[15P-T17-04] A Reduction of Thermal Conductivity through the Reinforcement of Al2O3 Nanofibers into BiSbTe Thermoelectric Alloy
キーワード:BiSbTe, Al2O3, Nanofibers, Water-Atomization, Thermal Conductivity
This study incorporated 6 wt.% Al2O3 nanofibers into p-type BiSbTe (BST) bulk and examined their impact on structural and thermoelectric properties. Additionally, spherical Al2O3 nanoparticles were introduced for comparison. BST powder was initially prepared using the water-atomization technique, and Al2O3/BST composites were fabricated through high-energy ball milling, followed by Spark Plasma Sintering (SPS) to produce bulk specimens. The addition of Al2O3 nanofibers led to reduced grain size in BST, attributed to the pinning effect of Al2O3, suppressing grain growth. The laminar-type microstructure revealed Al2O3 precipitates within BST grains, indicating polycrystallinity. While Al2O3/BST composites exhibited decreased electrical conductivity and Seebeck coefficient compared to pristine BST, the introduction of Al2O3 nanofibers resulted in a maximum reduced thermal conductivity of ~0.85 W m-1K-1 at 350 K. This reduction was attributed to effective phonon scattering via the Al2O3-BST interface, leading to enhanced thermoelectric performance, with a ZTmax of 1 at 350 K for pristine BST.