ELECTRICAL AND SHIELDING PROPERTIES OF ABS RESIN FILLED WITH NICKEL-COATED CARBON-FIBERS

Electrical conductivity and shielding effectiveness of nickel-coated c arbon fibers and their composites have been studied and the results ar e presented in this paper. A continuous electroplating device was used to plate nickel over the surface of the carbon fibers. The resistivit y of Ni-coated carbon fibers decreases with an increase in plating tim e. The optimum thickness of the coating is 0.2-0.5 mu m. A solvent met hod and Brabender mixing were used to prepare the composites of Ni-coa ted carbon fibers in ABS resin, the resistivity of which decreases wit h an increase in fiber content. At the same fiber content, the conduct ivity of the composites filled with Ni-coated carbon fibers is much gr eater than that of ordinary carbon-fiber-filled composites. To reach t he same resistivity as carbon-fiber-filled composites, the use of Ni-c oated carbon fibers as filler can greatly decrease the required volume fraction of fibers. The shielding effectiveness of the composites was obtained by experiment and by theoretical calculation; at high freque ncies, the two correspond very well. From experimental measurement, th e shielding effectiveness of ABS resin filled with 10 vol.% of Ni-coat ed carbon fibers is about 50 dB.