Preparation And Study Of Electromagnetic Wave Absorption Properties Of RGO NSs And ZnO Filled Ceramic Matrix Composites

With the rapid development of stealth technology and radar detection technology,stealth weapons have become an important factor in the decisive battles.Composite materials composed of dielectric loss absorbent and ceramic matrix exhibt the advantages of electromagnetic wave absorption properties and mechanical properties.The innovations of this paper are that this work studied the effect of rGO NSs distribution state on electromagnetic wave absorption properties.By in situ reaction,ZnO was coated by rGO NSs,and the composite(1 vol.%rGO NSs/8 vol.%ZnO)exhibits the optimal electromagnetic wave absorption properties.In this work,the composite materials of rGO NSs(reduced graphene oxide nanosheets)/Al₂O₃,ZnO/ZnAl₂O₄ and rGO NSs/ZnO/ZnAl₂O₄ were prepared.The effects of rGO NSs content and distribution on mechanical,the complex permittivity and electromagnetic wave absorption properties were studied.And the effects of ZnO content and particle size on electromagnetic wave absorption properties were studied.Based on the study of ZnO/ZnAl₂O₄composite materials,rGO NSs was added to adjust the complex permittivity and electromagnetic wave absorption properties.(1)The graphite flakes were chemically modified into graphite oxide by Hummer's method.After the ultrasonic treatment,the rGO NSs was prepared using hydrazine hydrate.Atomic force microscopy tests show that the transverse dimensions of the rGO NSs are about 5-10?m and the thickness is about 4.25 nm.Due to the high tensile strength of rGO NSs and the phenomenon of‘‘rGO NSs pulling-out”,when the rGO NSs content increases from 0 to 3 wt.%,the flexural strength of composite materials increases from 228.00 MPa to 313.75 MPa.The complex permittivity increases significantly with the increase of rGO NSs content.(2)When the Al₂O₃ particle size increases from 0.8?m to 15?m,the distribution state of rGO NSs changes obviously.The mechanical,the complex permittivity and electromagnetic wave absorption properties were studied.When the rGO NSs content is 1 wt.%,the composite material with Al₂O₃(15?m)exhits high imaginary part of complex permittivity.And the electromagnetic wave absorption properties and effective bandwidth are enhanced.(3)ZnO/ZnAl₂O₄ composite materials with ZnO as absorbent and ZnAl₂O₄ as matrix were prepared by in-situ reaction method.The effects of ZnO content and particle size on the mechanical,the complex permittivity and electromagnetic wave absorption properties were studied.The complex permittivity increases with the increase of ZnO content and the decrease of ZnO particle size.When the ZnO content increases from 0 vol.%to 8 vol.%and the particle size decreases from 1-2?m to 0.5-1.5?m,the composite material with a thickness of 2.2 mm exhibits the optimal electromagnetic wave absorption properties.(4)ZnO,rGO NSs and Al₂O₃ were used to prepare rGO NSs/ZnO/ZnAl₂O₄ composite materials.when the rGO NSs content increases from 0 vol.%to 1 vol.%while ZnO content fixe at 8 vol.%,the imaginary part of complex permittivity increases from 2.0-5.1 to 3.5-8.The ceramic with rGO NSs content 1 vol.%and ZnO content 8 vol.%shows the optimal electromagnetic wave absorption properties.The effective absorption bandwidth is 4 GHz.