Preparation And Absorbing Mechanism Of Modified Nanometer BaFe₁₂O₁₉

The microwave absorption material is playing the extremely vital role in the military and civil. Applies generally in the stealth airplane, the cannon, the tank and so on,simultaneously the more and more many attenuating material has used in electromagnetism equipment such as microwave communication, microwave darkroom, computer, microwave oven. The ferrites absorbing material is the double duplicate medium which has the certainly coefficient and the dielectric loss, and has certainly magnetic conductivity and magnetism lose.,hexagonal ferroxdure becomes the key point by its fine frequency sound characteristic which the people studied in recent years.This experiment used the Sol-gel SHS to obtained the M-type hexagonal Ba-ferrite and BaRexFe12-xO19 (Re=La, Nd) nanocrystals through the control gelatin. When pH≈7, citric acid∶Metallic ion (mol ratio) =1∶1, in forms the sol in the process to join the supersonic vibration to be possible to cause the ferrite particle size to change obviously small, the grain size reduces from 40nm to 10nm about. The experiment showed that the speed of heating-up and the sintering temperature have great influence on the grain structure and composition of the nanometer Ba-Ferrite. The M-type Ba-ferrite was obtained on 700℃, and the higher of the sintering temperature the better of the power's crystallinity. The sheet-like nanoparticles could be obtained in the sintering at 10℃/min, while nanorods were obtained at 40℃/min.Used the Sol-gel SHS method to prepare BaRexFe12-xO19 (Re=La, Nd), the experiment indicated that the rare-earth element seeped in the ferrite crystal lattice , and the crystal constant had the fill-out tendency. The rare earth doping has not changed the superficial appearance of the Barium ferrite. Used the method which non-homogeneous phase chemistry precipitated to prepare cladding 20mass% Ni(OH)2 and the TiO2 ferrite powder. The clad forms the nanometer level pellet also the quite even gable in the ferroxdure surface, thus gets up the modified ferrite surface performance effect.The Fe3+ in M-tapy BaFe12O19 most outer layer 5 electrons occupy 5 spatial tracks separately. The hysteresis cycle test indicated that the barium ferrite is one...