[T17] Composite/Hybrid Materials

[15P-T17-04] A Reduction of Thermal Conductivity through the Reinforcement of Al2O3 Nanofibers into BiSbTe Thermoelectric Alloy

*J. Ha¹, R. Vasudevan¹, E. Go¹ , S. Hong¹ (1.Kongju National University, Korea)

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.