The magnesium silicides (Mg2Si) based alloys are promising candidates for thermoelectric (TE) energy conversion for the middle-high range of temperature. These materials are very attractive for TE research because of the abundance of their constituent elements in the earth's crust. Mg2Si could replace lead-based TE materials, due to their low cost, non-toxicity [1, 2] and low density. In this work the role of several aluminum doping amounts (0.5 at%, 1 at%, 2 at% and 4 at%) in nanostructured dense Mg2Si materials was investigated. The synthesis process was performed by a planetary mill under inert atmosphere starting from commercial Mg2Si pieces and Al powder. After ball milling, the bulk samples were consolidated by means of Spark Plasma Sintering with density more than 90%. The morphology, composition and crystal structure of the samples were characterized by FE-SEM, EDS and XRD analyses. Moreover, the Seebeck coefficient analyses and the electrical and thermal conductivity measurements were performed for all samples up to 600 °C. The estimated ZT values resulted comparable with those reported in literature for these materials [3, 4], in particular the maximum ZT achieved was 0.42 for 2 at% Al doped sample at 600 °C.
Synthesis and characterization of Al-doped Mg2Si thermoelectric materials
S Fiameni;S Boldrini;S Battiston;A Famengo;F Agresti;M Fabrizio;S Barison
2012
Abstract
The magnesium silicides (Mg2Si) based alloys are promising candidates for thermoelectric (TE) energy conversion for the middle-high range of temperature. These materials are very attractive for TE research because of the abundance of their constituent elements in the earth's crust. Mg2Si could replace lead-based TE materials, due to their low cost, non-toxicity [1, 2] and low density. In this work the role of several aluminum doping amounts (0.5 at%, 1 at%, 2 at% and 4 at%) in nanostructured dense Mg2Si materials was investigated. The synthesis process was performed by a planetary mill under inert atmosphere starting from commercial Mg2Si pieces and Al powder. After ball milling, the bulk samples were consolidated by means of Spark Plasma Sintering with density more than 90%. The morphology, composition and crystal structure of the samples were characterized by FE-SEM, EDS and XRD analyses. Moreover, the Seebeck coefficient analyses and the electrical and thermal conductivity measurements were performed for all samples up to 600 °C. The estimated ZT values resulted comparable with those reported in literature for these materials [3, 4], in particular the maximum ZT achieved was 0.42 for 2 at% Al doped sample at 600 °C.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
