毕业论文移动版

摘要近些年来,随着千兆赫兹级频率波段下的无线电通信以及高频线路设备的飞速发 展,电磁干扰的问题已经受到了人们越来越多的关注。为了解决电磁干扰所带来的各 种各样的问题,人们研究了非常多不同种类的微波吸收材料。在这些材料之中,金属磁 性材料由于其具有高饱和磁化强度、高磁导率、高居里温度以及低矫顽力的特点而受 到重点关注。但是,由于金属磁性材料他们的电导率以及介电常数比较高,这就限制了 其应用。因此把金属磁性材料和某一些绝缘的材料掺杂做成复合材料就可能是解决这 些问题的其中一种途径。 80968

本文采用了静电纺丝法，高温煅烧结晶，并且结合氢热还原法成功的制成了本次 实验所需要的 Fe2Co/Al2O3 复合纳米纤维。并利用扫描电镜技术、X 射线衍射仪技术、 振动样品磁强计、和矢量网络分析仪等表征手段对目标产物样品的微观形貌、微观结 构、磁性能以及电磁特性进行了表征。结果表明，复合纳米纤维之中晶粒发育良好， 纯净，没有其他杂质。纤维直径伴随着 Al2O3 的含量的增加而变得较粗。磁性能的分

析显示出(1-x)Fe2Co/ x Al2O3 样品中 x=0 的介电常数的虚部ε″在 6 GHz 处出现其最大值； x=0。1 的样品的磁导率的虚部μ″在 16 GHz 处出现其最大值。这表明本次实验所 制得的复合材料的电磁损耗方式在低频的波段以介电损耗为主，在高频波段则以磁损 耗为主。之后利用电磁参数可以计算出本次样品的反射损耗，对复合纳米材料的微波 吸收性能进行了评估。在所有样品之中，x=0。15 的样品复合纳米纤维的反射损耗是最

好。反射损耗低于–10 dB 的带宽有 14。7 GHz。当涂层厚度为 1。9 mm 时，x=0。15 复合 纳米纤维在 5。5 GHz 处有反射损耗最小值，最小值为–22。3 dB。表现出了良好的微波 吸收性质，主要是因为在铁钴合金中添加氧化铝之后，压制了原本的涡流损耗效应， 加强了其介电损耗和磁损耗，使之本身的阻抗匹配更好，所以其微波吸收性能更好。 

毕业论文关键词：Fe2Co/Al2O3； 复合纳米纤维； 静电纺丝； 微波吸收

AbstractWith the rapid development of wireless communications and high-frequency circuit devices in the gigahertz range, electromagnetic interference(EMI) problems have attracted increasing attention recently。 Many kinds of microwave absorption materials(MAM) have been studied with the objective of solving the EMI problems。 Among all MAMs, metallic magnetic materials are especially focused on due to high saturation magnetization, high permeability, high Curie temperature and low coercivity。 However, the high electrical conductivity and high dielectric constant of metallic magnetic material limit the application。 The composite materials cantaining metallic magnetic material and certain insulation material may be a way to solve these problems。

In this paper, we used electrostatic spinning method, high-temperature calcination, and hydrogen thermal reduction process successfully to obtain Fe2Co / Al2O3 composite nanofibers。 X-ray diffraction, scanning electron microscopy, vibrating sample magnetometer, vector network analyzers characterized the microstructure technology target product, micro structure, magnetic and electromagnetic properties。 The results showed that the composite nanofibers grain was pure, without impurities and grew well。 The fiber diameter would increase when the proportion of Al2O3 increasing。 Analysis of magnetic displayed Fe2Co samples of the imaginary part of the dielectric constant ε " had a maximum value at 6 GHz place; (1-x)Fe2Co/ x Al2O3 x=0。1 imaginary part permeability μ" sample had a maximum value at 16 GHz 。This indicated that the main electromagnetic loss way was dielectric loss in the low frequency, magnetic loss in the high frequency。 And then we used electromagnetic parameters to calculate the return loss, which can assess the absorbing properties of composite nanomaterials of samples。 When the coating thickness is 1。9 mm, (1-x)Fe2Co/ x Al2O3   x=0。15   absorbing properties of the sample is preferably less than - 10 dB bandwidth reached 14。7 GHz, at a frequency of 5。5 GHz at the reflection loss has a minimum for - 22。3 dB。 This specimen showed a good microwave absorbing properties。 The main reason was that iron-cobalt alloy combined with alumina suppressed eddy current loss (责任编辑：qin)