Study On The Structure And Microwave Absorbing Properties Of Nd-Ni Base Alloy

In order to solve the problem of electromagnetic wave pollution and electromagnetic protection,the development of microwave absorbing materials has attracted extensive attention of researchers.In this paper,a series of Nd-Ni base alloy powders were prepared by vacuum arc smelting and high-energy ball milling.Their phase composition,powder particles,magnetic properties and electromagnetic parameters were detected by XRD,SEM,VSM and VNA,and their reflection losses were simulated by Matlab and Origin.The influence of the addition of rare earth elements,magnetic elements,non-metallic elements on the absorbing properties of the alloy structure was studied.This paper has not only successfully prepared high quality absorbing materials,but also has certain reference value to the improvement of the properties of relevant absorbing materials.The particles of Ce_xNd_1-xNi₅ alloy are flaky after grinding and show obvious ferromagnetism.With the addition of Ce,the saturation magnetization?M_s?of powder decreases first and then increases.The effective absorption peaks of powders with different Ce contents?RL?-10 d B?all appeared in the C band?4?8 GHz?.The Ce_0.7Nd_0.3Ni₅ powder has the lowest reflection loss at 6.64 GHz,which can reach-40.73 d B,and the absorption bandwidth is 1.11 GHz?6.17?1.28 GHz?.The peak reflection loss of Pr_xNd_1-xNi₅ alloy powder gradually moved to the low frequency direction with the addition of Pr.When the thickness is 2.1 mm,the reflection loss of Pr_0.3Nd_0.7Ni₅ alloy powder has the lowest frequency band,appearing at 6.64 GHz,and the reflection loss can reach-32.28 d B.So,the proper addition of Pr is beneficial to increase the microwave absorption performance of the material.After ball grinding,the particles of Dy_xNd_1-xNi₅ alloy powder exhibited flaky structure and gradually refined with the addition of Dy content.The effective absorption band of Dy_xNd_1-xNi₅ alloy powder gradually shifted to the low frequency direction with the addition of Dy content.Among them,Dy_0.2Nd_0.8Ni₅ and Dy_0.4Nd_0.6Ni₅ alloy powders have the widest absorption bandwidth and the lowest reflection loss respectively.It can be seen that the addition of rare earth can play a role in adjusting the absorbing properties of the alloy powder.As for NdNi_5-xFe_x alloy powder,its crystal spacing increases with the addition of Fe.The powder has obvious ferromagnetism and with the increase of Fe content,the saturation magnetization?M_s?increases and the H_c decreases.When the simulated thickness is 2.2 mm,NdNi_4.9Fe_0.1 has the best overall performance,with reflection loss of-29.29 d B and effective bandwidth of 1.29 GHz.It provides an idea for us to explore the alloy powder with excellent microwave absorption in S band.As for NdNi_5-xCo_x alloy,the M_s increases with the increase of Co content.At the same time,the effective absorption band of the alloy powder gradually moved to the higher frequency.Therefore,it is effective to adjust the absorption frequency band by adjusting the Co content of NdNi_5-xCo_x alloy powder.In the research of NdNi_5-xC_x alloy,we found that the alloy powder was mainly composed of NdNi₅ phase,and the addition of C element will cause the lattice volume decrease.With the increase of C content,the alloy particles after ball grinding gradually become smaller and thinner.The M_s and H_c gradually decrease with the increase of C content.The peak of reflection loss moves to high frequency with the increase of C content.C addition can effectively expand the absorption bandwidth of NdNi_5-xC_x alloy powder.When the thickness is 2.1mm,the reflection loss of NdNi_4.7C_0.3 reaches-39.55d B at 8.55GHz and the effective bandwidth reaches 1.51GHz.NdNi_4.5C_0.5 alloy powder has an absorption peak of-19.59d B at 8.93GHz and the effective bandwidth is 1.54GHz.In addition,adjusting C content can improve the impedance matching characteristics of the alloy.