Studies On Preparation And Properties Of Hollow Glass Microspheres Composite Microwave Absorber

Hollow glass microspheres is a good base material for synthesizing the wave absorption materials due to the characteristics of low density, huge surface area, excellent thermal and chemical stability, high mechanical strength and fine fluidity. Microwave absorptive materials such as iron-nickel alloy and iron nano-particles coated on hollow glass microspheres via electroless plating can effectively reduce the density of absorbing agents. In this paper, the iron-nickel alloy and iron coated core-shell particles are prepared by using hollow glass microspheres as the base core through electroless plating. The morphology and structure of the hollow glass microspheres-based core-shell particles are characterized; the magnetic properties and the microwave absorption properties are also discussed. The conclusions are followed:replacement of metal ions method and the amino-modified method are used to improved the activity of hollow glass microspheres, and the obtained iron-nickel alloy coated hollow glass microspheres have two different morphologies. The spherical structure of the iron-nickel alloy coated hollow glass microspheres core-shell particles of the saturation magnetization Ms is 34.54emu/g, higher than the membranous structure of the iron-nickel alloy coated hollow glass microspheres core-shell particles of the saturation magnetization(24.9emu/g). The optimal conditions of electroless plating iron-nickel alloy coated hollow glass microspheres is temperature 50℃, pH= 10, powder loading was 8 g/L.Electroless plating and sol-gel method are used to coated iron nanoparticles and the SiO2 layer on the surface of hollow glass microspheres respectively, and mechanism of the formation of SiO2 layer is also studied. SEM and XRD analysis show that the surface of hollow glass microspherescoated with the iron and SiO2 layers, respectively. Magnetic hysteresis curve analysis are pre-coated SiO2 powder coercivity He is 94.86kOe, saturation magnetization Ms is 14.98emu/g, while the post-coated SiO2 powder coercivity He as 100.55kOe, saturation magnetization Ms is 23.01emu/g. vector network analyzer on the glass microspheres/iron-nickel alloy, glass microspheres/Fe Composite Materials Characterization analysis shows that:when the filling ratio of glass microspheres/Fe-Ni:wax=1:4, thickness d= 2.5mm, the spherical structure of glass microspheres/iron-nickel composites the maximum reflection loss value of R=-49.28dB, and R<-10dB bandwidth is about 9GHz, while the membranous glass microspheres/iron-nickel composites the maximum reflection loss value of R=-33.8dB, and R<-10dB bandwidth is about 4GHz. the maximum reflection loss value of glass microspheres/iron composites is-11.17dB, while after coat a layer of SiO2, the maximum reflection loss value increase to-14.56dB.