中文摘要：

现代诊断学的发展使得纳米级超顺磁性的Fe3O4粒子在医学领域具有重要应用价值。本实验采用分解沉淀法制备磁性纳米Fe3O4粉体。讨论了离子对Fe3O4晶粒生长的抑制机理。对获得的粉体采用激光散射法粒度测试、XRD物相分析和粒晶的计算、AFM、TEM形貌观察、振动样品磁强计等方法进行表征，结果表明，所得Fe3O4粉体平均粒径为30nm、粒度分布均匀、分布带较窄且产物纯度高；饱和磁化强度约为71emu／g。

英文摘要：

Citrate ions were introduced as a complex compound in the co- precipitation method for ultrafine Fe3O4 nanoparticles preparation. Well-dispersed Fe3O4 nanoparticles were directly prepared. The principle of reaction was investigated. Dominant performance parameters of Fe3O4 nanoparticles were studied with X-ray diffraction （XRD）, laser granularity scatter, atomic force microscope （AFM）, transmission electron microscope （TEM）, and vibration showpiece magnetor （VSM）.The results showed that the as- prepared Fe3O4 nanoparticles had good dispersion and purity.The average diameter was about 30 nm, and saturation magnetization intensity was 71emu/g.