Absorbing Properties of Carbon Nanotubes/Cobalt Ferrites Composite Materials and Its Optimization

Using citric acid complex compound, cobalt ferrite( Co Fe2O4) was prepared by sol-gel process,and the composite materials with different carbon nanotubes mass fraction were obtained by mechanical mixing carbon nanotubes and cobalt ferrite. Absorbing properties and optimization of the composite materials were studied by using the electromagnetic parameters of the composite materials which were measured by the microwave vector network analyzer. The results show that absorbing properties are obvious affected by mass fraction of carbon nanotubes in the composite materials. When the coating is 1mm,the composite materials with the mass fraction of carbon nanotubes nearly 20% has the best absorption performance,the maximum peak value is-19. 2 d B,and the effective bandwidth of less than-10 d B is 3. 1 GHz. Based on the mechanism of microwave dielectric loss,the electric power loss density of coating was studied at the frequency range of 2-18 GHz,it show that absorbing property of coating is the best when the thickness of coating is thinner and the mass fraction of carbon nanotubes is nearly 20%.