Controllable Construction Of PtNiCoCu-based High-entropy Nanocrystalline/graphene And Its Electromagnetic Properties

In recent years,with the continuous development of science and technology,electromagnetic waves have been widely studied and widely used in wireless communication,navigation,satellite signals,household appliances,medical devices and other fields.However,electromagnetic waves have not only brought convenience to human life,but also brought great harm to our living environment.Therefore,it is particularly important to study the new high-performance electromagnetic wave absorption materials to reduce the harm of electromagnetic wave.Most electromagnetic wave absorption materials are mainly traditional alloys.Compared with traditional alloys,high entropy alloys have attracted wide attention in the field of electromagnetic absorption due to their high hardness,high strength,excellent magnetic performance,corrosion resistance,temperature stability and other excellent properties.However,graphene has good stability,extensive dielectric properties,and great diversity in morphology and microstructure.However,the single-layer graphene material has disadvantages such as poor impedance matching,weak attenuation ability and easy to cluster,which limits its application in the field of electromagnetic wave absorption materials.Therefore,graphene is usually combined with other materials as a substrate material to improve its impedance matching,reduce the density of the loaded materials,and improve the electrical and thermal conductivity.In this paper,the high entropy Pt₁₈Ni₂₆Fe₁₅Co₁₄Cu₂₇nanocrystals was constructed,and it was combined with reduced graphene oxide（r GO）to prepare Pt₁₈Ni₂₆Fe₁₅Co₁₄Cu₂₇/r GO composite material.By transmission electron microscopy and scanning electron microscopy,we can see that the Pt₁₈Ni₂₆Fe₁₅Co₁₄Cu₂₇nanocrystals are evenly dispersed on the surface of r GO,with a small size of about 3.3 nm.The electromagnetic wave absorption performance test found that when the Pt₁₈Ni₂₆Fe₁₅Co₁₄Cu₂₇/r GO sample thickness is 2 mm,the effective absorption bandwidth can reach 2.5 GHz,and when the Pt₁₈Ni₂₆Fe₁₅Co₁₄Cu₂₇/r GO sample thickness is 4 mm,the reflection loss can reach-41.8 d B frequency at 4.96 GHz,which fully indicates that Pt₁₈Ni₂₆Fe₁₅Co₁₄Cu₂₇/r GO has strong electromagnetic absorption performance and can be applied in the field of electromagnetic absorption materials.Similarly,the high entropy Pt₁₈Ni₂₆Cr₁₅Co₁₄Cu₂₇nanocrystals were constructed by colloidal synthesis strategy,and combined with r GO to prepare Pt₁₈Ni₂₆Cr₁₅Co₁₄Cu₂₇/r GO composite material.By transmission electron microscopy and scanning electron microscopy,we can see that the Pt₁₈Ni₂₆Cr₁₅Co₁₄Cu₂₇nanocrystals are evenly dispersed on the surface of r GO,with a small size of about 4.6 nm.The electromagnetic wave absorption performance test found that when the thickness of Pt₁₈Ni₂₆Cr₁₅Co₁₄Cu₂₇/r GO sample is 2 mm,the effective absorption bandwidth can reach 4.9 GHz,and the reflection loss can reach-51.8 d B at the frequencyof 12.17 GHz.Compared with Pt₁₈Ni₂₆Cr₁₅Co₁₄Cu₂₇/r GO,Pt₁₈Ni₂₆Cr₁₅Co₁₄Cu₂₇/r GO composite material has more excellent electromagnetic wave absorption performance,which can also be applied in the field of electromagnetic wave absorption materials.Therefore,in this work,our synthesized Pt₁₈Ni₂₆Fe₁₅Co₁₄Cu₂₇/r GO and Pt₁₈Ni₂₆Cr₁₅Co₁₄Cu₂₇/r GO composites open a new window in the field of electromagnetic wave-absorbing materials.