Properties of HPT-Processed Large Bulks of p-Type Skutterudite DD_0.7Fe₃CoSb₁₂ with ZT > 1.3

The influence of shear strain on the microstructural, physical, and mechanical properties was studied large bulk samples (diameter: 30 mm, thickness: 1 or 8 mm), which were consolidated by high-pressure torsion (HPT) from a commercial powder DD0.7Fe3CoSb12. Particularly, thick sample (mass �53 g) allowed measuring thermoelectric (TE) with respect to various orientations specimen in sample. All data compared those hot-pressed (HP) reference sample, prepared same powder. Transmission electron microscopy, as well X-ray diffraction profile analyses, Hall measurements, positron annihilation spectroscopy, supported these investigations. Furthermore, synchrotron for temperature range 300 825 K used evaluate changes grain size dislocation density thermal expansion coefficient via change lattice parameter during heating. In addition, hardness direct measurements HPT performed HP sample's values. With increase center rim electrical resistivity becomes higher, whereas conductivity lower, but Seebeck remained almost unchanged. For thin samples, enhanced balanced out decreased such that maximum ZT values (ZT = 1.3-1.35 at 856 K) do not vary much function throughout however, all ZTs are higher than thermal-electric conversion efficiencies 14-15 (for 423-823 K). similar high n-type skutterudites, fabricated fast sustainable way, p- skutterudites may serve legs TE generators, directly cut big bulks. ©