| The dissertation mainly studies on three issues:spinel ferrite nanotubes, the preparation of ε-Fe3N powder by sol-gel combustion in a low temperature and the preparation of Fe-N magnetic powder by nitrization of iron powder.Firstly, this dissertation mainly analyses ferrite nanotubes of cobalt, zinc or nickel, which were synthesized by template method. The experiment indicates the three samples are of the explicit tube-like structure via the transmission electron microscope. Furthermore, the formation conditions of them are alike, but particle sizes around the nanotube are not consistent. XRD results demonstrate that all nanotubes are made up of the spinel ferrites without any preferred crystallite orientation. What’s more, according to magnetic measurement, the samples have no distinct features of magnetocrystalline anisotropy.Secondly, using nanometer Fe foam fabricated by sol-gel combustion, the nitriding temperature for ε-Fe3N synthesis could be reduced, and the nitriding time could be effectively shortened. Fe foam is transformed into ε-Fe3N powder after being nitrided for0.5h at400℃. The experiment indicates that the soft magnetic and high frequency magnetic properties of the ε-Fe3N sample are very favorable.Finally, the Fe-N magnetic powder has been prepared by nitrization of iron powder. The effects of process parameters on the products such as the ratio of NH3/H2, the reaction temperature and the holding time of reaction temperature were investigated Besides we found the best way to synthesize Fe3N and Fe4N particles. |
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