Zn2+含量对纳米Ni1-xZnxFe2O4粉末在X波段吸波特性的影响
Effects of Zn2+ Content on Microwave Absorption Properties of Nanometer Ni1-xZnxFe2O4 Powder in X-band Frequencies
卢佃清, 刘学东, 徐 超, 周 朕
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作者单位：(淮海工学院 理学院, 江苏 连云港 222005)
中文关键字：Zn2+含量； 自蔓延燃烧； 纳米粉末； Ni-Zn铁氧体； 微波吸收
英文关键字：Zn2+ content; self-propagating combustion; nanometer powder; Ni-Zn ferrite; microwave absorption
中文摘要：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=1 mm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。
英文摘要：Ni1-xZnxFe2O4 (x=0.5, 0.65, 0.8) ferrite nanometer powders were prepared by sol-gel self-propagating combustion method, and sintered at 550, 800 and 1050℃, respectively for 2 h. The crystal structure was characterized for a series of Ni-Zn ferrite samples, and the electromagnetic properties were also studied for Ni-Zn ferrite samples sintered at room temperature as a microwave absorbing materials in a frequency of 8.2～12.5 GHz. The XRD results indicate that, as the amount of Zn2+ increases, the major phase takes on spinel structure, simultaneously a small quantity of other phases such as ZnO and Fe3O4 appear in the samples sintered at room temperature and 550℃; while the samples sintered at 800℃, and the phase is a good spinel structure. The results from VSM and network analysis show that the content changing of Zn2+ would affect the specific saturation magnetization and the coercive force, as well as the microwave absorbing properties, complex permittivity and complex permeability of the samples. The proper content of Zn2+ can heighten the natural resonant frequency of the nano-crystalline materials, widen its absorption band and enhance its complex permeability and magnetic loss property, which improves its microwave absorbing properties. When x=0.65 and the thickness d=1 mm, the capability of microwave absorbing of Ni0.35Zn0.65Fe2O4 is best. There are four absorption peaks, the maximum absorption quantity is 15.879 dB while the frequency f=11.2315 GHz. Within the scope of 9.0～11.7 GHz, the absorption quantity exceeds 8 dB, μ' exceeds 1.0 and μ" mostly exceeds 0.7, in which absorption values over 11dB and μ" over 1.0 reaches 1.2 GHz bandwidth.