Epoxy Resin Matrix Nanocomposites with Core-Shell Structure of NiZnFerrite/Ag and NiZnFerrite/PANi as Fillers for Microwave Absorber in Ka-band

摘要

The core-shell NiZnFerrite/Ag and NiZnFerrite/PANi (7:1 %wt) with epoxy resin forming a nanocomposite structure were synthesized by blending at 70 %vol content and introduced it into epoxy resin to be a microwave absorber. The phase and morphology characterization of the formation processes of NiZnFerrite/Ag and NiZnFerrite/PANi core-shell structure were studied using X-ray diffraction, transmission electron microscopy and scanning electron microscopy respectively. Microwave absorbing properties were investigated by reflectivity measurements in Ka-band (18 - 26 GHz). The reflection losses were calculated based on the model of a single layered plane wave absorber backed by a perfect conductor. The composite epoxy resin-NiZnFerrite/Ag shows matching frequency (f_(m1) = 20.7 GHz and f_(m2) = 23.2 GHz), maximum reflection loss (RL_(m1) = -20.8 dB and RL_(m2) = -29.8 dB) and bandwith (△f1 = 18.6 - 21.7 GHz and △f2 = 21.7 - 25.0 GHz). Further, the composite epoxy resin-NiZnFerrite/PANi shows matching frequency (f_(m1) = 20.9 GHz and f_(m2) = 23.2 GHz), maximum reflection loss (RL_(m1) = -20.1 dB and RL_(m2) = -24.6 dB) and bandwith (△f1 = 19.9 - 21.9 GHz and △f2 = 21.9- 25.0 GHz), for an absorber thickness of 3.6 mm.