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Researches on W-type Ferrites Composite Absorptive Materials

Author: ZhangWeiWei
Tutor: CaoQuanXi
School: Xi'an University of Electronic Science and Technology
Course: Materials Physics and Chemistry
Keywords: W -type barium ferrite Cenospheres Nanocomposite Microwave absorption Doping
CLC: TM25
Type: Master's thesis
Year: 2008
Downloads: 188
Quote: 0
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Abstract


This paper W-type hexagonal ferrite , barium ferrite as an object of study , the use of molten salt - co-precipitation method , sol - gel method and surface coating prepared by a series of barium ferrite grain . Composite thermal analyzer ( TG -DTA ) , X - ray diffraction (XRD) and scanning electron microscopy (SEM) Characterization of the surface structure of the material obtained in a different preparation process conditions and physical phase ; using the vector network the analyzer of electromagnetic parameters of the resulting sample and microwave reflectance measurement. The study showed that ( 1) using the sol - gel prepared precursor calcined at 1050 ℃ , can get a better degree of crystallinity Nanometer W - type barium ferrite . Rapid heating the grain size can be reduced to generate a product , but to shorten the holding time is not conducive to the crystallization of the product grains ; ( 2) Preparation of hollow microspheres surface-coated ferrite precursor , take the hollow microspheres and the ferrite the mass ratio of 1:1, controlling the pH of the reaction solution is acidic, can be coated better product . The electromagnetic parameters and the reflectivity of the test , cenospheres coated ferrite microwave absorption properties of the composite material is absorbed compared to a single W -type ferrite bandspread absorption performance enhancements ; ( 3 ) with the right amount of Al 3 < / sup> ion substituted ferrite Fe 3 < / SUP > to improve the ferrite microwave absorption capacity does not contribute to change , but the absorption band ; doping amount a ZnO , dielectric loss can be increased , while can also be adjusted to the absorption band ; (4) a single W-type and M type barium ferrite electromagnetic parameters between a dielectric loss of the former than the latter , and both having different characteristic absorption peaks . Made of composite absorber , the microwave absorption properties superior to a single type of ferrite .

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CLC: > Industrial Technology > Electrotechnical > Electrical materials > Microwave absorbing material
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