吸波材料的研究进展

吸渡材料的研究是隐身技术发展的关键,吸波剂的好坏对于吸波材料的性能有很大的影响。本文在对吸波材料以及其吸波原理进行介绍的基础上,大体阐述了有关吸波材料的研究进展,通过对几种常用的微波吸波剂的介绍,提出了未来吸波材料的发展将向着”薄、轻、宽、强”和耐腐蚀性等方面进行研究。     

吸波涂层材料的研究进展

吸波材料在军事和民用领域具有非常重要的意义,而提高吸波材料性能的关键是提升吸收剂的电磁性能和优化吸波材料的制备工艺。在讨论吸波材料的吸波原理之后,详细介绍了铁氧体、高温吸波材料、纳米吸波材料、复合吸波材料及导电高分子吸波材料这五种吸波涂层材料的最新研究进展,并分析各种涂层的主要特点,最后指出吸波材料向纳米化、复合化、性能可调的方向发展。     

纳米吸波材料的研究现状与发展趋势

评述了纳米吸波材料的特性及吸波原理,介绍了纳米铁氧体吸波材料、纳米金属吸波材料、纳米陶瓷吸波材料、纳米导电高分子吸波复合材料、碳纳米管吸波材料、纳米复合吸波材料研究现状及发展情况,指出了纳米复合吸波材料是未来纳米吸波材料的研究重点。     

铁氧体复合材料吸波性能研究进展

介绍了铁氧体吸波材料的概况。重点总结了近年来铁氧体复合材料的研究现状和吸波性能。详细介绍了聚苯胺/铁氧体复合材料、环氧树脂/铁氧体复合材料以及铁氧体与其它导电聚合物的复合材料的吸波性能,这些复合材料将是今后吸波材料研究和发展的重要方向。针对未来发展提出了建议。     

柔性橡胶吸波材料的研究进展

概述柔性橡胶吸波材料吸波基本原理,重点介绍铁氧体系橡胶吸波材料、金属铁微粉系橡胶吸波材料、碳系橡胶吸波材料以及多层橡胶吸波材料的研究状况。目前橡胶吸波材料的探索大多局限于实验室研究,橡胶吸波材料还未能成熟地进行工业化生产和应用,需要进一步探讨高温、低温、振动冲击等环境因素以及硫化体系和混炼工艺对橡胶吸波材料吸波性能的影响,开发能够吸收特定波长的橡胶吸波材料。     

新型吸波材料及其制备方法概述

介绍了国内外隐身技术的发展状况，对铁氧体吸波材料、纳米吸波材料、导电高分子吸波材料、耐高温陶瓷材料、结构型吸波材料等几种吸波材料的研究动态、制备方法及应用进行了描述和对比，总结了雷达吸收剂的发展趋势。     

纤维型雷达隐身吸波材料的研究进展

介绍了纤维在涂覆型吸波材料和结构型吸波材料中的应用及发展,结果发现,采用异型截面纤维、螺旋形纤维以及不同纤维混杂是得到“薄、轻、宽、强”吸波材料的有效方法。     

纳米吸波薄膜的研究进展

介绍了磁损耗型、介电损耗型和二者损耗机制兼备的纳米吸波薄膜的吸波机理和吸波性能,并总结分析了吸波薄膜的研究内容和研究方向。提出了纳米吸波薄膜亟待解决的问题,并对制备薄、宽、轻、强的吸波材料进行了展望。     

铁氧体吸波性能的研究与进展

铁氧体在吸波领域有广泛应用,因其具有良好的吸波性能。简述了吸波材料的吸波原理,从结构、性能、以及稀土掺杂等方面介绍了作为吸波材料重点之一的铁氧体的研究进展。     

微纳米吸波材料研究现状

介绍了微纳米吸波材料的吸波机理,叙述了铁氧体吸波材料、金属微粉吸波材料、多晶铁纤维吸波材料等常用吸波材料的特点与研究进展;着重分析了纳米材料的特点以及其作为吸波材料的独特性能,并简要介绍了具有独特性能的左手材料以及碳纳米管作为吸波材料的研究现状,在此基础上对吸波材料的研究前景进行展望.     

