Research on microwave electromagnetic properties of Tb-Fe-Cr alloy

The Tb-Fe-Cr alloy powders were prepared by the arc melting method and high energy ball milling. The phase structure and the microstructure of the alloys powders were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and then their microwave absorbing properties were analyzed by Vector network analyzer. The results showed that the absorption peak values of Tb9Fe88Cr3 alloy with a material thickness of 2.0 mm were lower than −16.5 dB when ball milling time was from 50 to 60 h, and the wide frequency of reflectivity under −10 dB were all more than 4 GHz. When the ball milling time was 50 h, the alloy powders had better electromagnetic properties. The absorption peak value of alloy reached −25.8 dB, and the wide frequency of reflectivity under −10 dB reached 4.8 GHz. When the ball milling time was more than 70 h, the alloy powders would become thinner, leading to worse electromagnetic properties of the alloy, the absorption peak shifted towards low frequency under the same material thickness. The TbxFe97–xCr3 (x=7, 9, 11, 13, 15 mol.%) alloy dealt with 60 h ball milling time had better wide-frequency characteristic under 1.8 mm of material thickness. The absorption peak shifted towards higher frequency region from lower frequency region with increased atom percent of Tb in the alloy, and the inflexion point appeared when x=13. At low frequency, the microwave absorbing properties of Tb11Fe86Cr3 alloy was better than those of the others. The absorption peak value of Tb15Fe82Cr3 alloy was −24 dB, and the wide frequency of reflectivity under −10 dB was 4.5 GHz.