Electromagnetic and Microwave Absorption Properties of the Flake-Shaped Pr-Ho-Fe Alloys in the C-Band

Abstract

The polycrystalline samples Pr _x Ho_2−x Fe₁₇ (x = 0.0, 0.1, 0.2, 0.3, 0.4) were prepared by arc melting and high-energy ball milling method. The influences of Pr substitution on phase structure, morphology, saturation magnetization and electromagnetic parameters were investigated by x-ray diffraction, scanning electron microscopy, vibrating-sample magnetometry and vector network analyzer, respectively. The results show that the particle size increased and the saturation magnetization decreased with increasing Pr content. The minimum absorption peak frequency shifted towards a lower-frequency region with increasing Pr concentration. The minimum RL of Pr_0.3Ho_1.7Fe₁₇ powder was −41.03 dB at 6.88 GHz with a coating thickness of 2.0 mm. With different thickness of 1.8–2.8 mm, the minimum reflection loss (RL) of Pr_0.3Ho_1.7Fe₁₇ powder was less than −20 dB in the whole C-band (4–8 GHz). The microwave-absorbing properties of the composite with different weight ratios of Pr_0.3Ho_1.7Fe₁₇/Co were researched. The microwave-absorbing peaks of the composites shifted to a lower frequency with increasing Co content. The minimum RL of Pr_0.3Ho_1.7Fe₁₇/Co(10%) was −42.51 dB at 4.72 GHz with a coating thickness of 2.6 mm. This suggests that the Pr-Ho-Fe will be a promising microwave absorption material in higher-gigahertz frequency, especially in the C-band.