共查询到18条相似文献,搜索用时 703 毫秒
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天然尖晶石型铁氧体(铁砂)与聚氨脂粘结剂制成的吸波涂料在7 ̄12GHz频段有两上吸收峰,涂层强度1.25mm时,吸收量5.2 ̄8.5dB,在基础吸波材料(铁砂)中添加尖晶石型铁氧体、顺磁性稀土材料和六角铁氧体制成复合吸波涂料,使期吸收量达18 ̄25dB,匹配厚度1.1 ̄1.2mm,两吸收峰间距〉4.4GHz,它加工简单,价格低廉。 相似文献
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采用化学共沉淀法制备了纳米Ni0.5Zn0.5CexFe2-xO4(x=0,0.005,0.01,0.015)铁氧体吸波材料,用AV3618型微波矢量网络分析仪测试了样品在8.2~12.5GHz范围内的微波吸收特性,实验结果表明:稀土元素铈的含量影响材料的吸波性能,当x=0.01时, 纳米Ni0.5Zn0.5CexFe2-xO4铁氧体的吸波性能最佳.对于Ni0.5Zn0.5Ce0.01Fe1.99O4铁氧体吸波材料,当涂层厚度为1mm时,在测试频段内有三个吸收峰,在8.8GHz处,其最大吸收衰减量为15.4dB,10 dB以上带宽达3.8GHz,适量掺杂稀土元素铈是提高镍锌铁氧体吸波材料性能的一种有效途径. 相似文献
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用铁砂代替Fe2O3,采用传统陶瓷烧结工艺,研制出几种M型六角晶系复合铁氧体吸波材料.有的样品最大衰减达到40dB,10dB带宽在4GHz左右,面密度普遍较小,在8~18GHz频率范围内具有良好的微波吸收特性;实验还发现随着厚度的减小,吸收峰的位置逐渐向高频偏移. 相似文献
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掺杂对锶铁氧体基复合材料吸波特性的影响 总被引:3,自引:0,他引:3
将锶铁氧体、铁砂、混合稀土加工成基础材料,通过掺入一系列的不同类型的吸收介质制成复合电波吸收材料,在8-18GHz频段内测其吸波特性.实验结果表明,在基础材料中掺入Cu粉,使吸收峰移向低频,匹配厚度变大.在基础材料中同时加入MnZn铁氧体,最大衰减量明显增加,-10dB带宽无明显变化.同时掺入几种不同类型的吸收介质,产生了部分的累积效果. 相似文献
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采用柠檬酸盐溶胶凝胶法制得尖晶石型纳米钴镍锰锌铜铁氧体,通过原子吸收光谱仪测定元素组成,XRD、透射电镜、网络分析仪研究矿物组成并研究其颗粒形貌与吸波性能。试验表明:所得产物为尖晶石立方晶系铁氧体;其中铁元素易于被钴取代,形成CoFe2O4;而Mn、Zn、Cu、Ni趋向于互相掺杂形成固溶铁氧体。铁氧体的平均粒径为50nm。采用网络分析仪研究了5~7GHz,9~11GHz,15~18GHz内铁氧体的吸波性能:尖晶石型立方晶系纳米铁氧体具有良好的微波吸收性能;适量提高锰、锌等掺杂元素含量,有助于提高材料的吸波性能。 相似文献
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用铁砂(磁铁矿)尾矿制备性能优良的电波吸收材料 总被引:9,自引:0,他引:9
用铁砂(磁铁矿)尾矿制备性能优良的电波吸收材料,在7~12GHZ频段,最大 收量达27db,、10dB带宽1.9GHZ,匹配厚度0.74mm,其综合性能优于精铁砂制备的吸收材料。因是废物利用,有较高的经济效益。经相变处理,磁性和结晶结构发生变化,对吸波材料的性能影响为:吸收量微降,两吸收峰间距加大,带宽增加,匹配厚度较大增加,达1.42mm。 相似文献
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(Ni,Zn,Co)2—W型复合钡铁氧体的制备及其微波吸收特性 总被引:9,自引:0,他引:9
用化学共沉法制备了(NiZnCO)2-W型平面六角晶系复合钡铁氧体,对其吸收特性进行分析研究,发现在8-12GHz频率范围内有两个吸收峰,最大吸收量达31dB,10dB带宽1.9GHz,匹配厚度3.83mm。同时比较了在相同工艺条件下,碳纤维的掺入对吸收特性的影响。 相似文献
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羰基铁/三元乙丙橡胶复合材料的吸波性能 总被引:5,自引:0,他引:5
为了探明吸波材料的厚度、吸收剂的含量与吸波性能之间的关系,以羰基铁为吸收剂、三元乙丙橡胶为基体制备了复合橡胶吸波材料,采用矢量网络分析仪研究了在2.6~18 GHz范围内羰基铁含量和吸波材料厚度对吸波性能的影响,并利用电磁理论分析了吸波材料的吸波性能.对于3 mm吸波材料,当羰基铁体积分数为45%时,在3.5 GHz处其反射率的最小值达-21.7 dB;在羰基铁含量一定的条件下,微波吸收性能与吸波材料的厚度并不成正比关系,当厚度<2 mm时,吸波材料的吸波效果较差;当厚度>2 mm时,随着吸波材料厚度的增加,最大吸收峰的位置向低频移动,并且最大吸收峰的峰值和指定反射率的频率带宽也呈减小的趋势.在相同厚度下,随着羰基铁含量的增加,吸波材料在电磁波吸收峰处的反射率不断减小,而且吸波材料吸收峰的位置也向低频移动;输入阻抗与空气阻抗越接近,吸波材料的吸波性能越好. 相似文献
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HUANG Dong-zhen WANG Zhi-hui LV Yan-hong HU Chuan-xin LI Wan-zhi LIANG wen-ting YAO Jun-min 《材料保护》2004,37(Z2)
With the rapid development of stealth technique, carbonyl iron powder is regarded as an ideal radar absorbing material. In this paper, radar absorbing properties of carbonyl iron powder was investigated by using nano composite and macroscopic multi- layer composite approach. The machine- chemistry composite methods were employed during the experiment to produce nano composite absorbent. Two carbonyl iron powders named HP1, HP2 and nano powder named HP3 were employed. Absorbents were obtained by adding 10% HP3 powder with average size of 28 nm to the HP1 and HP2 carbonyl iron powders by weight respectively. By a series of composite techniques, sample plate with the radar absorbing coating was prepared. Compared with the single coating, the wave absorbing properties were significantly improved. The working band in which the wave reflectivity was less than 5 db was 4.8 ~ 18 GHz with the coating thickness of 1.0 mm. The lowest reflectivity was found to be 12.34 db at 8 GHz. The wave absorbing coating with thin thickness,broadband and strong absorbing properties was obtained. 相似文献
