Fe基软磁合金的穆斯堡尔谱研究

发布时间：2018-06-16 14:36

本文选题：Fe基软磁合金 + 电磁波吸收剂　；参考：《电子科技大学》2015年硕士论文

【摘要】：Fe基软磁合金是目前研究非常热的信息功能材料之一,其优异的电磁性能受到了很广泛的关注。本文主要选用了Fe-Si-Al、Fe-Cu-Nb-Si-B两种Fe基软磁合金为研究对象,分别讨论了在不同的球磨时间和热处理工艺下它们所具有的电磁性能。重点引入穆斯堡尔谱的研究方法,利用穆斯堡尔谱极高的能量分辨率,研究球磨工艺和热处理工艺导致的固态相变,通过研究相变前后内部Fe原子核所处的周围原子环境的变化,揭示固态相变过程中细微的原子环境变化导致的静态磁性能的变化,从而解释改良后电磁性能的物理本质。本论文开展了以下的工作并得出了相关的结论:首先,通过对Fe-Si-Al球磨时间的控制,得出Fe-Si-Al颗粒的形状对磁性能有较大的影响。本文着重研究了未球磨的无规则颗粒和球磨30小时后的片状颗粒,对其进行了形貌、高频、静态磁特性的对比分析。结果表明随着球磨时间的增大,片状合金厚度减小,比饱和磁化强度减小,复数磁导率和复介电常数得到提高。XRD测试表明,随着球磨的进行,Fe-Si-Al的晶体结构逐渐从有序固溶体(D03型超晶格结构)转变为无序固溶体ɑ-Fe(Si,Al)结构。对球磨前后的样品进行了穆斯堡尔谱的测试,穆谱的拟合结果清楚地证实了有序固溶体向无序固溶体的转变。其次,通过对Fe-Cu-Nb-Si-B(FINEMET)合金的热处理,发现在热处理后出现了部分纳米晶相,实现了在片状粉体颗粒中高电阻率的非晶铁磁性相与低电阻率的纳米晶铁磁性相的共存。这种纳米复合结构能降低高频下的涡流损耗。最后,对于具有这种双铁磁性相的纳米复合结构,我们采用穆斯堡尔谱超精细相互作用参数的离散型的模型和分布式模型进行拟合,可从拟合结果中知晓非晶基体的晶化程度。对热处理后的片状化FINEMET合金粉体进行了电磁特性的测试,结果表明在1.93-3.2GHz范围内FINEMET合金粉体具有优良的电磁波吸收性能。
[Abstract]:Fe-based soft magnetic alloy is one of the hot information functional materials, and its excellent electromagnetic properties have been paid more and more attention. In this paper, two Fe-base soft magnetic alloys, Fe-Si-Al-Fe-Cu-Nb-Si-B, are chosen as the research objects. The electromagnetic properties of Fe-Si-Al Fe-Cu-Nb-Si-B alloys under different ball-milling time and heat treatment are discussed respectively. Mossbauer spectroscopy was introduced to study the solid phase transition caused by ball milling and heat treatment by using the extremely high energy resolution of Mossbauer spectrum. By studying the changes of the atomic environment around the Fe nucleus before and after the phase transition, the changes of the static magnetic properties caused by the minor changes in the atomic environment during the solid phase transition are revealed, thus explaining the physical nature of the improved electromagnetic properties. In this paper, the following work has been done and relevant conclusions have been drawn: firstly, by controlling the milling time of Fe-Si-Al, it is concluded that the shape of Fe-Si-Al particles has great influence on the magnetic properties. In this paper, the irregular particles in the ball mill and the flake particles after 30 hours of ball milling are studied. The morphology, high frequency and static magnetic properties of the particles are compared and analyzed. The results show that with the increase of ball milling time, the thickness of the sheet alloy decreases, the specific saturation magnetization decreases, and the complex permeability and complex permittivity increase. With the ball-milling, the crystal structure of Fe-Si-Al is gradually changed from the ordered solid solution (D03) superlattice to the disordered solid solution (FE-Si-Al). The Mossbauer spectra of samples before and after ball milling were measured and the fitting results of Mu spectra clearly confirmed the transition from ordered solid solution to disordered solid solution. Secondly, by heat treatment of Fe-Cu-Nb-Si-B-FINEMET alloy, it is found that part of nanocrystalline phase appears after heat treatment, and the coexistence of high resistivity amorphous ferromagnetic phase and low resistivity nanocrystalline ferromagnetic phase is realized. This nanocomposite structure can reduce eddy current loss at high frequency. Finally, for the nanocomposite structure with this kind of double ferromagnetic phase, the discrete model and the distributed model of the hyperfine interaction parameters of Mossbauer spectrum are used to fit the structure. The degree of crystallization of the amorphous matrix can be known from the fitting results. The electromagnetic properties of FINEMET alloy powder after heat treatment were tested. The results show that FINEMET alloy powder has excellent electromagnetic wave absorption property in the range of 1.93-3.2GHz.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG132.271

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