Flash Joule heating-enhanced in-situ synthesis of 3D graphene/ high-entropy alloy composites for efficient electromagnetic wave absorption

High-entropy alloys (HEAs) have emerged as a promising class of materials for electromagnetic wave absorption (EWA) due to their unique electronic structures and the synergistic effects of multiple components. However, the practical application of HEAs has been limited by their narrow Effective Absorption Bandwidth (EABw) and high density. Herein, the in-situ synthesis of 3D graphene/HEA composites via a novel method combining laser-induced synthesis and flash Joule heating (FJH) technology is reported. The unique 3D porous structure of graphene provides a lightweight and conductive matrix for the uniform distribution of HEA nanoparticles. The FJH treatment not only ensures the intimate contact between the graphene matrix and HEA nanoparticles but also refines the grain size of the alloy and optimizes the FeCoNiCuMn HEA composition. The resulting 3D graphene/HEA composites demonstrated exceptional EWA performance, achieving a minimum reflection loss of-62.23 dB at 2-18 GHz with a filler ratio of 20 wt% in paraffin wax. Moreover, the EABw reached 5.05 GHz with a filler ratio of 30 wt%. These findings highlight the potential of 3D graphene/HEA composites synthesized via laser-induction and FJH methods for developing advanced EWA materials with broad applications in electromagnetic compatibility, stealth technology, and communication systems.