杨木纤维/镍铁氧体复合中空微管的制备及吸波性能

Preparation and microwave absorbing properties of poplar fibers/NiFe_2O_4 composite microtubules with hollow structure

采用化学离析法制备杨木纤维,高温烧结形成杨木纤维碳材;Sol-gel法制备杨木纤维/镍铁氧体复合中空微管和镍铁氧体纳米粉料。利用XRD,SEM和矢量网络分析仪对3种样品的结构、形貌和吸波性能进行表征。结果表明:复合微管长度约为100μm,直径约为5μm,包覆的镍铁氧体层厚度约为1.5μm;复合微管的吸波性能远高于纳米粉料和杨木纤维碳材料,其在(2～18)GHz内的最大反射损耗达-30.4 dB(10.6 GHz),反射损失低于-10 dB的频率为(5.8～13.6)GHz。与已有研究结果比较,复合微管材料具有较低的质量分数和更宽的吸波频带。

The poplar fibers/NiFe2O4 composite microtubules and NiFe2O4 nanoparticles were prepared by a Sol-gel method.Poplar fibers were prepared by a chemical method of segregation and then the fiber-carbons were formed by high temperature sintering.The prepared materials were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),and a vector network analyzer(VNA).The results show that the composite microtubules maintain a hollow structure of poplar fibers.The length of the composite microtubules is about 100 microns,5 microns in diameter and the thickness of the coated nickel ferrite is about 1.5 microns.The microwave absorption properties of the poplar fibers/NiFe2O4 composite microtubules are better than those of the NiFe2O4 nanoparticles and the poplar fiber composite microtubules is-30.4 dB(10.6 GHz),the frequency range is from 5.8 GHz to 13.6 GHz for the reflectance loss less than-10 dB.Compared with the existing results,the composite microtubules have lower mass fraction and wider absorbing band.