Preparation of amorphous Fe₂O₃ powder with different particle sizes

A method for the preparation of amorphous Fe₂O₃ powder with particle size of about 25 nm is reported. The amorphicity of Fe₂O₃ nanoparticles was determined by X-ray diffraction (XRD), and by electron diffraction measurements. The control of the particle size has been demonstrated by transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetry (TG), surface area measurements (BET) and Quantum Design SQUID magnetization measurements. The magnetization of pure amorphous Fe₂O₃ is very low (<5 emu g^-1) and it crystallizes at 285 ± 10°C. The measured properties demonstrated a strong dependence of the particle size on the concentration of Fe(CO)₅ in decalin. The more dilute the solution, the smaller the particle size of the amorphous Fe₂O₃ product obtained.