Research On The Preparation And Microwave Absorption Properties Of The Ferriferous Oxide/Graphite Nanocomposites

Malysite absorbed by layers of graphite oxide can insert into the layers of graphite oxide, and ferriferous oxide/graphite nanocomposites are prepared after the heat treatment. During the preparation process, heat treatment temperature, ratio and species of raw material are the main factors affecting the component and the electromagnetic wave absorption properties of ferriferous oxide/graphite nanocomposites. The influences of the heat treatment temperature, the ratio and the species of raw material on the component, structure, electromagnetic properties of graphite oxide were investigated primarily. The results show that ferriferous oxide /graphite nanocomposites were prepared by the absorption of citric acid iron or iron nitrate into layers of graphite oxide and then by the heat treatment at different temperatures ranging from 600℃to 900℃. Ferriferous oxide/graphite nanocomposites whose raw material was citric acid iron had larger electromagnetic loss. With the improvement of the heat treatment temperature, the component, crystal structure and grain size changed largely. And the electric and magnetic properties had changed as well. Therefore, the temperature of heat treatment had greatly influenced on the electromagnetic wave absorption properties. The component, dielectric constant, permeability and microwave absorption properties could be changed according to the change of proportionOn the basis above, we prepared microwave absorption coat using appropriate ferriferous oxide/graphite nanocomposites. The influence of heat treatment temperature, ratio, species of raw material and thickness of the system on absorbing properties of the ferriferous oxide/graphite composites were investigated. Results show that ferriferous oxide/graphite nanocomposites using citric acid iron had better microwave absorption properties, which present wide frequencies range and large theory reflection loss. Heat treatment temperature exert large influence on the microwave absorption properties of the nanocomposites and reducing the heat treatment temperature can improve the microwave absorption performance in the low frequency range. With the increase of the proportion, absorption peaks moved to the lower frequency, the intensity of which improved firstly and then decreased. With the increase of thickness, absorption peaks moved to the lower frequency too.We compared ferriferous oxide/graphite nanocomposites with ferriferous oxide and the pyrolytic graphite oxide from structure, surface morphology, the electromagnetic parameters and the microwave absorption properties and then investigated the microwave absorption mechanism of ferriferous oxide/graphite nanocomposites. The results show that the microwave absorption mechanism of the ferriferous oxide/graphite nanocomposites are composed of conductance loss from graphite, dielectric loss from ferriferous oxide, the nanocrystallization of graphite and ferriferous oxide and the coupling effects between them. Compared with the traditional graphite and ferriferous oxides, the ferriferous oxide/graphite nanocomposites are more suitable for being an ideal microwave absorbing materials, because this materials correspond well with the requirement "thin, light, wide and comprehensive performance" of new absorbing materials.