Preparation of Bi–Fe3O4 nanocomposite through reduction of Bi2O3 with Fe via high-energy ball milling

High-energy ball milling of Bi2O3 and Fe in air and argon atmospheres led to a novel Bi–Fe3O4 nanocomposite. XRD investigation of the as milled powder shows that there are only two phases of Bi and Fe3O4. GTM results show that the reaction is completed after about 2.5 h with no ignition temperature. Mean crystallite sizes of the Bi and Fe3O4 in the composite were 22 and 18 nm, respectively, calculated by Scherrer's formula. The morphology of the as milled powder was also investigated by a TEM. A two-probe method was used to measure resistivity variation of the composite as a function of temperature, by which a percolation temperature of 229 °C was obtained.