化学镀镍碳纤维/环氧树脂复合材料电磁屏蔽性能

采用化学镀方法对碳纤维进行表面镀镍, 采用SEM、 EDX、 XRD分析了镀镍碳纤维的微观形貌、 镀层成分和镀层结构, 通过电阻测试研究了镀镍碳纤维的导电性。将体积分数为2.5%、 5%、 7.5%、 10%的镀镍碳纤维作为导电填料制备镀镍碳纤维/环氧树脂复合材料, 并用屏蔽室法测试了不同频段复合材料的屏蔽效能。结果表明: 碳纤维化学镀镍后, 表面形成了一层均匀的复合镀层, 镀层中镍的质量分数高达94%, 镀镍碳纤维的电阻值仅为碳纤维原丝的1/54。镀镍碳纤维/环氧树脂复合材料的电磁屏蔽能力较碳纤维原丝有所提高。复合材料的屏蔽效能随镀镍碳纤维添加量的增加而升高。在低频频段(kHz频段), 复合材料的屏蔽能力主要决定于材料的本征参数, 不同镀镍碳纤维含量的镀镍碳纤维/环氧树脂复合材料的屏蔽能力相差不大; 在中高频频段(MHz、 GHz频段), 镀镍碳纤维/环氧树脂复合材料屏蔽效能主要决定于材料的电阻率。

EMI shielding effectiveness of electroless nickel-plated carbon fibers/epoxy resin composites

Carbon fibers were plated with the electroless nickel plating method, the micro-morphology of nickel-plated carbon fibers, the microstructure and composition of coatings were studied with SEM, EDX, XRD. The conductivities of nickel-plated carbon fibers were tested with broadband resistance voltage instrument. The nickel-plated carbon fibers/epoxy resin conductive composites with volume percentage of 2.5%, 5%, 7.5%, 10% were made by mixing method, the shielding effectiveness of these composites was tested by shielding enclosure method. Results show that after nickel plating, a lay of uniform nickel coating is formed on the surface of carbon fibers. The quality fraction of nickel in the coatings is about 94%. The resistances of nickel plated carbon fibers are only 1/54 of original carbon fibers. The shielding effectiveness of the nickel coated carbon fibers/epoxy resin composites is higher than that of original carbon fibers. The shielding effectiveness of the composites increases with the increasing of nickel-plated carbon fibers content. On low frequency(~kHz), the shielding effectiveness of the composites depends on material intrinsic parameters, and the shielding effectiveness is almost independent on the nickel-plated carbon fibers content. While on high and intermediate frequency(~MHz, ~GHz), the shielding effectiveness is related with resistivity of the nickel coated carbon fibers/epoxy resin composites.