Synthesis and electromagnetic wave absorption performances of a novel (Mo0.25Cr0.25Ti0.25V0.25)3AlC2 high-entropy MAX phase

Herein, a novel kind of high-entropy MAX phases, (Mo0.25Cr0.25Ti0.25V0.25)(3)AlC2 powders were successfully synthesized by a newly proposed two-step solid state reaction process. The oxidation experiments demonstrate that the oxidation products of Al2Mo3O12 and rutile TiO2 are formed at about 600 and 800 degrees C, respectively. Besides, the dielectric and electromagnetic (EM) wave absorption properties of (Mo0.25Cr0.25Ti0.25V0.25)(3)AlC2 powders and those after oxidation at different temperatures were also examined. The results show that the as-synthesized (Mo0.25Cr0.25Ti0.25V0.25)(3)AlC2 powders possess excellent EM wave absorption performances with the minimum reflection loss (RL ) of -45.80 dB (at 1.7 mm thickness) and the maximum effective absorption bandwidth (E-AB) of 3.6 GHz (at 1.5 mm thickness). After oxidation at 40 0-80 0 degrees C, due to the coupling of conductivity loss and polarization loss, (Mo0.25Cr0.25Ti0.25V0.25)(3)AlC2 powders can retain good EM wave absorption properties in a certain frequency range. In this paper, the effects of oxidation on EM wave absorption properties of high-entropy MAX phases were systematically investigated for the first time. This work manifests that high-entropy MAX phases are promising EM wave absorbing candidates and can maintain good EM wave absorption performances after oxidation. (C) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

In this study, a novel kind of high-entropy MAX phases powder was synthesized successfully using a newly proposed solid state reaction process. The oxidation products of the powder were examined, and the dielectric and electromagnetic wave absorption properties were tested. The as-synthesized powder exhibited excellent EM wave absorption performances and could maintain good absorption properties after oxidation in a certain frequency range.