Preparation And The Capability Study Of Magnetic Absorbent

Electromagnetic wave absorbing material is a type of function material; It can absorb and attenuate the electromagnetic wave; and it can chang the electromagnetic wave energy into heatl energy or make the electromagnetic wave vanish by the way of interference. Magnetic absorbing material is currently a type of materials, which has been mostly researched and applied. the ferrite is the important representative of the magnetic absorbing materials. The ferrite absorbing material has its strong suits, such as strong absorption, relatively wider frequency, thinner matching thickness and lower cost. Its application and research have already outrun the military application field, besides reached public field more far and wide.In the paper, single-phrase M-hexagonal crystal BaFe12O19 and SrFe12O19 ferrite absorbent and composite-phrase spinel CaFe2O4/α-Fe2O3(hexagon) absorbent are prepared by low temperature Auto-combustion-Sol-Gel method.This method uses citric acid as complexing reagent, glycol as dispersant and ammonia to adjust pH value of the initial solution. There is a discussion on the effection between crystal type and particle size of the magnetic absorbent and some factors, including the type of complexing reagent and dispersant, the proportion between complexing reagen and nitrate, water volume, reaction temperature and reaction time, pH value and heat treatment. According to it, the optimum craft parameter will be determined. Using the craft may prepare single-phase and composite-phrase magnetic absorbents.By means of Differential Thermal Analysis (TG-DTG-DTA), Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and Vibration Sample Magnetometer (VSM), the crystallization temperature, the crystal particle dispersivity and the appearance, the reunion situation, the size of crystal surface of the main diffraction peak, the average size of the crystal particle and the crystal type, the sample magnetization, coercive force and the correlation performance are detected. Study the relationship between the calcine temperature and crystal lattice constant, crystal degree, density and strain by the software of Jade5.0.And discuss the reasons of the first step.In the article, paraffin wax is used as substrate material of the absorbing material. Disperse the absorbent into paraffin wax evenly. The relative dielectric constant and relative permeability are detected by the HB8510B vector network analyzer by the way of waveguide method. The relationships between tgδE, tgδM and tgδand frequency are discussed.