Preparation And Electromagnetic Properties Of FeSiAl Based Composite Films By Magnetron Sputtering

With the development of microwave electric vacuum device technology,higher requirements are put forward for microwave attenuation materials with virtues of thin,light,wide,strong apllied on the key devices.FeSiAl-based films have attracted much attention due to their advantages such as large saturation magnetization and low coercivity.However,the reported electromagnetic properties are still difficult to meet the requirements of practical applications as high-power,wide-band,and the technology of artificial coating and sintering are difficult to achieve the uniform coat in the present application.Based on the urgent need,the research on FeSiAl-based composite films in this paper has important theoretical significance and practical value.The main results obtained are as following:Firstly,the FeSiAl films were prepared by multitarget magnetron sputtering technology.The FeSiAl film with the mass percentage ratio of Fe to Si to Al being85.39 to 9.27 to 5.34 was obtained by optimizing technology parameter and demonstrates the better performances of both soft magnetic and attenuation.The real partμ’and imaginary partμ"of the complex permeability of the FeSiAl film are all greater than 100 in the range of 1.0<?<4.0 GHz.and the ferromagnetic resonance frequency?is 3.7 GHz.The proper current parameters respectively are Fe 1A,Si 235W,and Al 65W.Secondly,（FeSiAl）_1-x-（Al₂O₃）_x composite films were designed and prepared.The effect of Al₂O₃ volume fraction x on the resistivity,static and dynamic magnetic properties of the composite films were studied.The results show that with the increase of Al₂O₃ volume fraction x,the resistivityρand the coercivity H_c increase,the saturation magnetization M_s and the soft magnetic performance decreases,but it can improve the impedance matching.The complex permeability increases with the increase of x.When x is 0.19,the value of the imaginary part of complex permeabilityμ"reaches 950,which is the best value for the microwave attenuation performance of the composite films.Additionally,（FeSiAl/Al₂O₃）_n composite films with different periodic layers were prepared.The results show that with the increase of periodic layer n in the composite film,the saturation magnetization M_s increases and the coercivity H_c decreases,which improves the soft magnetic properties of the composite films.The complex permeability also increases with the increase of n.When n is 3,it reaches the best value and the imaginary part of the complex permeability is 380.The optimize composite film shows excellent electromagnetic loss in a relatively wide frequency range.In conclusion,the high performance FeSiAl based composite films developed in this paper can provide a new strategy for the diversified design and practical application of microwave attenuating film systems.