中溫鎂矽合金塊材之製程及其熱電性質

Manufacturing Processes and Thermoelectric Properties of Medium Temperature Magnesium Silicide Alloy Bulks

葉建弦(Chien-Hsuan Yeh) ； 楊侑穎(You-Ying Yang) ； 汪俊延(Jun- Yen Uan) ； 林育立(Yu-Li Lin)

《燃燒季刊》 99期 (2017/11) Pp. 29-40

https://doi.org/10.30041/CQ.201711_(99).0004

摘要

鎂矽合金具有低價格、無毒性、元素蘊藏豐富及重量輕等特性且在500 K~800K擁有高導電率及低熱傳導率，因此為相當具有應用潛力的中溫熱電材料之一。本研究利用熔煉鑄造法製作鎂矽原材，再搭配球磨、火花電漿燒結製備出鎂矽(Mg_2(Sn, Si, Sb))熱電合金塊材。為使試片製作品質穩定，嘗試調整熔煉與燒結製程，避免在合金試片出現純錫相而影響熱電性能。研究中也藉由Mg含量調整使合金導電率增加，而Seebeck係數則隨之降低。同時在調整微量Mg、Sb組成後所得之Mg_(2.16)Sn_(0.6)Si_(0.355)Sb_(0.045)熱電合金獲得最高功率因子(4.1×10^(-3) W/m．K^2)以及較低的熱傳導率(1.6 W/m．K)。綜合功率因子與熱傳導率結果，Mg_(2.16)Sn_(0.6)Si_(0.355)Sb_(0.045)合金塊材可獲得最佳ZT值在665 K達1.52。

關鍵字

熱電材料 ； 鎂矽合金 ； 火花電漿燒結 ； 熱電優值

並列摘要

Magnesium silicide alloy is known to hold many attractive properties like non-toxicity of the constituent elements, abundance in nature, lost cost and light weight. This alloy is also known to possess high electrical conductivities and low thermal conductivity in the temperature ranges of 500 K-800 K. Therefore, Mg_2Si has been considered as a potential environment-friendly high performance medium temperature thermoelectric material. In this research, Mg_2(Sn, Si, Sb) thermoelectric alloy bulks were prepared by casting, ball milling and spark plasma sintering. In order to stabilize the quality of the samples, we try to improve the melting and sintering processes and avoid the appearance of pure tin phase in the samples. Simultaneously, the Mg content was adjusted to increase the electrical conductivity and decrease the Seebeck coefficient. Mg_(2.16)Sn_(0.6)Si_(0.355)Sb_(0.045) thermoelectric alloy has the high power factor of 4.1× 10^(-3) W/m．K^2 and lower thermal conductivity of 1.6 W/m．K because Mg and Sb elements were adding appropriately. The maximum value of thermoelectric figure of merit of 1.52 was obtained for Mg_(2.16)Sn_(0.6)Si_(0.355)Sb_(0.045) at 665 K.

並列關鍵字

Thermoelectric material ； Magnesium silicide alloy ； Spark plasma sintering ； Thermoelectric figure of merit