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利用自反应淬熄法制备了Zn-Ti钡铁氧体空心陶瓷微珠吸波材料,这种材料具有核/壳结构,比一般的铁氧体密度小,是一种新型的吸波材料;通过SEM、EDS和XRD分析表明,该材料具有中空结构,成球规则,粒径分布均匀,经过热处理之后,由非晶相物质转变为了晶相物质,主要物相为Ba Zn Ti Fe10O19和Ba Fe12O19;通过吸波性能测试,该材料具有一定的吸波性能,经过热处理之后吸波性能提高了,其吸波最低反射率为–21.98 d B,反射率小于–10 d B的带宽大于2 GH Z。 相似文献
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为获得低频宽带吸波材料,本文采用共沉淀和原位聚合技术制备了羰基铁/CoFe2O4/PANI三元复合材料,并以此为介质层,借鉴超材料思想,设计了一种基于超材料结构的羰基铁复合吸波涂层,改善了低频吸波性能。分析了超材料的结构设计对羰基铁/CoFe2O4/PANI涂层吸波性能的影响,并对赋予超材料结构后的复合涂层的吸波机理进行了研究和讨论。通过仿真优化发现,在电阻膜方阻值为10mΩ/□和镂空十字电阻膜图案尺寸达到最佳时,在相同厚度下赋予超材料结构后的复合涂层具有比单一羰基铁涂层更宽的吸收频带以及更低的吸收频率,在3.8-6.9GHz频段内反射率均小于-10dB。研究表明,将超材料结构融入到羰基铁涂层性能改进中,能够有效提升其低频吸波性能。 相似文献
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讨论了电磁波的吸波机理,及其性能测量和计算方法,叙述了电阻型损耗、介电损耗、磁损耗型三种损耗机制的涂层材料及其电磁波吸收损耗机理,对不同种类的吸波材料在雷达波隐身方面的应用进行了全面的综述,介绍了这一研究方向的最新进展,并分析了每种材料的主要特点。重点讨论了铁氧体、碳纳米管、导电高聚物等吸波材料的微观结构、化学性质、电磁特性对吸波性能的影响。对于磁损耗材料来说,良好的磁性能是其不可忽视的优点,但其密度高,稳定性较差,影响了其性能发挥。针对其存在的缺点,通过掺杂改性、共混等方式可提升涂层材料的吸波性能。在碳系材料中,多壁碳纳米管的吸波性能较好,将磁损耗吸波材料与碳纳米管进行复合、包覆是目前吸波性能提高的主要手段。导电聚合物等新型吸波材料具有质量轻、导电性好的特点,单独使用时,阻抗匹配性差,通过对其掺杂改性或与磁损耗型材料复合,可增强其阻抗匹配性,提升吸波性能。最后,指出了雷达吸波材料未来的研究发展方向。 相似文献
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橡胶基复合吸波贴片的电磁性能研究 总被引:1,自引:1,他引:0
制备了一系列炭黑/羰基铁/硅橡胶复合吸波材料,研究了炭黑含量对羰基铁/硅橡胶电磁性能的变化规律.用同轴线法测试了炭黑和羰基铁在2~18 GHz的电磁参数.对复合材料的导电性能、吸波性能及屏蔽性能进行了测试,对其各项性能的变化规律进行了总结.研究发现,在羰基铁与硅橡胶质量比固定在50:100(即50 phr)时,随着炭黑含量的增加,各项性能都呈现出增强的趋势,但当炭黑质量与硅橡胶的质量比达到70:100后(即70 phr),再增加炭黑的加入量,各项性能几乎没有改变.另还对导电、吸波以及屏蔽性能的关系进行了分析. 相似文献
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Glass-coated amorphous FeCuNbSiB microwires were prepared by Taylor-Ulitovsky technique. X-ray diffractometry and scanning electron microscopy were used to investigate the microstructure and morphology of the glass-coated microwires respectively. The vibrating sample magnetometer and vector network analyzer were used to study the magnetostatic and microwave properties of glass-coated microwires. The experimental results show that the effective anisotropy of an array of 150 microwires of 10 mm in length is large than that of one microwire of 10 mm in diameter and an array of 150 microwires of 1 mm in diameter. The natural ferromagnetic resonance takes place as the microwave magnetic component is perpendicular to the microwires axis, and the electric dipole resonance takes place as the microwire is long or the short microwire concentration is moderate. The natural ferromagnetic resonance shifts to higher frequency with the larger microwire concentration. The electric dipole resonance is governed by the microwires length and concentration. The glass-coated FeCuNbSiB microwires can be used to design EMI filters and microwave absorbing materials. 相似文献
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采用泰勒法制备了直径范围在30~100μm之间的玻璃包裹Ni-Mn-In-Co合金纤维。利用综合物性测量系统(PPMS)研究了磁场对制备态和退火态纤维马氏体相变温度的影响,并且从M-B曲线中分别计算得出了制备态和退火态纤维的磁热效应。研究结果表明:制备态纤维在室温下为7M马氏体结构。在制备态和退火态纤维中,奥氏体相变开始温度随外加磁场变化速率(ΔAs/ΔB)分别为-1.6和-4 K/T。退火态纤维在As点附近发生磁场诱发马氏体向奥氏体逆相变。退火态纤维最大磁熵变为3.0 J/(kg·K),远大于制备态纤维的0.5 J/(kg·K)。Ni-Mn-In-Co合金纤维的大磁熵变和低成本使其成为最具潜力的磁制冷材料之一。 相似文献
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S. A. Baranov 《Surface Engineering and Applied Electrochemistry》2011,47(4):308-322
A theory of a magnetic domain model for glass-coated amorphous microwires is studied. The obtained theoretical results are
confirmed by experiments. Cast glass-coated amorphous microwires with positive magnetostriction have a rectangle hysteresis
loop, which is characterized by a coercive-force stable magnitude. The coercive-force magnitude and the fluctuations of this
magnitude are of theoretical and practical interest. The theory of the relaxation mechanism of magnetic reversal is constructed.
