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系統識別號 U0026-0812200911592503
論文名稱(中文) 以含水硫酸鋁為原料製備次微米級 片狀α-Al2O3之初步研究觀察
論文名稱(英文) The preliminary observation of the production of alpha alumina platelets obtained from hydrated aluminum sulfate
校院名稱 成功大學
系所名稱(中) 資源工程學系碩博士班
系所名稱(英) Department of Resources Engineering
學年度 94
學期 2
出版年 95
研究生(中文) 葉雅青
研究生(英文) Ya-Ching Yeh
電子信箱 n4693410@mail.ncku.edu.tw
學號 n4693410
學位類別 碩士
語文別 中文
論文頁數 68頁
口試委員 指導教授-顏富士
口試委員-向性一
口試委員-許志雄
中文關鍵字 醋酸  片狀氧化鋁  含水硫酸鋁 
英文關鍵字 hydrated aluminum sulfate  acetic acid  plate-like alumina 
學科別分類
中文摘要 片狀氧化鋁除了具有氧化鋁高熔點、耐磨性、絕緣性以及優異的機械強度外,因其具有二維的外型,常被添加到其他材料中當作補強物,形成多功能的複合材料。目前市場上所供應的片狀α-Al2O3粉末,其製作方法多為耗能的生產方式,則本研究以省能為前提,以含水硫酸鋁 (Al2(SO4)3‧17H2O) 為起始原料,利用醋酸水溶液重整含水硫酸鋁之粒形,再透過簡易的熱處理方式獲得次微米級的片狀α-Al2O3粉末。
實驗分兩部分:(1)析出試驗:以醋酸水溶液重整含水硫酸鋁之粒形,使其具有片狀外型。(2)熱處理試驗:改變脫水脫硫階段之升溫速率以獲得不同微結構之煆燒粉末。並由SEM觀察粒子之外型及統計其厚度分佈,以評估熱處理方式之改變對剝層的影響,以利得到生產次微米級片狀α-Al2O3粉末之適當的熱處理條件。
實驗結果顯示:(1) 在醋酸濃度10.8M、含水硫酸鋁濃度0.046M的環境下,可得單離的片狀含水硫酸鋁析出粉末。(2) 脫水階段的升溫速率小於200℃/min有利於片狀外型之維持,而大於500℃/min的升溫速率則會造成不規則的多孔質塊體出現。(3) 在脫硫階段以快速升溫熱處理的方式有助於剝層效益的發生。(4) 於脫水階段以 5℃/min 的升溫速率升溫至脫水溫度持溫得到片狀無水硫酸鋁後,再將此粉直接由室溫推入於1200℃的高溫爐持溫三分鐘,使其相變成 α-相並薄化,而達成剝層效應,即可獲得一純相、平均粒徑為15μm、平均厚度約在500nm、有50 %以上的面長/厚度之比值大於10。


英文摘要 Alumina exhibits properties of high melting point, wear resistance, thermal as well as electrical insulation, and perfect mechanical strength. Moreover, alumina powders of plate-like are used as reinforcements in various materials to form multiplicate functional composites because of its two-dimensional shape. Several methods for fabricating alpha alumina platelets supported to markets are mostly energy-consumption in the present days. Therefore, a method of energy-saving for producing platy α-Al2O3 particles is provided in this study. The hydrated aluminum sulfate was used as the starting materials and the acetic acid was used as habit modifier to manufacture platy hydrated aluminum sulfate. And then, a powder system of alpha alumina platelets with submicron-scale in thickness was obtained by simple heat treatments. The experiment is composed of two parts:
(1) Precipitated experiment: Using acetic acid as habit modifier to obtain the platy hydrated aluminum sulfate.
(2) Heat treatment experiment: To obtain calcined powders with different microstructure by changing the heating rate at dehydration and desulfuration stage. Afterward the morphology of particles was observed by SEM. The particle size distribution in thickness was calculated from at least 50 grains to estimate the effect of exfoliation caused by different heat treatments to acquire the appropriate conditions of fabrication of platy α- Al2O3 particles with submicron-scaled in thickness.
It was found from the first part of experiments that the suitable concentrations for platy hydrated aluminum sulfate precipitations of acetic acid and hydrated aluminum sulfate solution were 10.8 M and 0.046 M, respectively. From the second part of experiments, it revealed that the heating rate at dehydration stage should be less than 200℃/min to maintain the platy morphology. Once the heating rate was greater than 500℃/min, particles with irregular porous shapes would appear. On the contrary, rapid heating rate at desulfuration stage could not only maintain the outline of the platy particles but attain thinner platy alpha particles.
In conclusion, a platy alpha alumina powder system with submicron-size in thickness could be obtained by a two steps thermal treatment. Firstly, the platy anhydrous aluminum sulfate was prepared with a heating rate of 5℃/min at dehydration stage. Secondly, the calcined powder was send to a pre-heated furnace at temperature 1200 oC for 3 min to obtain the platy alpha alumina powder. The specifications for the platy alpha alumina powder are as followed: average particle size is 15 um, average particle size in thickness is about 500 nm, and particles with the plane length/thickness ratio larger than 10 are more than 50 %.


論文目次 中文摘要 I
Abstract Ⅱ
目錄 Ⅳ
圖目錄 Ⅶ
表目錄 XIII

第一章 緒論 1
1.1 前言 1
1.2 研究目的 2

第二章 理論基礎與前人研究3
2.1 含水硫酸鋁 (Alunogen (Al2(SO4)3‧17H2O)) 之基本性質 3
2.1.1 Alunogen (Al2(SO4)3‧17H2O) 之結構及特性 3
2.1.2 Alunogen (Al2(SO4)3‧17H2O) 熱處理後之過渡相變化及其結構 4
2.1.3 以含水硫酸鋁製備片狀α-Al2O3 5
2.2 晶粒外型重整之原理 5
2.2.1 結晶習性 (Crystal habit) 5
2.2.2 過飽和溶液之結晶析出 6
2.3 解理面與剝層 6

第三章 實驗步驟及方法 14
3.1 實驗構想與設計 14
3.2 實驗原料 14
3.3 實驗流程 15
3.3.1 片狀含水硫酸鋁的析出試驗 15
3.3.2 熱處理試驗 18
3.4 性質分析 21
3.4.1 煆燒粉末結晶相鑑定分析 21
3.4.2 粉末熱行為分析 22
3.4.3 顯微影像及結構分析 22
3.4.4 粒徑分佈 22

第四章 結果與討論  25
4.1 以醋酸水溶液 (acetic acid solution) 製備片狀含水硫酸鋁(Alunogen) 之製程條件觀察 25
4.2 片狀含水硫酸鋁(Sample A1.5) 之特性分析 29
4.3不同熱處理方式對片狀含水硫酸鋁 → α-Al2O3的微結構影響 29
4.3.1 固定升溫速率之熱處理對片狀含水硫酸鋁 → α-Al2O3的外型變化觀察 29
4.3.2 脫水階段的升溫速率改變對片狀 Alunogen → Al2(SO4)3 之微結構變化觀察 36
4.3.3 脫硫階段的升溫速率改變對片狀 Al2(SO4)3 →α-Al2O3 之微結構變化觀察 39
4.4 綜合討論—剝層的可行性 46

第五章 結論 49

參考文獻 50

Appendies 54

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