Study on the N-type thermoelectric material Bi2Te2.7Se0.3

• Main Authors: Jin-jia Ye, 葉晉嘉
• Other Authors: Ying-chung Chen
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/51305506482197497023

碩士 === 國立中山大學 === 電機工程學系研究所 === 99 === Bismuth telluride based compounds is known to be the best thermoelectric materials within the room temperature regime. In this study, the n-type Bi2Te3-based thermoelectric alloy was synthesized by powder metallurgy method. The Bi2Te2.7Se0.3 thermoelectric materials were prepared via the ball milling, cold pressing, and sintering processes. The effects of sintering time and temperature on the microstructures and thermoelectric properties were investigated and discussed. The X-ray diffraction patterns of Bi2Te2.7Se0.3 reveal that the compounds are single phase after the sintering processes. And the experimental results showed that the pores was reduced by the increased sintering temperature and time. According to the measurement results, the Seebeck coefficient was decreased at firest and then increased by the increased sintering temperature. The optimal Seebeck coefficient of -156.936(μV/K) was obtained as the sample was sintered at 350°C for 3h. The results also showed that the thermal conductivity was increased by the increased sintering temperature, whereas the electrical resistivity was reduced. The lowest thermal conductivity 0.816 (W/m‧K) was obtained as the sample was sintered at 350°C for 1h. On the other hand, the electrical resistivity of 1.6999×10-5(Ω-m) was obtained as the sample was sintered at 450°C for 2h. The figure of merit of 0.31 was obtained at room temperature as the sample was sintered at 375°C for 2h.