固態氧化物燃料電池之氣相法薄膜合成與鉍系封裝玻璃/氧化鋯之介面接合反應

Abstract

封裝玻璃在燃料電池的單電池組中，扮演著一個重要的角色。製造一妥適性的封裝玻璃系統（compliant sealing glass），其玻璃轉換溫度需小於燃料電池操作溫度，在材料設計上可說是一大挑戰。因為要考慮到玻璃轉換溫度、材料熱膨脹係數、高溫導電性與化學穩定度。因此本研究主要分為兩部分，第一部份在討論以氧化物與合金當做靶材，使用離子束濺鍍法 (IBSD) 進行鍍膜，選擇Si (100) 晶圓與NiO/YSZ 燒結體作為基材，討論靶材對於薄膜的影響、薄膜成長機制與微結構的觀察。第二部份則為封裝玻璃的合成，選用Pb- 與Bi-Zn-Si-B 氧化物玻璃，透過熱處理了解其結晶行為與物理特性的變化。並與8Y-YSZ塊材和薄膜在600-650oC 進行接合，研究其界面反應；以SEM與TEM進行為結構分析，XRD進行結晶相分析。無鉛的Bi系玻璃因為結晶產生而導致熱膨脹係數變化，使得玻璃系統在長時間使用上呈現負面結果。最後依循玻璃封裝的實驗結果設計一玻璃適用性評分表，可對其他封裝玻璃系統進行一系列的評估。

A complient sealing glass-ceramic with the following properties is needed for the preparation of solid oxide fuel cell (SOFC), The design of the sealing material to have a glass transition temperature (Tg) slightly lower than operation temperature (To), good match of the coefficient of thermal expansion (CTE) with SOFC components, chemically inert at To, non-electrical conductive and good wetting for gas tight is tough and a great challenge in engineering aspects. This study included tow major subjects. One is used ion-beam sputtering deposition (IBSD), sputtered oxide or metal targets on various ZrO2 substrates, which included Si (100) wafer and porous NiO/YSZ composite disk. The other is preparation of two sealing glasses, Pb- and Bi-Zn-Si-B-oxides, and analyze the crystallization behaviors have been conducted. X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM) with energy dispersive spectroscopy (EDS) were employed to study the best performance is contact with YSZ at 600-650oC for at least 10 hr, but the microstructural and phase evolution of the films and glasses. The results show that porous YSZ thin films with columnar crystalline structure on NiO/YSZ substrate or in amorphous state on Si wafer were observed. One Pb-free glass (B4 glass) has the microcracks induced by crystallization and CTE mismatch may play a negative role for the sealing. The discussion on the influence by different targets, substrates, phase transformation. Electric conductivity will be discussed.