中文摘要：

在水热合成α-Fe2O3十八面体和十二面体的基础上,以5%H2＋95%N2为还原介质,通过控制还原条件制备出纯相Fe3O4十八面体和十二面体颗粒。用X射线衍射、扫描电镜、X射线光电子能谱、透射电镜和振动样品磁强计等手段对样品进行了表征。结果表明,颗粒表面氟离子吸附层的存在是其形貌保持较好的重要原因。与其它形貌的Fe3O4颗粒比较,本文合成的多面体Fe3O4颗粒矫顽力较高,主要归因于吸附的氟离子层和材料的形貌结构。

英文摘要：

Octodecahedral and dodecahedral magnetite（Fe3O4） particles were prepared by reducing hematite（α-Fe2O3） polyhedra in 5%H_2＋95%N2 atmosphere.The samples were characterized by X-ray diffraction,scanning electron microscopy,X-ray photoelectron spectroscopy,transmission electron microscopy and vibrating sample magnetometer.The results show that the existence of fluorinion adsorption layer on the surface of particles may be primary reason for holding the polyhedral morphology. Magnetic analysis shows that the obtained Fe3O4 polyhedral particles possess higher coercivity than the Fe3O4 particles reported by others,mainly due to the adsorbed fluorinion and the morphology and structure of polyhedral particles.