Synthesis Of Spinel Ferrite Materials And Its Application In Microwave Absorption

Microwave absorption materials were deeply investigated in this article. In recent years, radio, television, telecommunication and electricity develop rapidly, which brings comfort and convenience to people. However, the deterioration of the electromagnetic environment is threatening people’s health. Thus it’s hot for scientists to design new microwave absorption materials with high performance and high reflection loss. This is not only important to the defense of stealth technology, but also meaningful to human health. Ferrite absorbing materials with low-cost, high efficiency of absorption, thin coating, wide frequency band, and other outstanding characteristics have a wide range of applications.In chapter three, three diamentionally ordered macroporous spinel nickel ferrite has been synthesized by using PMMA microspheres which has the same particle size and unified arrangement as hard template through nanocasting technique. We also use EG and methanol as solvent. The characteristic results from X-ray diffraction (XRD) analysis, Energy Dispersive X-ray (EDX), high resolution scanning electronmicroscopy (HR-SEM), nitrogen sorption analysis and magnetization measurements demonstrated the successful synthesis of three diamentionally ordered macroporous spinel nickel ferrite with surface area (19.4m2/g) and superparamagnetism. Using it as a microwave absorption material, the maximum reflection loss was-19dB that was obtained at17GHz with the matching thickness of3.5mm.In chapter four, NiFe2O4/Graphene nanocomposite has been successfully synthesized via a one-step hydrothermal method by using different and alkali sources. The microwave absorption propertie of the sample "NiFe2O4/Graphene" was investigated in terms of complex permittivity and permeability. It has both magnetic spinel nickel ferrite and electric graphite carbon, which may result from effective complementarities between the dielectric loss and the magnetic loss. Such results indicate that NiFe2O4/Graphene nanocomposite may be attractive candidate materials for microwave absorption applications.