Thermoelectric properties of thermoelectric modules consisted of porous FeSi2 based compounds fabricated by pressureless sintering

Single thermoelectric modules, which consist of porous p-type Fe0.9Mn0.1Si2 and n-type Fe0.94Co0.06Si2 compounds prepared by pressureless sintering, were fabricated and their thermoelectric properties were measured. It was found that the rate of the phase transition to β-FeSi2 for the Fe0.94Co0.06Si2 compound was faster than that for the Fe0.9Mn0.1Si2 compound. The power factor of p- and n-type compounds fabricated with coarse powders (<45 μm) was similar to that of p- and n-type compounds fabricated with fine powders (2–3 μm). A high power factor of all the p- and n-type compounds was obtained at 400–500°C. The maximum power of the thermoelectric modules increased with increasing temperature difference and porosity. It is demonstrated that the high maximum power of the module can be obtained with porous p- and n-type compounds fabricated by a pressureless sintering.