Partic. vol. 9 no. 2 pp. 179-186 (April 2011)
doi: 10.1016/j.partic.2010.07.025

Solvothermal synthesis of magnetic Fe₃O₄ microparticles via self-assembly of Fe₃O₄ nanoparticles

Wei Zhang, Fenglei Shen, Ruoyu Hong^*

rhong@suda.edu.cn

Abstract

Ferromagnetic Fe₃O₄ nanoparticles were synthesized and then self-assembled into microparticles via a solvothermal method, using FeCl₃·6H₂O as the iron source, sodium oleate as the surfactant, and ethylene glycol as the reducing agent and solvent. The obtained Fe₃O₄ microparticles were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and vibrating sample magnetometer (VSM). The size and morphology of the particles were examined using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The Fe₃O₄ microparticles of nearly monodisperse diameters, controllable in the range of 120–400 nm, consist of assemblies of Fe₃O₄ nanoparticles with a diameter of 22 nm. The effects of reaction time, amount of surfactant and NaAc on the products were discussed. Interestingly, by using the pre-synthesized Fe3O4 microparticles as the growth substrates, spherical and smooth-looking Fe₃O₄ microparticles with average diameter of 1 μm were obtained. A plausible formation process was discussed.

Graphical abstract

Keywords

Iron oxides; Magnetic microparticles; Oriented attachment; Solvothermal method