Porous high entropy alloys for electromagnetic wave absorption

Spherical high-entropy alloys (HEAs) were prepared as a template by the traditional ball milling method, and the pure porous HEAs electromagnetic (EM) wave absorbing material was successfully obtained by etching the template with nitric acid/copper nitrate solution. The crystal structure, chemical composition and distribution, EM parameters and EM wave absorbing performance were characterized in detail. The results showed that the excellent impedance matching, magnetic loss performance and good dielectric loss of porous HEAs were the key factors leading to the excellent EM wave absorbing performance. The effective absorption bandwidth of the porous HEAs samples can reach to 4.48 GHz at the thickness of 1.7 mm, and the minimum reflection loss can reach to −40.2 dB at the same time. The feature of strong absorption at the thin thickness make HEAs a possible new generation of efficient EM wave absorber. The preparation idea and method of the samples also have important reference value.