Study On Preparation And Microwave Absorbing Properties Of Cu₉S₅and Its Composites

Nowadays,the mobile devices of electronic products are updated rapidly,and the electromagnetic（EM）radiation generated by them will put human health in risk.At the same time,in order to gain dominance in military warfare and achieve the goal of"winning",the role of absorbing materials in avoiding detection methods such as radar and infrared cannot be underestimated.Ideal absorbing materials have the characteristics of"thin thickness,strong absorption capacity and broad absorption bandwidth".Today,absorbing materials are developing in the direction of multiple composites.In this paper,the preparation and wave absorption properties of Cu₉S₅and its composites were investigated with the semiconductor material Cu₉S₅as the main object.Firstly,the effect of different sulfur sources on the preparation of Cu₉S₅matrix was investigated,and the best matrix was determined to be prepared with thiourea as the sulfur source,which showed a porous lamellar structure as observed from the SEM images.The EM parameters were tested with a vector network meter,and the Cu₉S₅was found to be a dielectric loss-dominated absorbing material.By calculating the reflection loss values,the minimum RL value can reach-20.5 d B when the matched thickness is 1.3 mm,and the effective absorption band width is2.7 GHz,which is a better performance absorbing material.Following that,the preparation and performance study of Cu₉S₅-based composite absorbing materials were carried out.In the research work of synthesizing CSF composites.The Fe₃O₄spherical particles were prepared by a well-established solvothermal method and are effectively combined with Cu₉S₅to prepare Cu₉S₅/Fe₃O₄composite particles by hydrothermal method.The composition,magnetic properties and micromorphology of the samples were characterized using XRD,XPS,VSM,SEM,and TEM.By testing the EM parameters of each sample and calculating the reflection loss,it was found that the ratio of the mass concentration of the sample when mixed with paraffin wax has a certain influence on the EM parameters and wave absorption performance of the sample.The best absorption performance was achieved when the mass concentration of the sample was 50%,with a minimum RL of-39.5 d B.The combination of two absorption mechanisms,dielectric loss and magnetic loss,significantly improved the absorption performance of the composite particles compared to a single material.Subsequently,Cu₉S₅was effectively compounded with RGO to prepare Cu₉S₅/RGO（CSR）composite particles.In this part of the work,the purer GO was prepared using the Hummers method,followed by the one-step preparation of CSR composites via the solvothermal method.The reduction of GO to RGO was demonstrated using various characterization,and the CSR composites were successfully prepared.The flower-like structure exhibited under electron microscopy was observed to facilitate the effective absorption of incident EM waves.Selecting the best sample mass concentration ratio to test the EM parameters and simulating the RL value to evaluate the absorbing performance of the sample.Combining impedance matching,attenuation constants and various absorption mechanisms to analyze the absorption capability of the samples,it was found that CSR-2 had the best absorption performance with a maximum absorption intensity of-51.9 d B and a maximum effective absorption width of 3.92 GHz when the matching thickness was 2.8 mm.other composite samples could also meet the RL value of less than-10 d B.Finally,the Cu₉S₅@Ni composites were prepared by electroless plating with Ni on the surface of Cu₉S₅substrate,and the effect of the composite ratio and the electroless plating process on the microwave absorbing properties of the samples were studied.It was found that the wave absorption performance of the samples was enhanced when the added Cu₉S₅substrate content was increased.And only when the application time of electroless plating was changed,the application time was longer and the absorbing performance of the samples was enhanced.The best absorption performance of the sample Cu₉S₅@Ni-3 was obtained,with a minimum RL of-32.3 d B and an effective absorption bandwidth of 3.7 GHz at a matched thickness of 1.5 mm.