Preparation And Microwave Absorption Performances Of Hollow Multi-shell Microsphere

Compared with other nanomaterials,the multi-shell structure has a larger specific surface area,can provide more active sites,and has a wide range of applications in many fields.The composite of the multi-shell nanomaterial with other materials can effectively improve the electromagnetic wave absorption performance of the composite material.In this paper,hollow multi-shell material is synthesized by the sequential template method,and then is composited with carbon nanotubes to study the electromagnetic wave absorption properties of the composite material.The main contents are as follows:Single-,double-,and triple-shell ZnO hollow microspheres with a size of about 1?m are prepared by hydrothermal method and high-temperature calcination.The shell layer is a porous structure composed of ZnO nanorods.By analyzing the electromagnetic wave absorption performance of ZnO hollow microsphere composites with different shell numbers,it is proved that the multi-shell structure is very beneficial to improve the electromagnetic wave absorption performance of the composite material,and the triple-shell ZnO hollow microsphere composite material has better electromagnetic wave absorption performance.By analyzing the electromagnetic wave absorption performance of the ZnO hollow microsphere composite material with different carbon nanotubes content,it is found that the triple-shell ZnO hollow microsphere composite with 15%carbon nanotubes content has the best electromagnetic wave absorption performance,reaching-26.7 d B at a thickness of 2.2 mm,and an effective bandwidth of 4.9 GHz,and the frequency range where the reflection loss value is less than-10 d B is 10.8-15.7 GHz.Single-and triple-shell Fe₂O₃ hollow microspheres with a size of about 2.5?m were prepared by hydrothermal method and high temperature calcination.The shell layer is a porous structure composed of irregular Fe₂O₃ nanorods of about 100 nm.By analyzing the electromagnetic wave absorption performance of the Fe₂O₃ hollow microsphere composite material with different carbon nanotubes content,it is proved that the addition of carbon nanotubes can improve the electromagnetic wave absorption performance of Fe₂O₃ hollow microsphere composite materials.The results show that the triple-shell Fe₂O₃ hollow microsphere composite with 20%carbon nanotubes content has the best electromagnetic wave absorption performance,and the maximum reflection loss can reach-52.7 d B at a thickness of 3.7 mm and a frequency of 5.6 GHz,and the effective bandwidth is 2.1 GHz.The range of values less than-10 d B is 4.7-6.8 GHz.