Highly enhanced microwave absorption for carbon nanotube/barium ferrite composite with ultra-low carbon nanotube loading

Barium ferrite (BaFe12O19) is considered as potential microwave absorption (MA) material thanks to the large saturation magnetization, high Curie temperature, and excellent chemical stability. The integration of carbon nanotube (CNT) can improve the dielectric loss of BaFe12O19 for further enhanced MA performance, nevertheless, the MA performance is still not desirable because of the poor CNT dispersion in the CNT/BaFe12O19 composites, which usually prepared via the ball-milling method, unless high CNT loading was used. Herein, according to the thermal stability of CNT in different atmosphere and the formation mechanism of BaFe12O19 from precursor, CNT was introduced in the precursor of BaFe12O19 uniformly during auto-ignition process and calcined under different atmosphere. When CNT loading is only 2.0 wt%, the CNT/BaFe12O19 composites obtained exhibits a minimum reflection loss (RLmin) of -43.9 dB and effective bandwidth (with < -10 dB) of 3.9 GHz with the thickness of 1.5 mm, which are much superior to -10.2 dB and 2.2 GHz for pure BaFe12O19, and -13.6 dB and 2.5 GHz for CNT/BaFe12O19 composite prepared by ball-milling method. These results may pave the way to design high-performance BaFe12O19 based microwave absorbers. (C) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

Barium ferrite (BaFe12O19) is a potential microwave absorption material, but the performance is limited by the poor dispersion of carbon nanotubes (CNTs) in the composites prepared by ball-milling method. In this study, CNTs were uniformly introduced into the precursor of BaFe12O19 during the auto-ignition process and calcined under different atmospheres. The resulting CNT/BaFe12O19 composites exhibited significantly improved microwave absorption performance compared to pure BaFe12O19 and CNT/BaFe12O19 composites prepared by ball-milling method.