Synthesis and electromagnetic wave absorption property of Ni-Ag alloy nanoparticles

摘要

Ni-Ag alloy nanoparticles with various molar ratios were synthesized and embedded in the epoxy for the investigation of electromagnetic wave absorption properties in 2-40 GHz. The reflection loss measurement indicated Ni nanoparticles had a significant absorption in 18-40 GHz while no significant absorption was observed in the whole frequency range examined for Ag nanoparticles. Ni_1Ag_1 nanoparticles exhibited a significant absorption as Ni nanoparticles did, but the absorption frequency range shifted from 18-40 to 2-18 GHz. Interestingly and notably, both the Ni_3Ag_1 and Ni_1Ag_3 nanoparticles showed dual-frequency absorption in 2-18 and 18-40 GHz. It was suggested that the Ni- and Ag-rich micro-domains might be formed within the Ni_3Ag_1 and Ni_1Ag_3 nanoparticles, leading to the appearance of the second absorption due to the lags of polarization at the interfaces as the frequency was varied. The composition-related microstructure also affected the permittivity and permeability more significantly than the composition itself.