Synthesis of Al-doped Mg2Si1−xSnx compound using magnesium alloy for thermoelectric application

Hu, Xiang; Barnett, Matthew; Yamamoto, Atsushi

doi:10.1016/j.jallcom.2015.07.197

Cited by 16 publications

(8 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The case of Al diffusion into n-type Mg 2 (Si,Sn) was already discussed in a previous work, where no gradient was found after contacting with non-coated Al foils [30], similarly to the first results in this work (see line scans in SI). It also appears that Al is a poor dopant for this material system as shown in [49][50][51][52][53]. It is, therefore, unlikely that the diffusion of Al into the n-type TE material is at the origin of the change in carrier concentration.…”

Section: Discussionmentioning

confidence: 92%

Overcoming Asymmetric Contact Resistances in Al-Contacted Mg2(Si,Sn) Thermoelectric Legs

et al. 2021

View full text Add to dashboard Cite

Thermoelectric generators are a reliable and environmentally friendly source of electrical energy. A crucial step for their development is the maximization of their efficiency. The efficiency of a TEG is inversely related to its electrical contact resistance, which it is therefore essential to minimize. In this paper, we investigate the contacting of an Al electrode on Mg2(Si,Sn) thermoelectric material and find that samples can show highly asymmetric electrical contact resistivities on both sides of a leg (e.g., 10 µΩ·cm2 and 200 µΩ·cm2). Differential contacting experiments allow one to identify the oxide layer on the Al foil as well as the dicing of the pellets into legs are identified as the main origins of this behavior. In order to avoid any oxidation of the foil, a thin layer of Zn is sputtered after etching the Al surface; this method proves itself effective in keeping the contact resistivities of both interfaces equally low (<10 µΩ·cm2) after dicing. A slight gradient is observed in the n-type leg’s Seebeck coefficient after the contacting with the Zn-coated electrode and the role of Zn in this change is confirmed by comparing the experimental results to hybrid-density functional calculations of Zn point defects.

show abstract

Section: Discussionmentioning

confidence: 92%

Overcoming Asymmetric Contact Resistances in Al-Contacted Mg2(Si,Sn) Thermoelectric Legs

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Several attempts to synthesize Mg 2 Si 1-x Sn x by mechanical alloying in the past have resulted in the formation of either multi-phase or impure materials [29][30][31][32][33][34] . Only recently, high energy ball milling combined with a compaction step has been employed successfully to obtain n-type Mg 2 Si as well as n-and p-type Mg 2 (Si,Sn) 19,20,35,36 .…”

Section: Introductionmentioning

confidence: 99%

“…Several attempts to synthesize Mg 2 Si 1– x Sn x by mechanical alloying in the past have resulted in the formation of either multiphase or impure materials. − Only recently, high energy ball milling combined with a compaction step has been employed successfully to obtain n-type Mg 2 Si as well as n- and p-type Mg 2 (Si,Sn). ,,, So, on the basis of the previous reports it is clear that high energy ball milling is an efficient and attractive synthesis route; however, an understanding of Mg 2 Si 1– x Sn x phase formation and its underlying mechanism is still missing. Therefore, a detailed phase formation analysis to comprehend the synthesis mechanism was performed.…”

Section: Introductionmentioning

confidence: 99%

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

Sankhla

Patil

Kamila

et al. 2018

ACS Appl. Energy Mater.

View full text Add to dashboard Cite

Mechanical alloying by high energy ball milling is an attractive solid -state technique for synthesizing a diverse range of equilibrium and non-equilibrium phase materials. We have studied the synthesis of n -type thermoelectric Mg 2 Si 0.4 Sn 0.6 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 35h of milling. However, single phase pure material was only achievable after sintering, hence the synthesis of Mg 2 (Si,Sn) is a two -step process. Furthermore, a thorough study on the effect of varying synthesis parameters on the thermoelectric properties was performed. No strong influence of milling time on the thermoelectric properties was observed and just 2h 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 973K/20minutes. Mg 2 Si 0.4 Sn 0.6 synthesized by mechanical alloying achieved a thermoelectric figure of merit zT max~1 .4.

show abstract

“…Many conventional thermoelectric materials including alloys based on BiSbTe [13,14], PbTe [15,16], PbSe [17], skutterudite (based-on CoSb 3 ) [18], clathrate [19], Zintl [20] and half-Heusler alloys [21][22][23][24][25][26][27][28][29][30] are reported in the literature. Among these materials, recent works showed that Mg 2 X (X = Si, Sn, Ge) materials are potential interesting candidates as n-or p-type thermoelectric semiconductors at mid-temperature (500-800 K), depending on the nature of X [23][24][25][26][27][28][29][30][31]. These compounds are interesting due to their good thermoelectric performance, the abundance of toxic elements, very low thermal conductivity, good thermal and mechanical stability, but also lightweight in its component elements [24,32].…”

Section: Introductionmentioning

confidence: 99%

Influence of Sputtering Parameters on Structural, Electrical and Thermoelectric Properties of Mg–Si Coatings

et al. 2018

View full text Add to dashboard Cite

Mg–Si thin films (23 ≤ at.% Si ≤ 43) were deposited by co-sputtering of Mg and Si targets in an argon atmosphere. Two groups of samples were prepared with respect to sputtering parameters. The first Group I was synthesized while residual pressure in the reactor was lower than 7 × 10−4 Pa and the second Group II when reactor was pumped down to pressure higher than 7 × 10−4 Pa. The Mg2Si phase appeared for all as-deposited films of Group I around the stoichiometric composition region (29 ≤ at.% Si ≤ 37) and in the Mg-rich region (at.% Si < 29) the Mg2Si and Mg phases coexisted. An amorphous structure was obtained for all as-deposited films of Group II no matter their composition (34 ≤ at.% Si ≤ 38) and the Mg2Si structure was achieved after post annealing under air at temperature ≥140 °C. Thermal stability of Mg2Si thin films was investigated by annealing treatments under air. Superficial Mg2Si structural decomposition began at T > 500 °C and layer morphology and structure damaged while annealing temperature increased up to 700 °C. The films’ electrical resistivity, free carrier concentration and mobility as well as Seebeck coefficient were measured and thermoelectric power factors were discussed vs. composition.

show abstract

Synthesis of Al-doped Mg2Si1−xSnx compound using magnesium alloy for thermoelectric application

Cited by 16 publications

References 26 publications

Overcoming Asymmetric Contact Resistances in Al-Contacted Mg2(Si,Sn) Thermoelectric Legs

Overcoming Asymmetric Contact Resistances in Al-Contacted Mg2(Si,Sn) Thermoelectric Legs

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

Influence of Sputtering Parameters on Structural, Electrical and Thermoelectric Properties of Mg–Si Coatings

Contact Info

Product

Resources

About

Synthesis of Al-doped Mg2Si1−xSnx compound using magnesium alloy for thermoelectric application

Cited by 16 publications

References 26 publications

Overcoming Asymmetric Contact Resistances in Al-Contacted Mg2(Si,Sn) Thermoelectric Legs

Overcoming Asymmetric Contact Resistances in Al-Contacted Mg2(Si,Sn) Thermoelectric Legs

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

Influence of Sputtering Parameters on Structural, Electrical and Thermoelectric Properties of Mg–Si Coatings

Contact Info

Product

Resources

About

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