【作者】 杨伟；

【导师】 崔春翔；

【作者基本信息】 河北工业大学 ， 材料学， 2006， 硕士

【摘要】 Sm-Fe-N系纳米晶复合永磁材料具有优异的内禀磁性能,它的理论磁能积可高达1090kJ/m³,高于任何一种单相的永磁材料,并且其稀土含量少、化学稳定性好,有可能发展成为一种高性能的廉价稀土永磁材料。 本论文采用熔体快淬并退火晶化的方法制备了双相纳米复合Sm₃（Fe,M）₂₉N_x/α-Fe（M=Co,V,Mn）永磁材料。针对不同的合金成分,系统地研究了Fe含量的变化及Co、V、Mn的添加对Sm-Fe合金微观组织的影响,以及它们与磁性能的关系。 用X射线衍射仪、扫描电子显微镜、透射电子显微镜、振动样品磁强计等实验仪器和测量分析手段,着重研究了熔体快淬和晶化处理的工艺参数和显微结构对磁性能的影响。试验结果表明,Sm易于挥发,增加Fe含量,利于形成Sm-Fe相,并且复合元素的联合添加可以促进铸态合金内α-Fe相的晶粒细化及均匀分布。经过后续的晶化处理过程,钐铁合金随着晶化的时间不同、温度不同其磁性能也不同。氮化处理对磁性能有显著影响。当氮化时间过长时,合金样品会分解成SmN及α-Fe相,当氮化时间过短,样品内部出现未氮化的钐铁相区、氮浓度分布不均匀或氮浓度低,它们都会导致磁性能降低。我们的结论是:在480℃氮化6h后,随炉冷却至室温,样品的磁性能最佳。 此外,通过对合金样品的深入研究分析,发现在氮化前后过分地延长球磨时间将导致合金样品氧化严重,恶化磁体的磁性能。更多还原

【Abstract】 The series of Sm-Fe-N nanocrystalline composite magnets has excellent intrinsic magnetic properties. Because of their high magnetic energy product of 1090kJ/m3 together with low rare earth concentration and high chemical stability, they are believed to be promising new candidates for applications in inexpensive bonded permanent magnets.In this thesis ,the Sm₃（Fe, M）₂₉N_x/a-Fe （M=Co , V, Mn） nanocomposite permanent magnetic materials with high performance have been obtained by crystallizing over-quenched ribbons. The effects of Fe content, the additions of Co, V and Mn on the microstructure of Sm-Fe alloys and magnetic properties of the ribbons with different composition are systematically studied.X -ray diffraction, scanning electronic microscope, transmission electronic microscope and vibrating-sample magnetometer were used to analysis the processing parameters of melt spun and crystallization treatment, microstructure and magnetic properties. The result of experiment indicated that: As the saturated vapor tension is lower than that of Fe, Sm volatilized firstly which is propitious to form Sm-Fe phase. In the later crystallization process, the magnetic property of Sm-Fe alloys verify as the time and temperature of crystallization are changed. The condition of nitrogenation has a more notable effect on the magnetic property. If the time of nitrogenation is long enough, there are SmN and α-Fe phase in specimen of alloys. If the time of nitrogenation is too short, there is Sm-Fe phase of un-nitrogenation, the concentration of nitrogen is not of uniformity, and the concentration of nitrogen is far too low, all of above can result in decreasing of magnetic property. In order to obtain excellent magnetic property, our conclusion is that : When nitrogenation at 480 ℃,the optimal nitrogenation time is 6 hours.Besides, long-term ball milling deteriorated the magnetic properties. The reason is the oxidation of the power.更多还原