Orthogonal optimization design for preparation of Fe3O4 nanoparticles via chemical coprecipitation

Fe3O4 nanoparticles ranging from 8.9 to 12.2 nm were prepared by chemical coprecipitation based on L-16(4(5)) orthogonal experiments. The effects of five process parameters (pH, Fe2+/Fe3+ ratio, reaction temperature, ferric salt concentration, and crystallization temperature) on particle size and specific saturation magnetization of Fe3O4 nanoparticles were investigated. The micro-morphology, crystal structure, specific saturation magnetization, and surface properties were characterized by transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), vibration magnetometer (VSM), and Fourier infrared (FT-IR). The results indicate that Fe2+/Fe3+ ratio and pH are the main factors affecting particle size and specific saturation magnetization, respectively. The Fe3O4 nanoparticles are mostly spherical powders with a narrow size distribution and a high purity. The Fe3O4 nanoparticles can achieve high dispersion performance and suspension stability by in situ dispersion with double adsorption layers. (C) 2013 Elsevier B.V. All rights reserved.