Synthesis And Magnetic Properties Of Lron Nitrides

The saturation magnetic flux density of synthesis of iron nitrides is relatively high, its coercivity is very low, and it has good corrosion resistance. It is a potential candidate as the material of write head for ultrahigh-density magnetic recording. Research showed that, nitriding conditions (the ratio of NH3and H2, reaction temperature and time) have large effect on synthesis of iron nitrides, during the Nitriding process.The saturation magnetic flux density of Fe16N2is highest in all materials, but it will be decomposed into a-Fe and y’-Fe4N. Because of this, it is limited in practical use.Research showed that, the decomposition of Fe16N2phase will be restrained,and its synthesis temperature will be improved significantly under high pressure.The dissertation mainly studies on thress issues:the effect of nitriding conditions on synthesis of iron nitrides,ε-Fe3N synthesized by nitrided rapidly at low temperature and bulk of a"-Fe16N2synthesized by HTHP.The first chapter includes-Magnetic nano-materials,synthesis of iron nitrides and HTHP.The effect of the ratio of NH3and H2, reaction temperature and time on synthesis of iron nitrides is investigated in the second chapter.The third chapter introduce a way to synthesize ε-Fe3N rapidly at low temperature.The fourth chapter using mixed powder of Fe,Fe3N,which was mixed in accordance with the proportion of Fe16N2, the amorphous bulk material of nominal composition of Fe16N2was synthesized by high temperature and high pressure method (HTHP).By annealing at low temperature, the block material of a"-Fe16N2was prepared.