Formation Mechanism And Electromagnetic Microwave Absorbing Properties Of Carbon-Encapsulated Permalloy Nanoparticles Prepared Through Detonation

Carbon-encapsulated Fe-Ni alloy nanoparticles were synthesized through detonation using safety composite explosive precursors doped with Fe(NO3)(3)center dot 9H(2)O and Ni(NO3)(2)center dot 6H(2)O. The morphology, components, and structure of the synthesized carbon-encapsulated alloy nanoparticles were characterized through X-ray diffraction studies, Raman spectroscopy and Transmission electron microscopy attached with energy dispersive X-ray spectroscopy (EDS). Results show that the carbon-encapsulated Fe-Ni nanoparticles have a core-shell structure. The grains range from 40 to 60 nm in size and are distributed uniformly. The encapsulated metal core is mainly composed of different proportions of Fe and Ni. The outer shell is composed of graphite and amorphous carbon, and there are also onion carbon formed by the graphitization of diamond clusters in the vicinity of the nanoparticles. The electromagnetic characteristics of Fe-Ni alloy nanoparticles composites were measured by Agilent microwave network analyzer in the band of 2-18 GHz. The experimental results show that when the coating is 2 mm in thickness, the absorption layer whose atomic ratio of iron and nickel is 1:4 has double absorption peak, peak values are -14.6 dB (9.7 GHz) and -7.7 dB (14.3 GHz), and the absorption band ranges of -10 dB is from 8.5 to 11.8 GHz. The reflection loss R(dB) of the nanoparticles, whose atomic ratio of iron and nickel is 1:1, reaches to 30 dB at 12.88 GHz, and the absorption band of -10 dB is 9.7 similar to 14.4 GHz, which has wide absorption band and excellent absorbing property.