FeSiAlCr合金/W型六角晶系Ba铁氧体复合粉体的制备及微波特性

以雾化Fe85Si2Al6Cr7粉和溶胶凝胶法制备的W型六角晶系Ba1Co0.9Zn1.1Fe16O27铁氧体粉末为原料,通过高能球磨复合改性得到FeSiAlCr合金/W型六角晶系Ba铁氧体复合粉体。采用X射线衍射仪(XRD)和扫描电镜(SEM)对该粉体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系统测定粉体试样在2~18 GHz频段内的复介电常数和复磁导率以及吸波涂层试样板的吸波性能,研究该复合粉体的微波电磁特性和电磁损耗性能。结果表明,FeSiAlCr合金/W型六角晶系Ba铁氧体复合粉体颗粒保持W型铁氧体的六角片状晶粒形貌和微结构;其ε′、ε″、μ′和μ″均高于W型铁氧体而低于Fe合金的对应值;FeSiAlCr合金含量与复合材料的磁损耗和介电损耗的相对强弱密切相关,Fe合金含量适中的复合材料,其吸波涂层厚度为2 mm时,在2~18 GHz全频段的吸波性能高于20 dB,峰值点达50 dB。

Preparation and microwave characteristics of FeSiAlCr alloy/W-type hexagonal Ba-ferrite composite powder

Using atomized Fe85Si2Al6Cr7 powder and sol-gel W-type hexagonal ferrite of Ba1Co0.9Zn1.1Fe16O27 as raw materials,FeSiAlCr alloy and W-type hexagonal Ba-ferrite composite powders were synthesized by high-energy ball milling technology.Microstructure and morphology of the composites were analyzed by X-ray diffraction(XRD) and scanning electron microscopy(SEM).Complex permeability,complex permittivity and microwave absorbing ability in 2 18 GHz were measured by microwave vector network analyzer for the composite.Electromagnetic characteristics and microwave loss mechanism were also explored.Results show that,microstructure and morphology of W-type hexagonal ferrite are all maintained for the composite.Values of complex permittivity(ε′,ε″) and complex permeability(μ′,μ″) are all larger than those of the W-type ferrite but smaller than those of the Fe-alloy.Content of Fe-alloy in the composites is closely related with relative strength of magnetic loss vs dielectric loss.For the composites with moderate content of Fe-alloy,when thickness of the coating is 2 mm,the maximum value of microwave reflection loss is 50 dB and microwave absorption values are less than 20 dB in the whole frequency range of 2 18 GHz.