Research On Surface Modification And Anti-corrosion Performace Of Carbonyl Iron And Its Graphene Composite Absorbing Materials

The research of electromagnetic wave absorbing materials has developed rapidly with the progress of modern science and technology.Regardless of whether it is a civilian field or a military field,its related technology has been widely used.It can promote the research and large-scale use of mobile communications in the civilian field,and it can improve the development of stealth technology and the practical application of weaponry in the military field.However,the traditional"thin,wide,light,and strong"can no longer fully meet the requirements of the ever-changing environment for wave-absorbing materials.The development of wave-absorbing materials with good wave-absorbing performance and corrosion resistance has received much attention in various fields.Carbonyl iron is one of the most commonly used absorbing materials at present.It has large magnetic loss angle,high saturation magnetization and Curie temperature.In particular,flaky carbonyl iron has the characteristics of high dielectric and high magnetic permeability,it can effectively break the Snoek limit.In addition,the control of micro-topography and the treatment of surface modification can carry out the dielectric regulation of carbonyl iron conveniently.Graphene has good chemical stability and barrier properties as a new two-dimensional material.Moreover,the electromagnetic properties of graphene make it be the focus on the applications of absorbing materials.Firstlty,the flaky carbonyl iron and it is doped with Graphene Oxide?GO?and reduced Graphene Oxide?r GO?composite absorbing materials were subjected to high-temperature blue treatment in this paper.The purpose is to study the effect of bluing on the anti-corrosion and absorbing properties of carbonyl iron and its composite absorbing materials with graphene.Secondly,the research on the surface modification of carbonyl iron by composite coupling agents was carried out to achieve the purpose of dielectric regulation.The content and findings of this study are as follows:?1?Flaky carbonyl iron?CIP?was prepared by high-energy ball milling.Then,the obtained CIP was subjected to a high-temperature bluing treatment at 140?.Finally,according to the GB/T2423.18-2000,static corrosion experiments were performed on CIP and bluing CIP in 5%Nacl solution for 12h,24h,and 48h.The polarization curves of all samples were measured by an electrochemical workstation,and the results showed that the bluing treatment effectively improved the corrosion resistance of CIP.SEM,XRD,and Raman spectra all show that the bluing treatment successfully forms the Fe₃₄ on the surface of CIP.And,it does not affect the microstructure of CIP.Bluing can effectively improve the corrosion resistance and achieve the purpose of protecting CIP.It also can alleviate the influence of corrosive environment on electromagnetic parameters.At the same time,blue treatment reduce the dielectric constant and improve the impedance matching.?2?CIP/GO and CIP/r GO composite absorbing materials were prepared by the same method as the above high-energy ball milling.Then,the obtained CIP composite absorbing materials?CIP/GO and CIP/r GO?were blue-treatment.Finally,the same method as described above?5%Nacl solution?was used to study the static corrosion with different times on the composite absorbing materials and the bluing composite absorbing materials.The polarization curves of the CIP composite absorbing material and the bluing CIP composite absorbing material were measured by an electrochemical workstation.The result shows that the bluing treatment improves the corrosion resistance of the CIP composite absorbing material effectively.SEM,XRD spectrum and Raman spectrum all show that the microstruct of the composite absorbing materials still present a flaky structure,and the bluing treatment successfully forms Fe₃₄ on the surface of the samples.It improves the corrosion resistance of CIP/GO and CIP/r GO composite absorbing materials effectively,and achieves the purpose of protecting CIP composite absorbing materials in corrosive media at the same time.In addition,the bluing treatment alleviates the influence of the corrosive environment on the electromagnetic parameters.It improves the corrosion resistance of the composite absorbing material and reaches the goal of improving its wave absorbing performance.?3?Three coupling agents?calcium stearate+titanate+KH-560?were used to surface modify the CIP by single and composite coupling agents.The structure and absorbing properties of CIP which is modified by single coupling agent and composite coupling agents were analyzed and compared.The results show that the CIP modified by the composite coupling agent has a flaky structure with a more uniform size and distribution.XRD and Raman spectrum showe that the surface modification of the composite coupling agents has no significant effect on the phase and structure of the CIP.The VSM of samples indicates that the modification of composite coupling agents increase the saturation magnetization?Ms?of the sample,but the coercive force?Hc?does not change singnificantly.According to the transmission line theory,the reflection loss of the absorbing materials are calculated.When the thickness is 2 mm,the RL peak reached to-15 d B near 2 GHz for CIP modified by ternary coupling agents,the effective absorption bandwidth was 1 GHz?1.6-2.6 GHz?when the RL<-10 d B.Moreover,the addition of the composite coupling agents increases the magnetic loss angle of the CIP significantly,especially at high frequencies.