The thermoelectric properties of icosahedral Al–Pd–Ru quasicrystals were systematically investigated. A relatively wide single-phase region of the icosahedral phase was identified at 1273 K. Bulk samples were prepared by arc-melting, followed by annealing and spark plasma sintering. The thermoelectric properties, including the Seebeck coefficient, electrical conductivity, and thermal conductivity, were measured from room temperature to 873 K. All samples exhibited p-type conduction with a non-metallic temperature dependence of σ. A subsequent annealing after the SPS process was found to significantly enhance Seebeck coefficient, reaching a high value of approximately 110 µV K-1, while maintaining a relatively high electrical conductivity. This resulted in a large power factor of 780 µW m-1 K-2 at 573 K. Combined with a low thermal conductivity of 1.2 W m-1 K-1, a maximum dimensionless figure of merit of 0.24 was achieved at 573 K, which is one of the highest values reported for undoped quasicrystals. This study demonstrates the high potential of Al–Pd–Ru quasicrystals as p-type thermoelectric materials.
Iwasaki et al. (Thu,) studied this question.