水溶液沉淀法制备超细球形α-Al_2O_3  

Preparation of Ultrafine Spherical α-Al_2O_3 by Homogeneous Precipitation

作　　者：巢昺轩[1] 孔见[1] 王腾[1] 

机构地区：[1]南京理工大学材料科学与工程学院,南京210094

出　　处：《硅酸盐通报》2012年第1期166-170,共5页Bulletin of the Chinese Ceramic Society

摘　　要：以硫酸铝、氯化铝和尿素作为原料,在90℃条件下利用化学沉淀法制备了α-Al2O3粉末,探讨了活性剂PEG和NaCl的含量对颗粒形貌、尺寸和团聚情况的影响。利用XRD、SEM和TG/DSC对样品进行表征,结果表明:聚乙二醇(PEG)可以提高粉体的分散性,由TG曲线可知前躯体为无定形的AlOOH.0.25H2O,PEG的吸附效率为13.2%。前躯体在600℃和800℃煅烧2 h得到无形定的Al2O3和γ-Al2O3,1000℃即转变为α-Al2O3并伴随Na2SO4的特征峰,1200℃完全转变为α-Al2O3。加入一定量的NaCl能防止α-Al2O3粉末在1000℃高温煅烧时的团聚,[NaCl]=0.05 mol/L时能获得0.5μm的分散较好的球形α-Al2O3颗粒;当[NaCl]=0.1 mol/L时能获得大量纳米尺寸的球形α-Al2O3颗粒;当[NaCl]≥0.15 mol/L时,α-Al2O3颗粒团聚严重。Using Al2（SO4）3·18H2O、AlCl3 and CO（NH2）2 as the starting materials,α-Al2O3 powder was prepared by chemical precipitation process at 90 ℃.The content of surfactant PEG and NaCl on the morphologies,particle size and agglomeration status of Al2O3 powder were investigated.The powders were characterized by XRD,SEM and TG/DSC.The results showed that PEG can promote the dispersion of powder.From the TG curve,we can figure out that the precursor is amorphous AlOOH·0.25H2O with adsorptive efficiency of PEG as 13.2%.Amorphous Al2O3 and γ-Al2O3 can be get after precursor is calcinated at 600 ℃ and 800 ℃ respectively for 2 h.It will transform to α-Al2O3 at 1000 ℃ with diffraction peak of Na2SO4 and completely to α-Al2O3 at 1200 ℃.A certain amount of NaCl can effectively prevent agglomeration after calcinated at 1000 ℃,well-dispersed spherical α-Al2O3 grain with particle size of 0.5 μm can be achieved when is 0.05 mol/L while nano-sized spherical α-Al2O3 grain can be largely achieved when is 0.1 mol/L.Once is beyond 0.15 mol/L,the agglomeration of α-Al2O3 grain is severe.

关 键 词：水溶液沉淀法 球形氧化铝 团聚 前躯体 

分 类 号：TB383[一般工业技术—材料科学与工程]