Preparation And Properties Of Barium Ferrite/Nickel Zinc Ferrite Nanocomposite Absorbing Materials

Nowadays, electronic equipment has become an important pa rt in our life. However, electromagnetic radiation is produced when it is used, so it also brings us a serious harm. In order to aviod these harm, the study of absorbing material become very necessary, it can be used in body protection, electromagnetic shielding and so on. In addition, the study is also very important in enhancing military power to achieve the purpose of the stealth, it can make these military targets to be not detected by radar if the material is coating on the important military target. For example, stealth aircraft. Compared with other obsorbing materials, it can make more electromagnetic wave into the interior of the material due to the size of ferrite magnetic nanomaterials is small, then through the magnetic hysteresis and domain wall resonance methods convert the energy into heat energy, it will make the material with the very good microwave absorbing performance. It also can be applied in magnetic recording, high frequency transformer, magnetic resistance devices and sensors, etc.In this paper, using improved sol- gel method, Ni_xZn_1-xFe₂O₄,BaFe₁₂O₁₉ monomer and BaFe₁₂O₁₉/Ni_0.6Zn_0.4Fe₂O₄ nanoparticles with diferent composite proportion were prepared respectively and studied their morphology, size, distribution and the magnetic and absorbing performance.results show that:1、Under the condition of 650 ℃, Ni_xZn_1-xFe₂O₄ was prepared, the result showed it had good soft magnetic properties, when the content of nickel ions increased, the main peak of the XRD diffraction peak position shift mo ved to the right; Saturation magnetization was changed regularly and reach maximum Ms = 72.5 emu/g when x = 0.6.2、With the increase of calcination temperature, the size of Ni_0.6Zn_0.4Fe₂O₄ nanoparticles became larger, the morphology of materials changed from flake to spherical shape.3、BaFe₁₂O₁₉ showed good hard magnetic properties, coercivity and remanence were large, when the sintering temperature became higher, Its morphology changed from rod to flake, Ms and Mr were also followed gradually become larger, coercivity becomes smaller. When the calcination temperature was 1050℃, the BaFe₁₂O₁₉ ferrite’s reflection absorbance reached a maximum- 11.5dB at the frequency of 16.5GHz, microwave absorption performance was better.4、BaFe₁₂O₁₉/Ni_0.6Zn_0.4Fe₂O₄ nanoparticles with different composite ratios,with the proportion of Ni_0.6Zn_0.4Fe₂O₄ increased, the diffraction peaks of Ni_0.6Zn_0.4Fe₂O₄ were stronger than that of BaFe₁₂O₁₉, the main peak shifted to the right. When BaFe₁₂O₁₉: Ni_0.6Zn_0.4Fe₂O₄=1:2, saturation magnetization reached the maximum value, with the proportion of Ni_0.6Zn_0.4Fe₂O₄ increased, other composite proportion of nanomaterials’ s Ms showed an increasing trend.5、BaFe₁₂O₁₉/Ni_0.6Zn_0.4Fe₂O₄ composite nanoparticles(BaFe₁₂O₁₉: Ni_0.6Zn_0.4Fe₂O₄ =1:2) were prepared by different calcination temperature, When the heat treatment temperature was 950℃, it’s residual magnetization（Mr=30.65emu/g） and saturation magnetization（Ms=64.84emu/g） reached maximum. Compared with the pure phase of BaFe₁₂O₁₉ and Ni_0.6Zn_0.4Fe₂O₄ were prepared by 850℃,coercivity and residual magnetization of BaFe₁₂O₁₉/ Ni_0.6Zn_0.4Fe₂O₄ nanocomposites were prepared by 850℃ were between BaFe₁₂O₁₉ and Ni_0.6Zn_0.4Fe₂O₄; the saturation magnetization（Ms=55.61emu/g） was improved than the BaFe₁₂O₁₉（Ms=53.33emu/g） and Ni_0.6Zn_0.4Fe₂O₄（Ms=54.13emu/g） and the maximum reflection loss of the composite nanoparticles was higher than that of the two monomer, But its absorption frequency occurred offset.