钡铁氧体磁性材料的制备及吸波性能的研究

发布时间：2018-02-13 06:09

本文关键词： 溶胶-凝胶法离子取代钡铁氧体磁性能微波吸收性能　出处：《中北大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着现代雷达、微波通信和电子技术的飞速发展，以及在武器隐形技术上，，微波暗室上与抗电磁干扰的技术方面上的应用，微波吸收材料目前已经受到越来越多的人的关注。铁氧体吸收材料既有介电损耗又有磁性损耗的一种微波吸收材料。本文主要介绍钡铁氧体吸波材料及钡铁氧体/空心微珠复合吸波材料的最新研究进展及制备方法。由于钡铁氧体具有良好的粒度、较强的各向异性和适中的饱和磁化强度使其成为重要的磁性材料和吸波材料，广泛应用于高密度磁记录、高性能永磁体、微波器件以及在民用和军事技术中应用，因而备受人民关注。本研究是采用溶胶-凝胶法，制备出具有磁铅石型结构的钡铁氧体。柠檬酸络合分解法由于基本反应在溶液中进行，达到分子水平上的混合，因而颗粒细小且均匀，在制备超微铁氧体的方面优于其它方法。（1）为了优化工艺条件，采用柠檬酸法制备Ni-Mg-Co替代其中Fe元素的Ba(Ni0.5Mg0.45Co0.05)xFe12-xO19（x=0，1，2，3）纳米粉体，设计正交实验，重点考察了柠檬酸用量、替代量X、pH值、煅烧温度及保温时间对制备纳米钡铁氧体的影响，同时在正交实验的基础上考虑两个单因素变量替代量X和柠檬酸用量对其电磁性能的影响，最终得出柠檬酸法制备纯的粒径较小且分散均匀的纳米的最佳实验条件。（2）研究离子取代对BaM型铁氧体结构和电磁性能的影响。为了满足不同领域的各类需求通过Ni2+、Mg2+、Co2+取代M型钡铁氧体中Fe3+研究发现，离子取代钡铁氧体随着取代量的不同，磁性能和吸波性能有不同的变化趋势。结果表明：在最佳实验条件下可以制备单一相的钡铁氧体Ba(NiMg0.9Co0.1)Fe10O19纳米粉体；有其最大的饱和磁化强度以及在最佳匹配厚度2.0mm，同时在12GHz位置上的吸收峰最佳反射率为-16.2dB，吸收大于-10dB的峰宽达到了4.1GHz。（3）为了Ba(NiMg0.9Co0.1)Fe10O19钡铁氧体获得更好的吸波性能，因此选择合适两种粒径的空心微珠，空心微珠表面包覆单相的磁铅石型结构型的Ba(NiMg0.9Co0.1)Fe10O19复合粉体是采用溶胶-凝胶法制备的，Ba(NiMg0.9Co0.1)Fe10O19与空心微珠表面包覆的磁损耗与介电损耗在不同频段有不同的表现形式。由于Ba(NiMg0.9Co0.1)Fe10O19中加入空心微珠复合后其吸波性能变差，综合考虑其实验关键因素。我们需要知道如何控制好选择合适粒径的空心微珠和涂层的匹配厚度，从而获得更好的吸波性能。
[Abstract]:With the rapid development of modern radar, microwave communication and electronic technology, as well as the application in weapon stealth technology, microwave darkroom and anti-electromagnetic interference technology, Microwave absorbing materials have attracted more and more attention. Ferrite absorbing materials have both dielectric loss and magnetic loss. This paper mainly introduces barium ferrite absorbing materials and barium ferrite. The latest research progress and preparation methods of composite microwave absorbing materials with hollow microspheres are presented. Because barium ferrite has good particle size, Strong anisotropy and moderate saturation magnetization make it an important magnetic and absorbing material, widely used in high density magnetic recording, high performance permanent magnets, microwave devices, as well as in civilian and military technologies, As a result, people are concerned about it. In this study, barium ferrite with magnetic lead structure was prepared by sol-gel method. Due to the basic reaction in solution, citric acid complex decomposition method achieved molecular level mixing, so the particles were fine and uniform. It is superior to other methods in preparing ultrafine ferrite. In order to optimize the technological conditions, Ni-Mg-Co powder was prepared by citric acid method to replace Fe element Bani _ (0.5) mg _ (0.45) Co _ (0.05) X Fe _ (12-x) O _ (19) O _ (19) O _ (10) O _ (1) O _ (2) O _ (2) O _ (2) O _ (3) nanometer powder. The orthogonal experiment was designed. The effects of calcination temperature and holding time on the preparation of nanocrystalline barium ferrite were studied. On the basis of orthogonal experiment, the effects of the substitution amount X and the amount of citric acid on the electromagnetic properties of nanocrystalline barium ferrite were considered. Finally, the optimum experimental conditions for the preparation of nanometer nanoparticles with small particle size and uniform dispersion by citric acid method were obtained. The influence of ion substitution on the structure and electromagnetic properties of BaM type ferrite was studied. In order to meet the various demands in different fields, the study of Fe3 in Ni2 Mg2 / Co 2 substituted M type barium ferrite found that the substitution barium ferrite with different substitution amount. The results show that the barium ferrite Ba(NiMg0.9Co0.1)Fe10O19 nanocrystalline powders with single phase can be prepared under the optimum experimental conditions. With the maximum saturation magnetization and the optimum matching thickness of 2.0 mm, the optimum reflectivity of the absorption peak at 12GHz is -16.2 dB, and the peak width greater than -10 dB reaches 4.1 GHz. (3) in order to obtain better absorbing property of Ba(NiMg0.9Co0.1)Fe10O19 barium ferrite, two kinds of hollow microspheres were chosen. The magnetic loss and dielectric loss of hollow microspheres coated with single-phase magneto-lead type Ba(NiMg0.9Co0.1)Fe10O19 composite powders prepared by sol-gel method are different in different frequency range from that prepared by sol-gel method. When the hollow microspheres are added into the Ba(NiMg0.9Co0.1)Fe10O19, the absorbing property of the composite becomes worse. Considering the key factors of the experiment, we need to know how to control the matching thickness of the appropriate diameter hollow beads and the coating, so as to obtain better wave absorption performance.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM277

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