Research On Structure And Electromagnetic Properties Of Barium Contained Hexaferrites

Recently, with the development of microwave technology, microwave communication takes many conveniences to the life of human beings. But in the worldwide, microwave radiation do great harm to the health of human beings, thereby, microwave absorbing materials are widely researched and used to protect people's life. Barium hexaferrites become generally researched and well developed microwave absorbing materials because of their high electromagnetic loss during wide microwave frequency.In this paper, firstly, barium magnetoplumbite-type (M-type) hexaferrites is used as the based composition, Fe3+ cations in BaFenO19 are differently substituted by Zn2+-Ti4+ cation-pair through solid state action method. XRD, SEM are employed to study the construction and composition of the substitution, the complex permittivity and complex permeability of the samples between 2~18 GHz are tested through coaxial method by a network vector analyzer. The effect of substitution and the heat treatment system on the construction and composition of the production are discussed and analyzed.Secondly, keeping the substitution of Fe3+, the ratio of Zn2+-Ti4+ cation is changed with Co3+ or Al3+, adopting the same research method, two different three-chain-substitution-AlZnTi, CoZnTi of BaM are studied through the same study method of ZnTi substituted BaM.Finally, Ba2+ is substituted by Eu3+, and the effect of substitution and heat treatment is studied.The experimental insults shows that Zn-Ti cation pair can enhance the absorption of microwave from 2 to 18GHz. the absorption peak move towards high frequency with the increasing of the substituted ratio, and become wide. The samples show certain wide-frequency properties. The substitutions of Al, Co cause the absorption peak move to the medium frequency. And the substitution of Eu may cause the new absorption peak and make the finally product has stronger absorption. The heat treatment system can be helpful to shape the hexaferrites grain. Higher temperature improves the formation of hexaferrites grain, but sintering time should not be so long. The better sintering heat treatment should be sintering at 1300-1350℃ for 3-4 hours.