Hou Yi, Zhang Yani, Du Xiaoqing, Yang Yong, Deng Chaoran, Yang Zhihong, Zheng Lianxi, Cheng Laifei
Science and Technology on Thermostructural Composite Materials Laboratory, Northwestern Polytechnical University 710072 Xi'an China
Temasek Laboratories, National University of Singapore 5A Engineering Drive 1 117411 Singapore.
RSC Adv. 2018 Sep 28;8(59):33574-33582. doi: 10.1039/c8ra06941g.
Flexible FeSi/SiC ultrathin fiber mats have been fabricated by electrospinning and high temperature treatment (1400 °C) using polycarbosilane (PCS) and ferric acetylacetonate (Fe(acac)) as precursors. The crystallization degree, flexibility, electrical conductivity, dielectric loss and microwave absorption properties of the hybrid fibers have been dramatically enhanced by the introduction of Fe. FeSi nanoparticles with a diameter around 500 nm are embedded in SiC fibers. As the FeSi content increases from 0 to 6.5 wt%, the related saturation magnetization ( ) values increase from 0 to 8.4 emu g, and the electrical conductivity rises from 7.9 × 10 to 3.1 × 10 S cm. Moreover, the flexibility of FeSi/SiC hybrid fiber mats is greatly improved and remains intact after 500 times 180°-bending testing. Compared with pure SiC fibers, the FeSi/SiC hybrid fibers process higher dielectric and magnetic loss, which would be further advanced as more FeSi phase is introduced. At the optimal FeSi content of 3.8 wt%, the FeSi/SiC fibers/silicon resin composite (5 wt%) exhibits minimal reflection loss (RL) of -22.5 dB at 16.5 GHz and 2.5 mm thickness with a wide effective absorption bandwidth (EAB, RL < -10 dB) of 8.5 GHz. The microwave absorption performance can be further promoted by multi component stacking fiber mat composites which contain both low and high FeSi content layers. Furthermore, the position of the microwave absorption bands can also be simply manipulated by designing the stacking components and structure.
采用静电纺丝和高温处理（1400℃），以聚碳硅烷（PCS）和乙酰丙酮铁（Fe(acac)）为前驱体，制备了柔性FeSi/SiC超薄纤维毡。通过引入Fe，显著提高了复合纤维的结晶度、柔韧性、电导率、介电损耗和微波吸收性能。直径约500nm的FeSi纳米颗粒嵌入在SiC纤维中。随着FeSi含量从0增加到6.5wt%，相关的饱和磁化强度（ ）值从0增加到8.4emu g，电导率从7.9×10增加到3.1×10 S cm。此外，FeSi/SiC复合纤维毡的柔韧性大大提高，在500次180°弯曲测试后仍保持完好。与纯SiC纤维相比，FeSi/SiC复合纤维具有更高的介电和磁损耗，随着更多FeSi相的引入，这种损耗会进一步提高。在最佳FeSi含量为3.8wt%时，FeSi/SiC纤维/硅树脂复合材料（5wt%）在16.5GHz、厚度为2.5mm时表现出最小反射损耗（RL）为-22.5dB，有效吸收带宽（EAB，RL < -10dB）为8.5GHz。通过包含低FeSi含量层和高FeSi含量层的多组分堆叠纤维毡复合材料，可以进一步提高微波吸收性能。此外，通过设计堆叠组件和结构，还可以简单地控制微波吸收带的位置。
