磁性Fe_3O_4@SiO_2复合纳米颗粒的制备与表征

Preparation and characterization of magnetic Fe_3O_4@SiO_2 composite particles

采用化学共沉淀法和正硅酸乙酯水解法制备了SiO_2包覆的Fe_3O_4磁性颗粒,采用X射线衍射仪、接触角测定仪、振动样品磁强计、透射电子显微镜等多种测试手段对所制备的颗粒进行了表征。结果表明:磁性颗粒表面成功包覆了一层SiO_2,包覆后的颗粒粒径为20 nm左右,具有超顺磁性;接触角从包覆前的120°减小到90°左右,亲油性显著增强;复合Fe_3O_4颗粒的饱和磁化强度随SiO_2包覆量的增加而减小,其值为84 kA/m,达到了使用要求。

Fe3O4 magnetic particles prepared by chemical coprecipitation and tetraethoxysilane hydrolysis method were coated with SiO2. The prepared particles were characterized by X ray diffractometer, contact angle measuring instrument, vibrating sample magnetometer and transmission electron microscopy and so on. The results show that the surface of the magnetic particles is coated with a layer of SiO2, the size of the coated particles is about 20 nm with superparamagnetic property. The contact angle decreases from 120 to 90°, and the lipophilicity is significantly enhanced. The saturation magnetization of the composite Fe3O4 particles decreases with the increase of the coating amount of SiO2, its value is 84 kA/m, which can meet the application requirements.