不同球粉比對Bi_(0.4)Sb_(1.6)Te_3燒結合金微觀結構與熱電性質之影響

Effect of Different Ball to Powder Ratio on the Microstructures and Thermoelectric Properties of Bi_(0.4)Sb_(1.6)Te_3 Sintered Alloys

10.30041/CQ.201411_(87).0003

葉建弦(Chien-Hsuan Yeh)；林育立(Yu-Li Lin)；陳嬿如(Yan-Ru Chen)

碲化鉍銻 ； 球粉比 ； 熱傳導率 ； 微觀結構 ； 熱電性質 ； bismuth antimony telluride ； ball to powder ratio ； thermal conductivity ； microstructures ； thermoelectric properties

燃燒季刊

87期（2014 / 11 / 01）

13 - 25

繁體中文

碲化鉍銻(Bi_xSb_(2-x)Te_3)合金具有良好的導電性及低熱傳導率，為目前低溫（室溫~500K）區間最佳熱電轉換性能的熱電材料。本研究利用高溫熔煉、行星式球磨以及火花電漿燒結製程製作奈米結構Bi_(0.4)Sb_(1.6)Te_3合金。實驗中藉由改變球磨時的磨球與合金粉體比例，探討粉體不同細化程度對燒結合金微觀結構與熱電性質之影響。由相鑑定結果得知，經由球磨及燒結後所得塊材樣品是以Bi_xSb_(2-x)Te_3單一結晶相為主，並且呈現緻密層狀結構。熱電性質量測結果顯示導電率隨球粉比例增加而降低，而Seebeck係數則隨之增加。合金結構由於存在奈米析出物及微小空洞，有助於降低熱傳導率至1.00 W/m．K。綜合功率因子與熱傳導率結果，高球粉比例條件下所製備的Bi_(0.4)Sb_(1.6)Te_3合金在350K可獲得最高ZT值為1.19。

Bismuth antimony telluride (Bi_xSb_(2-x)Te_3) is the low temperature thermoelectric material with the excellent thermoelectric properties because of high electrical conductivity and low thermal conductivity. Alloy melting, ball milling and spark plasma sintering were used to prepare the nanostructure Bi_(0.4)Sb_(1.6)Te_3 thermoelectric materials in this study. Effect of the ball to powder ratio on the microstructures and thermoelectric properties of Bi_(0.4)Sb_(1.6)Te_3 alloys were investigated at temperature from 300 K to 500 K. The XRD results show the phase structure of all sintered alloys was the Bi_xSb_(2-x)Te_3 single phase and no second phase was observed. The sintered alloys exhibited the considerably dense structure with the fine laminar grains. The electrical conductivity decreased and Seebeck coefficient increased with the ball to powder ratio. The low thermal conductivity was about 1.00 W/m-K resulted from the nano-precipitations and small holes inside the microstructure. As the results, higher ZT value was obtained for Bi_(0.4)Sb_(1.6)Te_3 alloys with a maximum ZT value of 1.19 at 350K.