化学镀镍碳纤维/环氧树脂复合材料电磁屏蔽性能

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

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。

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.