Preparation and microwave-absorbing property of BaFe12O19 nanoparticles and BaFe12O19/Fe3C/CNTs composites

BaFe12O19 ferrite was firstly prepared through a sol–gel auto-combustion process, and then BaFe12O19/Fe3C/CNTs composites were synthesized from the acetylene chemical vapor deposition process with the introducing of BaFe12O19 ferrite at 400–600 °C. The structure and morphology of the BaFe12O19 ferrite and BaFe12O19/Fe3C/CNTs composites were studied using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray. The microwave-absorbing properties of pure BaFe12O19 and such composites were investigated in the frequency range of 2–18 GHz through the evaluation of the experimental data based on the transmission line theory. The reflection loss results showed that the microwave absorption of BaFe12O19/Fe3C/CNTs composites performed better as the reaction temperature increasing up to 500 °C, due to the generation of the high-purity helical CNTs. The composites obtained at 600 °C performed well in electromagnetic wave loss at low frequency, owing to effective interfacial polarizations and good dispersion of magnetic nanoparticles. The composites were very potential for lightweight and strong electromagnetic attenuation materials at relatively low frequency.