无机材料学报

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水热合成的纳米γ-AlOOH的热分解动力学

杨 琪1, 胡文彬2   

  1. (1. 上海工程技术大学 材料工程学院, 上海 201620; 2. 上海交通大学 金属基复合材料国家重点实验室, 上海 200240)
  • 收稿日期:2009-05-03 修回日期:2009-06-18 出版日期:2010-01-24 网络出版日期:2010-01-24

Thermal Decomposition Kinetics of γ-AlOOH Nanocrystalline Prepared by Hydrothermal Method

YANG Qi1, HU Wen-Bin2   

  1. (1. Materials Engineering College, Shanghai University of Engineering Science, Shanghai 201620, China; 2. State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, China)
  • Received:2009-05-03 Revised:2009-06-18 Published:2010-01-24 Online:2010-01-24

摘要: 以氯化铝、氢氧化钠为原料, 在水热条件下制备的纳米γ-AlOOH为宽度10~30nm、 长度100~300nm、 长径比5~15的条状物. 由于纳米γ-AlOOH比表面积很大, 表面羟基的作用不能忽略不计, 因此纳米γ-AlOOH的热分解过程表现出不同的特征, 表面羟基即化学吸附水脱出过程应作为单独的过程对待. 纳米γ-AlOOH的热分解过程分为4个阶段:物理吸附水的脱出; 化学吸附水的脱出; 结构水脱出并转变为氧化铝中间相; 氧化铝中间相中残留羟基的脱出. 4个阶段的激活能E分别为:-1.21、-16.57、-167.62和-7.61kJ/mol.

关键词: 薄姆石, 热分解, 动力学, 激活能

Abstract: γ-AlOOH nanocrystaline with width of 10-30nm, length of 100-300nm and aspect ratio of 5-15 were prepared under hydrothermal condition by using aluminum chloride and sodium hydroxide as starting materials. Because of high proportion surface hydroxyl, the thermal decomposition of γ-AlOOH nanocrystalline demonstrates different features, and desorption of surface hydroxyl or chemisorbed water should be treated as separate stage. The thermal decomposition of γ-AlOOH nanocrystalline should be divided to four stages: 1) desorption of physisorbed water; 2) desorption of chemisorbed water; 3) desorption of molecular water and conversion into transition alumina; 4) desorption of residual hydroxyl in transition alumina. And the activation energies of the four stages are -1.21,-16.57,-167.62 and -7.61kJ/mol, respectively.

Key words: boehmite, thermal decomposition, kinetics, activation energy

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