Metallic Ni, Cu, and Ag Dispersed on Expanded Graphite for Radiation Shielding

A simple liquid-reduction method to prepare the metallic particles/expanded graphite (EG) composites has been developed and the electromagnetic shielding effectiveness (SE) of the materials is studied. With this method, we have successfully implanted the nanoparticles of Ni, Cu, and Ag into EG. It is shown that their SE at low frequencies is significantly increased by dispersing the metallic particles on EG, especially for the composites of 30% metal content. At the frequency range of 300 kHz-1 GHz, with the surface density only 0.096 g/cm
²
, the SE can reach as high as 70-105 dB. Compared with the EG, the SE has gained 17 dB at 300 kHz.