Study on preparation and electromagnetic shielding properties of silver-coated ferrosilicochrome powder
[Objective]This study focuses on the preparation and properties of high-performance electro-magnetic shielding materials for electronic equipment in marine environments.[Methods]The surface mor-phology,phase composition,electrical conductivity and ferromagnetic properties of the original ferrosilico-chrome powder(FeSiCr)and silver-coated powder(FeSiCr@Ag)are analyzed with a scanning electron micro-scope,X-ray diffractometer,four probes and vibrating sample magnetometer,and a vector network analyzer is used to test the S parameters of the samples.A salt spray test chamber is used to simulate the corrosion behavi-or of the coating under marine environment conditions and observe its macro and micro morphology.Mean-while,an electrochemical workstation is used to monitor the corrosion behavior of the coating in a mass frac-tion of 3.5%NaCl solution and study its corrosion mechanism.[Results]The results show that the silver plating layer is compact and complete with the increase of the silver nitrate(AgNO3)addition.After electro-less silver plating,the conductivity can reach 586.79 S/cm and the X-band shielding efficiency reaches 80 dB.After 96 h of accelerated corrosion in a humid heat and high salt spray environment,the surface of the resin coating prepared by FeSiCr@Ag shows no corrosion phenomenon.The self-corrosion potential of the coating before and after electroless silver plating is-0.4 V and-0.09 V respectively,indicating that the penet-ration rate of the corrosive medium into the coating slows down after silver plating,and a good corrosion in-hibition effect is achieved.[Conclusions]The modified FeSiCr@Ag material has highly efficient electro-magnetic shielding performance and good corrosion resistance properties.
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