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(e′,e″) 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.