Enhanced Low-Frequency Electromagnetic Wave Absorption by CoFe Alloy/C Microspheres Synthesized from Metal-Organic Frameworks
Abstract
The development of low-frequency absorption materials is pivotal for the significant reduction of electromagnetic interference and the enhancement of the electromagnetic environmental quality. Further research is essential to deepen and expand the scope of low-frequency absorption studies. In this study, nanoscale CoFe/C composite materials were synthesized from cobalt-iron bimetallic metal-organic frameworks (MOFs) via a hydrothermal synthesis process, followed by heat treatment. The dispersion of CoFe alloy particles and the morphology of the composites were effectively controlled by modulating the cobalt-to-iron element ratio in the precursors, thereby optimizing the absorption capabilities in a mid-low frequency range. The prepared Co3Fe7/C composite achieved a notable minimum reflection loss (RLmin) of -55.05?dB in the C-band at a thickness of 3.46?mm, with an effective absorption bandwidth (EAB) of 2.2?GHz (5.40-7.60?GHz), covering 55% of the C-band. Furthermore, at a thickness of 1.67?mm, the EAB was extended to 5.12?GHz. The nanoscale core-shell structured CoFe alloy/carbon composites demonstrate considerable potential as exceptional low-frequency absorption materials, due to their favorable dispersion, high magnetic responsiveness, and the presence of numerous heterogeneous interfaces.