Effect of rare earths on microwave absorbing properties of RE-Co alloys

The powders of RE2Co17 (RE=Y, Ce, Nd, Ho, Er) and HoxCo100–x (x=6, 8, 10, 12) alloys were prepared by the arc melting method and high-energy ball mill process. The compositions and morphologies of the alloys were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the microwave absorbing properties were studied by a vector network analyzer. The results showed that the alloy of Y2Co17 had better absorbing properties at low frequencies and its lowest reflectivity value was −9.5 dB at 3.8 GHz. The lowest reflectivity value of Ho2Co17 alloy was −13.7 dB at 7.02 GHz and it obtained large absorbing bandwidth. Reflectivity value less than −5 dB was from 5.1 to 10.2 GHz. When x=6 and x=8, the alloys of HoxCo100–x consisted of Ho2Co17 phase and Co phase. They had good radar absorbing properties. With increase in Ho content, the minimum reflectivity value worsened and the absorbing peak frequency shifted toward higher frequencies. But when x=12, the absorbing peak frequency shifted toward lower frequencies but the minimum reflectivity value worsened.

Graphical AbstractHo2Co17 alloy powder not only has good minimum reflectance, but also has a wide absorption bandwidthFigure optionsDownload full-size imageDownload as PowerPoint slide