:Article
Title:Mechanical Alloying of Optimized Mg2(Si,Sn) Solid Solutions: Understanding Phase Evolution and Tuning Synthesis Parameters for Thermoelectric Applications
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Sankhla, Aryangerman aerospace center, institute of materials research, köln, germanyhttps://orcid.org/0000-0002-1527-6902
Patil, AkashGerman aerospace center, Institute of materials research, Köln, GermanyUNSPECIFIED
Kamila, HasbunaGerman aerospace center, Institute of materials research, Köln, GermanyUNSPECIFIED
Yasseri, MohammadGerman aerospace center, Institute of materials research, Köln, Germany and Justus Liebig university Giessen, Institute of inorganic and analytical chemistry, 35392 Giessen, GermanyUNSPECIFIED
Farahi, NaderGerman aerospace center, Institute of materials research, Köln, GermanyUNSPECIFIED
Müller, EckhardGerman Aerospace Center, Institute of Materials Research, Köln, Germany and Justus Liebig University Giessen, Institute of Inorganic and Analytical Chemistry, 35392 Giessen, GermanyUNSPECIFIED
de Boor, JohannesGerman aerospace center, institute of materials research, köln, germanyhttps://orcid.org/0000-0002-1868-3167
Date:9 January 2018
Journal or Publication Title:ACS Applied Energy Materials
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
DOI :10.1021/acsaem.7b00128
Publisher:American Chemical Society (ACS)
ISSN:2574-0962
Status:Published
Keywords:High energy ball milling, Magnesium silicide stannide, Mechanical alloying, n-type Mg2Si0.4Sn0.6, Phase Formation, Sintering profile optimization, Thermoelectric properties
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Technology
DLR - Research area:Raumfahrt
DLR - Program:R SY - Technik für Raumfahrtsysteme
DLR - Research theme (Project):R - Systemtechnologien
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Research > Thermoelectric Materials and Systems
Deposited By: Yasseri, Mohammad
Deposited On:13 Nov 2018 08:39
Last Modified:31 Jul 2019 20:20

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