金属纤维电磁屏蔽材料的研究进展

描述电磁辐射的危害及电磁屏蔽材料的屏蔽机制,重点阐述金属纤维制备电磁屏蔽织物、电磁屏蔽聚合物材料及电磁屏蔽建筑与装饰材料的应用及研究进展,并对未来电磁屏蔽材料的发展趋势作预测,指出开发具有高吸收率、低反射率与低透射率的高性能、低消耗兼绿色环保的新型电磁屏蔽材料是未来的研究重点,同时对材料内部组织与结构进行优化,改进成型工艺,提高其电磁屏蔽效能     

绿色建筑与电磁屏蔽材料

随着人类对工业化社会的反省和对后现代化社会的思考,人类寻求健康宜居的生存环境及追求社会可持续发展的欲望愈加强烈,绿色建筑成为当今热门话题。绿色建筑材料作为绿色建筑发展基石,是实现绿色建筑标准的核心和关键内容。系统地阐述了绿色建筑的内涵和绿色建筑材料的发展现状以及绿色建筑生态水泥材料、绿色建筑墙体砌筑材料、绿色建筑玻璃材料、绿色建筑屋顶材料、绿色建筑饰面涂料等绿色建筑材料的技术性能。同时阐述了人类宜居健康生活环境对于绿色建筑材料发展的需求,以及当今日益严重的电磁辐射污染对人类健康造成的侵害。重点论述了绿色建筑屏蔽材料的工作原理,提出了未来绿色建筑电磁屏蔽材料的发展策略,以及在绿色建筑电磁屏蔽生态水泥、绿色建筑电磁屏蔽墙体材料、绿色建筑电磁屏蔽门窗玻璃材料、绿色建筑电磁屏蔽屋顶饰面材料、绿色建筑电磁屏蔽饰面涂料等方面的实验研究成果,并对绿色建筑电磁屏蔽材料的研究进展和存在的主要问题进行了探讨。最后对绿色建筑电磁屏蔽材料的发展进行了预见和展望。     

三层电磁屏蔽复合材料结构设计

随着信息和电子技术的飞速发展,对电磁屏蔽性能的要求越来越高,电磁屏蔽材料由单一材料向复合材料的方向发展。复合材料屏蔽效能不仅取决材料本身,还与复合材料的结构密切相关。本文以3层机械电磁屏蔽复合材料为基础,运用Schelkunoff的传输线理论研究电磁屏蔽复合材料的结构与电磁屏蔽效能的关系为以后电磁屏蔽结构设计提供基础。研究结果表明Cu＋非晶＋Cu3层复合结构电磁屏蔽性能在射频段明显优于Cu＋Cu＋非晶3层复合结构,但在0．1MHz以下的频率段和800MHz以上频率段差别并不大。     

非晶态合金填充氯化聚乙烯的电磁屏蔽性能研究

通过混炼和压片工艺制备了非晶态合金填充的氯化聚乙烯电磁屏蔽橡胶。通过SEM、XRD、屏蔽效能测试和拉伸试验,研究了填充比对电磁屏蔽效能和拉伸强度的影响。结果表明,材料在10 MHz～100 MHz频率范围内的屏蔽效能最大,可以达到28 dB,具有一定的屏蔽效果。体系中可以形成一定的导电通路,但没有达到体系的阈值。非晶态合金的加入可以提高屏蔽橡胶的低频吸收损耗,屏蔽效能随频率升高呈下降趋势。非晶态合金对橡胶基体的拉伸强度有一定影响。     

非晶态合金在电磁屏蔽领域中的应用现状

非晶态合金是性能优异的软磁材料,在电磁屏蔽领域获得了良好的应用效果。本文在介绍电磁屏蔽机理的基础上,对非晶态合金作为电磁屏蔽材料在国内外的研究和应用情况进行了综述,并对今后的应用前景进行了展望。     

电磁屏蔽涂镀层的研究现状及进展

主要讨论了电磁屏蔽（EMS）的基本原理和相关的电磁屏蔽知识，简述了国内外近年来重点开发的各种电磁屏蔽化学涂层、镀层，总结了当前电磁屏蔽涂镀层的研究现状和进展，为解决敏感设备的电磁屏蔽（EMS）问题和进一步研究开发电磁屏蔽涂镀层材料提供参考。     

