Electromagnetic wave absorption properties of carbon-encapsulated Co–Cu alloy nanoparticles prepared by gas explosion

Abstract

The carbon-encapsulated Co–Cu alloy nanoparticles (Co–Cu@C) with core-shell structure can improve the dispersion of metal alloy nanoparticles. Co–Cu@C was successfully prepared by a convenient gas explosion method, using C6H6–O2 as the explosion source and cobalt(III) acetylacetonate and cupric(II) acetylacetonate as the precursor. The effect of heat treatment on phase, morphology, magnetic properties and electromagnetic (EM) wave absorption performance were studied. The characterization results indicate that the initial sample was Co–Cu@C in spherical or quasi spherical shape with Co–Cu alloy as metal core and amorphous carbon as shell. After heat treatment, the Co–Cu alloys were decomposed into Co and Cu, and the nanoparticles were Co@C and Cu@C with core-shell structure. The magnetic properties and EM wave absorption properties of the nanoparticles were improved significantly after heat treatment. The magnetic properties of Co–Cu@C increased distinctly by 2.4 times. The reflection loss value of original Co–Cu@C is −4.3 dB, and it could be increased by 44% after heat treatment. Heat treatment is an effective method to improve the magnetic and EM wave absorption properties of the Co–Cu@C prepared by gas explosion.