Studies on the influence of double-layer electroless metal deposition on the electromagnetic interference shielding effectiveness of carbon fiber/ABS composites

Electromagnetic interference (EMI) shielding effectiveness (SE) of single-layer or double-layers electroless metals, such as nickel/phosphorus-pure nickel (NiP-Ni), Ni-NiP, NiP-Cu, Ni-Cu, coated carbon fiber reinforced acrylonitrile-butadiene-styrene (ABS) composites was investigated. The resistivity and anti-oxidization of conductive fillers were important factors for EMI shielding composites. Although the resistivity of electroless copper-coated carbon fiber (ECCF) is much lower than that of electroless nickel-coated carbon fiber (ENCF), electroless copper films on the carbon fibers are readily oxidized during compounding processes. The resistivity of ECCF/ABS composites increased significantly after composite fabrication. As a result, the EMI SE of ECCF/ABS composite showed a poor EMI SE (37 dBm) among those electroless metals-coated carbon fiber reinforced ABS composites. The coated double layers electroless metals on the conductive fillers were obtained by electroless method. The outside metal layer, which possessed better anti-oxidization, provided suitable protection for the conductive fillers. Thus, the EMI SE of the ECCF/ABS composite can improve effectively. The best EMI SE of double-layers electroless coated-metals/ABS composites could be reached 65 dBm. (C) 2003 Elsevier B.V. All rights reserved.