Influence of sedimentation of atoms on structural and thermoelectric properties of Bi-Sb alloys

Bi-Sb合金の構造と熱電特性における原子沈降の影響

Januszko, K.*; Stabrawa, A.*; 緒方 裕大; 徳田 誠*; Khandaker, J. I.*; Wojciechowski, K.*; 真下 茂*

Januszko, K.*; Stabrawa, A.*; Ogata, Yudai; Tokuda, Makoto*; Khandaker, J. I.*; Wojciechowski, K.*; Mashimo, Tsutomu*

Functionally graded thermoelectric materials (FGTMs) have been prepared by sedimentation of atoms under a strong gravitational field. Starting samples of BiSb alloys with different composition x were synthesized by melting of metals and subsequent annealing of quenched samples. Strong gravity experiments were performed in a unique ultracentrifuge apparatus under acceleration of over 0.510 G at temperatures of 538 K and 623 K. As a result of sedimentation, large changes in chemical composition (x = 0.45 to 1) were obtained. It was found that the changes in chemical composition were correlated with alterations of the Seebeck coefficient. The obtained experimental data allowed the development of a semiempirical model for the selection of optimal processing parameters for preparation of Bi-Sb alloys with required thermoelectric properties.