溶胶-凝胶法制备核壳SiO2／Fe3O4复合纳米粒子的研究  

Preparation of Core-shell SiO_2/Fe_3O_4 Nanocomposite Particles via Sol-gel Approach

作　　者：刘冰[1] 王德平[1,2] 黄文旵[1,2] 姚爱华[1] 井奥洪二[3] 

机构地区：[1]同济大学材料科学与工程学院,上海200092 [2]同济大学先进土木工程材料教育部重点实验室,上海200092 [3]东北大学环境研究科,日本仙台980-8579

出　　处：《无机材料学报》2008年第1期33-38,共6页Journal of Inorganic Materials

基　　金：国家自然科学基金(50572072，50272041);上海市科委纳米专项(0452nm059)

摘　　要：采用溶胶-凝胶法,以尺寸约10nm的Fe_3O_4纳米粒子为种子,碱催化正硅酸已酯(TEOS)水解、缩合,制备了磁性可控的核壳结构SiO_2/Fe_3O_4复合纳米粒子.系统研究了醇水比、NH_4OH及TEOS的浓度对复合纳米粒子形貌和性能的影响,并分析了SiO_2/Fe_3O_4复合纳米粒子的生成机理.结果表明,SiO_2的生长主要是SiO_2初级粒子在Fe_3O_4表面的聚集生长,醇水比为4:1、NH_4OH浓度为0.3mol/L和TEOS浓度低于0.02mol/L时,随TEOS浓度的增大,SiO_2壳层增厚,复合粒子饱和磁化强度下降,矫顽力基本不变,仍具有良好的超顺磁性.Core-shell structural SiO2/Fe3O4 nanocomposite particles with adjustable magnetic properties were prepared via a sol-gel process, in which the hydrolysis and condensation of TEOS were conducted on the surface of Fe3O4 nanoparticles under the aid of basic catalyst. The effects of the volume ratio of alcohol to water, the concentrations of ammonium and TEOS on the appearances and properties of the nanocomposite particles were investigated. The mechanism of the formation of SiO2/Fe3O4 nanocomposite particles was analyzed. Results show that silica shell is mainly formed from the aggregative growth of silica primary particles on the surface of Fe3O4 nanoparticles. With increasing the concentration of TEOS in the range of 0-0.02mol/L, the silica shell thickness increases on the condition of 0.3mol/L of NH4OH and 4：1 ratio of alcohol to water. Although the saturation magnetization of the nanocomposite particles decreases with the thickness of silica shell increasing, the coercive force of the particles is almost unchanged. And more, the nanocomposite particles remain favorable superparamagnetism.

关 键 词：溶胶-凝胶 核壳结构 四氧化三铁 二氧化硅 

分 类 号：TM228[一般工业技术—材料科学与工程] TB34[电气工程—电工理论与新技术]