【作者】 刘伟；

【导师】 段玉平；

【作者基本信息】 大连理工大学 ， 材料加工工程， 2017， 硕士

【摘要】 为了满足对涂层“薄、轻、宽、强”的要求,尽可能提高涂层的吸波性能,本文以片状铁硅铝为主要吸收剂构建吸波涂层,并从吸收剂复合化和结构设计两方面着手,探究提升片状铁硅铝涂层吸波性能的方法。扫描电子显微镜（SEM）和透射电子显微镜（TEM）被用来对片状铁硅铝（FFSA）、炭黑（CB）以及二氧化硅（SiO₂）等吸收剂的微观形貌进行观察,而吸收剂的电磁参数则通过网络矢量分析仪（VNA）进行了分析,并据此对吸收剂的吸波机理进行了研究。在此基础上以FFSA为主要吸收剂,以CB和SiO₂为复合吸收剂制备吸波涂层,研究吸收剂复合化对FFSA涂层吸波性能的影响。为了研究结构优化对涂层吸波性能的影响,在连续涂层的基础上,对FFSA和FFSA/CB涂层进行了非连续化结构设计,研究了结构优化对涂层吸波性能的影响。同时也制备研究了具有三明治结构的FFSA/CF涂层,分析了碳纤维织布（CF）的加入对涂层吸波性能提升的影响。研究结果表明:FFSA、CB和SiO₂是三种不同类型的吸收剂,FFSA是一种典型的磁损耗型吸收剂,其对电磁波的损耗主要归因于高频的自然共振;CB是一种电阻型吸收剂,粒径较小,易发生团聚形成导电网络,粒子的阻尼振动、多重反射和散射以及涡流损耗是其损耗电磁波的主要方式;而SiO₂是一种透波材料。以FFSA和CB为吸收剂制备了FFSA/CB复合吸波涂层,CB的加入使得涂层的涂层的吸收峰值出现了下降,有效吸收频宽（RL<-8d B）得到拓宽,吸波性能有了较大提升。将SiO₂加入到FFSA吸波涂层后发现,其有效吸收频宽（RL<-8dB）没有出现显著变化,但吸收峰值降低比较明显,表明吸收剂的复合化以及透波剂的加入可以显著提升FFSA涂层的吸波性能。对FFSA涂层和FFSA/CB涂层进行非连续化结构设计发现,具有非连续结构的涂层与原来的连续涂层相比,吸收峰值出现了下降,有效吸收频宽（RL<-8d B）变宽,吸波性能的提升十分显著,且随着非连续单元尺寸的变小,这种吸波性能的提升变得更为明显。通过对三明治结构的FFSA/CF吸波涂层研究发现,较单一的FFSA涂层具有更好的吸波性能,尤其是当涂层中碳纤维长度方向与电磁波的电场矢量方向平行时,吸收峰值明显向高频进行了移动,吸收峰值和有效吸收频宽（RL<-8d B）均的到了很大程度的提升,进一步对涂层进行非连续结构设计,吸波性能同样得到了较大改善。更多还原

【Abstract】 On the basis of meeting the request of thin in thickness,light in weight,wide absorption bandwidth and strong absorption performance,fabricating absorption coatings with stronger absorption performance is the research emphasis.In this dissertation,the absorption coatings are fabricated using flaky FeSiAl as the main absorber.And using the methods of adding composite absorber and structure design to improve the absorption performance of coatings.In this dissertation,the morphology of flaky FeSiAl（FFSA）,carbon black（CB）and silicon dioxide（SiO₂）are tested by scanning electron microscopy（SEM）and transmission electron microscopy（TEM）.The electromagnetic characteristics are tested by vector network analyzer（VNA）.The electromagnetic wave absorption mechanisms of these absorbers are studied by analyzing the results above.Absorption coatings are using flaky FeSiAl as the main absorber,CB or SiO₂ as composite absorber to investigate the impact of composite absorber on absorption performance.Discrete structure is applied on FFSA and FFSA/CB coatings to study the effect of structure design on absorption performance.Moreover,FFSA/carbon fiber（CF）coatings with sandwich structure are fabricate to investigate the impact of carbon fiber on improving the absorption performance.Discrete structure are also applied on this kind absorption coatings to better the absorption performance.The results show that:FFSA,CB and SiO₂ are three different types of absorbers.FFSA is a magnetic loss type absorber and its loss mechanism can be attributed to the natural resonance in high frequency.CB as a resistive-type absorber,is easy to aggregated to form conductivity networks because of the small particle size.Damped vibration,multiple reflection and eddy current loss are the main methods it consumes electromagnetic wave.SiO₂ is a type of wave-transmitting material without strong ability of consuming electromagnetic wave.In the FFSA/CB composite coatings,the addition of CB can reduce the absorption peak values and broaden the absorption bandwidths（RL<-8d B）.The improvement of absorption performance is very obvious.In the FFSA/ SiO₂ composite coatings,although the absorption bandwidths（RL<-8dB）doesn’t broaden obviously,the absorption peak values reduce remarkably.All these manifest that adding composite absorber is an effective method to improve the absorption performance of FFSA coatings.Discrete structure are applied on the FFSA coatings and FFSA/CB composite coatings and the absorption performance comparison is made between two type structures.Results show that the absorption coatings with discrete structure possess better absorption performance.They have lower absorption peak values and wider absorption bandwidths（RL<-8d B）.And the absorption performance improve greater with the reduction of discrete unit sizes.Compared with FFSA coatings,FFSA/CF coatings in sandwich structure possess better absorption performance.Especially when the length direction of CF is parallel to the electric field direction of the incident wave,the absorption peak shift toward higher frequency range,the lower absorption peak values and the wider absorption bandwidths were obtained.Further cutting these coatings into discrete structure,the absorption performance improve as experiments show before.更多还原