Superparamagnetic, High Magnetic α-Fe & α″-Fe(16)N(2) Mixture Prepared from Inverse Suspension-Polymerized Fe(3)O(4)@polyaniline Composite

Oleic acid (OA)-modified Fe(3)O(4) nanoparticles were successfully covered with polyanilines (PANIs) via inverse suspension polymerization in accordance with SEM and TEM micrographs. The obtained nanoparticles were able to develop into a ferrite (α-Fe) and α″-Fe(16)N(2) mixture with a superparamagnetic property and high saturated magnetization (SM) of 245 emu g(−1) at 950 °C calcination under the protection of carbonization materials (calcined PANI) and other iron-compounds (α″-Fe(16)N(2)). The SM of the calcined iron-composites slightly decreases to 232 emu g(−1) after staying in the open air for 3 months. The calcined mixture composite can be ground into homogeneous powders without the segregation of the iron and carbon phases in the mortar without significantly losing magnetic activities.