Ni-coated carbon nanotubes/Mn-Zn ferrite composite as viable microwave absorbing materials

This paper presents the design, development and characterization of the spinel ferrite [Mn _0.2Zn _0.8Fe ₂O ₄] powders and Nickel (Ni)-coated multiwall carbon nanotubes (MWNTs). A combination of Mn _0.2Zn _0.8Fe ₂O ₄ spinel ferrites particles and Nickel (Ni)-coated multiwall carbon nanotubes (MWNTs) were introduced into epoxy resin to be a microwave absorber. The structural characterizations and surface morphology of Mn _0.2Zn _0.8Fe ₂O ₄ and MWNTs were investigated by X-ray diffraction (XRD) and scanning electron microscopy respectively. The electromagnetic wave absorption characteristics of the composites have been studied in the frequency interval of 12-15GHz.The results for Mn _0.2Zn _0.8Fe ₂O ₄/EP, Mn _0.2Zn _0.8Fe ₂O ₄/MWNTs/EP and Mn _0.2Zn _0.8Fe ₂O ₄/Ni-coated MWNTs/EP microwave absorbers for the same thickness have been reported. It has been found that the Mn _0.2Zn _0.8Fe ₂O ₄/Ni-coated MWNTs/EP composites show the broadband characteristics with minimum absorption of 5 dB about 2.6 GHz and the maximum absorption of 37.05 dB at 14 GHz for a coating thickness of 2 mm. Therefore, Mn _0.2Zn _0.8Fe ₂O ₄/Ni-coated MWNTs/EP composites will be a suitable microwave absorptive material for 12-15GHz.