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以羰基铁粉(CIP)和二氧化锰为吸收剂,石蜡为基体制备了羰基铁粉/二氧化锰复合材料。在2~18 GHz的微波频段,测量了所制复合材料的介电常数和磁导率,在吸收剂质量分数为80%的基础上,讨论了二氧化锰与羰基铁粉的比例对复合材料吸波性能的影响。结果表明,随着二氧化锰与羰基铁粉质量比的增加,复合材料的磁导率实部和虚部及介电常数实部均逐渐减小,吸收峰向高频方向移动。当?(MnO2:CIP)为2:3时,所制复合材料的吸波性能最好,当涂层厚度为1.5 mm时,其反射损耗(RL)小于-10 dB的带宽达6.7 GHz(10.0~16.7 GHz)。 相似文献
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Synthesis and microwave dielectric properties of Si/C/B powder 总被引:1,自引:0,他引:1
Si/C/B powders were synthesized by carbothermal reduction of xerogels containing boride. Colorless, transparent and monolithic gel was obtained by using tetraethoxysilane, saccharose, tributyl borate, ethanol and distilled water as starting materials. When the xerogel was fired at 1 600 ℃ in the static argon atmosphere, the XRD pattern commences to show the crystallite peak corresponding with C. β-SiC was synthesized at 1 700 ℃, but amorphous remainders could not be eliminated completely. The XRD results show that the boron possibly enters into the silica network, leading to the formation of borosiloxane. Microstructure offl-SiC powders consists of agglomerated particles with diameters ranging from 30 to 100 nm. Though the samples prepared at 1 600 ℃ and 1 700 ℃ have better dielectric loss tangent than the sample at 1 500 ℃ due to exiting crystalline material, the dielectric constant and dielectric loss tangent of three samples reveal lower values. 相似文献
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基于电卡效应的固态制冷技术,具有高效、环境友好、轻量、低成本和易于小型化等优点,是替代传统压缩机制冷的理想技术之一。在施加或去除电场时产生较大极化变化的铁电材料,则是制备基于电卡效应固态制冷器件的理想材料。近年来,人类对环境可持续发展的需求,使无铅块体陶瓷的电卡效应研究成为铁电材料领域的研究热点之一。本文首先回顾电卡效应研究历史上的标志性事件,随后简要介绍电卡制冷的原理,提出了在室温附近获得宽温区和大电卡温变的材料设计思路,之后系统综述了BaTiO3基、Bi0.5Na0.5TiO3基和K0.5Na0.5NbO3基无铅块体陶瓷电卡效应的研究进展,重点分析了这三类无铅块体陶瓷电卡效应的独特优势和面临的挑战,最后对无铅块体陶瓷电卡效应的发展趋势进行了展望。 相似文献
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