▎ 摘　　要

A ternary composite of NiFe2O4@SiO2@RGO was synthesized using a three-step method. A facile hydrothermal route (NiFe2O4)was used in the first step, and the modified Stober method (NiFe2O4@SiO2)in second step, followed by reduced reaction of GO using a hydrothermal reaction (NiFe2O4@SiO2@RGO). The obtained samples were characterized by various instruments and The TEM analysis indicated that NiFe(2)O(4)particles were homogenously enwrapped by SiO2. The NiFe(2)O(4)particles with a size of about 1015 nm are core, SiO(2)forms shell and the core-shell structured NiFe2O4@SiO(2)disperses on the surface of RGO. The ternary composite shows the best microwave absorption properties (-42.9 dB), which is higher than NiFe2O4(-11.3 dB)and NiFe2O4@SiO2(-25.9 dB). This is mainly attributed to the synergistic effects between permittivity and permeability and enhanced effects at the interfaces. For the NiFe2O4@SiO2@RGO composite, the maximum reflection loss can reach-42.9 dB at 12.2 GHz and the absorption bandwidth with the reflection loss below-10 dB is 6.2 GHz(from 10.1 to 16.3 GHz)for a thickness of 3 mm. Our results indicate that the core-shell structured NiFe2O4@SiO2 on graphene is a promising microwave absorbent with thin thickness, light weight, strong absorption, and broad bandwidth. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.