Study On The Synthesis And Microwave Absorbing Properties Of ZnCo₂O₄

With the development of 5G technology,electronic equipment relying on electromagnetic wave as information carrier has been widely used in civil and military fields.Although electromagnetic wave promotes the development of human society,it produces nonnegligible radiation pollution.Therefore,the research on absorbing materials is crucial for the advance of modern society in health.As a new type of dielectric absorbing material,ZnCo₂O₄possesses the advantages of simple preparation,good impedance matching,high dielectric loss and strong designability,which provides a new idea for the development of absorbing materials.By hydrothermal reaction and high-temperature calcination,this study has prepared the spherical ZnCo₂O₄material whosestructure,morphology,and electromagnetic parameters are characterized in order to investigate its absorbing property.The details are as follows:First,to explore the formation conditions of the spherical ZnCo₂O₄material.By adjusting the urea content,reaction temperature and reaction time,the growth conditions of the spherical ZnCo₂O₄material are examined.The structure and morphology of the samples are characterized by XRD and SEM.The results show that it is more favorable to synthesize the spherical ZnCo₂O₄samples of high purity and good morphology when the urea content is between 8-14 mmol,the reaction temperature between 100-140℃,and the reaction time between 8-20 h.Second,orthogonal experiment is designed to optimize the process parameters in preparing the ZnCo₂O₄material.The orthogonal table is designed with reaction temperature,reaction time,zinc ion concentration and urea content as factors.Thestructure and morphology of the samples are characterized by XRD and SEM.The electromagnetic parameters of the samples are measured by vector network analyzer.Taking the peak value of reflection loss and absorption bandwidth as the index of measuring the absorption property of the ZnCo₂O₄material,it draws the conclusion based on an range analysis that the influence order of four factors on the peak value of reflection loss and absorption bandwidth of ZnCo₂O₄material,namely,reaction temperature,zinc ion concentration,reaction time,and urea content.The final optimized process parameters are:T（℃）=130℃,t（h）=16 h,[Zn²⁺]（mol/L）=0.015mol/L,Urea（mmol）=8 mmol.The Experiment is carried out based on the final optimized process parameters to characterize the experimental samples.The results show that the absorption capacity of ZnCo₂O₄is mainly caused by the dielectric loss,and its absorption bandwidth and peak value of the reflection loss are respectively-15.501 d B,1.694 GHz.Third,the effects of anionic surfactant SDS,cationic surfactant CTAB and nonionic surfactant PVP on the structure,morphology and microwave absorption properties of the materials are studied.Thestructure andmorphology of the samples are characterized by XRD and SEM.The electromagnetic parameters of the experimental samples are measured with the help of vector network analyzer.The results show that the addition of surfactant changes the morphology and improves the absorption property of the spherical ZnCo₂O₄ material.