Mechanical alloying and thermoelectric properties of Co doped FeSi/sub 2/

Mechanical alloying process has been used to produce a Co doped iron-silicide. As-milled powders were of metastable state and fully transformed to /spl beta/-FeSi/sub 2/ phase by subsequent isothermal annealing. Mechanically alloyed powders were successfully consolidated by vacuum hot pressing. As-consolidated iron silicides consisted of untransformed mixture of /spl alpha/-Fe/sub 2/Si/sub 5/ and /spl epsiv/-FeSi phases. Subsequent isothermal annealing at 830/spl deg/C in vacuum led to the thermoelectric semiconducting /spl beta/-FeSi/sub 2/ phase transformation. Fraction /spl beta/-FeSi/sub 2/ increased with annealing time and saturated at 100 hours of annealing. Thermoelectric properties of Co doped iron-silicide after isothermal annealing as a function of temperature were investigated from room temperature to 600 K. Transport properties at room temperature were also evaluated in this study.