La-Ho-Fe合金的制备及其微波吸收特性研究

采用电弧熔炼及高能球磨工艺制备出LaxHo2-xFe17(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。LaxHo2-xFe17合金的最小反射峰频率向低频方向移动。其中La0.2Ho1.8Fe17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,La0.2H1.8Fe17合金的反射损耗均小于-10 dB,这表明LaxHo2-xFe17是有前途的微波吸收材料,并具有良好的吸收特性。

Preparation and Microwave Absorption Propertiesof La-Ho-Fe Alloys

The LaxHo2-xFe17 (x=0.0, 0.2, 0.4, 0.6, 0.8) powders were prepared by arc melting and high energy ball milling method. The influence of the La substitution on phase structure, morphology, magnetic properties and electromagnetic parameters were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating-sample magnetometry (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 La content. The minimum absorption peak frequency shifts towards a lower frequency region with the increase of La content. The minimum RL of La0.2Ho1.8Fe17 reaches -28.72 dB at 8.72 GHz, and the frequency bandwidth of R<-10 dB reaches about 2.32 GHz with the best matching condition d=1.8 mm. The reflection loss with the thickness ranging of 1.2-2.4 mm could reach -10 dB, which indicates the particles be considered as the promising microwave absorbing materials with better absorption properties.