Preparation and microwave absorption properties of Ni(Co/Zn/Cu)Fe2O4/SiC@SiO2 composites

Ni(Co/Zn/Cu)Fe2O4/SiC@SiO2, a microwave absorber, was prepared by the sol-gel method. The phase structure and the morphology of the microwave absorbers were characterized by X-Ray Diffraction (XRD) and scanning electron microscopy (SEM), respectively. Laser sizer (LS) and X-ray photoelectron spectroscopy (XPS) analysis show the core-shell structure of SiC@SiO2. Coaxial method was used to measure the microwave absorption properties of the prepared composites in the frequency range of 2-18GHz. When 70wt% SiC is wrapped by 30wt% SiO2, and 50wt% NiFe2O4 is added into 50wt% SiC@SiO2, the as-prepared powders are found to have advanced microwave absorption properties with a minimum reflection loss (RL) of -32.26dB at about 6.08GHz, and the available bandwidth is approximately 2.1GHz when the RL is below -10dB.