メカニカルグラインディング法による単相 β-Zn4Sb3 熱電材料の作製

Abstract

Single phase β-Zn4Sb3 was prepared by mechanical grinding (MG). Source materials for the Zn4Sb3 ingots were prepared using three different processes after the direct melting of constituent elements. The ingot was obtained by quenching the melt in water within an evacuated quartz ampoule and heat-treated for a total of 200 h in two stages at 723 K and 673 K. The resultant ingots were mechanically ground and sintered at 623 K by hot pressing. The sintered materials were obtained as crack-free single phase β-Zn4Sb3 and characterized by X-ray diffraction, differential thermal analysis (DTA) and thermoelectric property measurements. The thermal conductivity of the sintered materials was 0.88 Wm−1 K−1 at room temperature and this value was slightly lower than that reported for the materials prepared by a conventional powder metallurgy method. Results indicate that the β-Zn4Sb3 single phase of the dimensionless figure of merit ranged from 1.06-1.31 at 573 K.