采用溶胶凝胶法制备了平面六角铁氧体,并用扫描电镜(SEM),X射线衍射仪(XRD)对它的形貌以及相结构进行了表征,用矢量网络分析仪(VAZ)研究了不同比例的Ni/铁氧体混合物的微波吸收性能。结果发现,随着混合物中的平面六角铁氧体含量增多,混合物的微波吸波吸收峰向高频方向移动,当混合物由20%Ni+80%铁氧体组成时,混合物的微波吸收性能最佳。当吸波涂层厚度为2 mm时,在12 GHz处,最小反射率为–20 d B,小于–10 d B的带宽达到了4 GHz。当吸波涂层厚度增加时,吸收峰频率向低频移动,吸收峰值先变小,后增大。当厚度达到一定值时,混合物在2~18 GHz之间出现2个吸收峰,这对于研究宽频吸收具有重要意义。
The Sr-W type planar hexagonal ferrite was synthesized by a sol-gel method, and its morphology and phase structure were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The microwave absorbing properties of the mixtures with different ratios of Ni/ferrite were studied by vector network analyzer(VAZ). The results demonstrate that with the increase of hexagonal ferrite content, the microwave absorbing peaks of the mixtures shift to higher frequencies, and when the mixture consists of 20% Ni and 80% Sr-W-type ferrite, its microwave absorbing performance is the most advantageous. When absorbing coating thickness is 2 mm, the minimum reflectivity and absorbing peak frequency is –20.69 d B at 12.08 GHz and the bandwidth less than –10 d B reaches 4 GHz. The absorbing peak shifts to low-frequency with the increase of absorbing coating thickness, and when the coating thickness reaches a certain value, the two absorbing peaks appear in the mixture in the frequency range of 2~18 GHz, which is of significance to explore the absorbing material with bandwidth effect.