Synthesis Of Magnetic Particles On T-ZnOw And Test Of Its Electromagnetic Properties

Dielectric material T-ZnOw and nanosized magnetic materials (Fe₃O₄, Fe) have a good performance in microwave absorption in certain frequency bands. To make sure that the composite has good microwave absorption both in low-frequency band and high-frequency band, magnetic particles were in situ synthesis on the surface of T-ZnOw.In this thesis, nanosized magnetic particles (Fe₃O₄, Fe) were prepared. According to the orthogonal experimental method, the best parameters of the preparation were determined.Base on the best parameters above, T-ZnOw/Fe₃O₄ composite was prepared. Morphology and components of the composite were analysed by scanning electron microscopy, X-ray diffraction, Infra-red and energy loss spectrum. According to the results, the best parameters of the preparation were as follows: T-ZnOw must be modified by TEOS before the preparation; N₂ is required through the experiment; the volume ratio of alcohol to water is 2:5; the quality ratios of FeCl₂·4H₂O and FeCl₃·6H₂O to surface modified T-ZnOw is 1:3.7. With the best parameters, the T-ZnOw/Fe₃O₄ composite kept the tetra-needle-like morphology and had integrity crystal made of ZnO and Fe₃O₄ crystal, the particle diameter of Fe₃O₄ is about 19.99nm.Between the frequency band 2-18GHz, the microwave absorption of Fe₃O₄, Fe and T-ZnOw/Fe₃O₄ composite were tested. In the frequency band 6-13 GHz, the peak of microwave absorption of Fe₃O₄ is -8.5dB; the peak of microwave absorption of Fe is -7.5dB in the frequency band 2-6GHz, the microwave absorption of Fe₃O₄ is better than Fe. The microwave absorption of T-ZnOw/Fe₃O₄ composite in the frequency band 2-18GHz is good, and the bigger of the thickness of the T-ZnOw/Fe₃O₄ composite flat, the better microwave absorption it has.