Bi2Te3 compound has proved to possess the greatest figure of merit at 573- 673 K. In this research, it was attempted to synthesis Bi2Te3 thermoelectric specimens through mechanical alloying (MA) followed by spark plasma sintering (SPS). Evaluation of the effects of milling and SPS parameters as well as specimen thickness to achieve the best microstructural and thermoelectric properties was the aim of this research. To synthesis Bi2Te3, Bi and Te powders were mechanically alloyed under an argon atmosphere in a stainless steel vial and ball-to-powder weight ratio of 15:1 for different times. The synthesized powders were sintered using SPS at different temperatures. To characterize the Bi2Te3 powders and bulk samples, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis were carried out. Furthermore, the band gap energy was measured by UV-vis spectra analysis. Moreover, the Seebeck voltage and electrical conductivity were determined at different temperatures. The experimental results illustrated that by enhancing the sintering temperature from 623 to 673 K, the maximum Seebeck coefficient increases from 136 to 156 μV/K. To investigate the effect of thickness, the specimens were sintered at the optimum temperature of 673 K with thicknesses of 1, 1.5, 2, 3 and 4 mm. The results showed that by decreasing thickness, the maximum Seebeck coefficient increases from 144 to 166 μV/K and electrical conductivity increases from 0.35×105 to 1.42×105 S/m and in conclusion, power factor increases from 0.76 to 3.94 mW/m K2.

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