Z型六角铁氧体的制备及高频电磁性能研究

发布时间：2018-01-16 01:30

本文关键词：Z型六角铁氧体的制备及高频电磁性能研究　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：自本世纪以来,通讯和电子技术飞速发展,各类新型通讯设备和家用电器更型换代越来越快,几百兆左右的高频段磁性材料已经无法满足电子领域发展的需要。磁性材料中六角铁氧体材料由于其较大的磁晶各向异性而具有较高的截止频率,因而具有较大的发展潜力。六角铁氧体中的Z型(分子式Ba3Co2Fe24O41)具有低矫顽力、高截止频率和高磁导率而引起了广泛关注。本毕业论文将以Z型六角铁氧体材料为研究对象,在深入分析了其晶体结构,物理性能和合成工艺机理后,对材料的离子替代,掺杂改性和制备工艺做了细致深入研究。全文主要内容如下:一、研究了不同类型离子取代,尤其是稀土离子对晶相、微观形貌和微波磁性能的影响。本文对Z型六角铁氧体分子式中每种阳离子进行离子取代,用于取代的离子包括磁性金属离子和非磁性金属离子,其中磁性金属离子又包括磁矩大于Fe3+的和磁矩小于Fe3+的两种。研究表明取代离子的数量、半径和占位对Co2Z的性能有重大影响,另外原料中氧化物的熔点和电阻率也能影响到最终的性能。二、研究了掺杂对晶相、微观形貌和微波磁性能的影响,尤其是掺杂低熔点氧化物所导致的液相烧结对微波磁性能的影响。通过XRD、SEM和矢网仪表征表明3%的Bi2O3在1000 oC条件下有助于实现样品的低温烧结,并能取得不错的Q值,可以用于改善微带天线磁性能,进而提高天线增益。使用已经基本成相的尖晶石铁氧体与预烧之后的Z型六角铁氧体粉料混合后进行烧结,最终发现这种掺杂后两种铁氧体能够保证各自的单相性,并且颗粒贴在一起,这使得样品能够在微观上出现大量的界面,使其介电极化效应增强,介电性能大幅提高,最终改善了电磁波吸收性能。三、研究了氧气气氛烧结对样品晶相、微观形貌和微波磁性能的影响。研究表明氧气气氛能够通过抑制Fe3+离子还原成Fe2+而控制其损耗,最终提高Co2Z的Q值,扩展其应用频段。
[Abstract]:Since this century, with the rapid development of communication and electronic technology, all kinds of new communication equipment and household appliances are changing more and more quickly. Hundreds of megabytes of high-frequency magnetic materials can no longer meet the needs of the development of electronics. Hexagonal ferrite materials in magnetic materials have a higher cut-off frequency due to their larger magnetocrystalline anisotropy. The Z type in hexagonal ferrite (molecular formula Ba3Co2Fe24O41) has low coercivity. High cut-off frequency and high permeability have attracted wide attention. This thesis will focus on Z-type hexagonal ferrite material, after in-depth analysis of its crystal structure, physical properties and synthesis mechanism. The main contents of this paper are as follows: 1. Different kinds of ion substitution, especially rare earth ion pair crystal phase are studied. Effects of micromorphology and microwave magnetic properties. In this paper, each cation in the molecular formula of Z type hexagonal ferrite is replaced by ions, including magnetic metal ions and nonmagnetic metal ions. The magnetic metal ions include those whose magnetic moment is greater than Fe3 and whose magnetic moment is less than Fe3. It is shown that the number, radius and occupation of substituted ions have great influence on the performance of Co2Z. In addition, the melting point and resistivity of the oxide in the raw material can also affect the final performance. Secondly, the effects of doping on the crystal phase, microstructure and microwave magnetic properties are studied. In particular, the effect of liquid phase sintering induced by doping low melting point oxides on microwave magnetic properties was investigated by XRD. SEM and sagittal meter characteristics show that 3% Bi2O3 can be used to improve the magnetic properties of microstrip antennas. It is helpful to achieve low temperature sintering of the samples at 1000oC, and can obtain good Q value, which can be used to improve the magnetic properties of microstrip antennas. Then, the antenna gain is improved. The spinel ferrite, which has been basically formed, is mixed with the pre-fired Z hexagonal ferrite powder to be sintered. Finally, it was found that the two kinds of ferrite after doping can guarantee their monophase and stick together, which makes the samples have a large number of interfaces in the microcosmic, so that the dielectric polarization effect is enhanced. The dielectric properties were improved greatly, and the electromagnetic wave absorption was improved. Thirdly, the sintering effect of oxygen atmosphere on the crystal phase of the samples was studied. The results show that the oxygen atmosphere can control the loss of Fe3 ion by inhibiting its reduction to Fe2, and finally increase the Q value of Co2Z and expand its application frequency band.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM277

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