LAUSR

Abstract In this paper, the effect of rare earth Y on the wave absorption properties of Fe95Si1B2P0.5Cu1.5 alloy powders was investigated, regarding its problem of impedance mismatch in the S-band and C-band. The results show that the introduction of Y induces B atoms into the lattice of α-Fe, causing lattice distortion, while producing Fe2B and Y2Fe13.725Si0.275B. The content of Y affects the powders morphology, and the powders particles change from flake to bulk as the Y content increases. The addition of Y increases the real and imaginary parts of the magnetic permeability, while decreasing the real and imaginary parts of the dielectric constant. Furthermore, the main dielectric loss of the alloy powders turns from conduction loss to relaxation polarization, but the magnetic loss of the alloy powders remains the same as eddy current loss and natural resonance. Meanwhile, the dielectric loss is drastically reduced with little change in the magnetic loss of the alloy powders, which provided the conditions for improving the impedance matching of the material. The addition of Y substantially improves the effective absorption bandwidth and impedance matching of the alloy powders. Among the powders, Fe94.5Si1B2P0.5Cu1.5Y0.5 alloy powders shows superior absorption performance in the S-band and C-band: the minimum reflection loss (RLmin) can reach −42.405 dB at 3.5 mm, and in the thickness range of 1–5 mm, it can achieve full-band absorption in the S-band and C-band, including a maximum effective absorption bandwidth (EAB, RL ≤ 10 dB) of 4.25 GHz at a thickness of 2.4 mm and a EAB of 4.05 GHz at a thickness of 2.5 mm, which encapsulates the entire C-band.