Preparation of Single-Phase ZnSb Thermoelectric Materials Using a Mechanical Grinding Process

Abstract

Single-phase zinc antimonide (ZnSb) was prepared using a mechanical grinding (MG) process. The ZnSb source ingots were prepared by direct melting of the constituent elements. Two processes were used to prepare the ingots. One of the processes involved quenching the molten material in water in an evacuated quartz ampoule. In the other process, an additional step consisting of heating for 100 h at 723 K was performed after quenching. The ground materials were obtained by mechanically grinding the resultant ingots and then hot-pressing at 673 K. The materials were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), and thermoelectric property measurements. The results indicated that the materials were crack free and single phase. The thermal conductivity of the ground materials was 1.41 Wm -1 K -1 at room temperature. This value was lower than that reported in the available data for materials prepared by conventional melt growth and powder metallurgy methods. The ZnSb single phase was found to have a dimensionless figure of merit of 0.6-0.8 at 573 K.