制备SiO_2包覆的Fe_3O_4磁性纳米复合粒子

Preparation and characterization of SiO_2 coated Fe_3O_4 nanoparticles

首先用化学共沉淀法制备出柠檬酸三铵改性的Fe3O4磁性纳米粒子,然后用反相微乳液法制备了SiO2包覆的Fe3O4磁性纳米复合粒子。用X射线衍射仪(XRD),透射电子显微镜(TEM),傅立叶-红外光谱仪(FTIR)和振动样品磁强计(VSM)表征SiO2包覆的Fe3O4磁性纳米复合粒子。结果表明,SiO2成功包覆在Fe3O4表面,且饱和磁化强度下降,但矫顽力趋近于零,仍显示超顺磁性。

Magnetite nanoparticles modified with triammonium citrate were synthesized by a chemical coprecipitation method.Then,the magnetite nanoparticles coated with silica were synthesized by a reverse micelle method.The composite nano particles were characterized by X-ray diffraction（XRD）,transmission electron microscopy（TEM）,Fourier transform infrared spectroscopy（FT-IR）,and vibrating sample magnetometer（VSM）.The results show that the primary silica is coated successfully on the surface of Fe3O4 nanoparticles and their saturation magnetization decrease.The coercivity of the composite nano particles is near zero,implying the composite nano particles are of superparamagnetic properties.