Synthesis And Magnetic Properties Of Fe Core-shell Nanoparticles

Fe nanoparticles with different size and magnetic properties were synthesized in different liquid system with polyvinylpyirolidone (PVP) as protective agent and sodium borohydride as reducer. Transmission electron microscope (TEM), X-ray diffraction(XRD) and vibration sample magnetometer (VSM) were used to characterize these Fe nanoparticles. The size of Fe nanoparticles synthesized in aqueous solution was about 130nm, Its saturation magnetization and coercivity were 106.52emu/g and 352.10G. respectively. The size of Fe nanoparticles synthesized in ethylene glycol-water system was about 12nm, Its coercivity was 1.451G, which displayed superparamagnetism property.Fe/Ni,Fe/Cu and Fe/Ag Core-shell nanoparticles were synthesized in ethanol-water solution with polyvinylpyirolidone(PVP) as protective agent and sodium borohydride as reducer. The core-shell particles were characterized by using various techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDS), thermogravimetric analysis (TGA), and vibration sample magnetometer (VSM). The results showed, that the Fe/Ni, Fe/Cu and Fe/Ag core-shell particles were spherical, catenarian and uuiform. The shell thickness of Fe core-shell nanoparticles increased with the increase of the relative content of surface coating materials. The MS of Fe core-shell particles obtained at similar conditions was decreased as following sequence:Fe/Ni, Fe/Ag, Fe/Cu.The oxidation resistance property of Fe/Cu core-shell particles was much better than Fe nanoparticles in the air.