Effects of cobalt substitution on structure and microwave absorption properties of PrNi5 alloy

Abstract

The polycrystalline samples PrNi5–xCox (x=0.0, 0.1, 0.2, 0.3, 0.4) were synthesized by arc smelting and high energy ball milling method. The phase structure, morphology, saturation magnetization and electromagnetic parameters of the alloy powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and vector network analyzer (VNA), respectively. The results revealed that the lattice parameter a and c and unit-cell volume V increased with the increasing amount of Co substitution. The saturation magnetization increased as Co content increased. The minimum absorption peak frequency shifted towards lower frequency region with the increasing amount of Co substitution. And the minimum reflection loss of the PrNi5–xCox powders increased first and then decreased with the increasing amount of Co substitution. The PrNi5–xCox alloys possessed the excellent microwave absorbing properties. The minimum reflection loss of the PrNi4.9Co0.1 alloy all could reach −20.0 dB with the coating thickness ranging from 1.8 to 3 mm. The minimum reflection loss of PrNi4.9Co0.1 powders was −36.20 dB at 7.76 GHz, and the frequency bandwidth of R<–10 dB reached about 1.50 GHz with the best matching condition d=2.0 mm.