【作者】 严超；

【导师】 胡曙光；

【作者基本信息】 武汉理工大学 ， 材料学， 2011， 硕士

【摘要】 随着现代电子科技技术的飞速发展,电子设备高频化、数字化,电磁辐射所带来的危害越来越严重。为了防止外部的电磁干扰和电磁信号的泄漏,削减电磁波对人体的伤害以及电磁波对建筑物的探测能力,研究具有优良吸波效能的水泥基复合材料在国防、民用,乃至保护人体健康方面都具有重要意义。阻抗渐变型水泥基复合吸波材料是一种多功能建筑结构材料,它能有效地将电磁波转化为电能、热能或其他形式能量,使电磁波达到衰减,在吸收电磁波的同时还具有优良的隔热保温性能。本文主要针对目前国内外民用、军用建筑对电磁防护的迫切性与水泥基吸波材料存在的问题,提出了具有优良吸波功能的阻抗渐变型水泥基复合材料的设计思路与方法,对水泥基复合吸波材料的组成、结构与性能进行了系统的研究,为高性能水泥基吸波材料的设计、研究、制备提供了理论基础。本文开展的主要工作及取得的成果有：依据电磁波传播规律及阻抗匹配原理,结合水泥基材料自身的特点,通过对水泥基材料基体组分、匹配层及损耗层优化设计,提出了具有不同阻抗结构的层状水泥基复合材料(匹配层+损耗层)的设计思路和方法。通过复合高电磁参数的钢渣、粉煤灰、高钛重矿渣等矿物掺合料,改善基体材料的介电损耗性能,系统研究了矿物掺合料种类及掺量、聚合物表面改性对水泥基复合吸波材料基体吸波性能的影响规律。结果表明掺入10%橡胶微粉和30%的钢渣,可以改善介质材料表面的阻抗匹配及材料内部对电磁波的损耗能力。在优化基体上系统研究了闭孔膨胀珍珠岩、玄武岩纤维和石墨微粉作为吸波组分对水泥基复合材料对吸波性能的影响规律。结果表明,珍珠岩作为低电磁参数多闭孔材料,具有优良的电磁损耗特性,最佳掺量为50vol%-60vol%；玄武岩纤维本身含有一定的介电损耗物质,内部结构多孔,具有一定的吸波功能,掺入0.5%-1.0%左右最佳；石墨作为电阻损耗型吸波剂,掺量控制在0.2%-0.4%为宜。在水泥基复合材料基体及吸波性能影响因素研究的基础上,研究制备了具有阻抗渐变结构的双层水泥基复合吸波材料：以石墨复合珍珠岩等作为损耗层吸波组分；以橡胶微粉复合珍珠岩等作为匹配层填充材料。通过调整匹配层填充材料的比例来调整介质材料材料表面的电磁参数,使材料表面的输入阻抗与自由空间的波阻抗匹配；通过调整损耗层吸波组分含量及制备工艺,使吸波剂均匀分布于透波骨料形成的电磁波传输通道上,实现对电磁波的有效损耗。结果显示：匹配层填充60%珍珠岩、10%橡胶微粉和损耗层填充0.4%石墨、60%珍珠岩、0.5%纤维的试样,在测试频段8-18GHz内,反射率都低于-10dB,最小反射率达到-23.35dB,表现了优良的吸波性能。闭孔膨胀珍珠岩保证了水泥基复合材料的高气孔率,减小了空气的对流,同时玄武岩纤维绝缘性好,复合两者提高了材料的保温隔热性能,实现了水泥基复合材料功能的多样化。更多还原

【Abstract】 With rapid development of modern electronic science and technology, the harm due to electromagnetic radiation which result in electronic equipment with high frequency and digitization is more and more serious. In order to prevent external electromagnetic interference and electromagnetic signals leak and reduce the harm of electromagnetic wave on human body and detecting ability on buildings, the study on cement-based composite materials with excellent absorbing property has important significance in defense, civil, and protecting human health.Cement based materials with resistance gradual changing structure are a kind of functional building materials. It can effectively will electromagnetic wave into electrical energy, heat or other forms of electromagnetic energy, which reached the electromagnetic wave absorbing attenuation, and also has excellent heat insulation performance. The article mainly aims at civil and military buildings at home and abroad for the urgency of electromagnetic protection and current cement base absorbing material existent problem, put forward with excellent the impedance gradient absorbing function of type cement base composite materials. Relative disciplines of composition, structure and performances were mastered, high-performance cement-based materials were designed and produced that were wave absorption, splitting resistance, heat preservation, durability and environmental protection. Significant basement and theoretical guidance were provided for designing, production and application of the materials.In this article, the main tasks and achievements are as below:According to the electromagnetic wave propagation law and impedance matching theory, combined with the characteristics of cement-based material itself, through optimization design on cement base material composition, matched layer and depletion layer, the design idea and method that the structure with different impedance layered cement matrix composites (matched layer+depletion layer) was put forward.Electromagnetic parameters change rule of matrix cementitious material was studied through adding steel slag, fly ash, high titanium heavy slag, etc.. Then dielectric and magnetic loss mechanism on electromagnetic wave of the matrix cementitious material was proved up. The article systematically analyzed the influence law of absorbing properties, which due to the mineral admixture and surface modification of polymer on matrix composite. Results showed that adding 10% mass fraction of rubber micro-powder and 30% mass fraction of steel slag could improve matching impedance of surface material and electromagnetic waves loss ability of internal material. On the basis of optimizing matrix, the influences of obturator perlite, basalt fiber and graphite powder as the absorbing losses components mixed in cement-based composites to absorbing properties were studied systematically. The results showed that, as the obturator materials with low electromagnetic parameters, perlite has excellent electromagnetic loss characteristics, whose optimal dosage from 50vol % to 60vol % (volume dosage); basalt fiber contains some dielectric loss substances, its internal structure is porous and it has microwave transparency function, adding about 0.5% to 1.0% will be best; as the resistance loss type absorbing agent, Graphite dosage should be controlled in 0.2% to 0.4%.On the basis of research on cement base composites matrix and absorbing performance factors, double-layer absorbing materials with resistance gradual changing structure were designed and produced:Graphite composite perlite as loss layer absorbing components; rubber micro-powder composite perlite as matched layer fillers. Through adjusting matched layer materials filled ratio to adjust material surface electromagnetic parameters, which make the input impedance on material surface and the wave impedance in free space matching. Through adjusting depletion layer absorbing component content and preparation technology, make absorbing agent evenly distributed in electromagnetic wave transmission channel formed by wave-permeating aggregate, this will realize the effective loss of electromagnetic wave. The result shows:filling the matched layer with 60% expanded pearlite and filling the depletion layer with 0.4% graphite,60% expanded pearlite and 0.5% basalt fibre, in test frequency within 8 to 18GHz, reflectivity will all below -10dB, the minimum reflectivity reach -23.35 dB, which have showed excellent absorbing performance. Combined with cement base composite insulation performance testing, reveals the lottery wave-aggregate obturator rate, high polymer modification and fiber disorderly to distribution form three-dimensional interpenetrating networks structure on the influence mechanism insulation materials, realized the cement base composite materials multifunction change.更多还原