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采用乙烯基三甲氧基硅烷偶联剂对羰基铁粉94RC进行表面包覆改性,制备了不同厚度的改性羰基铁粉-氯丁橡胶复合薄膜.实验表明,单层复合薄膜厚度为1.58、面密度为3.30kg/m2时,吸收率超过-8dB的合格带宽达到5.2GHz,增加单层膜的厚度,可以使最大吸收峰值向高频移动,并使吸收频带增宽.根据电磁波传播特性和阻抗匹配原理设计并制备了由透波层、过渡吸收层、强磁损耗层组成的厚度0.64、面密度0.71kg/m2的3层复合薄膜,其最大吸收率为-13.45dB,吸收率超过-8dB的合格带宽5.51GHz. 相似文献
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Ting Zhang Daqing Huang Ying Yang Feiyu Kang Jialin Gu 《Materials Science and Engineering: B》2013,178(1):1-9
Fe3O4/carbon composite nanofibers were prepared by electrospinning polyacrylonitrile (PAN)/acetyl acetone iron (AAI)/dimethyl formamide (DMF) solution, followed by stabilization and carbonization. SEM and TEM observations reveal that the fibers are lengthy and uniform, and are loaded with well-distributed Fe3O4 nanoparticles, which are evidenced by XRD. Electrical and magnetic properties of the samples were studied to show the effect of enhancement of electrical conductivity and magnetic hysteresis performance. Finally, the permittivity and permeability parameters were measured by a vector network analyzer, and the reflectivity loss was calculated based on Transmission Line Theory. Results show that Fe3O4/C composite nanofibers exhibit enhanced properties of microwave absorption as compared to those of pure carbon nanofibers by: decreasing reflectivity loss values; widening absorption width and improving performance in low frequency (2–5 GHz) absorption. Absorption properties can be tuned by changing AAI content, carbonization temperature, composite fiber/paraffin ratio and coating thickness. It is shown that with coating thickness of 5 mm and fiber/paraffin ratio of 5 wt.%, the bandwidth for reflection loss under ?5 dB can reach a maximum of 12–13 GHz in the range of 2–18 GHz, accompanying with a minimum reflection loss of ?40 to ?45 dB, and preferred low frequency band absorption can also be obtained. The mechanisms for the enhanced absorption performance were briefly discussed. It is supposed that this kind of composite material is promising for resolving the problems of weak absorption in the low frequency range and narrow bandwidth absorption. 相似文献
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采用HP-8510B微波矢量网络分析仪测试了超细SiC、SiC晶须和纳米SiC的电磁参数,并对三者的电磁参数进行了比较,结果表明粒径较小的纳米SiC的电磁参数在大部分所测试频段上均高于其余二者.根据电磁波传输线理论计算了3种SiC吸收剂的反射率曲线,发现纳米SiC的吸波性能明显优于超细SiC和SiC晶须.纳米SiC吸收剂的吸收峰随着厚度的增加而增大,谐振频率随着厚度的增加而向低频转移.纳米SiC吸收剂在涂层厚度为5.0mm时,吸收峰值可达-8.45dB,谐振频率为7.12GHz,小于-5dB的频宽为1.8GHz. 相似文献
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短切中空多孔碳纤维复合材料的吸波性能 总被引:6,自引:0,他引:6
以中空多孔聚丙烯腈(PAN)原丝为原料, 通过预氧化处理和碳化处理工艺制备了中空多孔碳纤维, 采用SEM和XRD对其微观结构和晶体结构进行了表征, 并对其吸波性能进行了分析. 研究结果表明, 中空多孔碳纤维是一种非石墨结构的电损耗型雷达波吸收剂; 随着短切中空多孔碳纤维体积分数的提高, 随机分布的纤维/石蜡复合吸波材料的介电常数随之增大; 用所得的电磁参数结果计算了不同厚度材料的反射率, 在2~18GHz频率范围内, 当体积分数为33.30%, 厚度为2mm时, 最低反射率为-21.36dB, 其中<-5dB的反射率带宽为5.17GHz, <-10dB的反射率带宽为2.88GHz. 相似文献