| With the development of electric and electronic industry, the use of electronic products and telecommunication equipment making the electromagnetic pollution worse.Thus the research and development of new low-cost, high-absorbency of the absorbing materials are a common concern to all countries. An" ideal"microwave absorbing material owns such advantages as low thickness, low density, wide band width and flexibility simultaneously. However, individual absorbent could not meet all the above requirements.Organic-inorganic nanocomposites is considered to be the best microwave absorption materials.In this paper, considering the magnetic loss of ferrite,the dielectric loss of polyaniline and reduced graphene oxide as well as their physical and chemical properties. The structure, morphology, microwave absorption properties of the products were characterized by Fourier transform infrared spectra(FT-IR), X-ray diffraction(XRD), transmission electron microscopy(TEM), scanning electron microscopy(SEM) and vector network analyzer in 2-18GHz, respectively. The main results can be summarized as follows:(1) Using Ni(NO3)2·6H2O, Fe(NO3)3·9H2O, Zn(NO3)2·6H2O as raw material, the nanocrystalline NixZn1-xFe2O4 ferrite and novel NixZn1-xFe2O4/Polyaniline ferrite nanocomposites were parepared by hydrothermal method and in situ emulsion polymerization, respectively. The investigation results indicate that the lattice parameters, size and saturation magnetization Ms of ferrite are enhanced by increasing Ni ions content. Ferrite particles uniformly load on PANI polymer chain with clear cube structure, particle size of about 20 nn. When x=0.7, ferrite and aniline the mass ratio of 1:2, PANI/Ni0.7Zn0.3Fe2O4 nanocomposites exhibit excellent microwave absorption performances, with a maximum reflection loss (RL) of -40.21 dB observed at 17.73 GHz.(2) Using Ni(NO3)2·6H2O, Fe(NO3)3·9H2O, Zn(NO3)2·6H2O, graphene oxide as raw material, the RGO-Ni0.7Zn0.3Fe2O4 composite were parepared by hydrothermal method. The effect of proportion of composite materials on the microwave absorption properties were investigated. By means of HC1 as dopant were prepared through in situ polymerization of RGO/Ni0.7Zn0.3Fe2O4/PANI ternary composite materials, microwave absorption properties of the composite materials are greatly improved, the ratio of GO to composites has important influence on the performance of microwave absorption. Moreover, the maximum reflection loss of the RNP2 composite is- 35.31dB, with the thickness of 5mm and the widest absorption band (RL<-10 dB) is 2.80 GHz (4.20-7.00 GHz). Within the scope of the thickness of 4.5 to 5 mm more than -20 dB and in low frequency and high frequency have a absorption peak, respectively.(3) Using Ni(NO3)26H2O, Fe(NO3)3·9H2O, Zn(NO3)2·6H2O, Co(NO3)2·6H2O and as raw material, the Ni0.4Co0.2Zn0.4Fe204 ferrite and novel Nio.4Co0.2Zn0.4Fe2O4/Polyaniline nanocomposites were parepared by hydrothermal method and in-situ polymerization method, respectively. The effect of ferrite content on the microwave absorption properties were investigated. It was found that the as-prepared different proportions of Nio.4Coo.2Zn0.4Fe2O4/PANI nanocomposites with Nio.4Co0.2Zn0.4Fe2O4 ferrite as the nucleus, PANI as the shell, the ferrite uniformly dispersed in PANI matrix.with the content of ferrite increased, the saturation magnetization of the material increases, conductivity and microwave absorption properties were first increased and then decreases. When the ferrite content reaches 20 wt% in composite materials, the microwave absorption performance achieve the best -25.24 dB, and the widest absorption band (RL<-10 dB) is 4.91 GHz (11.22-16.13 GHz) with the thickness of 2 mm. |
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