摘要
W-type barium ferrites doped with Gd^3＋,Ba1-xGdx（Zn0.3Co0.7）2Fe16O27（x = 0,0.05,0.10,0.15,0.20）,were prepared by a sol-gel method.The effects of Gd^3＋ substitution on their microstructure,electromagnetic properties and microwave absorptive behavior were analyzed.The XRD patterns showed the single phase of W-type barium ferrite when x ≤ 0.15.Microwave electromagnetic properties of samples were studied at the frequency range from 2 GHz to 18 GHz using a network analyzer（Agilent 8722ET）.The complex permittivity ε（ε＇,ε＇＇） increased gradually when x ≤ 0.10,but it decreased as x = 0.15.The real permeability（μ＇） decreased with the increase of Gd^3＋ content,while the imaginary permeability（μ＇＇） increased when x ≤ 0.10.All these reasons were discussed using the electromagnetic theory.Furthermore,the ferrite-epoxy compound coating materials with 80 wt.% of Ba0.9Gd0.1（Zn0.3Co0.7）2Fe16O27 were prepared to measure the microwave absorbing properties.The maximum of reflection loss（RL） reached about-27 dB and RL was below-10 dB in the frequency range of 8-18 GHz when the thickness was 1.92 mm.
W-type barium ferrites doped with Gd^3＋,Ba1-xGdx（Zn0.3Co0.7）2Fe16O27（x = 0,0.05,0.10,0.15,0.20）,were prepared by a sol-gel method.The effects of Gd^3＋ substitution on their microstructure,electromagnetic properties and microwave absorptive behavior were analyzed.The XRD patterns showed the single phase of W-type barium ferrite when x ≤ 0.15.Microwave electromagnetic properties of samples were studied at the frequency range from 2 GHz to 18 GHz using a network analyzer（Agilent 8722ET）.The complex permittivity ε（ε＇,ε＇＇） increased gradually when x ≤ 0.10,but it decreased as x = 0.15.The real permeability（μ＇） decreased with the increase of Gd^3＋ content,while the imaginary permeability（μ＇＇） increased when x ≤ 0.10.All these reasons were discussed using the electromagnetic theory.Furthermore,the ferrite-epoxy compound coating materials with 80 wt.% of Ba0.9Gd0.1（Zn0.3Co0.7）2Fe16O27 were prepared to measure the microwave absorbing properties.The maximum of reflection loss（RL） reached about-27 dB and RL was below-10 dB in the frequency range of 8-18 GHz when the thickness was 1.92 mm.
基金
supported by the Pre-research Foundation of CPLA General Equipment Department (NO.9140A××××6401)
