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

Mostafa Oulfarsi; Nicolas David; Lionel Aranda; Ghouti Medjahdi; Hilaire Ihou-Mouko; Anne Dauscher

doi:10.1021/acsami.2c21971

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

ACS Appl Mater Interfaces. 2023 May 10;15(18):22616-22625. doi: 10.1021/acsami.2c21971. Epub 2023 May 1.

Authors

Mostafa Oulfarsi¹, Nicolas David¹, Lionel Aranda¹, Ghouti Medjahdi¹, Hilaire Ihou-Mouko², Anne Dauscher¹

Affiliations

¹ Université de Lorraine, UMR CNRS 7198, Institut Jean Lamour, Nancy 54011, France.
² HOTBLOCK ONBOARD (HBOB), 43 Chemin du Vieux Chêne, Meylan 38240, France.

PMID: 37126574
DOI: 10.1021/acsami.2c21971

Abstract

The use of Mg₂Si_0.6Sn_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 Mg₂Si_0.6Sn_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.

Keywords: SEM; TGA; TXRD; n-type Mg2Si0.6Sn0.4; oxidation mechanisms; thermoelectricity.