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氧化铝微纳米粉体的简易合成研究

时间:2019-10-05 21:58来源:毕业论文
采用溶胶凝胶法制备了γ-Al2O3及α-Al2O3 微纳米粉体。以硝酸铝、糖类或羟基酸(葡萄糖、蔗糖、淀粉、乳糖等糖类以及抗坏血酸、酒石酸)、聚乙烯吡咯烷酮、去离子水等为原料,通过改

摘要采用溶胶凝胶法制备了γ-Al2O3及α-Al2O3 微纳米粉体。以硝酸铝、糖类或羟基酸(葡萄糖、蔗糖、淀粉、乳糖等糖类以及抗坏血酸、酒石酸)、聚乙烯吡咯烷酮、去离子水等为原料,通过改变不同的反应物(糖的种类及酸的种类)、硝酸铝与糖类的配比、溶液pH值、热处理温度、表面活性剂的添加量等因素,来控制凝胶产物的物相和粒度。采用X射线衍射(XRD)、扫描电镜(SEM)、热重-差热(TG-DSC)等分析手段对产物进行组分、微观结构等表征,揭示了不同糖类在不同pH值及不同热处理温度下产物的粒径、物相及形貌的变化趋势以及氧化铝不同晶型之间的转变温度,并探讨出纳米Al2O3 微纳米粉体的最优合成路线。实验结果表明:18974
(1)    采用葡萄糖、蔗糖、淀粉、乳糖等糖类以及抗坏血酸、酒石酸作为原料,能够合成出Al2O3 微纳米粉体,且该方法的产率也较高;
(2)    采用葡萄糖为原料,pH值为8时,所获得的前驱体所需热处理温度较低。所得产物晶粒粒径小,物相均匀;
(3)    本实验制备的γ-Al2O3 纳米晶粉体粒径较小,在1200 °C时γ-Al2O3转变为α-Al2O3,制备的α-Al2O3 的粒度为微米级。
关键词: 溶胶凝胶法;氧化铝;糖类
毕业设计说明书(毕业论文外文摘要
Title  Facile preparation of alumina powders via sol-gel process
Abstract
γ-Al2O3 and α-Al2O3 powders were prepared by sol-gel process using Al(NO3)3•9H2O, de-ionized water, ammonia, polyvinyl pyrrolidone (PVP, K-30), typical saccharides (glucose, sucrose, starch, lactose) or ascorbic acid, tartaric acid as raw materials. In a typical procedure, transparent solution was obtained by dissolving Al(NO3)3•9H2O, one type of saccharides into de-ionized water. Then the solution was dried at temperature close to the boiling point of solvent to induce the formation of sol and dried gel. γ-Al2O3 and α-Al2O3 powders were prepared by heating the dried gels at different temperatures in air. The phase structure and grain sizes of the calcined powders were adjusted by changing pH of the solution, the type of saccharide, the molar ratio of Al(NO3)3•9H2O to saccharide, the heating temperatures and the content of PVP. The phase analysis and microstructure were performed by X-ray diffraction (XRD),scanning electron microscope (SEM), thermogravity-differential scanning calorimetry (TG-DSC).Based on the results, the following conclusions can be claimed: 源`自<六:维;论-文>网/www.lwfree.cn
 (1)γ-Al2O3 and α-Al2O3 powders can be obtained by using glucose, sucrose, starch, lactose, ascorbic acid, tartaric acid as raw materials. This sol-gel method is effective and low cost in preparation of Al2O3 powders with high yield;
(2)Theγ-Al2O3 can be prepared at temperature as low as 600-650 ℃ when the pH value of glucose-mediated sol-gel process is 8;
(3)The XRD investigation results indicate that the particle sizes of the γ-Al2O3 powders obtained in the experiment is in nanometer range, the crystalline phase of the Al2O3 powders transform from γ phase to α phase at about 1200℃, and the particle sizes of theα-Al2O3 powders is in micrometer range.
Keywords: Sol-gel; Al2O3 powders; Saccharide
 目次
第一章  概述    1
1.1 引言    1
1.2纳米氧化铝的晶体结构    2
1.2.1 γ-Al2O3    3
1.2.2 β-Al2O3    3
1.2.3 α- Al2O3    3
1.3纳米氧化铝的制备方法    4
1.3.1气相法    4
1.3.2固相法    5
1.3.3液相法    5
1.4本文的研究目的及研究内容    9 氧化铝微纳米粉体的简易合成研究:http://www.lwfree.cn/huaxue/20191005/40299.html
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