摘要

p-Type Pr (z) Fe4- (x) Co (x) Sb-12 (z = 0.8, 1.0 and x = 0, 0.5, 1.0) skutterudites were synthesized by encapsulated melting and annealing and were consolidated with hot pressing. The effects of Pr filling and Co substitution for Fe (charge compensation) on the transport and the thermoelectric properties were examined. A few secondary phases, such as Sb and FeSb2, were formed together with the skutterudite phase, but the formation was suppressed with increasing Pr and Co contents. We confirmed that Pr filled in the voids and that Co was substituted for Fe in all specimens because the lattice constant increased with increasing Pr content and decreased with increasing Co content. The electrical conductivity decreased slightly with increasing temperature, showing degenerate semiconductor characteristics. The Hall and the Seebeck coefficients showed positive signs, indicating that the major carriers were holes (p-type conduction). The electrical conductivity and the thermal conductivity were decreased due to a decrease in the carrier concentration with increasing Pr and Co contents. As a result, the dimensionless figure of merit, ZT, was improved by Pr filling and Co substitution, and a maximum ZT = 0.89 was obtained at 723 K for Pr0.8Fe3CoSb12.

  • 出版日期2014-12