Thermal conductivity and electromagnetic shielding effectiveness of composites based on Ag-plating carbon fiber and epoxy

摘要

Thermally conductive and electromagnetic interference shielding composites comprising low content of Ag-plating carbon fiber (APCF) were fabricated as electronic packing materials. APCF as conductive filler consisting of carbon fiber (CF) employed as the structural component to reinforce the mechanical strength, and Ag enhancing electrical conductivity, was prepared by advanced electroless Ag-plating processing on CF surfaces. Ag coating had a thickness of 450 nm without oxide phase detected. The incorporation of 4.5 wt % APCF into epoxy (EP) substrate yielded thermal conductivity of 2.33 W/m.K, which is approximately 2.6 times higher than CF-EP composite at the same loading. The APCF-EP composite performed electromagnetic shielding effectiveness of 3835 dB at frequency ranging from 8.2 to 12.4 GHz in the X band, and electromagnetic reflection was the dominant shielding mechanism. At loading content of APCF up to 7 wt %, thermal conductivity of APCF-EP composites increased to 2.49 W/m.K. Volume resistivity and surface resistivity decreased to 9.5 3 x 10(3) Omega.cm and 6.2 3 x 10(2) Omega, respectively, which approached a metal. (C) 2015 Wiley Periodicals, Inc.