|Cite this article as:|
|Qiuying Li, Yiheng Lu, and Zhuoyan Shao, Fabrication and characterization of environmental resistance and flexible microwave absorber sheet based on a composite filler with waste fly ash as the core filled silicone rubber, Int. J. Miner. Metall. Mater.,(2022). https://doi.org/10.1007/s12613-022-2517-1|
In this study, a new type of composite filler was designed by a modified sol-gel method using solid waste fly ash, Fe(NO3)3∙9H2O and Ni(NO3)2∙6H2O as raw materials. The composite filler was a spherical core-shell structure composed of fly ash as the core and NiFe2O4 as the shell. Further, the composite filler was added into the silicone rubber to fabricate the high temperature vulcanized microwave absorption materials. XRD, FTIR, XPS and SEM confirmed NiFe2O4 was successfully coated on the surface of fly ash and formed a uniform and continuous coating layer. As expected, silicone rubber filled with the composite filler had a minimum reflection loss of -23.8 dB at 17.5 GHz with a thickness of 1.8 mm, while the effective absorption bandwidth was as high as 12 GHz. The addition of the composite filler greatly enhanced the microwave absorption properties of the system, which were resulted from multiple losses mechanism: interface polarization losses, magnetic losses and multiple reflection losses. Also, silicone rubber filled with the composite filler exhibited excellent thermal stability, high flexibility, environmental resistance, and hydrophobicity compared with silicone rubber. Therefore, this work not only responds to the green chemistry to achieve efficient fly ash recovery, but also devises a new strategy to prepare microwave absorption materials with strong potential for military and civilian applications.