Preparation Of Absorbing Materials Barium Ferrite BaFe₁₂O₁₉ By Sol-gel Technique

In recent years, rapid development of the microwave technology, microwave information has played a very important role for people's lives and bring about many convenience. However, in the global, microwave radiation for human health hazard can not be ignored. thus microwave-absorbing materials are widely used in human security protection, and elimination of microwave darkroom equipment, communications and navigation system electromagnetic interference, security, information security and improve the overall performance and SNR, electromagnetic compatibility, or coaxial and waveguide components, and other civil absorbed many aspects. In addition, with the radar, microwave detection of rapid technological development, particularly the military confrontation electromagnetic interference, such as stealth and anti-stealth make people take more and more attention on the research on the microwave-absorbing materials. Ferrite absorbing materials for it's high absorption efficiency, thin coating, the frequency bandwidth is one of the studied materials.As the main absorbing materials, ferrite BaFe₁₂O₁₉ the study on the process of preparation of is the basis for other research work. Barium ferrite powder characterized mainly by the performance parameters powder composition, particle shape, size and status of crystallization. Therefore, the preparation method of ferrite and temperature absorbing properties relationship is extremely important for ferrite BaFe₁₂O₁₉. In this paper Fe(NO₃)₃·9H₂O,Ba(NO₃)₂ as the basic raw materials, by sol-gel method, the conditions for the existence of complex agent citric acid, by adjusting the pH value of the high purity absorbing properties Flake better the six-party M-crystal-type magnetic lead barium ferrite BaFe₁₂O₁₉. By X-ray diffraction (XRD), electron microscopy analysis (SEM), magnetometer, and network analyzers, and other modern technology are used to characterize product of preparation phase, the size and topography, magnetic properties and absorbing properties. And optimize the preparation of conditions. The results show that the barium ferrite BaFe₁₂O₁₉ magnetic crystal is the six-party lead-type structure and the size is small, flake, grain distribution is uniform with the size 10-50μm, and greater coercivity. And in 8-18 GHz BaFe₁₂O₁₉ has better absorption capacity. The better preparation of conditions are as follows: barium nitrate (Ba(NO₃)₂): nitrate iron (Fe(NO₃)₃): citric acid (C₆H₈O₇·H₂O) =1:12:19 (ratio), pH value 3-7,210±5℃insulation at 1h, 60±5℃at the insulation 1h, 650±5℃insulation 3h.