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利用溶胶-凝胶自蔓延燃烧反应制备了Ni1-xZnxFe2O4(x=0.5,0.65和0.8)铁氧体纳米粉末,将粉末分别在550、800和1050℃下退火2 h,研究了各退火样品的晶体结构及自燃烧样品在X波段(8.2～12.5 GHz)的电磁性质。XRD分析表明,随Zn2+含量的提高,在自燃烧及550℃退火后,除尖晶石主相外,还有微量的ZnO、Fe3O4杂相;经800℃及其以上较高的温度退火后,所得样品呈完好的尖晶石相。VSM及微波矢量网络测量表明,Zn2+含量影响材料的比饱和磁化强度和矫顽力以及吸波性能、复介电常数和复磁导率;适当的Zn2+含量可提高纳米晶材料的自然共振频率,展宽其吸收频带,提高其复磁导率和磁损耗性能,改善其吸波性能。当x=0.65时,纳米Ni0.35Zn0.65Fe2O4粉末的吸波性能最好。当涂层厚度d=1mm时,其在测试频段内有四个吸收峰,在频率f=11.2315 GHz处,最大吸收值为15.879 dB;在9.0～11.7 GHz,吸收值达8 dB以上,μ’值达1.0以上,μ“值基本在0.7以上;其中吸收值超过11 dB和μ”值超过1.0的带宽达1.2 GHz。
Ni1-xZnxFe2O4 (x = 0.5, 0.65 and 0.8) ferrite nanoparticles were prepared by sol-gel self-propagating combustion. The powders were annealed at 550, 800 and 1050 ℃ for 2 h. Crystal structure and self-burning samples in the X-band (8.2 ~ 12.5 GHz) electromagnetic properties. XRD analysis showed that with the increase of Zn2 + content, a slight amount of ZnO and Fe3O4 miscellaneous phases were found in addition to the main phase of spinel after self-combustion and annealing at 550 ℃. After annealing at 800 ℃ and above, The resulting sample was intact spinel phase. VSM and microwave vector network measurements show that the Zn2 + content affects the specific saturation magnetization, the coercive force, the microwave absorbing property, the complex permittivity and the complex permeability of the material. The proper Zn2 + content can increase the natural resonance frequency of the nanocrystalline material, Broaden its absorption band, improve its complex permeability and magnetic loss performance, improve its absorbing performance. When x = 0.65, the nano-Ni0.35Zn0.65Fe2O4 powder has the best microwave absorbing property. When the thickness of the coating is d = 1mm, it has four absorption peaks in the test frequency band, the maximum absorption value is 15.879 dB at the frequency of f = 11.2315 GHz, the absorption value is above 8 dB at the frequency of 9.0-11.7 GHz, Values above 1.0, μ "values are mostly above 0.7; bandwidths up to 11 dB with absorbance values above 1.0 and bandwidths up to 1.0 reach 1.2 GHz.