Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/47660
標題: Process Development, Property Improvement and Barrier Layer Preparation of Bagage Clathrate Thermoelectric Materials
鋇鎵鍺晶籠熱電材料的製程開發、特性提升與阻障層製備
作者: 張立信
關鍵字: 材料科技
基礎研究
摘要: One of the key points for applying thermoelectric technology into producing renewable energy is a thermoelectric material which possesses excellent thermoelectric figure-of-merit. The figure-of-merit of thermoelectric materials is derived from thermoelectric power, electrical conductivity and thermal conductivity. The clathrates have normally a very low value of thermal conductivity due to their complicated structures and the accompanying rattler effect. In recent years, the clathrates mainly composed of BaGaGe were found to have excellent thermoelectric properties. However, due to the high cost of making a single crystal, a power process will be used in this project to prepare the BaGaGe clathrates. In this three-year project, to develop a powder process which can produce BaGaGe clathrates with stable thermoelectric properties will be the aim at the first year. The BaGaGe clathrates process procedure in this project includes melting, pulverizing and hot pressing. Property variations accompanying deviations in composition and structure which are caused by each step will be evaluated. Besides the thermoelectric properties, the mechanical and thermal properties of bulk will be measured. The aim at the second year is the improvement of properties of BaGaGe clathrates. Both approaches, reducing grain size and introducing dilute B element, will be attempted. Increasing material strength and, meanwhile, no bad influence on thermoelectric properties are expected through these approaches. The aim at the third year is trying to prepare barrier layers suitable for BaGaGe thermoelectric materials. Two kinds of barrier layers will be developed. One lies between substrate and electrode as anti-diffusion layer preventing reactions between electrode metal and BaGaGe elements. Another covers substrate surface for preventing the loss of volatile elements via vaporization.
具有良好熱電優值的熱電材料是要將熱電技術普遍用於製造再生能源的關鍵所在。熱電材料的熱電優值由熱電勢、電導率與熱導率所共同決定。晶籠化合物由於有複雜結晶結構,且伴隨振子效應,因此具有非常低的熱導率。近年來,以鋇鎵鍺做為主要成分的晶籠化合物被發現具備優異熱電特性。然而,由於單晶製程成本較高,本計畫中將以粉末製程來製備鋇鎵鍺晶籠化合物。本三年期計畫第一年將以開發可製備出具穩定熱電性質之鋇鎵鍺晶籠化合物的粉末製程為目標。在本計畫中,製作程序包含熔煉、製粉、熱壓等步驟。各個步驟所產生的成分與結構誤差導致的性質變異將加以評估。除熱電相關特性外,塊材的機械與熱性質將一併量測。第二年的目標則是鋇鎵鍺晶籠化合物特性的提升。計畫將嘗試降低材料晶粒尺寸與添加微量硼元素兩方法。一方面期待藉由這兩方法,可提高材料強度;另一方面亦希望這些方法對熱電相關性質不會有不良影響。第三年的目標則是嘗試製備出適用於鋇鎵鍺熱電材料之阻障層。本計畫將開發兩類阻障層,一位於基材與電極間,做為抗擴散層,防止電極金屬與基材鋇鎵鍺元素反應。第二類是覆蓋於基材表面。由於鎵元素在高熱容易揮發,此類阻障層是被用來防止元素散失。
URI: http://hdl.handle.net/11455/47660
其他識別: NSC100-2221-E005-039-MY3
文章連結: http://grbsearch.stpi.narl.org.tw/GRB/result.jsp?id=2393687&plan_no=NSC100-2221-E005-039-MY3&plan_year=101&projkey=PB10101-4144&target=plan&highStr=*&check=0&pnchDesc=%E9%8B%87%E9%8E%B5%E9%8D%BA%E6%99%B6%E7%B1%A0%E7%86%B1%E9%9B%BB%E6%9D%90%E6%96%99%E7%9A%84%E8%A3%BD%E7%A8%8B%E9%96%8B%E7%99%BC%E3%80%81%E7%89%B9%E6%80%A7%E6%8F%90%E5%8D%87%E8%88%87%E9%98%BB%E9%9A%9C%E5%B1%A4%E8%A3%BD%E5%82%99
Appears in Collections:材料科學與工程學系

文件中的檔案:

取得全文請前往華藝線上圖書館



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.