共查询到18条相似文献,搜索用时 78 毫秒
1.
2.
3.
采用溶胶-凝胶法制备锂锌铁氧体(Li0.435Zn0.195Fe2.37O4,LZFO),界面聚合法制备纯聚苯胺(PANI)和PANI纳米纤维/LZFO复合材料。通过SEM、XRD、FTIR和矢量网络分析(PNA)等对材料的物相、结构和吸波性能进行了表征和分析。结果表明:制备出的样品分别为PANI、LZFO和不同配比的PANI纳米纤维/LZFO复合材料。在2~18 GHz范围内,PANI纳米纤维/LZFO复合材料的电磁波反射率<-10 dB的波段有2个,吸波性能较纯PANI和LZFO有了很大提高,并且拓宽了吸波频带,当PANI纳米纤维/LZFO复合材料中PANI纳米纤维的质量分数为10%,其综合吸波性能最佳,电磁波反射率<-10 dB的波段分别为2.5~5.5 GHz波段和14.5~16.5 GHz波段,最大吸收峰可达到-33.8 dB。而PANI和LZFO在电磁波反射率<-10 dB的波段只有1个。因此通过PANI纳米纤维接枝铁氧体,可调节电磁参数,提高材料的吸波性能。 相似文献
4.
本文通过水热法制备纳米Ni0.6Zn0.4Fe_2O_4,研究了晶化温度对样品纯度、粒度、形貌及电磁波吸收性能的影响。结果表明:当晶化温度为160℃时,粒子形貌不规则,并未完全形成Ni0.6Zn0.4Fe_2O_4;纯相Ni0.6Zn0.4Fe_2O_4的形成温度为180℃,粒子呈类球形结构,分布均匀,平均粒径约为20~25nm;但温度高于180℃时,尖晶石结构不稳定性增加,有杂相α-Fe2O3生成,粒子明显增大,团聚严重。晶化温度180℃,晶化时间8h制得的纯相纳米Ni0.6Zn0.4Fe_2O_4吸波性能最好,损耗因子在3.5GHz处达到最大值为1.08。利用共振损耗理论对纳米镍锌铁氧体的吸波机理进行分析,通过Helmholtz方程推导出纳米镍锌铁氧体本征振动频率的计算公式。 相似文献
5.
利用溶胶直接自蔓延反应制备了镍锌铁氧体纳米粉末,采用XRD分析了其结构。以聚乙烯醇为基体(PVA)制备了炭黑,镍锌铁氧体复合材料吸波平板;采用矢量网络分析仪测量了其在2~18GHz频带上的吸波性能。结果表明:具有双层结构的炭黑,镍锌铁氧体复合材料具有较好的吸波效果,试样厚度为3mm;当面层镍锌铁氧体的质量分数为40%,底层炭粉的质量分数为20%时,在8~18GHz的测试频段范围内,复合材料最大吸收峰值为-15.7GHz,优于-6dB的有效带宽为6.4GHz;当底层炭粉的质量分数为15%时,复合材料最大吸收峰值为-13.6GHz,优于-6dB的有效带宽为8.2GHz。 相似文献
6.
本文对含5种粒度的烧结Mn-Zn铁氧体填充环氧树脂基复合材料的微波吸收特性进行了研究。结果表明:其中4种粒度的铁氧体的复合材料具有相似的微波衰减特征、而含-80~120目的铁氧体试样对微波衰减作用较强、吸收峰相对较宽,且向高频方向移动。 相似文献
7.
LiZn铁氧体的制备和吸波性能研究 总被引:3,自引:0,他引:3
用溶胶-凝胶法制备了Li0.35Zn0.3Fe2.35O4粉体,采用HP8722ES矢量网络分析仪测量了样品在2~18GHz频率范围的复介电常数εr(εr=ε′-jε″)和复磁导率μr(μr=μ′-jμ″).采用传输线理论公式,对材料的吸波性能进行了模拟.结果表明,随着匹配厚度d的增加,吸波性能增强.当d=4mm时,材料的吸波曲线出现双吸收峰;d=5mm时,材料的吸收峰值位于4.4GHz,反射率为-19.96dB,-10dB吸收带为2.8~9.0GHz,带宽为6.2GHz.吸波材料在低频区有良好的吸波性能. 相似文献
8.
9.
应用水热法掺杂钴离子到纳米镍锌铁氧体粉末中,制备处纳米镍锌钴铁氧体,继而用钴离子代替镍离子制备钴锌铁氧体.并利用XRD、TEM、VNA对其进行表征和分析,研究了纳米镍锌钴铁氧体和纳米钴锌铁氧体的样品粒度、形貌、电磁损耗性能及吸收性能.结果表明:纳米镍锌钴铁氧体由原先纳米镍锌铁氧体的类球形转变为不规则四边形结构.掺杂钴离子后增加吸收器的带宽, 改善材料在低频率的吸波性能。钴锌铁氧体中当Co2+: Zn2+=1: 1时,对于电磁波吸收性能比镍锌钴铁氧体要好,在16.47 GHz处到达33.9 dB. 相似文献
10.
