Structural features and thermoelectric properties of spark plasma assisted combustion synthesised Magnesium silicide doped with Aluminium

Vivekanandhan, P.; Murugasami, R.; Kumar, Singh Appu; Kumaran, S.

doi:10.1016/j.matchemphys.2019.122407

Cited by 8 publications

(5 citation statements)

References 32 publications

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“…The Al doped material presents broader peaks, which is attributed to the decrease of the crystalline size and the introduced lattice strain; this was caused from the introduction of aluminum and the thermochemical diffusion process. Furthermore, the peak broadening is considered to be affected from crystallite size, while strain broadening is neglected [32], which is in agreement with Al doped materials [33].…”

Section: Samplesupporting

confidence: 67%

Synthesis and Characterization of Al-doped nanostructured Mg2Si and Ag2Se by Pack Cementation and Ball Milling Processes

Stathokostopoulos,

Sidiropoulos,

Karagiannis

et al. 2023

Proceedings of 11th International Conference of the Balkan Physical Union — PoS(BPU11)

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Thermoelectricity is a green method of energy production by converting waste heat into electricity. Silicides and selenides are candidate materials for thermoelectric applications due to their high performance in their operating temperature range. Additionally, they are composed of abundant and negligibly toxic elements. The current study focuses on the fabrication of alternative thermoelectric materials, aiming to develop compounds with advanced thermoelectric properties. Pure Mg 2 Si and Aldoped Mg 2 Si samples are synthesized by Pack Cementation, and Ag 2 Se powder is produced via Ball Milling (BM). The chosen synthesis methods are suggested as environmentally friendly, fast and economic. The samples were structurally characterized by X-ray diffraction (XRD), while the morphology and the chemical composition were studied by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). In the case of magnesium silicide, the thermoelectric phase was formed without residual traces of the initial elemental powders. The Al addition diffused in the material homogeneously and no secondary phases were developed. Regarding the Ag 2 Se powder, α-phase (low temperature) was obtained after 2.5 h of mechanical alloying (BM) the elements. SEM and XPS analysis detected traces of unreacted Ag and Se, indicating that the ball milling process should last longer to achieve a complete reaction between the elements.

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Section: Samplesupporting

confidence: 67%

Synthesis and Characterization of Al-doped nanostructured Mg2Si and Ag2Se by Pack Cementation and Ball Milling Processes

Stathokostopoulos,

Sidiropoulos,

Karagiannis

et al. 2023

Proceedings of 11th International Conference of the Balkan Physical Union — PoS(BPU11)

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“…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

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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.

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“…Moreover, Ag is well-known as a p-type dopant for Mg2(Si,Sn), it is therefore plausible that its diffusion into the n-type material decreases its carrier concentration. On the other hand Al was predicted and shown to be a rather poor dopant in Mg2(Si,Sn) [62][63][64][65][66], with the data focusing on the Si-rich side of the spectrum. In our case of hypothetical uncontrolled Al-doping, the effect on carrier concentration would therefore be expected to be rather weak.…”

Section: Discussionmentioning

confidence: 99%

Aluminum as promising electrode for Mg2(Si,Sn)-based thermoelectric devices

Camut

Pham

Truong

et al. 2021

Materials Today Energy

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Structural features and thermoelectric properties of spark plasma assisted combustion synthesised Magnesium silicide doped with Aluminium

Cited by 8 publications

References 32 publications

Synthesis and Characterization of Al-doped nanostructured Mg2Si and Ag2Se by Pack Cementation and Ball Milling Processes

Synthesis and Characterization of Al-doped nanostructured Mg2Si and Ag2Se by Pack Cementation and Ball Milling Processes

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

Aluminum as promising electrode for Mg2(Si,Sn)-based thermoelectric devices

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