Fe3O4磁流体制备及磁性能研究

Preparation of Fe_3O_4 magnetite fluids and their magnetic properties

采用共沉淀法制备了3种不同粒径的Fe3O4纳米粒子,并分别将其分散在水中制备成磁流体。采用超导量子干涉仪分别测量了不同粒径磁粒子及其磁流体的磁性能。实验结果显示:粉末状Fe3O4粒子的比饱和磁化强度和矫顽力均随粒径的增加而增大;磁流体中的磁粒子比饱和磁化强度也随着粒径的增加而增大,但3种样品的矫顽力均为零,显示出超顺磁性;相同粒径的Fe3O4粒子,在磁流体中的比饱和磁化强度较粉末状态时为低。

Magnetite particles with three average diameters were prepared by the method of co-precipitation. Three water-based magnetic fluids were prepared by dispersing these particles into water. The magnetic properties of the magnet- ic fluids were determined by SQUID. The experimental results demonstrated that specific magnetization and coercive force of the magnetite particles increased with the enhancement of diameters. The specific magnetization of magnetite particles in water also increased with the increasing of diameters, while all their coercive force was zero. The specific magnetization of magnetite particles with same diameter in magnetic fluids was lower than that of in the powder state.