纳米纤维状γ-Al_2O_3粉体的制备与表征

Preparation and Characterization of Nano-Fibrious γ-Al_2O_3

以工业级氢氧化铝和氢氧化钠为原料,制备偏铝酸钠溶液,然后在旋转填料床内将偏铝酸钠溶液通过化学沉淀法制备成拟薄水铝石,最后在适当的条件下煅烧拟薄水铝石得到纳米氧化铝粉体。利用TG,TEM,XRD等多种测试手段,对产品的结构特征和粒子形态进行了研究,讨论了煅烧过程中温度对晶粒尺寸、形貌的影响。实验结果表明,不同的煅烧条件所制备的粉体的晶相和形态有所不同,在一定煅烧温度下可得到形状呈纤维状、晶相为γ相、直径约5～10nm、长约50～150nm的纳米氧化铝粉体。

This paper presents a simple and economical route for preparing nano-fibrous γ-Al_2O_3.The nano-fibrous γ-Al_2O_3 was prepared through the following steps:1.preparation of sodium alumina solution with industrial aluminium hydroxide and sodium hydroxide;2.preparation of pseudoboehmite by carbonation of the sodium alumina solution in a rotating packed bed;3.calcination of the pseudoboehmite at given temperature to obtain the fibrous γ- Al_2O_3.Thermogravimetry (TG),powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) are used in the analysis and characterization of the sample.The influence of calcination temperature on the crystal phase as well as the surface area and microstructure of the alumina are discussed.Experimental data indicate that samples with different microstructure and crystal phase could be produced through variation of calcination conditions.Nano-fibrous γ-Al_2O_3 with a large specific area and narrow size distribution can be prepared by this method.