Synthesis of Iron Nitride Powder and Their Phase Transformation from Paramagnetism to Ferromagnetism under Pyrolysis Process

Abstract

The synthesis of Fe₂N powder from FeC₂O₄ powder and their thermal decomposition behavior were studied, and their magnetic properties were investigated. FeC₂O₄ powder, which is a starting material of iron nitride, was prepared by the precipitation method in ethanol solvent (FeCl₂aq.-H₂C₂O₄⋅EtOH), consequently fine powder was obtained. Fe₂N powder was prepared by the thermal decomposition of fine FeC₂O₄ powder under NH₃ gas flow at 410°C, and the pyrolysis temperature was lower than that of FeC₂O₄ made from water solvent (FeCl₂aq.-(NH₄)₂C₂O₄aq.). When the Fe₂N powder was heated in air and under Ar gas flow, the pyrolysis started at 150°C and 350°C, respectively. Fe₃N single phase was obtained by pyrolysis of Fe₂N powder at 400°C under Ar gas flow, and iron nitride transformation from paramagnetism to ferromagnetism was caused.