Studies of nickel and copper-coated cenosphere-polymer composites for electromagnetic interference shielding

Recently, electronic devices such as televisions, office automated appliances, computers, etc., have been using housing as a shield to reduce Electro Magnetic Interference (EMI) and Radio Frequency Interference (RFI). Polymer housing is conductive and increases the shielding effectiveness. This study involves preparing polymer-composites and determining their effectiveness as EMI-shielding materials. Non-conductive, hollow, spherical, fly-ash cenosphere particles (45-100 μm) have been used for electroless surface-coating with nickel and copper in order to make them electrically conductive. The metal-coated cenospheres (2% and 5% by weight) are blended with Polycarbonate (PC) to produce polymer-metal-coated cenosphere composites. The surface morphological analysis, chemical composition and phase analysis of the metal-coated cenospheres have been carried out using Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX) and X-Ray Diffraction (XRD), respectively. Both nickel and copper are well-deposited on the pre-treated and activated cenosphere surfaces. EMI-shielding effectiveness of Polycarbonate-5% Nickel-Coated Cenosphere (PC-NCC) composites and Polycarbonate-5% Copper-Coated Cenosphere (PC-CCC) composites have been studied by means of coaxial holder method.