高錳矽化物(HMS)是極具潛力發展為中溫型發電之P型熱電材料。高錳矽化物為一種不匹配相(Incommensurate phase),目前發現的有四種高錳矽化物之相,分別為Mn4Si7、Mn11Si19、Mn15Si26與Mn27Si47,這四種相皆為螺旋階梯狀排列的晶體結構。 高錳矽化物之熱電性質通常會藉由摻雜或固溶其他元素改善。本研究採用錫摻雜至高錳矽化物中,使用電弧熔煉與火花電漿燒結的方式,製備多晶摻雜錫之高錳矽化物塊材,並且研究其相組成與微結構。我們選用的錫摻雜比例為0.1at%、0.5at%、1at%和1.5at%。之後對經火花電漿燒結的高錳矽化物塊材進行熱電性質量測,量測的溫度範圍介於323K~773K之間;發現在摻雜量為0.1at%的時候,會有最低的晶格導熱率,並且有最高的ZT值。 ;Higher manganese silicide (HMS) is considered to be a promising p-type thermoelectric material for use in intermediate-temperature power generation. It is well known that HMS exist as several incommensurable phases such as Mn4Si7, Mn11Si19, Mn15Si26, Mn27Si47, and all of these compounds are Nowotny chimney phases exhibiting tetragonal crystal structure.
Thermoelectric performance is improved through compositional optimization by doping or substitution. In this work, we prepared polycrytstalline HMS with Sn additions by arc melting and subsequent spark plasma sintering (SPS). The phases, composition, and microstructures of the Sn-doped polycrystalline HMS bulk were investigated. In this study, we select doped-Sn ratio of 0.1at%, 0.5 at%, 1 at%, and 1.5at%. After SPS, we measured the thermoelectric properties of sintered bulk sample from 323K to 773K. We found that the thermal conductivity was significantly improved when the Sn was 0.1at%. The HMS with Sn has the best the ZT is 0.1at%.