Study On Preparation And Properties Of Electromagnetic Absorbing Material Based On Solid Waste Of Mn-Zn Ferrite

The rapid development of communication technology has resulted the increasingly complex and deteriorating electromagnetic environment,the most pressing issue is to develop a new absorbing material which is more broadband,more efficient,more stable,thinner and cheaper.The soft ferrite solid waste comes from the production of magnetic devices,which have excellent magnetic loss performance and low price,it can be a promising absorbing material with effective utilization.This paper is trying to use magnetic separation and membrane filtration to purify the solid waste of Mn-Zn ferrite,and then using the ion doping and polymer composite to enhance the microwave absorption performance of the solid waste.In this paper,Zn²⁺and Mn²⁺were incorporated into the ferrite lattice with the metod of mechanical alloying and high temperature sintering,which can further enhanced the magnetic loss performance.The designing orthogonal experiments have systematically studied the influence of sintering temperature,holding time and doping ratio on its electromagnetic properties,mechanical properties and microwave loss.This paper has drawn the four-dimensional slice diagrams through nearly a hundred group of experiments and then finally find the optimal corresponding parameter of the absorbing property,the prepared absorber has shown the excellent performance in UHF（30-300MHz）and P-band（0.3-1GHz）,and the RL（reflection loss）in the whole P-band is more than-30d B.With the method of situ oxidation polymerization,the magnetic and electrical composites with PANI（polyaniline）coated with MZF（ferrite solid waste）were produced.The intrinsic dipole of PANI and the interface dielectric dipole of the composite material palyed an important part in enhancing dielectric loss,and adjusting the impedance matching characteristics of the material.This paper also studied the influence of PANI on the input impedance and microwave absorption ability of the composite material.The prepared MZF-1.5PANI sample has achieved an excellent microwave absorption performance by adjusting the thickness,in f=9GHz,d=3.4mm,the RL reached-54.36d B,the effective absorption bandwidth（RL<-10d B）of MZF-1.5PANI sample at d=2.6mm reached an extremely wide 4.17GHz.In addition,this paper have designed the hot pressing molding by the boron modified phenolic resin and compounded with ferrite solid waste,and studied the influence of process,resin type and composite ratio on electromagnetic properties and microwave absorption properties.The 30%boron-phenolic resin composite absorber in f=14.52GHz,d=1.6mm,the maximum RL can achieve-56.06d B,the 40%boron-phenolic resin composite absorber with a thickness of only 2.3mm can achieve the effective absorption bandwidth of 4.12GHz.So,a kind of electromagnetic wave absorber with high temperature resistance,wide frequency and strong absorption was successfully produced through resin reinforcement.The result shows that the absorbing performance of solid waste can be significantly enhanced in low frequency band by ion doping,and it is easier to obtain the broadband,efficient and lightweight electromagnetic wave absorbers by the polymer polymerization.This paper has value in resource saving and research on microwave absorption mechanism in special environment.