超声波辅助水热合成条件对Fe_3O_4纳米微粒生长及磁性的影响

Effects of Hydrothermal Synthesis Method Assisted by Ultrasonic Wave on Nanocrystal Growth and Magnetism of Fe_3O_4

以FeCl3.6H2O,FeCl2.4H2O和NH3.H2O为原料,在超声波辅助下,用水热法合成了纳米磁性Fe3O4粒子,借助X射线衍射仪（XRD）、透射电镜（TEM）仪及振动样品磁强计（VSM）对产物Fe3O4进行分析,结果表明,当反应物物质的量之比（n（Fe^3＋）/n（Fe^2＋））为1.75,pH=13得到的前驱物,控制水热合成温度为140-160℃,水热处理时间为3-5 h时,可制备出纯相的反尖晶石结构的Fe3O4纳米微粒,随着水热合成温度的升高和时间的延长晶体发育越完整,平均粒径越大.磁性测量表明,饱和磁化强度和矫顽力也随着Fe3O4纳米微粒平均粒径的增大而增大.

The Fe3 O4 nanometer magnetic particles were synthesized through reacting FeCL3·6 H2 O with FeCl2·4H2 O and NH3·H2 O by hydrothermal method assisted by ultrasonic wave, and characterized by X-ray diffraction（XRD）, transmission electron microscope（TEM） and vibrating sample magnetometer （VSM）. The experimental results showed that Fe3 O4 nanocrystal particles of mis-spinel structure with high purity was obtained at the adopted n （Fe^3＋ ）/n （Fe^2＋） = 1. 75, pH= 13, 3-5 hour and 140-160 ℃. Perfect and larger Fe3 O4 nanocrystal was obtained with the increasing temperature and reaction time. The VSM results showed that magnetic saturation moment and coercivity also were larger with the increment of the average grain size of Fe3O4 nanocrystal.