Investigation ofFe2O3/SiO2Nanocomposite by FESEM and TEM

B C Ang,Irwan Nurdin,I I Yaacob

doi:10.1155/2013/980390

Abstract

Superparamagnetic maghemite nanoparticles were synthesized using Massart’s procedure. Nanocomposites that consist of the synthesized maghemite nanoparticles and silica were produced by dispersing the as-synthesized maghemite nanoparticles into the silica xerogel prepared by sol-gel technique. The system was then heated for 3 days at 140°C. The structure, morphology, and texture of the system were analysed by FESEM and TEM. The result from FESEM showed that the silica gel forms a network structure, which contained numerous pores, with an average pore size of 15 nm. EDX line profile analysis was carried out, and the result indicated that the embedded particles were iron oxide. EELS showed the presence of Fe-L2signal, which confirmed the presence of iron oxide particles within the silica matrix. The average diameters were 5.0 nm for as-synthesized maghemite nanoparticles and 4.4 nm for the embedded maghemite nanoparticles in silica xerogel matrix. The embedded maghemite nanoparticles in nanocomposite also showed a narrower distribution compared to as-synthesized particles. The magnetization values at 10 kOe applied field,Ms10 kOe, were 9.53 emu/g and 1.79 emu/g for as-synthesized and embedded nanoparticles, respectively. A reduction in average crystallite size was observed for the dispersed maghemite particles after formation of the nanocomposite indicating a slight dissolution of maghemite nanoparticles in silica gel.

Highlights

Maghemite is a technologically important magnetic material which has a wide range of applications in information storage [1, 2] and catalysis [3]
For samples TF1, the diffraction patterns show a broad shoulder of the silica gel and crystalline peaks, which come from the maghemite nanoparticles
The Field Emission Scanning Electron Microscope (FESEM) micrograph clearly showed that most of the maghemite nanoparticles were embedded into the pores of the silica matrix

Summary

Introduction

Maghemite is a technologically important magnetic material which has a wide range of applications in information storage [1, 2] and catalysis [3]. Nanocrystalline maghemites, in particular, have gained much interest due to their magnetic properties, which are strongly dependent on particle and crystallite sizes. It is very difficult to prevent unwanted crystallite coarsening and particle aggregation To overcome these problems, several attempts have been made to disperse maghemite nanoparticles in various matrix materials such as silica [5, 6], porous glass [7], and polymer [8, 9]. In 1step procedure, maghemite nanocomposite is produced in a single step where maghemite nanoparticles and silica gel are produced simultaneously In this procedure, various methods are used such as microemulsion [13,14,15], sol-gel [16], arcdischarge [17], reactor [18], and low-pressure flames [19]. Maghemite nanoparticles are produced by Massart’s procedure and are dispersed in silica matrix

Sample Preparation

Characterization

Results and Discussion

Conclusion