Thermoelectric Properties of Ca-Mg-Si Alloys

Abstract

To improve thermoelectric performance of p-type, Ca-Mg-Si alloys were synthesized by mechanical alloying (MA) and/or solid-liquid reaction (SLR phase, and its was metallic trend ( ' 0) with low electrical resistivity . It is well-known that Mg 2 Si is n-type semiconductor. These results indicate that the CaMgSi is p-type. Its was estimated at 750$900 mVÁK À1 (p-type) at 600 K and its was lower than that of Mg 2 Si above 600 K. The P of CaMgSi single phase is expected more than 1:4 Â 10 À3 WÁm À1 ÁK À2 (600 K). Thus, CaMgSi is attractive material with high thermoelectric performance of p-type.

Quantitative analysis of interstitial Mg in Mg2Si studied by single crystal X-ray diffraction

“…Magnesium silicide (Mg 2 Si) has attracted much attention as one of the promising thermoelectric materials due to the lightweight property and high natural abundance [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Mg 2 Si belongs to the anti-fluorite type structure wherein the 8c (1/4 1/4 1/4) and the 4a (0 0 0) sites are occupied by Mg and Si, respectively [19].…”

Conducting grain boundaries enhancing thermoelectric performance in doped Mg2Si

“…Along these perspectives, doped Mg 2 Si-based systems are promising thermoelectric materials and thus have been extensively studied. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] An added advantage of Mg 2 Si-based thermoelectric materials is the possibility of producing compatible n & p-type thermoelectric elements by suitable doping for thermoelectric devices operating in the intermediate temperature range. An enhanced ZT greater than unity has been accomplished in Mg 2 Si when simultaneously alloyed with Sn with small levels of Sb doping which serves as electron donors.…”

“…An enhanced ZT greater than unity has been accomplished in Mg 2 Si when simultaneously alloyed with Sn with small levels of Sb doping which serves as electron donors. Although undoped Mg 2 Si exhibits a small ZT ('0.1), a trace amount of doping with alkali and alkaline-earth elements, 10,11 transition metals, 5,7,8 rare-earth elements, 6,10 and nano-inclusions 17 trigger the materials ZT significantly, with major contribution due to a substantial increase in material's electrical conductivity (r), despite that one observes a moderate decrease in the Seebeck coefficient (a) and thermal conductivity (j), in all these cases.…”

High-throughput heterodyne thermoreflectance: Application to thermal conductivity measurements of a Fe–Si–Ge thin film alloy library

“…[17][18][19][20] In addition, their abundance and low average costs make them excellent thermoelectric candidates. However, due to the complexity of the ternary materials, a wide range of compositions have to be studied to find optimal compositions that would maximize the thermoelectric figure of merit.…”