溶胶-凝胶法制备W型Ba_1Co_(0.9)Zn_(1.1)Fe_(16)O_(27)铁氧体及其吸波特性

Preparation of W-type Ba_1Co_(0.9)Zn_(1.1)Fe_(16)O_(27) hexagonal ferrite by sol-gel technology and its microwave absorbing properties

以硝酸钡、六水硝酸锌、无水硫酸钴和九水硝酸铁为原料,采用溶胶—凝胶工艺和＂两步热处理法＂制备Ba1Co0.9Zn1.1Fe16O27铁氧体材料,采用X射线衍射仪（XRD）和扫描电镜（SEM）对该材料的微结构和形貌进行分析和观察,利用微波矢量网络分析仪测定材料在2~18 GHz频段内的复介电常数和复磁导率,研究煅烧温度对材料微结构和电磁性能的影响。结果表明,煅烧温度对Ba1Co0.9Zn1.1Fe16O27铁氧体的微结构、形貌、微波电磁参量和吸波性能影响显著。煅烧温度1 200℃时,获得颗粒尺寸较大且大小均匀的单相W型六角晶系铁氧体粉体;由该粉体压制而成的铁氧体材料具有良好的微波电磁特性和吸波性能,当该铁氧体单层吸波材料厚度为2.2 mm时,反射损耗可达-33.6 dB,优于-10 dB的带宽为4.2 GHz,可应用于民用抗电磁辐射吸波材料设计和军用隐身材料设计。

W-type hexagonal ferrite of Ba1Zn1.1Co0.9Fe16O27 was prepared by sol-gel technology and two-step heat treatment process.The effect of sintering temperature on microstructure,and electromagnetic characteristics of the hexagonal ferrite was investigated,microstructure and morphology of the materials were analysed by x-ray diffraction meter（XRD） and scan electron microscope（SEM）,and the complex permeability and permittivity in 2~18 GHz were measured by vector network analyzer.The results show that calcination temperature has stronger effects on the structure,morphology,electromagnetic characteristics and microwave absorbing ability of the hexagonal ferrite.The uniform and pure W-type hexagonal ferrite powder can be synthesized when pH is 7 and the calcination temperature is 1 200 ℃.The hexagonal ferrite material compacted by the W-type hexagonal ferrite powder presents good electromagnetic characteristics and microwave absorbing ability.When the layer thickness of the hexagonal ferrite material is 2.2 mm,the maximum value of microwave reflection loss is ？33.6 dB and the frequency range is 4.2 GHz where the microwave absorption values are less than ？10 dB.The hexagonal ferrite material prepared can be used as electromagnetic radiation microwave absorbing and military shape-concealing material.