Mechanical alloyingand thermoelectric properties of the Co doped FeSi₂

Soon-Chul Ur

Nano Technology Laboratory, Dept. ofMaterials Science and Engineering, Chungju National University, Chungju,Chungbuk, 380-702, Korea

Mechanical alloying process has been used to produce a Co doped iron-silicide.As-milled powders were of metastable state and fully transformed to b- FeSi₂ phase by subsequent isothermal annealing. Mechanicallyalloyed powders were successfully consolidated by vacuum hot pressing.As-consolidated iron silicides consisted of untransformed mixture of Fe₂Si₅and FeSi phases. Subsequent isothermal annealing at 830K in vacuum led to thethermoelectric semiconducting b -FeSi₂ phasetransformation. Fraction b -FeSi₂increased with annealing time and saturated at 100 hours of annealing.Thermoelectric properties of Co doped iron-silicide after isothermal annealingas a function of temperature were investigated from room temperature to 600 K.Transport properties at room temperature were also evaluated in this study.