Ferrite/carbon composited materials,especially the bio-derived composited materials possessing both environmental friendliness and outstanding microwave absorption performance,attract numerous attentions for solving t...Ferrite/carbon composited materials,especially the bio-derived composited materials possessing both environmental friendliness and outstanding microwave absorption performance,attract numerous attentions for solving the"electromagnetic problem"in the Gigahertz frequency range.In this work,we demonstrate a bio-derived ferrite/carbon material by compositing functional carbonized cotton fibers(CCFs)and Fe_(3)O_(4)nanoparticles with optimized microwave-absorption properties.By adjusting the carbonization conditions systematically,the Fe_(3)O_(4)loading contents and the microwave absorption properties can be varied simultaneously-and,indeed,optimized and tuned.The CCFs-Fe_(3)O_(4)composites exhibited a minimum reflection-loss capacity RL(d B)of-56.8 d B at 10.9 GHz with a thickness of 1.67 mm,and its effective absorption bandwidth(RL(d B)<-20 d B)was found to broaden to 7.1 GHz.Electromagnetic characterizations,coupled with microstructure analyses,revealed that the enhancement in microwave absorption was triggered by the different microstructures of CCFs-Fe_(3)O_(4)composites-attributable to the different carbonization processes.These different conditions result in different amounts of Fe_(3)O_(4)attachment sites and lead to the enhancement of dielectric polarization at localized microstructures.The present work of bio-derived ferrite/carbon materials has important implications in understanding structure-performance relationships in dielectric-magnetic materials,and,meanwhile,could well be extended to a microwave-absorber design approach.展开更多
基金support from the SFI-NSFC bilateral funding scheme(grant number SFI/17/NSFC/5229)。
文摘Ferrite/carbon composited materials,especially the bio-derived composited materials possessing both environmental friendliness and outstanding microwave absorption performance,attract numerous attentions for solving the"electromagnetic problem"in the Gigahertz frequency range.In this work,we demonstrate a bio-derived ferrite/carbon material by compositing functional carbonized cotton fibers(CCFs)and Fe_(3)O_(4)nanoparticles with optimized microwave-absorption properties.By adjusting the carbonization conditions systematically,the Fe_(3)O_(4)loading contents and the microwave absorption properties can be varied simultaneously-and,indeed,optimized and tuned.The CCFs-Fe_(3)O_(4)composites exhibited a minimum reflection-loss capacity RL(d B)of-56.8 d B at 10.9 GHz with a thickness of 1.67 mm,and its effective absorption bandwidth(RL(d B)<-20 d B)was found to broaden to 7.1 GHz.Electromagnetic characterizations,coupled with microstructure analyses,revealed that the enhancement in microwave absorption was triggered by the different microstructures of CCFs-Fe_(3)O_(4)composites-attributable to the different carbonization processes.These different conditions result in different amounts of Fe_(3)O_(4)attachment sites and lead to the enhancement of dielectric polarization at localized microstructures.The present work of bio-derived ferrite/carbon materials has important implications in understanding structure-performance relationships in dielectric-magnetic materials,and,meanwhile,could well be extended to a microwave-absorber design approach.
