Dependence of the thermoelectric properties of CeFe$_{3.5}$Co$_{0.5}$Sb$_{12}$ on the parameters of mechanochemical synthesis and spark plasma sintering

$p$-type skutterudite of CeFe$_{3.5}$Co$_{0.5}$Sb$_{12}$ nominal composition was prepared by mechanochemical synthesis and spark plasma sintering. Compared to traditional synthesis methods, the proposed approach makes it possible to reduce the time for preparation of skutterudite thermoelectrics by more than an order of magnitude. By varying both the grinding time and the sintering temperature, it was possible to reduce the amount of secondary phases FeSb$_2$ and Sb, the presence of which has a negative effect on the Seebeck coefficient in particular and on the thermoelectric figure of merit in general. The highest value of thermoelectric figure of merit, $zT$ = 0.4 at 773 K, demonstrated the sample obtained after 30 minutes of grinding and sintered at 798 K.