歸因於最近的能源危機，研究人員一直致力於尋找更好的能源安排方式，特別是通過提高能源系統效率。熱電發電機具有將廢熱轉化為電能的優點，在此方面是為一強力的候選者。過去常見的熱電材料有Bi2Te3、PbTe-BiTe，而比較新興的熱電材料有Mg2Si N-type 、Mn2Si P-type 、方鈷礦 Skutterudites CoSb等等，在本研究中，考慮到低成本與環保的好處，我們嘗試合成鉍、鎂和矽作為材料系統製作熱電材料。 本研究是將在經過滾動式研磨機充分混合的粉體，通過在氬氣氛下在爐管中進行固態反應法反應，製備不同比例的鉍摻雜矽化鎂化合物（Mg2Si+Bix，X=0.01, 0.02, 0.03），為增加其載子濃度，以達到電導的提升。隨後在研磨和篩選緻密化後進行火花電漿燒結（SPS）。另外也透過急冷旋鑄法為縮小其晶粒大小，以降低其熱導。 量測的部分通過X光繞射分析和SEM測量並觀察完整樣品的組成和微觀結構。通過雷射閃光法熱傳導分析儀（LFA）、阿基米德、ZEM-3和示差掃描熱分析儀（DSC）研究熱電性能，以獲得包括熱導係數，電導率和 Seebeck 係數等參數，經過計算以獲得最終的數字和熱電優值ZT。本研究在鉍摻雜0.02的部分，擁有熱電優質 ZT=0.384。最終目標是製造高 ZT 值的矽化鎂化合物，以作為具有高性能轉換效率的熱電材料應用。 ;Since the recent energy crisis, researchers have dedicated in searching for a better way to utilize energy, especially by increasing energy system efficiency. Thermoelectric generators might be the predominant candidate, owing to its ability of transferring waste heat into electric power. In this work, taking the benefits of low costing and eco-friendly, we attempt to synthesis bismuth, magnesium, and silicon were selected as the material system. Bi-doped magnesium silicide compounds were prepared by reacting in tube furnace under argon atmosphere after mixing them all with the rolling machine. Spark plasma sintering (SPS) was later operated after grinding and screening for densification. In addition, we also try to decrease the grain size by melt spinning. The composition and microstructure of complete sample were measured and observed by using X-ray diffraction and SEM, respectively. The thermoelectric properties were be studied by laser flash analysis (LFA), Archimedes, ZEM-3, and differential scanning calorimeters (DSC) to obtain the parameter including thermal conductivity, electrical conductivity, and Seebeck coefficient in order to get the final figure and merit ZT. The final goal is to fabricate the high-ZT magnesium silicide that possesses high performance for energy applications.
