Abstract.
Core-shell composite structure of NiZn-ferrite coated with polyaniline was prepared by in situ polymerization of aniline at different aniline-volume to ferrite-weight ratios (Aniline/NiZn-ferrite = 1/1, 2/1, 3/1). The composite samples were introduced into epoxy resin forming sheet to serve as a microwave absorber. Chemically and morphologically, the composite samples were characterized by FTIR, XRD, EDAX and TEM. The electrical conductivity of the composites was measured by four-point probe technique. Microwave absorbing performances were investigated by measuring reflectivity in 8–18 GHz using PR-17 microwave reflectometer. IR analysis indicated successful formation of polyaniline. XRD revealed a spinel structure of the prepared NiZn-ferrite and EDAX indicated the right elemental composition of the produced ferrite. TEM clearly confirmed the core-shell structure of prepared NiZn-ferrite/polyaniline composite. It is found that the electrical conductivity of the NiZn-ferrite particles can be enhanced by the conductive PANI coating and increased by increasing the PANI/ferrite ratio in the composite. All samples were found to absorb microwave with some differences in the average reflection loss with respect to preparation ratios. In general, the maximum reflection loss frequency can be determined by controlling aniline to NiZn-ferrite ratio.