Broadband electromagnetic wave absorption of Ni0.5Zn0.5Nd0.04Fe1.96O4 ferrites modified by nano-silver particles

Ferrite materials have the potential to become excellent absorbing materials due to their high magnetic loss and good impedance matching. However, the disadvantages of high density and lack of dielectric loss capability limit its application. Herein, we used the citric acid sol-gel method and the self-propagating combustion method to prepare neodymium-doped nickel-zinc ferrite (NZNF), then the target effect of Sn²⁺ and an improved electroless silver plating process was used to plate a layer composed of silver nanoparticles (Ag NPs) with strong dielectric loss on the NZNF, and a magnetic/dielectric composite material (NZNF@Ag) with a heterogeneous structure was prepared. The number and particle size of Ag NPs on the surface of NZNF can be precisely controlled, thereby greatly enhancing the dielectric loss capability with little impact on the magnetic loss. The huge difference in conductivity between conductors and semiconductors promotes the occurrence of polarization at the heterogeneous interface and significantly enhances the electromagnetic wave absorption ability of the composite material. In the 2–18 GHz frequency band, the best sample can obtain an effective bandwidth of 6.82 GHz when the matching thickness is 2.1 mm. Combining conductors with semiconductor materials to obtain significantly enhanced interfacial polarization provides a new idea for improving the performance of wave absorbing materials.     

高吸油性树脂的研究进展与展望

高吸油性树脂是一种新型功能高分子材料。其在吸油机理上与传统的吸油材料完全不同。对高吸油性树脂的吸油原理、热力学与动力学方面的理论研究进行了介绍;对影响树脂合成与性能的聚合单体、交联方式、聚合工艺、温度与时间等都进行了系统的论述;对当前高吸油性树脂在环境保护、工业原料等方面的应用也作了综述。最后展望了高吸油性树脂的发展方向,指出其在理论研究、新技术开发、应用领域拓展这三个方面需要重点关注。     

离子取代与六角铁氧体RAM的结构及微波吸收性能

综述了离子取代与六角铁氧体结构、静磁特性、微波吸收性能的关系.表明离子取代可以有效地控制六角铁氧体的Ms,HA等静磁性能,改善其微波电磁性能,使其在亚毫米及毫米波段具有较好的微波吸收特性.对铁氧体在RAM材料中的发展进行展望.     

MXene-derived TiC/SiBCN ceramics with excellent electromagnetic absorption and high-temperature resistance

Demand for high-performance electromagnetic (EM) wave absorbing materials with high-temperature resistance is always urgent for application in a harsh environment. In this contribution, two-dimensional material, Ti₃C₂T_x MXene, was introduced into a hyperbranched polyborosilazane. After pyrolyzation, the as-prepared TiC/SiBCN ceramics present excellent EM wave absorption in X-band. The TiC nanograins appearing after annealing provide multilevel reflection and interface polarization. Dipole polarization formed at interface defects, in company with interfacial polarization, also makes a great contribution to enhanced EM wave absorption. The TiC/SiBCN nanocomplex prepared with 5 wt% Ti₃C₂T_x MXene possesses a minimum reflection coefficient of −45.44 dB at 10.93 GHz and abroad bandwidth 8.4 and 12.4 GHz, almost covering the entire X-band. Tuning the thickness in the range of 2.35-2.54 mm, the effective absorption band can achieve the entire X-band. And the EM wave absorbing performance has been maintained to a large extent at 600°C with the minimum reflection coefficient of −26.12 dB at 12.13 GHz and the effective absorption bandwidth of 2 GHz. Last but not the least, TiC/SiBCN ceramics offer a good thermal stability in argon as well as in air atmosphere, making it possible to serve in high-temperature detrimental environments. This study is expected to provide a new perspective for the design of high-performance absorbing materials that are able to be used in harsh environments, especially in high temperatures.     

吸波材料的微波损耗机理及结构设计

就吸波材料与电磁波的相互作用及其损耗机理进行了阐述。通过对吸波材料与电磁波相互作用的研究和不同类型吸波材料微波损耗机理的详细探讨，对研制高宽频、质轻、红外微波隐身兼容复合型吸波材料进行了展望，并提出了材料结构设计的思路。     

High temperature absorbing coatings with excellent performance combined Al2O3 and TiC material

A series of challenges are impeding the development of high temperature electromagnetic (EM) wave absorbing materials in x band. In this study, to deal with this problem, a coating, (1-x).wtAl₂O₃∼x.wtTiC, is designed and prepared using plasma spraying technology. Its permittivity increases with temperature and TiC content, which endows it with a good EM impedance at high temperature. The coating possesses excellent EM absorbing performance at 800 ℃. When the x value equals 0.2 and thickness 1.6 mm, the coating exhibits an EAB of 3.45 GHz at 800℃, and a reflection loss lower than -8 dB in whole x band. The XRD result shows that only two phases exist in the coating. The SEM images illustrate that TiC is unevenly dispersed in Al₂O₃, causing loss of conductivity and interface polarization. The finding not only broadens the application of TiC-based materials but also indicates the promising future of this material system.     

