SYNTHESIS AND STUDY OF CORE-SHELL γ-Fe2O3/SiO2 NANOCOMPOSITE PARTICLES

Core-shell silicon/magnetic nanocomposite particles have great advantage over the traditional material, such as the excellent magnetic, electrical, mechanical, biological activity and catalytic properties. It is widely applied in magnetic recording materials, biomedicine and specialty paper. The research focuses on synthesis and study of core-shell gamma-Fe2O3/SiO2 nanocomposites by sol-gel method. The research aims to synthesize nanoparticles with gamma-Fe2O3 as the core and SiO2 as the shell. The dosage of gamma-Fe2O3, Ammonia water, TEOS, the ratio of alcohol to water, reaction time, temperature and stirring speed effect on the properties of nanoparticles were studied. The synthesized products were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), infrared spectrometer (FTIR), differential scanning calorimetry (DSC). The reaction mechanism and the optimum synthesis process are discussed. The research shows that high yield synthesis of hollow silica spheres with controllable size, and wall thickness can be realized by a modified Stober sol-gel method using tetraethoxysilane (TEOS) as silica source in ethanol solution of ammonia. The polyelectrolyte such as sodium polyacrylate is the key factor controlling the hollow sphere of SiO2. The wall thickness of nanoparticles can be adjusted by modifying the concentration of polyelectrolyte, TEOS and ammonia. The optimum reaction condition is ethanol dosage 50 mL, TEOS 0.5 mL, ammonia 2 mL and deionized water 10 mL, gamma-Fe2O3 0.06 g, reaction time 8 h, reaction temperature 30 degrees C stirring speed 150 r/min