INFLUENCE OF THE SHAPE OF SHIELDING FILLERS ON ELECTROMAGNETIC PROPERTIES OF Fe@Ag CORE–SHELL COMPOSITE PARTICLES
ZHAO Suling 1,2, CHEN Jing 1,2, WANG Yilong 1,3
1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070
2. Center for Material Research and Testing, Wuhan University of Technology, Wuhan 430070
3. School of Sciences, Wuhan University of Technology, Wuhan 430070
Cite this article:
ZHAO Suling CHEN Jing WANG Yilong. INFLUENCE OF THE SHAPE OF SHIELDING FILLERS ON ELECTROMAGNETIC PROPERTIES OF Fe@Ag CORE–SHELL COMPOSITE PARTICLES. Acta Metall Sin, 2012, 48(8): 977-982.
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.
Supported by Fundamental Research Funds for the Central Universities (No.121214007), Weapons Equipment Pre–Research Foundation (No.9140A31030110JB3403) and Manufacture–Study–Research Program of Guangdong Province (No.2010B090400091)