Microwave absorbing properties of Ag-coated Ni-Zn ferrite microspheres prepared by electroless plating

作者：Kim Jong Hyuk; Kim Sung Soo^*

来源：Journal of Alloys and Compounds, 2011, 509(12): 4399-4403.

DOI：10.1016/j.jallcom.2011.01.050

• Siler-coating
• Ferrite
• Electroless plating
• Microwave absorbers

This investigation presents an electromagnetic radiation absorptive omposition comprising Ag-coated ferrite microspheres dispersed in a silicone rubber matrix for use as a thin microwave absorber in GHz frequencies. Ni-Zn ferrite microspheres with an average diameter of 50 mu m were prepared by spray-drying and sintering at 1130 degrees C. A conductive Ag layer was coated on the ferrite spheres by electroless plating. Uniform Ag coating can be obtained using the plating solution with a high AgNO(3) concentration. For particle compacts of the conductive Ni-Zn ferrite spheres, electrical resistance is reduced to as low as 10(-2) Omega. Rubber composites containing the Ag-plated ferrite spheres exhibit a high value of both real and imaginary parts of complex permittivity, while the complex permeability spectrum is not significantly changed with Ag plating. Due to the conductive and magnetic property of the microspheres, matching thickness can be reduced to as low as 2 mm at the frequency of 7.6 GHz, which is much thinner than non-coated ferrite absorbers.

• 出版日期2011-3-24