竹节状碳化硅晶须吸波性能研究

采用电磁波吸收材料来降低电磁波对设备的干扰及对人体的伤害,是目前常用的电磁波防护手段之一。特定结构碳化硅晶须作为一种一维介电材料,其优于普通的晶须、块状和颗粒状的吸波性能引起了研究人员的关注。本研究以生竹粉、硅粉和二氧化硅为原料,通过碳热还原法在不同温度下制备了竹节状碳化硅晶须,并对其结构和吸波性能进行了检测分析。结果表明：以1400℃烧结的竹节状晶须制备的试样在厚度为3 mm,频率为9.1 GHz时,最小反射损耗达到-14.4 dB,有效吸收带宽为1.8 GHz,吸波性能最好,具有进一步研究价值。     

Recent advances in carbon nanotubes-based microwave absorbing composites

With the blossom of information industry, electromagnetic wave technology shows increasingly potential in many fields. Nevertheless, the trouble caused by electromagnetic waves has also drawn extensive attention. For instance, electromagnetic pollution can threaten information safety in vital fields and the normal function of delicate electronic devices. Consequently, electromagnetic pollution and interference become an urgent issue that needs to be addressed. Carbon nanotubes (CNTs) have become a potential candidate to deal with these problems due to many advantages, such as high dielectric loss, remarkable thermodynamic stability, and low density. With the appearance of climbing demands, however, the carbon nanotubes combining various composites have shown greater prospects than the single CNTs in microwave absorbing materials. In this short review, recent advances in CNTs-based microwave absorbing materials were comprehensively discussed. Typically, we introduced the electromagnetic wave absorption mechanism of CNTs-based microwave absorbing materials and generalized the development of CNTs-based microwave absorbers, including CNTs-based magnetic metal composites, CNTs-based ferrite composites, and CNTs-based polymer composites. Ultimately, the growing trend and bottleneck of CNTs-based composites for microwave absorption were analyzed to provide some available ideas to more scientific workers.     

Electromagnetic wave absorbing properties of In–Sn/rGO composites supported by impurity defect

With the fast development of E-communication technology, effective electromagnetic wave absorbing materials are highly needed to address the growing electromagnetic pollution. Herein, Indium doped tin microsphere/reduced graphene oxide (In–Sn/rGO) composites with rich impurity defects were synthesized via the sol-gel and hydrothermal method. The excellent microwave absorption of In–Sn/rGO composites can be attributed to the modifications of electronics status and Fermi energy level after In doping. This can significantly increase the carrier mobility between In–Sn microspheres and rGO sheets to strike a superior interfacial polarization loss. As a result, the maximum absorptivity can reach ?51.16 dB at 8.73 GHz (thickness: 3.5 mm) with a lower filler loading of 10 wt%. Meanwhile, the synthesized In–Sn/rGO composites also exhibit an ultra-wide absorbing frequency range of 13.84 GHz (within the X band, Ku band, and most of the C band). This research provides a new idea for the synthesis of effective microwave absorbing material by introducing impurity defects.     

Rutile TiO2 nanorod with anomalous resonance for charge storage and frequency selective absorption

TiO₂ is not among the traditional electromagnetic (EM) absorbing material candidates owing to its poor response in the EM wave region. Although the EM wave absorption performance can be improved by hybrid and/or hydrogenated TiO₂, the difficulty and risk of the experimental process are increased. Herein, rutile TiO₂ nanorod was successfully prepared by two-step method. The analysis of dielectric properties exhibits that rutile TiO₂ nanorod has excellent charge storage capacity. The results of EM wave absorbing performance show that impedance matching caused by anomalous resonance leads to frequency selective absorption. Such anomalous resonance is due to the resonant polarization of ionic clusters formed by oxygen ions and titanium ions. Moreover, metastructure design shows that the EM absorption frequency and the EM wave absorption bandwidth can be tuned through the design of metamaterial. Our founding will broaden the field of vision for the design of EM wave absorbing materials in the future.