Research on microwave properties of Fe/Al2O3 composites

The fine Fe powders embedded Al₂O₃ (mass %=0.5,1,2,5) are prepared by using citric nitrate sol-gel method and hydrogen reduction process. SEM and laser particle size analyzer are employed to characterize their morphology and particle size respectively. Complex permittivity, permeability and electromagnetic wave absorption properties of Fe/Al₂O₃ composites (where, Al₂O₃ wt% = 0%, 0.5% 1%, 2 %, 5%, respectively in Fe/ Al₂O₃ compound) with 33vol% powders were investigated in 0.5-7GHz.The results show that Fe / Al₂O₃ powders have a flake-like shape with a wide particle size disturbution from micrometer to submicrometer. The real parts of complex permittivity of the Fe/Al₂O₃ composites increase as Al₂O₃ content increases from 0 to 5%, and the imaginary parts of complex permeability of the samples exhibit several slightly damped ferromagnetic resonances. The microwave absorbing properties of Fe/Al₂O₃composites are superior to that of Fe composite.