3D打印技术在快速制造复杂形状零件方面获得了越来越多的关注。将锰锌铁氧体(MZF)作为增强体填充到聚乳酸(PLA)中,通过球磨混合和熔融挤出法制备出MZF/PLA复合线材,利用熔融沉积成形(FDM)制备出MZF/PLA复合材料。采用XRD、 SEM和矢量网络分析仪对不同复合比例的MZF/PLA复合材料的微观形貌、力学性能和电磁性能进行表征,并计算不同厚度的反射损耗,研究MZF的含量对复合材料吸波性能的影响。结果表明:当MZF含量为10wt%时,MZF/PLA复合材料的拉伸强度相比纯PLA提升了17.6%,随着MZF含量的提升,复合材料的吸波性能随之增强。当MZF的含量达到50wt%,在12.7 GHz处,厚度为7.4 mm时反射率达到最小值-55.3 dB,在厚度为7.9 mm时,有效吸波频带宽为4.5 GHz。因此,基于FDM制备的3D打印MZF/PLA复合材料具有良好的吸波性能和承载能力,是一种非常有前途的3D打印微波吸收材料。 相似文献
11.
Fabrication and properties of microwave lithium ferrites 总被引:2,自引:0,他引:2
12.
掺杂对高导MnZn铁氧体微结构和性能的影响 总被引:1,自引:0,他引:1
采用传统陶瓷工艺制备了高磁导率MnZn铁氧体材料。从分析材料微观结构入手,研究了P2O5和Nb2O5的掺入,组以适配的工艺条件和不同的比例掺入,来研究对高磁导率MnZn铁氧体材料性能的影响。少量P2O5掺杂可使铁氧体晶粒尺寸增大,均匀性改善,起始磁导率提高。但若掺杂过量,晶粒中气孔率增加,起始磁导率下降,损耗也大为增加。在配方为Zn0.15Mn0.78Fe2.07O4的材料中,当P2O5掺杂量为0.16%(wt)时,起始磁导率可达10697。Nb2O5的添加起到细化晶粒的作用,可以改善材料的频率特性,降低材料损耗,磁导率稍有降低,但当Nb2O5的质量分数>0.005%时,会显著降低材料的起始磁导率。 相似文献
13.
Zicheng Wang Xulin Yang Mingzhen Xu Junji Wei Xiaobo Liu 《Journal of Materials Science: Materials in Electronics》2013,24(7):2610-2618
An aromatic, diether-linked phthalocyanine resin (Pc) was prepared from 4,4′-bis (3,4-dicyanophenoxy) biphenyl (BPh) and investigated for morphology, microstructure, dielectric, conductivity and microwave absorption properties at different annealing temperatures from 300 to 800 °C. The results showed that the annealing temperature could significantly change the morphology and microstructure of the Pc polymer, leading to the generation of carbon-Pc polymer composites, and enhance the microwave absorbing and electrical properties of the Pc polymer. The dramatic electrical and dielectric transition happened when the annealing condition was 550 °C 24 h. The conductivity of the samples exhibited a transition of electrical behavior from an insulator to semiconductor of approximately 10+2 S/cm. Pc polymer exhibited excellent microwave absorption properties in the frequency range of 0.5–18.0 GHz after sintering process. The microwave absorption of the annealing Pc polymer can be mainly attributed to the dielectric loss rather than magnetic loss. The sample annealed at 500 °C 24 h had two strong microwave absorbing peaks and achieved a maximum absorbing value of ?44 dB around 10.7 and 17.5 GHz when the thickness was 3.0 mm. The novel carbon-Pc polymer composites were believed to have potential applications in the microwave absorbing area. 相似文献
14.
Mn0.764 Zn0.187 Fe2.049 O4 and Mn0.687 Zn0.272 Fe2.041 O4 ferrites containing 0.05 wt% CaO, 0.05 wt% SnO2 and 0.05 wt% V2O5 were prepared by conventional methods using manganite (-MnOOH) as a source of MnO. The partial-calcined ferrites were made by calcining the mix consisting of total amount of ZnO and one third or half amount of Fe2O3 and MnO required for the formation of the Mn-Zn ferrites and sintering the mix consisting of the previously calcined mix and the remaining two thirds or half the amount of Fe2O3 and MnO. Calcination was conducted at 900 °C for 2 h and sintering at 1335 °C for 1 h. The secondary maximum in permeability (SMP) of uncalcined ferrites was shifted to higher temperature and does not clearly appear in the initial permeability against temperature plot. The values of initial permeability of the uncalcined ferrites increase rapidly with increasing temperature up to 100 °C, then either increased gently or levelled off. In the working temperature range, 80 to 100 °C, the values of all the ferrites, regardless of the degree of calcination were well above 2000. Above 80 °C, the uncalcined and one-third calcined ferrites had the lowest and the second lowest loss factor values (<3 × 10–6), respectively. A dense and homogeneous structure of smaller grains with small pores was prevalent in the uncalcined and one-third calcined ferrites. 相似文献
15.
16.
The dependence of microstructure on sintering conditions during hot pressing have been investigated and the densification
mechanisms have been used to explain the observed results. The effect of addition of excess ZnO content over stoichiometry
on permeability has been studied in the normal sintered Mn-Zn ferrites. 相似文献
17.
18.
K. P. Andryushin A. A. Pavelko A. V. Pavlenko I. A. Verbenko L. A. Shilkina S. P. Kubrin L. A. Reznichenko 《Technical Physics Letters》2011,37(7):617-621
Based on an analysis of the structure and physical properties of bismuth ferrite (BiFeO3) modified by rare-earth (RE) elements, solid solutions characterized by the presence of spontaneous magnetization, low- and high-temperature relaxation, and maximum microwave absorption have been found. It is established that these materials exhibit a secondary periodicity in their properties. The observed effects are related to the appearance of symmetry phase transitions, specific features of the crystal chemistry of RE elements, and changes in the type of solid solutions. 相似文献