Multifunctional interstitial-carbon-doped FeCoNiCu high entropy alloys with excellent electromagnetic-wave absorption performance

Electromagnetic-wave absorbing(EMA)materials that have efficient absorption performances,great me-chanical properties and chemical stability are rare and yet essential for communication security and pro-tection.Herein,flaky interstitial-carbon-doped FeCoNiCu high entropy alloys(HEAs)as novel EMA ma-terials were successfully prepared by high-energy ball-milling method.Interstitial-carbon doping as a modulating approach impacted the phase forming,morphology and electromagnetic properties of Fe-CoNiCu HEAs.Impedance matching was significantly optimized via tuning interstitial carbon contents.The carbon-doped FeCoNiCu HEAs with appropriate carbon contents delivered superior EMA performance compared with other HEAs EMA materials.Strong reflection loss as low as-61.1 dB in the Ku band,broad effective absorption bandwidth of 5.1 GHz was achieved for FeCoNiCuC_(0.04).Moreover,the carbon-doped FeCoNiCu HEAs exhibited excellent mechanical hardness and chemical stability.This work not only suggests that interstitial-carbon doping is an available approach to tuning electromagnetic properties of HEAs,but also presents carbon-doped FeCoNiCu HEAs as promising EMA materials for civilian and mili-tary due to the efficient absorption,broad bandwidth,great durability and stability.