Journal of Inorganic Materials

• Research Paper • Previous Articles     Next Articles

Preparation of Core-shell SiO2/Fe3O4 Nanocomposite Particles via Sol-gel Approach

LIU Bing1, WANG De-Ping1,2, HUANG Wen-Hai1,2, YAO Ai-Hua1, Ioku Koji3   

  1. 1. School of Material Science and Engineering, Tongji University, Shanghai 200092, China; 2. Key Laboratory of Advanced Civil Engineering Materials of the Ministry of Education, Tongji University, Shanghai 200092, China; 3. Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, Japan
  • Received:2007-01-19 Revised:2007-03-22 Published:2008-01-20 Online:2008-01-20

Abstract: 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.

Key words: sol-gel, core-shell structure, magnetite, silica

CLC Number: