硅橡胶吸波复合材料的研发进展

介绍了硅橡胶吸波复合材料的基本性能要求,主要制备方法,分类及特点。探讨了吸波剂的结构、形状、尺寸、用量,吸波剂与基体的界面,吸波层的结构设计和厚度,测试温度,测试频率,入射角度等测试条件等因素对吸波性能的影响。综述了采用磁损耗型、电损耗型、复合型、生物型吸波剂的复合材料性能特点,并展望了硅橡胶吸波复合材料未来的发展方向。     

吸波涂层的制备及其与红外隐身涂料的兼容性研究

依据阻抗匹配原理制备了一种3层雷达吸波涂层，并在吸波涂层表面喷涂一定厚度的可见光、红外伪装涂料，比较了喷涂伪装涂料前后涂层吸波性能的变化。实验结果表明，三层结构的设计对提高涂层的吸波性能具有重要的影响，将电介质材料与磁介质材料复合所制备的吸波涂层具有厚度薄、面密度低、吸波频带宽的特点。雷达吸波涂层与可见光、红外隐身涂层复合后，其吸波性能基本保持不变。     

纤维增强树脂基吸波复合材料的研究进展

简述了吸波材料的电磁屏蔽机制、吸波剂的分类和损耗机制以及微波波段的划分与应用,并从材料的选择、结构的设计以及获得的吸波效果等方面对目前纤维增强树脂基吸波复合材料的研究进行了对比总结,重点阐述了单层结构、多层结构、多层夹心结构以及频率选择表面的主要特点和研究现状。最后提出了纤维增强树脂基吸波复合材料目前存在的问题,并对今后的发展进行了展望。     

铁氧体复合吸波剂对水泥基复合材料吸波性能的影响

采用2种类型的铁氧体作为吸波剂,制备水泥基复合吸波材料。通过弓形法测定水泥基平板在8～18GHz频率范围内的反射率,研究了铁氧体的种类、2种铁氧体复合体积比对水泥复合材料吸波性能的影响。结果表明:2种不同类型的铁氧体粉复合作为微波损耗剂时,不论单层还是双层水泥基层板,其吸波性能均显著高于单一的铁氧体吸波剂;当2种铁氧体总掺量为30%(质量分数)且体积比为1:1掺入水泥砂浆时,所制备的双层水泥板的最小反射率为–16dB,在8.3～11.5GHz和12.3～18.0GHz宽频率范围内反射率均小于–10dB。     

含碳纤维格栅结构吸波复合材料的实验研究

本文研究了碳纤维频率选择表面(FSS)结构在雷达吸波复合材料的应用,考察碳纤维结构的尺寸及其在吸波材料中的位置,并首次探讨了不同形式的碳纤维FSS结构组合形式对吸波复合材料的影响.实验结果表明,在不添加任何吸波剂的情况下引入碳纤维FSS结构可提高材料的吸波性能.碳纤维结构的尺寸及其在吸波材料中的位置均对材料的吸波性能有不同程度的影响.含两层碳纤维结构材料的吸波性能要优于含单层碳纤维结构的复合材料.     

2mm短切碳纤维吸波涂层的制备与吸波性能

基于雷达吸波涂层薄、轻、宽、强的要求,以2 mm短切碳纤维为吸收剂,水性聚氨酯为基体树脂,制备了碳纤维吸波涂层,将芳纶纸蜂窝与碳纤维吸波涂层进行匹配,并采用矢量网络分析仪测试了涂层的吸波性能。结果表明,单层碳纤维吸波涂层在厚度较薄时吸波性能较差,添加匹配层后性能有所改善。将不同碳纤维含量的吸波涂层与芳纶纸蜂窝进行匹配,制备了多层匹配碳纤维吸波涂层,涂层的吸收强度和有效吸收带宽均得到明显提升,通过调整碳纤维涂层和芳纶纸蜂窝的匹配方式,复合涂层在4.1~13.6 GHz频率范围内均能实现有效吸收。     

电磁波吸收层的设计与吸波材料的应用

介绍雷达吸波材料与吸波结构，以及电磁波吸收层的电性能设计方法，并探讨了单层和双层吸收层的设计。     

频率选择性阻尼夹芯吸波复合材料

提出多层吸波预浸料层和吸波阻尼层相互嵌合的频率选择性阻尼夹芯吸波复合材料,通过规律性调节吸波预浸料层和吸波阻尼层的厚度,实现对不同频段电磁波的吸收,运用Matlab对其吸波频率选择性进行了理论分析,吸波预浸料层和吸波阻尼层的具体厚度可以根据电磁吸波频段的具体要求来设计。电磁吸波试验验证了电磁吸波频率的选择性以及理论分析方法的有效性和合理性。模态试验、自由衰减试验获得了模态参数、阻尼损耗因子随吸波预浸料厚度变化的曲线,实验数据表明:随着试件吸波预浸料层厚度的增加,电磁吸收频率发生改变,模态固有频率升高,模态阻尼比增大,阻尼损耗因子增加。     

聚氨酯基吸波贴片的制备及吸波性能研究

通过辊压成型工艺制备了以MZ、炭黑为吸波剂的聚氨酯基吸波贴片,研究了吸波剂配比对吸波贴片电磁、吸收特性的影响,进一步探讨了吸波贴片衰减入射电磁波的机理。结果表明:随吸波剂填充量的增加,ε'等电磁参数明显增大,一方面增强了吸波贴片的衰减特性,另一方面削弱了其与自由空间的阻抗匹配程度;吸波贴片对入射电磁波的干涉作用导致其吸收峰位置随吸波剂含量、贴片厚度增加而趋向低频;1.5 mm厚、填充80wt%MZ的吸波贴片具有良好的吸波性能,其反射率在9.18 GHz~17.37 GHz频段低于-10 d B,基本满足水面舰艇在X、Ku波段的雷达隐身需求。     

乙炔炭黑/铁氧体复合材料的阻抗匹配设计及其吸波性能研究

从阻抗匹配设计的角度,用铁氧体、乙炔炭黑(CB)等填充丁腈橡胶(NBR)制备了不同结构的吸波材料,用自由空间法测试了复合材料的吸波性能。结果表明:铁氧体的输入阻抗比CB的小,与自由空间的匹配较好;二层和四层结构的吸波材料明显好于单层结构的吸波材料的性能;二层和四层结构的吸波材料明显好于单层结构的吸波材料的性能,四层结构NBR/CB(100/25)复合材料的最大吸收衰减达到11.4 d B。     

航天用吸波材料的制备及研究进展

简述了吸波材料的研究意义,综述了涂覆型吸波材料的研究现状和应用进展,重点介绍了单层电磁损耗型、多层介质匹配吸收型、干涉(谐振)型、电路模拟型、等离子体吸收型、手征型、导电高聚物型、泡沫夹芯型、贴片型和表面波吸波材料的主要特点和最新研究现状,最后对涂覆型吸波材料的发展趋势进行了展望。     

碳纳米管涂料的研究进展

综述了碳纳米管涂料的最新研究进展,介绍了碳纳米管在复合材料、导电、电磁屏蔽、吸波、吸热、抗菌等特殊涂料中的应用。初步探讨了碳纳米管涂料特殊性能的机理,指出了纳米涂料产业化所面临的困难,并对今后的发展进行了展望。     

The electromagnetic absorbing properties of plasma-sprayed TiC/Al2O3 coatings under oblique incident microwave irradiation

High performance absorbing coatings attract great interest because of the urgent demand for radar stealth technology. However, most reported absorbing coatings focused on the incident microwave were perpendicular to the surface of the coatings. Here, a kind of absorber of TiC/Al₂O₃ was prepared by plasma spraying method and the influence of TiC content and oblique incident microwave irradiation on the absorbing properties of TiC/Al₂O₃ were reported. The absorbing performance firstly increased and then decreased with increasing the TiC content due to the impedance matching and attenuation constant cannot match well at the same time. Meanwhile, compared with TE polarization, TM polarization of the plasma-sprayed TiC/Al₂O₃ coatings was more sensitive to the incident angle. This study demonstrates the feasibility of plasma-sprayed TiC/Al₂O₃ absorbing coatings for electromagnetic applications.     

电结晶磷酸钙生物涂层表面复合蛋白质方法的研究

采用电结晶共沉积和吸附方法,把与骨形成蛋白等电点相接近的牛血清白蛋白复合到磷酸钙生物涂层表面,ＩＲ和ＵＶ光谱分析表明：相同电注密度下电结晶共沉积法复合的牛血清白蛋白量多于吸附法,大电流密度时电结晶共沉积和吸附法复合的牛血清白蛋白的量高于小电流密度。     

Thermal Degradation of Fiber Coatings in Mullite-Fiber-Reinforced Mullite Composites

The thermal degradation behavior of single-layer BN and of double-layer BN/SiC chemically vapor-deposited fiber coatings in mullite-fiber-reinforced mullite composites was investigated by means of transmission electron microscopy after processing and heat treatment of the composites at 1000°, 1200°, and 1300°C for 6 h in air. The single-layer BN coatings were ˜0.7 mu m thick and consisted of turbostratic BN with (0001) basal planes lying parallel to the surfaces of the fibers plus nanosized areas that had no preferential orientation. This microstructure remained unchanged up to 1000°C; however, distinct coarsening of the randomly oriented BN crystallites occurred in the temperature range of 1000°-1200°C. The single-layer BN coatings were stable against oxidation, up to 1200°C. At higher temperatures, degradation of the coatings via oxidation occurred. Double-layer BN/SiC coating systems consisted of BN that was 0.08 mu m thick and SiC layers that were 0.16 mu m thick and deposited onto the mullite fibers. The turbostratic BN was highly anisotropic and did not undergo any microstructural change, up to 1300°C. The outer SiC layer of the double-layer coating system improved the oxidation resistance of BN in the 1200°-1300°C temperature range, despite a partial oxidation of SiC to SiO₂.     

温控涂料太阳辐射吸收系数的测试方法

采用双球法测量温控涂料的漫反射比,公式计算得到涂料的太阳辐射吸收系数α,并且通过测量涂料表层涂膜温度的变化,从而得出太阳辐射吸收系数与涂料表层温度的相互关系。     

单/双层水泥基平板的微波吸收性能

依据阻抗匹配原理与电磁波传播规律,提出表层透波、内层吸波的双层法设计,该设计具有电磁波吸收性能的层状水泥基平板结构.研究了硅灰和橡胶粉对表面层阻抗匹配的影响;同时还对碳纤维、钢纤维、碳纤维与铁氧体粉复合以及钢纤维与碳纤维复合作为内层吸收剂时,水泥基平板材料在8～18GHz频段内的吸波性能进行了研究.结果表明:硅灰和橡胶颗粒可以明显地改善水泥平板与自由空间的阻抗匹配:与单层相比,在相同碳纤维掺量时,双层吸波砂浆反射率下降-3dB左右;30%质量分数铁氧体与碳纤维复合作为吸波材料的损耗层的吸收剂,反射率在-10dB以下(12.5～18.0GHz),且随着入射频率的增加反射率下降.     

Comparison of electrochemical behavior of CrN single-layer coating and Cr/CrN nanolayered coating produced by cathodic arc evaporation physical vapor deposition

The aim of the present work is to study the CrN single-layer coating and the Cr/CrN nanolayered coating by cathodic arc evaporation physical vapor deposition (CAE-PVD) on AISI 304 stainless steel and to assess the electrochemical behavior of the coatings. Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) were utilized to study the morphology and microstructure of the coatings. The mechanical behavior of the coatings was studied by the nanoindentation technique. The electrochemical behavior of the formed coatings in 3.5 wt.% NaCl solution was investigated via electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) tests. Based on the microscopic images, it was realized that both CrN and Cr/CrN coatings were formed having a dense structure on the substrate. The results of EIS measurements showed gradual changes in the polarization resistance of the Cr/CrN nanolayered coating during the immersion time. However, significant changes in the polarization resistance of the CrN single-layer coating were seen by increasing immersion time comparing with the Cr/CrN coating. The higher polarization resistance of the Cr/CrN coating can be attributed to the effects of the interface between the layers in comparison to the CrN coating.     

太阳能吸热涂层的研究现状

综述了我国近年来太阳能吸热涂层的研究现状，包括非选择性涂层和选择涂层两大类，其中选择性涂层又可分为电镀涂层，阳极化涂层，真空镀膜涂层和选择性涂料层。，