Electromagnetic and microwave absorption properties of Er-Ho-Fe alloys

The Er chi Ho2-chi Fe17(chi = 0.0, 0.1, 0.2, 0.3, 0.4) powders were prepared by arc melting and high energy ball milling method. The influence of the Er substitution on phase structure, morphology, saturation magnetization, electromagnetic parameters was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and vector network analyzer (VNA), respectively. The results show that the saturation magnetization increases and the average particle size increases with the increase of Er content. The minimum absorption peak frequency shifts towards a lower frequency region with the increase of Er content. The Er0.3Ho1.7Fe17 powder can achieve the minimum RL of -24.07 dB at 6.96 GHz with a thickness of 2.0 mm and the minimum RL is less than -20 dB at the thickness range from 2.0 to 3.0 mm. The minimum RL of Er-0.3 Ho1.7Fe17 is -37.26 dB at 5.68 GHz and the frequency bandwidth of R < -10 dB reaches about 1.2 GHz with a thickness of 2.4 mm. And the microwave absorbing properties of the composite with different weight ratios of Er0.3Ho1.7Fe17/ graphene were researched. The microwave absorbing peaks of the composite shift to lower frequency with the increase of graphene content. The values of the minimum RL of Er0.3Ho1.7Fe17/graphene are close to -10 dB with absorbing coating thicknesses increased. (C) 2018 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.