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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.
Two kinds of spherical and flaky Fe @ Ag core-shell composite particles were prepared by liquid phase chemical reduction Ag technique.The phase, surface morphology and chemical composition of these two kinds of shielding fillers were characterized and their magnetostatic properties were analyzed. The effect of filler shape on electromagnetic properties such as complex permeability, conductivity and shielding effectiveness of the composites was investigated. The results showed that the two kinds of composite particles were all Fe @ Ag core-shell composite particles with core-shell structure, Uniform and dense. The spherical and flaky Fe @ Ag core-shell composite particles have good soft magnetic properties. Compared with the shape-isotropic shielding filler, the electromagnetic shielding composite with the sheet-shaped Fe @ Ag core-shell composite particles as filler The material has higher complex permeability and lower volume resistivity. The composite exhibits a shielding effectiveness (SE) of -51 to -55 dB over the frequency range of 30-1500 MHz, which is better than that of the spherical Fe @ Ag core Shell composite particles as filler electromagnetic shielding composite material.And the theoretical essence of the electromagnetic shielding composite material with sheet-like Fe @ Ag core-shell composite particles is also found to have stronger electromagnetic wave absorption loss and higher shielding effectiveness.