Ultrafast Laser Synthesis of Cr2AlC MAX Phase and Selective Etching-derived Cr2CTx MXene for High-Performance Electromagnetic Wave Absorbers

Abstract

Conventional methods for synthesizing Cr₂AlC MAX phase powders often suffer from long processing times, limited purity, and poor scalability, which hinder their application in electromagnetic wave (EMW) absorption at high temperatures. In this work, high-purity Cr₂AlC MAX phase powders (96.3 wt%) were successfully synthesized via laser-induced self-propagating synthesis (LSS) using Cr₇C₃, Cr₃C₂ and Al powders as raw materials. Compared to conventional heating, this method greatly shortened the synthesis period by 10–240 times. The obtained Cr₂AlC powders showed excellent high-temperature EMW absorption performance. Even after oxidation at 973 K for 3 h, the absorber maintained strong absorption with a minimum reflection loss (RL_min) of −32.76 dB at 2.1 mm. Furthermore, Cr₂CT_x MXene prepared by selective HF etching of as-prepared Cr₂AlC exhibited good EMW absorption capacity, the Cr₂CT_x MXene before and after shear exfoliation respectively reached RL_min values of −19.59 dB (at 13.34 GHz) and −17.96 dB (at 14.71 GHz) with effective absorption bandwidth of 2.91 GHz and 3.57 GHz. These results demonstrate the promising potential of as-prepared Cr₂AlC and its MXene derivative for high-performance high-temperature EMW absorption applications.