针状ε-Fe_3N超细磁粉合成及其稳定性研究

Study on Preparation of Acicular Ultrafine ε-Fe_3N Magnetic Powder and Its Stability

使用氧气还原氮化法，以针状α－ＦｅＯＯＨ为原料制备了超细针状－Ｆｅ３Ｎ磁粉。并且研 究了工艺条件对－Ｆｅ３Ｎ超细磁粉生成的影响及－Ｆｅ３Ｎ超细磁粉的稳定性。实验结果表明，氨 气与氢气的比例是影响磁粉生成的关键因素。氢气／氨气＝０．２７是生成－Ｆｅ３Ｎ最佳反应条件。 采用合适的热处理工艺和还原氮化过程可以防止颗粒断裂、球化和烧结。通过表面氧化处理的方 法可以提高针状－Ｆｅ３Ｎ超细磁粉的耐蚀性。

The ultrafine acicular ε-Fe_3N magnetic powder is prepared from acicular α- FeOOH by the process of reduction in hydrogen and following nitridation in ammonia. The effect of technological conditions on the production and the stability of Fe_3N is dis- cussed. The results show that the ratio of hydrogen and ammonia(H_2/NH_3) is the key fac- tor of the production of magnetic iron nitride powder. To get -Fe_3N, the best ratio is 0.27. The appropriate heat treatment, and reduction and nitridation process can decrease cavities of perticles and prevent particles from breakup, spheroidization and sinter. Through the way of oxidizing the surface can improve the stability of acicular ultrafine ε-Fe_3N magnetic powder.