For the more precise comparison of the theory and the experiment, a series of experimental measurements is needed, which are
also discussed in the paper. 相似文献
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The effect of mechanical stress on Ni63.8Mn11.1Ga25.1 microwire crystalline structure and properties
《Intermetallics》2013
We studied structure and magnetic properties of Heusler alloy microwires. The dependence of the phase composition of the annealed microwires on the presence of glass coating has been found. The crystalline structure of the glass-coated samples is composed of two cubic crystalline phases of different density. The samples annealed without coating are in the single-phase state. The two-phase state is supposed to be caused by intrinsic stresses resulted from the action of opposite sign stresses in different microwire sections. The magnetic properties of the fabricated Heusler-type microwires differ from their bulk and thin film counterparts. Annealing of microwires considerably affect magnetic properties at room temperature. Unusual magnetic behavior is connected with two-phase structure of microwires. 相似文献
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《Intermetallics》2014
We observed that magnetic properties (Giant magneto.-impedance effect and domain wall dynamic) of glass-coated microwires are closely related with the peculiarities of the fabrication technique involving rapid solidification of metallic alloy surrounded by glass coating from the melt.We present studies of the interfacial layer between the metallic nucleus and glass coating and studies of the inhomogeneities related with fabrication process of thin ferromagnetic microwires.We observed gas bubbles within the glass coating with volume content of about 8–12%. The sizes of the bubbles were between 1 and 15 μm. The existence of such bubbles might be the origin of the inhomogeneities in the internal stresses distribution.Using scanning electron microscope JEOL JSM-6610 we obtained the image of the interfacial layer and the elements distribution within the glass coating and metallic nucleus. This allowed us to estimate the thickness of the interfacial layer.Understanding of the origins of the interfacial layer and defects may help for improvement of the existing technology for thin composite wires fabrication and enhance their magnetic properties. 相似文献
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S. A. Baranov 《Surface Engineering and Applied Electrochemistry》2009,45(6):441-445
The skin-effect theory is presented using the example of an amorphous ferromagnetic material taking into account the ferromagnetic
resonance. The theoretical dependence of the impedance of a microwire on its magnetic permeability is determined. The results
allow analyzing experiments on studying the high-frequency properties of amorphous microwires. 相似文献
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S. A. Baranov M. Yamaguchi K. L. Garcia M. Vazquez 《Surface Engineering and Applied Electrochemistry》2008,44(6):425-427
Correlation between frequency of natural ferromagnetic resonance of the cast glass coated amorphous microwires and high-frequency
absorption of a composite material from this microwire is investigated.
The article is published in the original. 相似文献
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Jacob Torrejón Germán Infante Giovanni Badini-Confalonieri Kleber R. Pirota Manuel Vázquez 《JOM Journal of the Minerals, Metals and Materials Society》2013,65(7):890-900
Multilayer microwires with biphase magnetic behavior are revisited in this work. They are fabricated by the combination of ultrarapid solidification and electroplating techniques, and they are composed by ferromagnetic nucleus, intermediate glass layer, and ferromagnetic outer shell. Different magnetic configurations have been explored: soft/hard (CoFeSiB/CoNi and FeSiB/CoNi), soft/soft (CoFeSiB/FeNi), and hard/soft (FePtSi/FeNi). Their magnetic properties are mainly determined by the magnetic interactions between both magnetic phases: (I) a magnetoelastic coupling that arises from the mechanical stresses induced during the growth of the external magnetic shell and (II) a magnetostatic bias field that arises from uncompensated magnetic charges of the hard layer. Most outstanding static (i.e., low-field hysteresis loops) and dynamic (i.e., magnetoimpedance and ferromagnetic resonance) properties are reviewed in this article. The possibility to tailor the magnetization reversal of the soft phase through the tuning of those magnetic couplings places multilayer biphase microwires in a very competitive position as functional sensing elements suitable for a number of technological applications. In particular, we focus on their use in multifunctional sensor devices and fluxgate applications. 相似文献
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《Intermetallics》2014
We studied giant magnetoimpedance (GMI) effect and magnetic properties of Fe70.8Cu1Nb3.1Si14.5B10.6 and Fe71.8Cu1Nb3.1Si15B9.1 Finemet microwires. We observed that GMI effect and magnetic softness of glass-coated microwires produced by the Taylor–Ulitovski technique can be tailored either controlling magnetoelastic anisotropy of as-cast FeCuNbSiB microwires, and/or controlling their structure by heat treatment or by changing the fabrication conditions. High GMI effect has been observed in as-prepared Fe-rich and heat treated microwires with nanocrystalline structure. 相似文献
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In the present work, we have studied the low field absorption (LFA) at 9 GHz of a set of Co-based glass-coated microwires in the presence of tensile stresses along the wire axis. The results reveal that the absorption profiles bear valve-like features associated with microwave magnetoimpedance effect. The stress applied along the wire axis compensates the reverse effect of magnetic field on absorption. The peak shown in the derivative LFA spectra becomes wider with increasing stress and moves to higher field, corresponding to the magnetization process. A larger ratio of metal to total diameter was found to be favorable to microwave absorption due to the smaller anisotropy and also gave rise to a larger magnetostriction constant. The influences of stress/magnetic field on the absorption as well as the shift of feature stress with wire geometry were discussed in the context of an effective microwire-based sensor design. Calculations of magnetostriction constant by the derived field dependence of anisotropy field were also performed to demonstrate the usefulness of stress tunable microwave absorption characteristics as a research tool. 相似文献