Research Of Fe₃O 4 Nanoparticles Coated With Oxide

In this thesis,Fe₃O₄ï¼ SiO₂ nanoparticles and Fe₃O₄ï¼ TiO₂nanoparticles were prepared with a reverse micelle method by using ofFe₃O₄ nanoparticles as the cores, respectively. And the crystalline structure,particle size, morphology and magnetic properties of these nanoparticleswere characterized by XRD, TEM, FT-IR and VSM. The detailed contentswere given as follows:1)Monodisperse Fe₃O₄ nanoparticles have been prepared on conditionthat iron acetylacetonate (Fe(acac)₃) as Fe resource,1,2-dodecanediolasreductant,oleic acid, oleylamine and dibenzyl ether as surfactants. Theas-prepared nanoparticles were characterized by XRD, TEM, FT-IR andVSM,and the results showing that the nanoparticles with good dispersibilitywere spherical in shape,the average particle size of about 6.0nm , thenear-zero coercivity indicating their superparamagnetic properties.2)Fe₃O₄ï¼ SiO₂ nanoparticles were prepared through a reverse micelleprocess by using of Fe₃O₄ nanoparticles acidized with hydrochloric acidsolution(1.0mol/L) as the cores. The results obtained from thecharacteriztions of XRD, TEM, FT-IR and VSM, show that (i) the primarysilica has been coated successfully on the surface of Fe₃O₄ nanoparticles;(ii)the Fe₃O₄ï¼ SiO₂ nanoparticles with the average size of about 25.0 nm werespherical in shape; (iii) their saturation magnetization decreased with theincrease of TEOS concentration, while their coercivity kept zero levelindicating their superparamagnetic properties.3)Fe₃O₄ï¼ TiO₂ nanoparticles were prepared through a reverse micelleprocess by using of Fe₃O₄ nanoparticles acidized with hydrochloric acidsolution(1.0mol/L) as the cores. The results obtained from thecharacteriztions of XRD, TEM,FT-IR and VSM, show that (i) the primarysilica has been coated successfully on the surface of Fe₃O₄ nanoparticles; (ii)their saturation magnetization decreased,while their coercivity kept zerolevel indicating their superparamagnetic properties.