Abstract
	A semiconducting iron disilicide FeSi2 is one of the promising thermoelectric material for the high-temperature thermoelectric generator. The main advantage of using FeSi2 over other thermoelectric materials are that the cost of raw materials are relatively cheaper. Moreover, FeSi2 has good resistance to thermal oxidation in the normal air and is nontoxic. In this research, Fe1-xCoxSi2 alloy (x = 0, 0.01, 0.03, 0.05) in ?-phase were prepared by the mechanical alloying of elemental powder, cold-press and pressureless sintering at 900?C for various times. XRD (X-Ray Diffraction) was employed to identify the structural phase of Fe1xCoxSi2 while Seebeck coefficient and resistance were measured to evaluate the thermoelectric and electrical properties. It was found that 10 minute-sintering enhanced the formation of ?-phase. Sintering for longer time resulted in the disappearance of ?-phase but enhancement of ?-phase and ?-phase instead. The density of all samples was approximately 2.1 g.cm-3 which is 50 % less than that reported in the literature, indicating the presence of voids. The majority carriers in our undoped-FeSi2 was p-type but changed to n-type after doping with cobalt. The resistance of all samples decreased with increasing temperatures which is typical for semiconductor. The room temperature Seebeck coefficient in the  range from 130 to -80 ?V.K-1 was obtained. The highest absolute value of 383 ?V.K-1 was observed at around 250 ?C for undoped-FeSi2. The addition of cobalt reduced the Seebeck coefficient but increased the electrical conductivity. This result is of good sign for the potential use of FeSi2 for the thermoelectric application, especially at high temperatures.