Preparation And Characterization Of Magnetic Hollow Microsphere And Its Composites

In this paper, Mn-Zn ferrite hollow microspheres were prepared by two kinds of preparation methods, and we tried to find a better preparation method in the experimental process. In order to improve the absorbing properties, Mn-Zn ferrite were composited by carbon nanotubes, and also doped by different rare earth, studied absorbing properties between 0-6000 MHz.(1) The cubic spinel Mn-Zn ferrite hollow microspheres were prepared by solvothermal method and self-assembly method, changing the reaction conditions(such as reaction temperature, reaction time, etc.), the effect of the morphology, magnetic properties and wave absorbing properties of ferrite particles were studied. The results showed that the prepared products were spinel ferrite hollow microspheres, and compared to the self-assembly method,the particle size distributed uniform, scattered good with a diameter of about 500 nm by using solvothermal method. The magnetic properties of Mn Zn ferrite prepared by solvent thermal method is greater than self-assembly method, the saturation magnetization was 92.3270 emu?g-1.(2) Mn0.6Zn0.4Fe2O4/CNTs composite materials were prepared by solvothermal method,explored the composite with different mass ratio of carbon nanotubes on ferrite absorbing properties. X-ray diffraction(XRD), and transmission electron microscopy(TEM) analysis results showed that Mn Zn ferrite hollow spheres and carbon nanotubes composite, and when the composite quality of the carbon nanotubes was 1%, the absorbing performance of the composites was the best, reflection loss value was-11.3479 dB.(3) Mn0.6Zn0.4NdxFe2-x O4 and Mn0.6Zn0.4Dyx Fe2-xO4(x = 0, 0.3, 0.5, 0.7, 1) hollow microspheres were prepared by solvent thermal method, and studied the effect of different doping ratio on wave properties. The absorbing properties were characterized by using a vector network analyzer, the results showed that, when the proportion of dysprosium doped was 0.05, the properties of Mn0.6Zn0.4DyxFe2-x O4 hollow spheres was the best, reflection lossvalue was-9.6184dB; when the proportion of neodymium doped was 0.03, the properties of Mn0.6Zn0.4NdxFe2-x O4 hollow spheres was the best, reflection loss value was r-18.1992 dB.And by force of contrast, found that the wave absorbing performance was better than the absorption of dysprosium doped neodymium.(4) Explored the composite with different mass ratio of carbon nanotubes on Mn0.6Zn0.4Nd0.03Fe1.97O4 absorbing properties. Comparison of the absorption properties of Mn0.6Zn0.4Fe2O4/CNTs with carbon nanotubes and rare earth elements Co doped ferrite. The analysis showed that the rare earth element and the co-doping of carbon nanotubes could not improve the wave absorbing properties of Mn0.6Zn0.4Nd0.03Fe1.97O4, but it is improved compared with the absorption of Mn0.6Zn0.4Fe2O4/CNTs.