Preparation of aqueous dispersion of colloidal α-Fe nanoparticle by phase transfer

The synthesis of α-Fe nanoparticles via Fe3O4 nanoparticles using Fe-oleate2 complex was studied. Fe-oleate2 was prepared from the reaction of iron chloride and sodium oleate in water. The thermal decomposition of the Fe-oleate2 complex was carried out under the pressure of 40 Pa at 400 °C without any solvent and resulted in Fe3O4 nanoparticles. The produced Fe3O4 nanoparticles were collected as colloidal solution with CHCl3. The Fe3O4 nanoparticles were mixed with salt powders and annealed at 700 °C under Ar + 5% H2 gas. The salts were washed out from the produced α-Fe nanoparticles with water. The produced α-Fe nanoparticles are well dispersed in aqueous phase. The magnetic properties and crystallinity of the produced nanoparticles were chracterized by SQUID and XRD.