【作者】 高建霞；

【导师】 崔春翔；

【作者基本信息】 河北工业大学 ， 材料学， 2004， 硕士

【摘要】 Sm₂Fe₁₇N_x是一种具有优异内禀磁性能的稀土金属间化合物，它的出现使永磁材料进入了一个新的时代。但其对制备工艺参数相当敏感，不易稳定的制取高性能的Sm₂Fe₁₇N_x。本课题从Sm-Fe合金的制备工艺入手，加入过渡族元素Nb，有效地控制工艺参数，以获得磁性能最佳的Sm-Fe-N型永磁体。 首先通过HDDR（氢化—歧化—脱氢—重组）工艺制备Sm₂Fe_17-xNb_xN_y合金（x=0.5，1，2，3）。然后通过扫描电镜和能谱仪、X射线衍射仪以及振动样品磁强计等分析手段对它的微结构和磁性能进行检测，通过比较分析研究。 本文重点研究了添加过渡族Nb元素对Sm-Fe合金相组成和微结构的影响，实验研究发现：添加微量的Nb元素可以有效的改善Sm-Fe合金铸态组织的显微结构。当Nb的原子比为1时的铸态组织基本为均匀的接近单相的Sm₂Fe₁₇组织，已接近于退火后的组织，从而可以避免冗长的均匀化退火化过程而直接用于制造永磁体，极大的降低了生产成本，并能有效的提高磁性能的稳定性。还对Nb的具体作用机理进行了初步探讨。 对经过HDDR处理后的Sm₂Fe_17-xNb_x合金采取不同的工艺进行氮化处理。分别对其氮化2小时，6小时，9小时和12小时。通过对得到的磁粉磁性能的比较得出最佳处理工艺，以避免氮化过程中软磁相的产生和Sm₂Fe_17-xNb_xN_y的分解。通过对不同成份配比，不同氮化工艺下得到磁粉的磁性能进行对比，得出了一些重要结论。更多还原

【Abstract】 Sm2Fe17Nx is an outstanding coercive permanent magnetic material of rare-earth metallic compound. Its appearance made the magnetic material enter a new era. But it is very difficult to get steady and high quality Sm2Fe17Nx as its properties are sensitive to the parameters of the preparing technology. So this paper is to discuss how to control the processing parameters so as to obtain the optimum microstructure and composition, thus we can get the excellent properties of Sm2Fe17-xNbxNy rare-earth permanent magnetic material.Sm2Fe17-xNbxNy alloys are prepared through HDDR(Hydrogen-Disproportionation-Desorption-Recombination) method. Through using scanning electron microscope with energy-dispersive X-ray analysis, X-ray diffraction technique and vibrating sample magnetometer etc, we can observe the microstructure and measure the magnetic properties of alloys.Through analyzing the phase composition and microstructure of Sm2Fe17-xNbx alloys (x=0.5,1,2,3), we study the influence of the addition of element Nb on the microstructure of Sm2Fe17 alloys . The results show that the as-cast structure of Sm2Fe17-xNbx alloys can be improved effectively. When the atomic ratio of Nb is one, the structure is homogeneous and almost composed of the single Sm2Fe17 phase. It’s nearly the same structure as that after annealing. So it can reduce the production cost and increase the stability of magnetic properties. The effect mechanism of Nb is also introduced.Finally we compare the data obtained from diffusion experiments conducted on powders of the Sm2Fe17-xNbx alloys after nitrifing. The powders were nitrifed for 2h, 6h, 9h and 12h respectively. They reveal the behavior of N atom in alloys. By investigating the magnetic properties of Sm2Fe17-xNbxNy magnetic powders with different composition and different nitriding time, the relationship between the magnetic properties and different composition and parameters of the preparation process is summarized. So it can prevent the formation of soft magnetic phase and decomposition of Sm2Fe17-xNbxNy during nitriding.更多还原