【摘要】 运用液相化学还原Ag技术,制备了球形和片形2种Fe@Ag核壳复合粒子.表征了这2种屏蔽填料的物相、表面形貌和化学组成,研究了其静磁性能,分析了填料的形状对复合材料的复磁导率、电导率和屏蔽效能等电磁特性的影响.结果表明:2种复合粒子均为核壳结构完整的Fe@Ag核壳复合粒子,其Ag壳层均匀且致密;球形和片形Fe@Ag核壳复合粒子均具有良好的软磁性能;与形状各向同性的屏蔽填料相比,以片形Fe@Ag核壳复合粒子为填料的电磁屏蔽复合材料的复磁导率更高,体积电阻率更低,该复合材料在电磁波频率范围为30—1500 MHz内的屏蔽效能(SE)为-51—-55 dB,优于以球形Fe@Ag核壳复合粒子为填料的电磁屏蔽复合材料.并且从理论上分析了片形Fe@Ag核壳复合粒子的电磁屏蔽复合材料对电磁波的吸收损耗更强和屏蔽效能更高的物理本质.更多还原

【Abstract】 Due to the rapid growth of radio frequency radiation sources,electromagnetic shielding composite materials have become a research hotspot in civil control of electromagnetic radiation technology and military equipment shielding technology.The shielding effectiveness(SE) of these electromagnetic shielding composite materials has much to do with the structures,volume resistivity and magnetic properties of the fillers.Spherical and flaky Fe@Ag core-shell composite particles were synthesized by a liquid electroless plating method in this work.The phase,morphology and chemical composition of spherical and flaky particles were characterized.The magnetic property of fillers was analyzed.The effects of the shape of these shielding fillers on complex permeability, conductivity,magnetic properties and shielding effectiveness of their composition material were investigated.The results showed that spherical and flaky carbonyl iron powders/silver core-shell composite particles both had intact core-shell microstructure.Silver coating of these spherical and flaky composite particles were compact and even.Spherical and flaky Fe@Ag core-shell composite particles both had excellent soft magnetic properties,which shape of composite particles didn’t influence their magnetic properties.Compared with the electromagnetic shielding composite material based on isotropous shielding fillers,spherical Fe@Ag composite particles,the electromagnetic shielding composite material containing flaky core-shell composite particles showed higher complex permeability, lower volume resistivity and higher shielding effectiveness.In the frequency of electromagnetic wave ranging from 30 MHz to 1500 MHz,the shielding effectiveness of the electromagnetic shielding rubber containing flaky particles is -51——55 dB.And the physical essence of better shielding effectiveness and stronger absorbing loss of composite materials containing flaky fillers was theoretically analyzed.更多还原