纳米稀土永磁材料的微磁模拟与球磨制备

发布时间：2018-04-30 12:11

本文选题：纳米永磁材料 + 永磁薄膜　；参考：《四川师范大学》2017年硕士论文

【摘要】：磁性是物质的基本属性,也是物理学研究的重要内容。永磁材料是电磁转化的核心部件,是重要的电子信息材料,其应用范围包括消费电子、移动互联网通讯、新能源汽车、节能设备以及新能源产业。在风力发电设备,永磁高铁电机,航空航天仪表和核磁共振机等设备中都需要更高性能的永磁体。纳米稀土永磁材料因其优异的磁性能、广阔的应用前景和巨大的市场价值,使其成为当前磁学研究领域的重要内容。本文以SmCo_5/Fe/SmCo_5纳米复合永磁薄膜和NdFeB微纳米颗粒的球磨制备工艺为研究对象,主要做了两个方面的研究:(1)采用微磁学方法模拟计算了SmCo_5/Fe/SmCo_5硬软磁复合多层膜的退磁化过程。微磁学计算结果与文献上报道的实验结果进行了对比。通过分析微磁学计算结果得到了软磁层厚度变化对纳米多层膜矫顽力的影响。本文的计算工作还给出了纳米复合薄膜中软磁相厚度为6纳米和12纳米时硬磁相和软磁相的微观磁矩在退磁过程中的演变情况,能够对实验表征和解析计算结果进行补充。计算结果表明软磁厚度由小变大时,在6纳米之后形核场和矫顽力逐渐开始分离,SmCo_5/Fe/SmCo_5硬软磁复合多层膜的矫顽力机制由成核变为钉扎。(2)采用控制球磨温度的实验方法和表征设备研究了温度对球磨制备NdFeB微纳米颗粒的粒度分布、微观形貌结构、矫顽力等的影响。本文测量了低温球磨时球磨罐内温度的变化,改进的温度控制方法使得球磨时的温度范围更加确定。实验表明温度对球磨制备的NdFeB微纳米颗粒的形貌结构,粒度分布影响十分显著,进而也影响了材料的矫顽力等磁性能。整体上,与常温球磨相比,低温球磨工艺产生的微纳米颗粒更加细小均匀,并且磁性能要优于常温球磨。此外低温球磨能够减少微纳米颗粒在球磨时产生的团聚体数量,但是球磨时间过长却并不能让颗粒继续细化。不同的低温温度对球磨NdFeB颗粒的细化效果影响也不同。
[Abstract]:Magnetism is not only the basic property of matter, but also the important content of physics research. Permanent magnet is the core component of electromagnetic transformation, and is an important electronic information material. Its applications include consumer electronics, mobile Internet communications, new energy vehicles, energy-saving equipment and new energy industry. Higher performance permanent magnets are needed in wind power plants, permanent magnet high-speed motors, aerospace instrumentation and nuclear magnetic resonance machines. Due to its excellent magnetic properties, wide application prospects and great market value, nanocrystalline rare earth permanent magnetic materials have become an important subject in the field of magnetic research. In this paper, the preparation process of SmCo_5/Fe/SmCo_5 nanocomposite permanent magnetic films and NdFeB microparticles by ball milling is studied in two aspects. (1) the demagnetization process of SmCo_5/Fe/SmCo_5 hard soft magnetic composite multilayers is simulated and calculated by micromagnetics method. The results of micromagnetic calculation are compared with the experimental results reported in the literature. The influence of the thickness of soft magnetic layer on the coercivity of nano-multilayer films was obtained by analyzing the results of micromagnetics calculation. In this paper, the evolution of the magnetic moments of hard and soft magnetic phases in the demagnetization process of the soft magnetic phase with the thickness of 6 nm and 12 nm is also given, which can be used to supplement the experimental characterization and analytical calculation results. The results show that when the soft magnetic thickness changes from small to large, After 6 nm nucleation field and coercivity began to separate SmCoS 5 / Fe / SmCo5 hard soft magnetic composite multilayer film from nucleation to pinning. (the experimental method and characterization equipment of controlling ball milling temperature were used to study the effect of temperature on the preparation of ball milling. Particle size distribution of NdFeB microparticles, The influence of microstructure, coercivity and so on. In this paper, the change of temperature in the ball mill tank is measured. The improved temperature control method makes the temperature range of ball mill more definite. The results show that temperature has a significant effect on the morphology and particle size distribution of NdFeB microparticles prepared by ball milling, and also affects the coercivity and other magnetic properties of the materials. On the whole, compared with the normal temperature ball mill, the microparticles produced by the low temperature ball milling process are more fine and uniform, and the magnetic properties are better than those of the normal temperature ball milling process. In addition, low temperature ball milling can reduce the number of agglomerates produced by ball milling, but too long milling time can not further refine the particles. The effect of low temperature on the refining effect of ball milling NdFeB particles is also different.
【学位授予单位】：四川师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM273

【参考文献】