Microstructures and thermoelectric properties of Co-doped iron disilicides prepared by rapid solidification and hot pressing

Microstructure and thermoelectric properties of β-FeSi2 ceramics fabricated by hot-pressing and spark plasma sintering

“…4e and f, W1 and W2 regions are ␤-FeSi 2 phase, and W3 region is -FeSi phase. The result is corresponding to the report from Zhao and co-workers [21]. The difference in the microstructures of the HP and SPS samples lies in the densification mechanism [22].…”

“…For the hot-pressed samples, electrical conductivity increases with pressing temperature. This can be explained by the higher densities resulting from high sintering temperature [21], as shown in Fig. 3.…”

Thermoelectric properties of nanostructured FeSi2 prepared by field-activated and pressure-assisted reactive sintering

“…During the transformation of ␣ + → ␤, the stacking faults provide drag resistance and the addition of Cu is likely to decrease the stacking fault energy and enhance the formation rate of the ␤-phase subsequently [7,8]. In the work by Chen et al [2], annealing the powders prior to uniaxial hot-pressing was found to aid in the transformation to the ␤-phase and to the control of grain growth.…”

“…It is a line compound that is stable up to 982 • C where it undergoes eutectoid decomposition to form the metallic-conducting ␣-Fe 2 Si 5 and -FeSi phases. Iron disilicide is of technological interest due to the potential application as thermoelectric and optoelectronic materials [2][3][4][5]. As thermoelectric (TE) material, it is of interest for application in the temperature range of 225-530 • C. In addition to having a relatively high Seebeck coefficient and good oxidation resistance, ␤-FeSi 2 has the advantages of being a non-toxic and environmentally benign material whose constituent elements are abundant and relatively economically attractive.…”

“…Investigations have been made during the past decade to improve the TE properties of the silicide by doping optimization and microstructural modifications [2,[5][6][7][8][9]. Doping of ␤-FeSi 2 with metals, such as Co and Mn to produce n-type and p-type materials, respectively, is aimed at improving the Seebeck coefficient and electrical conductivity [6,9], Desimonia's results indicated that addition of Al improved the stabilization of ␤-FeSi 2 phase and reducing the amount of -FeSi from 20 to 6%.…”