Fe_3O_4八面体微晶的水热法制备与表征

Hydrothermal Synthesis and Characterization of Octahedral Fe_3O_4 Microcrystals

在乙二醇与水(VC2H6O2/VH2O=5∶8)的混合溶剂中,通过K4[Fe(CN)6]与NaOH在200℃水热反应12h,制备了Fe3O4的八面体.采用X射线衍射仪、扫描电镜和透射电子显微镜对产物进行表征,并在室温下测试了它的磁学性能,结果表明,Fe3O4八面体为单晶面心立方相结构,尺寸约为0.7～6.3μm.它的矫顽力(Hc)为77.5Oe,饱和磁化强度(Ms)为98.53emu/g,剩余磁化强度(Mr)为6.27emu/g.研究了乙二醇,NaOH的浓度,反应温度和时间对产物形貌的影响,结果表明乙二醇在Fe3O4八面体的形成过程中起着关键作用,并提出了可能的生长机理.

Octahedral Fe3O4 microcrystals have been synthesized through a simple hydrothermal reaction of K4[Fe（CN）6] with NaOH in aqueous ethylene glycol （Vc2H6O2/VH2O =5 ： 8） at 200℃ for 12 h. The morphology and structure of Fe3O4 octahedrons were characterized with powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results showed that the Fe3O4 octahedra are single crystals with the face-center cubic structure and a size distribution from 0.7 to 6.3 μm. Magnetic properties of Fe3O4 octahedra have been detected by a vibrating sample magnetometer at room temperature. The coercive force, saturation magnetization and remanent magnetization of Fe3O4 octahedra are about 77.5 Oe, 98.53 emu/g and 6.27 emu/g, respectively. The influence of ethylene glycol, concentration of NaOH, and reaction temperature and time on the morphology development was experimentally investigated. It was found that ethylene glycol molecules have a significant effect on the formation of Fe3O4 octahedra. A possible mechanism was also proposed to account for the growth of these Fe3O4 octahedra.