Thermoelectric properties of BiSb_x (x=0.6-0.8) thermoelectric materials fabricated by different processing

摘要

In order to improve the thermoelectric properties, hot-pressing sintering and ultra high pressure sintering methods were adopted to fabricate BiSb_x. The phase and crystal structures were determined by X-ray diffraction analysis (XRD). The thermoelectric properties were measured at 303 K along the direction parallel to the pressing direction. The electric conductivity of the samples was measured at 303 K by the four-probe technique. To measure the Seebeck coefficient, heat was applied to the samples placed between two Cu discs. The thermoelectric electromotive force (E) was measured upon applying small temperature differences (ΔT < 2℃) between the both ends of the samples. The Seebeck coefficient of the samples was determined from the value of E/ΔT. The results indicate that the thermoelectric properties of the samples fabricated by UHPS (ultra high pressure sintering) method are much higher than that by HPS (hot pressing sintering) method and have the highest values at x=0.7.