Electrodeposited carbon fiber and epoxy based sandwich architectures suppress electromagnetic radiation by absorption

Functional polymer composites are in huge demand in electronic industry in general and for electromagnetic interference shielding in particular, due to ease of processing, design flexibility and lightweight. Herein, efforts are made to enhance electromagnetic interference shielding effectiveness in epoxy/carbon fiber composite, by electrodepositing magnetic particles on the surface of carbon fiber. This approach results in 100% enhancement in shielding effectiveness with respect to epoxy/Carbon fiber composites. Electrodeposition, an industrially viable and a scalable technique, is adopted here to obtain nickel decorated carbon fiber. Various nickel deposited carbon fiber morphologies are obtained by varying the applied current. Various microstructures of nickel deposited carbon fiber are obtained and the final parameters are fixed. Further, X-ray diffraction confirms the presence of nickel on the carbon fiber surface. In addition magnetic, electrical, thermal behaviour of nickel deposited carbon fiber is evaluated systematically. Epoxy/carbon fiber composites are fabricated using vacuum assisted resin transfer moulding technique. 2-Layered sandwich structure is prepared with layer 1 as nickel deposited carbon fiber and layer 2 as only carbon fiber. EMI shielding effectiveness is measured in the frequency range of 12-18 GHz. Epoxy with nickel deposited carbon fiber and bare carbon fiber sandwich architecture showed excellent shielding effectiveness up to 50 dB and with maximum absorption of up to 40 dB at 15 GHz. Thermal studies are also carried out to understand the materials response at higher temperature and frequency. Such thin, light-weight, excellent EM absorbers can be used as EMI enclosures for battery casings of hybrid electric vehicles, communication systems etc.