尿素水解法制备球形磁性Al_2O_3复合材料  

Preparation of Magnetic Spherical Al_2O_3 Composite Particles by Hydrolyzation of Urea

作　　者：王巧巧[1] 官月平[1] 郎宇琪[1] 刘会洲[1] 

机构地区：[1]中国科学院过程工程研究所分离科学与工程实验室

出　　处：《化学通报》2007年第2期112-116,共5页Chemistry

基　　金：国家自然科学基金(20221603);国家高技术研究发展计划项目(2002AA302211)资助项目

摘　　要：利用酸化法在磁性Fe3O4纳米粒子表面包覆SiO2膜,制备了Fe3O4/SiO2复合粒子。然后将该复合粒子超声分散在尿素和铝盐的混合溶液中,利用油中成型法制备出球形纳米磁性Al2O3复合材料,通过水热焙烧等工序处理得γ-Al2O3。实验中采用XRD、TEM、BET、AGM等方法对复合粒子的性能进行了表征,探讨了制备过程对产物晶型的影响、产物的孔结构变化和磁学性能。另外添加的SiO2膜阻止了磁性Fe3O4纳米粒子的进一步团聚,使得Fe3O4纳米粒子保持较小尺寸并均匀分散在产物中,复合材料表现出超顺磁性;同时SiO2膜防止了磁核部分与Al2O3包覆层在高温焙烧时发生反应;还起到加强粘结的作用,使得Al2O3在使用过程中不容易脱落。A silica film was coated onto the surface of ferriferous oxide nano-particles with the method of acidification of sodium silicate solution. Then Al2O3 was coated onto Fe3O4/SiO2 particles using sol-gel method. And γ-Al2O3 was obtained after heat treatment and calcination process. The composite particles were characterized by XRD, TEM, BET and AGM respectively. The crystal style, the hole structure and magnetism of the final product were discussed. The presence of silica film prevented Fe3O4 particles from assemblage, so that the final product had superparamagnetic properties. The silica film avoided the reaction between Al2O3 and Fe3O4 when the particles were calcined. And the film also made Al2O3 adhere to F3O4 so that Al2O3 would not fall off.

关 键 词：FE3O4 AL2O3 SiO2尿素磁性 

分 类 号：TQ133.1[化学工程—无机化工]