Preparation and Properties of SrFe12O19/ZnFe2O4 Core/Shell Nano-powder Microwave Absorber

The nano-powder microwave absorber SrFe12O19/ZnFe2O4 with core-shell structure were prepared by two-step citrate sol-gel, with analytically pure Fe(NO3)(3), Sr(NO3)(2) and Zn(NO3)(2) as the main materials. The XRD, TEM, VSM and vector network analyzer were used to analyze the chemical component, structure, morphology and magnetic property of the nano-powder. The results show that when the molar ratio of and SrFe12O19 to ZnFe2O4 is 1:2 and calcined temperature is 850 degrees C, the composite powder has obvious core-shell structure and the particles are scattered homogeneously in ellipsoidal shapes or bar shapes, the particle size of the nano-powder ranges from 35 nm to 45 nm; The saturation magnetization and remanent magnetization of the composite are larger than that of the soft phase, but smaller than that of the hard due to the exchange coupling between the hard and soft phases, the coercivity larger than that of the SrFe12O19, The maximum reflection loss reaches to -35.3 dB at 17.5 GHz when matching thickness of 2 mm, with excellent absorbing properties.