Electromagnetic Properties of Silver Coated Iron Based Alloy Powders Prepared by Chemical Reduction Method

摘要

The synthesis of silver coated iron base alloy (Sendust : Fe-Si-Al) powder having the both effects of shielding and suppressing of electromagnetic wave was studied. Depending on thickness of silver coating layer, the electromagnetic properties of the dispersed particles complexed with organic binder were examined. EDS-SEM, XRD, ohm meter, network analyzer (PNA8364A) measurements were used to characterize the electromagnetic properties. The silver coated powders have a better microwave absorbance than non coated powder in the low frequency range of below 1.0GHz, which is due to a high dielectric constant and dielectric loss of the silver in microwave frequencies magnetic loss in addition to conduction loss. Reflection loss of the 5% silver containing composite was found to be -6 dB at 1.0GHz with 1.0mm thickness. It is, therefore, successfully proposed that the silver coated sendust flake powders with controlled electrical properties and thickness can be used as thin microwave absorbers in quasi-microwave frequency band.