石墨烯基电磁功能材料

二维纳米材料拥有优异的电学、热学和力学性能,在高技术领域展现出巨大的应用潜力。其中,石墨烯具有大的比表面积和高的载流子浓度,是当代科技关注的对象。系统地展示了石墨烯基电磁功能材料的电磁响应机制以及吸波与屏蔽性能。在研究的电磁波频段(2~18 GHz),电磁损耗一般包括电导损耗、多重弛豫、磁共振及磁涡流。详细地介绍了这四种电磁损耗行为的物理形成机制和响应特性,总结了不同石墨烯基电磁功能材料的电磁损耗来源,并提出了设计高性能电磁功能材料的策略。随后,展示了高性能电磁功能材料的应用标准,给出了微波吸收与电磁屏蔽的响应规律,提出了两种改善电磁响应性能的方法。在电磁功能材料性能方面,介绍了石墨烯基电磁功能材料在微波吸收和电磁屏蔽领域最新研究进展。所涉内容涵盖石墨烯单相材料、异质材料及高温介电特性和电磁响应。另外,还系统地分析了石墨烯基电磁功能材料当前发展所面临的关键问题,并展望了未来的研究与发展方向。     

基于磁控溅射技术的电磁屏蔽层研究

为了解决电子系统塑料机盒的抗EMI问题,提出了一种采用多靶磁控溅射技术对塑料内表面进行金属化的新环保工艺,利用屏蔽效能对电磁兼容性作了理论分析,并对金属化层的膜系结构、溅射工艺、附着强度等作了较为深入的研究.研究结果表明:衰减损耗是各层屏蔽效果线性相加的结果;反射损耗与各层相对位置关系无关;层数多或各屏蔽层的反射越大,则屏蔽效果越好.试验表明:采用Cu/1Cr18Ni9Ti的金属屏蔽层结构,可以获得良好的屏蔽效能及耐候性,其中500nm Cu 100nm 1Cr18Ni9Ti较宜.     

ABS电镀铁镍的工艺方法

比较详尽地介绍了在ＡＢＳ工程塑料上电镀铁／镍的工艺方法，并对镀层的电磁屏蔽性能进行了测试。结果表明，ＡＢＳ镀Ｆｅ／Ｎｉ复合材料具有良好的电磁屏蔽效果，且制备简便，价格低廉。     

某电磁屏蔽方舱的设计与应用

对某电磁屏蔽方舱进行设计,从方舱的电磁屏蔽原理入手,对方舱大板间连接处、通风窗、电源接口窗、线孔和推拉门等孔口处进行屏蔽设计,方舱完成后采用双脊波导喇叭天线进行屏蔽效能测试。结果表明：该方舱接口处全部达到了屏蔽指标要求,方舱整体满足60dB的屏蔽效能要求。可为同类型屏蔽方舱的设计与应用提供一定的参考借鉴。     

Polypyrrole-based conducting hot melt adhesives for EMI shielding applications

Intrinsically conducting hot melt adhesives (ICHMAs) have been developed, based on polypyrrole (PPy) blends, for use in electronic and telecommunication applications requiring shielding against electromagnetic interference (EMI). These advanced materials have been formulated to exhibit significant EMI shielding effectiveness (SE) while retaining the superior properties of conventional hot melt adhesives. The conductivity properties, adhesion characteristics and both near- and far-field EMI SE behaviour of these ICHMAs at room temperature are investigated as a function of PPy content. The environmental stability of the conductivity is also reported. Potential use of such new materials in current and future electronic applications is anticipated.     

Microwave absorption,reflection and EMI shielding of PU–PANI composite

In order to allow electronic components to coexist without harmful electromagnetic interference (EMI) it is necessary to develop new shielding and absorbing materials with high performance and a large operating frequency band. Conducting polymer composites have been found to be suitable for EMI shielding and for the dissipation of electrostatic charge. In the present study polyaniline–polyurethane (PANI–PU) composite was considered for these applications. The microwave absorption, microwave reflection and EMI shielding properties of PANI–PU composite is evaluated both at S-band and X-band frequencies. The material is found to have good microwave absorption and is a potential candidate for EMI shielding applications.     

