四氧化三铁磁性纳米粒子的合成及表征

Preparation and Characterization of Fe 3O 4 Magnetic Nano particles

采用滴定水解及 Ｍ ａｓｓａｒｔ 合成法分别制备了直径在 ８ ｎｍ 左右的 Ｆｅ３ Ｏ４ 磁性纳米粒子，粒子的结构组成通过 Ｘ射线粉衍射得到证实．透射电镜研究表明，由滴定水解法制备的磁性粒子的外形主要为球形，粒子大小比较均匀，所有粒子都在 ５～１０ ｎｍ 之间．而由 Ｍａｓｓａｒｔ 合成法制备得到的 Ｆｅ３ Ｏ４ 磁性粒子则呈现从球形到立方体形的多种形态，并且粒径分布较宽．磁性测量表明，由滴定水解及 Ｍ ａｓｓａｒｔ 合成法合成的 Ｆｅ３ Ｏ４ 磁性粒子的饱和磁矩分别为 ７１ 和 ６９ Ａｍ ２ｋｇ－ １，仅比块体 Ｆｅ３ Ｏ４ 的磁性低约２０％ ．

The Fe 3O 4 magnetic nano particles prepared by the titration hydrolyzation and Massart′s method have been studied with X ray diffraction, transmission electron microscopy (TEM) and superconducting quantum interference device (SQUID) magnetometry. The average diameter of the two kinds of Fe 3O 4 nano particles are similar (~8 nm) but their particle shapes are quite different. The Fe 3O 4 particles obtained from titration hydrolyzation are mainly spherical while those from Massart′s method are somewhat irregular, varying from spherical to cubic. At 300 K, the two kinds of particles exhibit superparamagnetic behavior and their magnetic saturation moments are 71 A·m 2/kg (titration) and 69 A·m 2/kg (Massart) respectively, which are only ~20% less than that of bulk Fe 3O 4.