Thermal Stability Study from Room Temperature to 1273 K (1000 °C) in Magnesium Silicide

Stefanaki, E. C.; Hatzikraniotis, Euripides; Vourlias, G.; Chrissafis, K.; Kitis, G.; Paraskevopoulos, K. M.; Polymeris, George S.

doi:10.1007/s11661-016-3682-5

Cited by 10 publications

(4 citation statements)

References 77 publications

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“…Since MgO and SnO 2 have the lowest enthalpies of formation (Δ H f ° ) in Mg 2 Si 0.6 Sn 0.4 , a higher driving force for the oxidation of Mg and Sn at 500 °C is provided. This is confirmed by the XRD results of the sample showing the presence of MgO, SnO 2 , SnO, Sn, and no oxidation of Si (Figure ) after decomposition in air at 500 °C, which is also consistent with data from the literature on the oxidation of Mg 2 Si − and other Mg alloys . This is also consistent with the thermogravimetric studies presented in Figure c, where a significant increase in sample mass of Mg 2 Si 0.4 Sn 0.6 at 500 °C was noted.…”

Section: Resultssupporting

confidence: 91%

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Thermal Stability of Mg₂Si_0.6Sn_0.4 under Oxidation Conditions

Oulfarsi

Nugent

Aranda

et al. 2023

ACS Appl. Mater. Interfaces

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The use of Mg 2 Si 0.6 Sn 0.4 under air in thermoelectric modules in the mid-temperature range of 400−600 °C is linked to its ability to resist oxidation. In this study, oxidation experiments performed at 400 °C under air evidenced the stability of the material, either under static conditions (up to 100 h) or under severe heating-cooling cyclic conditions (up to 400 cycles), showing its ability to be used in a reliable way at this temperature. By combining thermogravimetry, scanning electron microscopy, temperature X-ray diffraction analysis, and mechanical and thermodynamic considerations, a mechanism is proposed explaining how Mg 2 Si 0.6 Sn 0.4 further undergoes decomposition with time under air when treated above 500 °C. The presence of Sn and the formation of various oxides are the key parameters of the material's degradation.

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Section: Resultssupporting

confidence: 91%

“…Several groups have studied the oxidation behavior of Mg 2 Si/Mg 2 Sn alloys by thermogravimetry analysis (TGA), scanning electron microscopy (SEM) analysis, and/or X-ray diffraction (XRD) monitoring. − …”

Section: Introductionmentioning

confidence: 99%

Thermal Stability of Mg₂Si_0.6Sn_0.4 under Oxidation Conditions

Oulfarsi

Nugent

Aranda

et al. 2023

ACS Appl. Mater. Interfaces

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“…The sample exhibited only clear Bragg peaks from the face‐centered cubic (fcc) antiflourite structure with the space group Fm3m. Throughout all three aforementioned synthesis stages, a weak diffraction peak at 2θ ≈ 43° represents a small amount of MgO impurity. This is a common impurity for all Mg 2 Si‐based materials, as Mg is volatile and highly reactive to residual oxygen at high temperatures via the oxidation process of every type of Mg 2 Si‐based compounds . The amount of MgO is more or less the same after the two heating stages, but a small increase is monitored on the powdered samples of the sintered pellets.…”

Section: Resultsmentioning

confidence: 99%

Thermoelectric Properties of Bi‐Doped Mg₂Si_0.6Sn_0.4 Solid Solutions Synthesized by Two‐Step Low Temperature Reaction Combined with Hot Pressing

Polymeris¹,

Vlachos²,

Symeou³

et al. 2018

Physica Status Solidi (a)

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The goal of this study is to investigate the influence of the amount of Bi doping on the microstructure and thermoelectric properties of the Mg 2 Si 0.60 Sn 0.4 material studied by X-ray diffraction, scanning electron microscopy, and thermoelectric measurements. The results of the present study provide strong evidence for the presence of a number of secondary phases with different stoichiometries, including Si-rich and Sn-rich phases, besides the main matrix and the MgO. Phase separation could be attributed to preferential occupancy of the dopant (bismuth in the present case) on tin sites in the lattice, leading to segregated darker regions that are observed in the SEM micrographs, which arose as a result of nondiffusion of Si in the matrix. The electron concentration increases with increasing Bi concentration, similar with Sb. The optimum amount of Bi seems to correspond to Mg 2 Si 0.57 Sn 0.4 Bi 0.03 with maximum dimensionless figure of merit of %1.2 at 850 K, arising from a high power factor 36 mW cm À1 K À2 and a low lattice thermal conductivity of %1.5 W m À1 K À1 . These materials exhibit a high thermoelectric figure of merit, which is one of the best among all reported Mg 2 Si 1Àx Sn x compounds on the Si-rich side.

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“…A long reaction time may also risk the decomposition of Mg 2 Si into Mg and Si. 30,31 Influence of the reaction temperature…”

Section: Influence Of the Reaction Timementioning

confidence: 99%

Monolithic porous magnesium silicide

et al. 2017

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a Macroporous magnesium silicide monoliths were successfully prepared by a two-step synthesis procedure. The reaction of gaseous magnesium vapor with macro-/mesoporous silicon, which was generated from hierarchically organized meso-/macroporous silica by a magnesiothermic reduction reaction, resulted in monolithic magnesium silicide with a cellular, open macroporous structure. By adjusting the reaction conditions, such as experimental set-up, temperature and time, challenges namely loss of porosity or phase purity of Mg 2 Si were addressed and monolithic magnesium silicide with a cellular network builtup was obtained.

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Thermal Stability Study from Room Temperature to 1273 K (1000 °C) in Magnesium Silicide

Cited by 10 publications

References 77 publications

Thermal Stability of Mg₂Si_0.6Sn_0.4 under Oxidation Conditions

Thermal Stability of Mg₂Si_0.6Sn_0.4 under Oxidation Conditions

Thermoelectric Properties of Bi‐Doped Mg₂Si_0.6Sn_0.4 Solid Solutions Synthesized by Two‐Step Low Temperature Reaction Combined with Hot Pressing

Monolithic porous magnesium silicide

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Thermal Stability Study from Room Temperature to 1273 K (1000 °C) in Magnesium Silicide

Cited by 10 publications

References 77 publications

Thermal Stability of Mg2Si0.6Sn0.4 under Oxidation Conditions

Thermal Stability of Mg2Si0.6Sn0.4 under Oxidation Conditions

Thermoelectric Properties of Bi‐Doped Mg2Si0.6Sn0.4 Solid Solutions Synthesized by Two‐Step Low Temperature Reaction Combined with Hot Pressing

Monolithic porous magnesium silicide

Contact Info

Product

Resources

About

Thermal Stability of Mg₂Si_0.6Sn_0.4 under Oxidation Conditions

Thermal Stability of Mg₂Si_0.6Sn_0.4 under Oxidation Conditions

Thermoelectric Properties of Bi‐Doped Mg₂Si_0.6Sn_0.4 Solid Solutions Synthesized by Two‐Step Low Temperature Reaction Combined with Hot Pressing