Microwave absorption performance of in situ synthesized Fe3O4-SiO2 hybrid fibres with enhanced environmental stability

Abstract

Fe3O4-SiO2 hybrid fibres were prepared by a combination of sol-gel and electro spinning techniques. The X-ray diffraction peaks of the fibres at 30.5, 35.5, 43.0, 57.0 and 62.6 correspond to the (220), (311), (400), (511) and (440) Fe3O4 planes and confirm the formation of Fe3O4 in the amorphous silica matrix. Si and Fe elemental mappings at the microstructural level were determined by scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry (EDS). The results reveal the uniform distribution of Si and Fe in the hybrid fibres. The Fe3O4-SiO2 hybrid fibres are immersed in the test hydrochloric acid solution with pH=1 and still can be magnetized and attracted to an external magnet after 6h in the solution. The heat- and flame-resistant performances of the hybrid fibres are demonstrated. Moreover, the prepared Fe3O4-SiO2 hybrid fibres display good microwave absorption performance in the range of relatively high frequencies. At a thickness of 5mm, the bandwidth corresponding to reflection loss below −10dB reaches approximately 11GHz (7–18GHz), covering the entire X-band (8.0–18.0GHz) and Ku-band (12.0–18.0GHz).