Heterogeneous nucleation in the polyol process for the synthesis of FeCo alloy powders

Here, we report a polyol method to prepare monodispersed FeCo alloy particles with Pt seeds added in the production of nanoparticles. The prepared samples were characterized by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and magnetic measurements. Structural studies revealed that the FeCo nanoparticles had a body-centered cubic (BCC) structure. FE-SEM analysis demonstrated a sphere morphology for the FeCo alloy particles. The size of the FeCo nanoparticles could be well tuned by changing the number of Pt-seed partices in the FeCo alloy. The magnetic properties of the FeCo alloys were investigated as a function of the Pt-seed concentration and temperature. The saturation magnetization and coercivity of the FeCo nanoparticles were found to depend on the molar ratio of Fe/Co, as well as the number of Pt-seeds, and increased with increasing FeCo concentration. A higher value of the saturation magnetization, 218 emu/g, was obtained for the 0.07-M concentration of FeCo alloy. In the process of producing an FeCo alloy powder by heterogeneous nucleation, a powder having minute sizes could be produced under the experimental conditions of a Pt-seed-added temperature of 90 °C and a Pt/FeCo mole ratio of 8 × 10 −5 , and showed far superior properties.