臺灣博碩士論文加值系統

本研究主要是以Pechini process和sol-gel process合成鋯鈦酸鉛粉末，然後比較兩種合成法從前驅物溶液到溶膠時，以及溶膠到粉末的化學特性。其中sol-gel 合成法在反應過程中的分子形狀的改變以及粉末的結晶機制是我們研究的重點。
由實驗結果得知，sol-gel 合成的前驅物溶液在反應初期分子是由略為疏鬆的圓形小顆粒，接著隨著分子量及極限黏度的變化轉變為稍微緊密的圓形小顆粒，最後因為靜電力排斥(electrostatic repulsion) 使得分子為內有負電荷分支狀(branch)的分子鏈；而由XRD繞射分析我們知道鋯鈦酸鉛粉末必需先形成焦綠石(pyrochlore)才能轉換成鈣鈦礦(pervoskite)。
而在Pechini process的XRD和SEM 元素分析中，我們知道其前驅物溶液不易溶解於乙二醇中，因此在熱處理時會可能產生部分的固態反應。由SEM觀察我們知道Pechini process在800℃/8h可得到純的鋯鈦酸鉛粉末，而且出現結晶顆粒所需的熱處理溫度比sol-gel process低。而在所形成的結晶顆粒方面，Pechini process所形成的晶粒約為2μm比sol-gel process的晶粒0.5-0.8μm大。

內容大綱
第一章 前言
1.1 研究背景 ……………………………………………….1
1.2 研究動機 ……………………………………………….3
1.3 研究方向 ……………………………………………….4
1.4 研究方法與預期目標 ...……………………………….4
第二章 文獻回顧
2.1溶膠-凝膠合成方法的種類及差異 ……………………5
2.2凝固點下降之理論 …………………………………11
2.3黏度測試理論 …..……………………………………13
2.4 黏度與分子量的關係 …………………………………16
第三章 實驗方法
3.1 實驗藥品…………………………………………………19
3.2 實驗儀器 …..…………………………………………21
3.3 Pechini 實驗步驟 ………………………………………21
3.3.1 PZT前驅物溶液的合成 ………….…..………....21
3.3.2 傅立葉紅外線光譜(FTIR)的觀察 …..…………21
3.3.3 熱重量分析儀(TGA)的測定 ………………….22
3.3.4示差熱分析(DTA)的測定 ………………….22
3.3.5 XRD的鑑定 ………………………………..22
3.3.6 SEM 的分析 ………………………………..23
3.3.7 TEM 的分析 ………………………………..23
3.4 Sol-gel process實驗步驟 …………………………..23
3.4.1 PZT前驅物溶液的合成 …………………...23
3.4.2 熱重量分析(TGA)的量測 ……………………23
3.4.3 示差熱分析(DTA)的量測 ……………………23
3.4.4 傅立葉紅外線光譜(FTIR)的觀察 …..…………23
3.4.5 反應過程分子量的量測 ….………………...24
3.4.6 反應過程極限黏度的量測 …….……………...24
3.4.7 膠化時間(gelation time)的量測 ……………..25
3.4.8 SEM的觀察 ………………………..….26
第四章 實驗與結果 ……………………………………………..30
4.1 Pechini process ………………………………………30
4.1.1 酯化反應之FTIR量測的探討 ….………………30
4.1.2 凝膠的熱性質分析 …………………………32
4.1.3 繞射分析 ………………………………………35
4.1.4 SEM的觀察 ………………………………………37
4.1.5 TEM觀察 ………………………………………42
4.2 Sol-gel process …………………………………….. 45
4.2.1 FTIR的探討 ………………………………………45
4.2.2 極限黏度的變化 ………………………..………47
4.2.3 分子量變化 ………………………………………55
4.2.4 熱性質分析 ………………………………………63
4.2.5 繞射分析 ………………………………………65
4.2.6 SEM的觀察 ………………………………………68
第五章 討論 ……………………………………………………73
5.1 sol-gel process前驅物的化學反應 ………………….73
5.2 反應期間分子形狀轉變之探討 ………………….74
5.3 兩種合成方法的比較 ………………………………..81
5.3.1 從溶膠到凝膠的比較 …………………………81
5.3.2 結晶機制的比較 ………………………………..81
5.3.3 結晶形態的比較 ………………………....82
第六章 結論 …………………………………………………….86
參考文獻 ……………………………………………………………88
附錄 ⅠPechini proecess 之化學計量 ………………………………..92
附錄 ⅡSol-gel process 之化學計量 ………………………………..93
附錄 ⅢJCPDS 卡 …………………………………………………….94

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