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

The ErxHo（2-x）Fe（17）（x = 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 ErxHo2-xFe17 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 ErxHo2-xFe17 is-37.26 dB at5.68 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 ErxHo2-xFe17/graphene are close to-10 dB with absorbing coating thicknesses increased.

La-Ho-Fe合金的制备及其微波吸收特性（英文）

采用电弧熔炼及高能球磨工艺制备出La_xHo_(2-x)Fe_(17) (x=0.0, 0.2, 0.4, 0.6, 0.8)合金微粉,借助XRD、SEM、VSM和网络矢量分析仪等仪器分别研究La替换对合金微粉的结构、形貌、磁性能及其微波吸收性能的影响。结果表明,随着La含量的增加,饱和磁化强度和平均颗粒大小都有所增加。La_xHo_(2-x)Fe_(17)合金的最小反射峰频率向低频方向移动。其中La_(0.2)Ho_(1.8)Fe_(17)合金具有最好的吸波效果,在最佳匹配厚度1.8 mm下,La0.2Ho1.8Fe17合金的最小反射损耗在8.72 GHz处达到–28.72 dB,反射损耗小于–10 dB的频带宽度达到2.32 GHz。当厚度在1.2～2.4 mm范围里,La0.2Ho1.8Fe17合金的反射损耗均小于–10dB,这表明La_xHo_(2-x)Fe_(17)是有前途的微波吸收材料,并具有良好的吸收特性。