Recent advances of electromagnetic interference shielding Mg matrix materials and their processings: A review

In terms of lightweight electromagnetic interference (EMI) shielding structural materials, Mg matrix materials have proven to be the best, due to their exciting properties (e.g. low density, high specific strength, good electrical conductivity and excellent EMI shielding properties) and their wide range of applications in lightweighting in electronics, automotive and aerospace industries. Through processing, such as alloying, heat treatment, plastic deformation and composite processing, Mg matrix materials can be obtained with tailorable properties which can play a key role in designing materials for EMI shielding. This work introduces an overview of the research on the EMI shielding properties of Mg matrix materials as well as their EMI shielding mechanisms over the past few decades, focused on the influence of alloying, heat treatment, plastic deformation and composite processing for the EMI shielding properties of Mg matrix materials. At the end, conclusions and future perspectives are provided.     

Materials for electromagnetic interference shielding

Materials for the electromagnetic interference (EMI) shielding of electronics and radiation sources are reviewed, with emphasis on composite materials and resilient EMI gasket materials, which shield mainly by reflection of the radiation at a high frequency.     

Intrinsic electromagnetic radiation shielding/absorbing characteristics of polyaniline-coated transparent thin films

The present study aims to investigate the electromagnetic wave transmission, reflection, and absorption characteristics of polyaniline (PANI)-coated transparent thin films. To investigate the intrinsic electromagnetic radiation shielding/absorbing characteristics of PANI-coated transparent thin films, the optical transmittance, sheet resistance, and electromagnetic interference (EMI) shielding efficiency (SE) of the films were systematically investigated. In addition, the applicability of an SE formula is checked by comparing the present experimentally measured SE values with calculated SE values. The results show the potential use of PANI-coated transparent thin films as an EMI shielding/absorbing material that satisfies both optical transmission and EMI SE requirements for transparent bodies such as windows or doorways of buildings.     

Enhanced Electromagnetic Interference Shielding of Mg–Zn–Zr Alloy by Ce Addition

The effects of Ce addition on microstructure and electromagnetic interference(EMI) shielding response of Mg–6Zn–0.5Zr(ZK60) alloy have been investigated.Ce addition resulted in grain refinement and higher density of Mg–Zn–Ce and Mg Zn2 intermetallic particles in the alloy.In particular,this was substantially remarkable as the addition of Ce was up to 1.0 wt%.It is interesting to note that as-extruded ZK60 alloy with 1.0 wt% Ce addition exhibited an EMI shielding effectiveness(SE) exceeding 70 d B at the frequency range of 30–1,500 MHz,which was significantly higher than that of ZK60 alloy without Ce addition and reached the requirement of high protection.The superior SE was probably related to the increased reflection and multiple reflection of electromagnetic radiation induced by Ce addition.Direct artificial aging at 150 °C for 25 or 50 h led to a further increase of 7–10 d B in the SE of the alloy with 1.0 wt% Ce addition.The advantages of excellent shielding capacity and favorable mechanical strength make the Mg–Zn–Zr–Ce alloy an attractive shielding candidate material for a variety of technological applications.     

质子酸处理二维碳化钛/碳纳米管复合材料的电磁屏蔽性能与机械性能

通过质子酸胶体处理,实现了碳化钛Ti₃C₂T_x的制备。此外,使用单壁碳纳米管(SWCNT)作为增强成分,提升了质子酸处理碳化钛(H-MXene)的机械性能——不仅保持了电磁屏蔽性能,而且将拉伸性能提升了近400%。结果表明,H-MXene和碳纳米管具有作为高机械性能电磁(EMI)屏蔽复合材料的潜力。     

热处理效应对Sn-Al与Sn-Ca纳米薄膜的电磁屏蔽机制

利用溅镀Sn-Al纳米薄膜和Sn-Cu纳米薄膜讨论结晶机制与膜厚对电磁波屏蔽特性的影响,比较了Sn-Al和Sn-Cu薄膜的高温显微组织、导电性与电磁波屏蔽性能。结果表明,高温处理提高了Sn-Al纳米薄膜的电磁波屏蔽性。在低频条件下,高Cu摩尔浓度的Sn-Cu纳米薄膜不能有效改善电磁波屏蔽性;高温处理后,低Cu摩浓度的Sn-Cu纳米薄膜能提高低频的电磁波屏蔽性,而高频下的电磁波屏蔽性则呈相反趋势。