Preparation And Microwave Absorbing Properties Of Barium Ferrite

With the development of modern science and technology, various electronic, electrical equipment has become one of the indispensable parts of our daily life and social development. But, during the operation of the equipment, they will produce electromagnetic radiation and interference which will make our living space electromagnetic environment worsen and seriously affect our lives.electromagnetic pollution has become a new and threatening pollution after water, air and noise pollution. Electromagnetic pollution is very hard to prevent, and it not only affects the communication, but also constitutes a threat to human health. So the research of absorbing materials is of great significance.Absorbing agent itself performance determines the absorbing performance of the composite absorbing material. In this paper, barium ferrite with different morphology and element doping were prepared by the electrostatic spinning and sol-gel Auto-combustion methods. We studied the effect of morphology and element doping on its performance by using different preparation methods, improvement of preparation technology and element doping method. We analyze the character by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM), vector network analyzer (VNA). The magnetic properties can be control by changing the morphology and element doped on the magnetic control.Using electrostatic spinning method, by adjusting the addition amount of polymer, using different solvents, coaxial spinning method, we successfully prepared the linear fiber, ribbon fiber, hollow fiber and gossamer barium ferrite. And virgulate barium ferrite was prepared by sol-gel auto-combustion method. By studying the relationship of morphology and properties of barium ferrite, we found that the change of morphology can effectively adjust its coercive force of barium ferrite, especially the hollow fibers prepared by coaxial electrospinning which can effectively reduce the coercive force values while retaining high saturation magnetization.In addition, Sr, Ce, La, Co and multielement doped barium ferrite were successfully prepared by electrostatic spinning and sol-gel auto-combustion method. We can find that compared with barium ferrite fibers, the saturation magnetization of Sr-doped barium ferrite fibers reduced. And the saturation magnetization of barium ferrite poders prepared by sol-gel auto-combustion method can reach 61.97emu/g. La and Co doping can make the diffraction peaks of barium ferrite powders move. When calcined at 1200℃, the size of the grains can reach to micrograde, but as the temperature increase, the coercive force of the sample decreased, and the saturation magnetization intensity increased.the coercive force of samples calcined at 1200℃ about 400 oe which presented some soft magnetic. In addition the saturation magnetization can reach 60 emu/g which is higher than no-doped barium ferrite.