Fabrication and microwave absorbing properties of (Z-type barium ferrite/silica)@polypyrrole composites

The organic-inorganic hybrid materials with many potential applications have been studied widely. Moreover, the fabrication of Z-type barium ferrite/silica (Z-BCF/SiO2) is still challenging owing to the intricate structure and preparation process. Here, the double core-shell (Z-type barium ferrite/silica)@Polypyrrole composites ((Z-BCF/SiO2)@PPy) have been successfully fabricated by in-situ chemical synthesis method. The structure, morphology and electromagnetic performances of the composites were characterized by TG, IR, XRD, SEM, TEM and VSM. The results indicated that the Z-BCF/SiO2 particles were efficiently coated by PPy, and the (Z-BCF/SiO2)@PPy composites have the more superior electrical conductivity than Z-BCF/SiO2 composites, but their saturation magnetization declines to some extent. It is related to the content of relevant component. More meaningfully, the PPy coating improved the microwave absorbing properties of composites in the 2-18 GHz frequency range. A minimum reflection loss (RLmin) value of -19.65 dB is obtained for the (Z-BCF/SiO2)@PPy composites with 66.67 wt% PPy with thickness of merely 2 mm, and its absorption bandwidth below -8 dB reaches 5.56 GHz. Furthermore, the favorable absorption can be extended to the range of 18-26 GHz. Therefore, the novel ternary composites with excellent microwave absorbing properties may have potential applications in electromagnetic shielding field. (C) 2014 Elsevier B.V. All rights reserved.