离子取代镍基铁氧体的性能及吸波涂层优化设计

刘  渊，刘祥萱，王煊军，张泽洋，李  茸，郭  磊

(第二炮兵工程大学 603教研室，西安 710025)

摘 要：在同等实验条件下，以镍铁氧体为基体，通过溶胶?凝胶法，制备二元镍基复合铁氧体Ni_0.5A_0.5Fe₂O₄(A= Zn, Co, Mn, Cu)。用X射线衍射仪、扫描电子显微镜、振动样品磁强计和矢量网络分析仪对粉末的结构及电磁性能进行表征并对其吸波性能进行优化设计。结果表明：4种离子取代后均能形成在室温条件下具有超顺磁性的纯净镍基铁氧体粉末。离子取代使铁氧体样品的复介电常数实部ε′增大，虚部ε″在2~6 GHz和13~18 GHz变小，在6~13 GHz增大。Zn²⁺、Mn²⁺、Cu²⁺ 3种离子取代样品与未进行离子取代的NiFe₂O₄相比，其复磁导率实部μ′变化不大，而Co²⁺离子取代样品的μ′整体要大于其他几种离子取代样品及未取代样品的μ′；在2~11 GHz进行Zn²⁺、Co²⁺、Mn²⁺3种离子取代样品的虚部μ″变大，且以Ni_0.5Zn_0.5Fe₂O₄的最大，Cu²⁺取代样品的虚部μ″与未取代样品的虚部μ″相比变化不大。利用传输线理论优化设计时发现，Co²⁺取代后的复合铁氧体没有匹配点，Zn²⁺取代后的复合铁氧体匹配效果最好，在最佳匹配厚度为5.63 mm时，其最小反射率峰值为?36.26 dB，小于?10 dB的频宽可达4.7 GHz。

关键词：镍基铁氧体；溶胶凝胶法；离子取代；磁性能；优化设计

Performance of nickel ferrite replaced by different ions and optimization design of absorbing coating

LIU Yuan, LIU Xiang-xuan, WANG Xuan-jun, ZHANG Ze-yang, LI Rong, GUO Lei

(No. 603 Faculty, Xi’an Research Institute of High Technology, Xi’an 710025, China)

Abstract:The binary nickel composite ferrites Ni_0.5A_0.5Fe₂O₄ (A=Zn, Co, Mn, Cu) were prepared under the same condition via sol–gel method. The powder structure and electromagnetic properties were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and vector network analyzer, and its absorbing coating was optimized. The results show that the replacement of four kinds of ions can form pure nickel ferrite powders with super paramagnetic at room temperature. After the ions replacement, the real part ε′ of complex permittivity of the ferrite samples increases, and the imaginary part ε″ of complex permittivity of the ferrite samples decreases in 2?6 GHz and 13?18 GHz while increases in 6?13 GHz. The real part μ′ of complex permeability of the samples replaced by Zn²⁺, Mn²⁺ or Cu²⁺ has little change compare with that of NiFe₂O₄, while μ′ of the sample replaced by Co²⁺ is greater than those of other samples whether being replaced or not; the imaginary part μ″ of the samples replaced by Zn²⁺, Co²⁺ or Mn²⁺ becomes larger in 2?11 GHz, and that of Ni_0.5Zn_0.5Fe₂O₄ is the largest one, that of the sample replaced by Cu²⁺ has little change compared with that of the sample before replacement. It is found by the design of coating optimization that the composite ferrite replaced by Co²⁺ has no match point, and the composite ferrite replaced by Zn²⁺ has the best match point. The minimum microwave reflection loss is ?36.26 dB under the match thickness of 5.63 mm, and the bandwidth less than ?10 dB can reach 4.7 GHz.

Key words:nickel ferrite; sol-gel method; ion replace; magnetic property; optimization design