锂锌铁氧体微纳米纤维的电纺制备及吸波性能

采用静电纺丝技术结合后续热处理制备了尖晶石型Li_0.35Zn_0.3Fe_2.35O₄微纳米纤维. 利用差示扫描量热(DSC)-热重分析(TGA)、 傅里叶变换红外光谱(FTIR)、 X射线衍射(XRD)和场发射扫描电子显微镜(FESEM)等手段研究了煅烧温度(700, 800, 900, 1000 ℃)对产物物相和形貌的影响; 利用矢量网络分析仪分析了纤维状产物的吸波性能. 研究结果表明, Li_0.35Zn_0.3Fe_2.35O₄在700 ℃及以上温度煅烧后可生成单一尖晶石结构. 随着煅烧温度的升高, 产物依次呈现出微纳米纤维状、 三维网络状、 竹节状和颗粒状的微观形貌. 随着匹配厚度增加, 微纳米纤维状Li_0.35Zn_0.3Fe_2.35O₄的最低反射率向低频移动, 在8 GHz以下的最佳匹配厚度为6 mm, 在此厚度下吸波性能优良, 最低反射率为-26 dB, 对应的吸收频率为5.0 GHz, 低于-10 dB的吸收频带为4.0~8.0 GHz, 带宽为4 GHz.

Electrospinning Fabrication and Microwave Absorption Properties of Lithium Zinc Ferrite Micro/Nanofibers

Spinel-type Li0.35Zn0.3Fe2.35O4 micro/nanofibers were prepared through electrospinning and calcination technique.The crystalline phase and micromorphology of the samples calcined at various temperatures(700, 800, 900 and 1000 ℃) for 2 h in air were examined by differential scanning calorimetry(DSC)-thermalgravimetric analysis(TGA), Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD) and field emission scanning electron microscopy(FESEM).Microwave absorption properties of Li0.35Zn0.3Fe2.35O4 micro/nanofibers were determined with a vector network analyzer.The results showed that pure spinel structure formed at 700 ℃ and above.As the temperature increased, Li0.35Zn0.3Fe2.35O4 exhibited micro/nanofibrous, 3D network, bamboo-like or granular morphology.The minimum reflectivity of Li0.35Zn0.3Fe2.35O4 micro/nanofibers at 700 ℃ moved to a low frequency as the matching thickness increased.The matching thickness of Li0.35Zn0.3Fe2.35O4 micro/nanofibers was 6 mm below 8 GHz, at which the microwave absorption properties were fine.The minimum reflectivity could reach-26 dB at 5.0 GHz, and the frequency band with reflectivity less than-10 dB was 4.0-8.0 GHz.