Dispersion of magnetic metals on expanded graphite for the shielding of electromagnetic radiations

The composites of nanoparticles of magnetic metals Co, Ni, and Ni-Fe dispersed on the nanolayers of expanded graphite (EG) were prepared by the impregnation of EG with ethanol solutions of metal acetates, followed by drying and reduction in H-2. Such composites combined the properties of high electric conductivity of EG and magnetic conductivities of dispersed metals, and thus exhibited the high shielding effectiveness in a wide range of frequencies. Specifically, the composite containing 30%Ni and 70%EG reached the shielding effectiveness of 70-105 dB at frequencies from 300 kHz to 1.5 GHz. (c) 2007 American Institute of Physics.