Research On The Transport Properties Of β-FeSi₂ Based Thermoelectric Materials

β-FeSi2 based thermoelectric materials were prepared by melt-spinning(MS), levetation-melting(LM) and mechanical alloyiny(MA). Their thermoelectric properties and the mechanism of (3 phase transition were studied by means of the measurements of transport properties, XRD analysis, SEM observations.On the studying of transport properties of p-FeSi2 based alloys, it was observed that cobalt is a effective n-typed dopant while mangnese benefits to the p-typed alloy. It was found that the p-FeSi2 based alloys with 0.67t.% cobalt for n type or 2.67at.% mangnese for p type have the maximum of power factor.The SmSi2 phase was found in Fei.xSmxSi2. With the increasing of x, Fe1-xSmxSi2 converts into n type from p type and Feo.6Smo.4Si2 alloy has the maximum power factor. As for as the alloys with two metal dopants are concerned, the transport properties are controlled by the total atom number while the element Sm plays more important roll in the decreasing of electrical resistivity.The β-FeSi2 based alloys doped with light elements (N, C) or germanium have high Seebeck coefficients and the power factors, for example, the power factor of alloy Feo.9iCro.o9Sii.6Geo.4 is 10 times as high as p-FeSi2Rapidly solidified β-FeSi2 thermoelectric materials have better transport properties and need shorter annealing time because more finer structure was produced by this way. The alloying of Sm in p-FeSi2 alloys slows down the p phase transformation.