Particle size dependence in low temperature nitridation reaction for Fe16N2

Low temperature nitridation of α-Fe powder was studied by reduction of α-Fe2O3 with three particle sizes using flow hydrogen. Most suitable α-Fe2O3 powder had an average particle size of 60 nm. After hydrogen reduction, the α-Fe showed average particle size of about 120 nm. The yield of ferromagnetic Fe16N2 obtained at 140 °C for 100 h was the highest of its nitrided product among the products nitrided in a temperature range of 130–170 °C. Thermal decomposition of iron pentacarbonyl was also applied to obtain a narrow particle size distribution of monodispersed α-Fe spherical particles of 30 nm. It was performed in the presence of oleic acid stabilizer in octyl ether solvent.