Fe_3O_4磁性超细微粒的SiO_2表面包覆改性

Surface Modification of Fe_3O_4 Ultrafine Particles by Coating SiO_2

用化学沉淀法制备Fe3O4磁性颗粒,然后在偏硅酸钠溶液中进行的酸化处理,获得了表面包覆SiO2层的Fe3O4磁性颗粒。采用X射线衍射仪、扫描电镜、光电能谱仪分析了Fe3O4微粒的形貌、相成分及磁性能。结果表明,Fe3O4微粒表面包覆SiO2,没有使Fe3O4微粒的平均粒径明显增大,对Fe3O4微粒的磁性能没有影响;由于SiO2层的空间位阻作用,限制了Fe3O4磁性颗粒的团聚和晶粒尺寸的长大,并提高了Fe3O4磁性颗粒的耐候性。

Fe3O4 magnetic ultrafine particles were prepared by chemical-precipitiation method, and by subsequent acidizing the particles in sodium metasilicate solution, SiO2-coated particles were obtained. The particles were characterized by XRD, SEM, xPs. The results suggest that the average particle diameter of Fe3O4 particles coated with SiO2 has not been increased obviously, and the property of the particles has not been changed. The steric hindrance from amorphous SiO2 coating prevents the agglomeration of particles and growth of Fe3O4 crystals, enhanceing the weather resistance of the Fe3O4 particles.