Synthesis and characterization of Ag/Fe₃O₄ electromagnetic shielding particles

Ag/Fe₃O₄ nano-composites are synthesized by electroless silver plating technique and characterized by X-ray diffraction, scanning/transmission electron microscope, magnetic measurement equipment and vector network analyzer. They show the silver layer coated on the surface of the particles successfully, and which can enhance the dielectricity and permeability properties of the ferromagnetic particles. The dielectric loss values of the composites are more than 1.0 in the almost whole test frequency range and the imaginary part of permeability of Ag/Fe₃O₄ is higher than real part in 2-5 GHz. The value of H_c is increased to 165.2 Oe due to the extended relaxation time of magnetic domain deflection of the magnetic powders which covered by silver layer. And the calculated microwave loss is more than 20 dB in the whole frequency range. As a result, the Ag/Fe₃O₄ nano-composites are expected to be used as electromagnetic shielding particle material in multiband smoke agent.