PERFORMANCE VS CONVENIENCE OF MAGNETIC CARBON-METAL NANOCOMPOSITES: A LOW-COST AND FACILE CITRATE-DERIVED STRATEGY FOR FECO ALLOY/CARBON COMPOSITES WITH HIGH-PERFORMANCE MICROWAVE ABSORPTION

摘要

Magnetic carbon-based composites reside at the frontier of high-performance microwave absorbing materials (MAMs) due to their dual loss mechanisms and tunable electromagnetic properties. In this study, we review the construction of magnetic carbon-metal composites in recent years, and introduce a facile citrate-derived strategy to produce FeCo alloy/carbon composites through a direct pyrolysis of the resultant gels, where citric acid is employed as both a carbon source and a complexing agent. It is found that the dosage of citric acid determines the crystalline phase and particle size of magnetic FeCo alloy particles, as well as the content of carbon components. Electromagnetic analysis indicates that the electromagnetic functions of these composites are highly dependent on their specific compositions, where carbon components favor high complex permittivity and FeCo alloy particles take charge of complex permeability. When the chemical composition is optimized, good attenuation ability and characteristic impedance matching are created in the composite, resulting in desirable microwave absorption properties. The absorption performance is comparable to most homologous composites reported. Considering the low-cost and easy preparative process, we believe that this citrate-derived strategy may be instructive and helpful for practical applications of various magnetic carbon-based composites in the field of microwave absorption.