Lewis acid molten salt etched porous lamellar Ti2AlC powders for enhanced microwave absorption

Abstract

Ti2AlC can be used as a microwave absorbent due to its good electrical conductivity. However, Ti2AlC powders synthesized using conventional solid phase reaction show low reflection loss (RL) and narrow effective absorption width (EAB), which greatly limits its application in the field of microwave absorption. Herein, porous lamellar Ti2AlC powders were firstly synthesized in NaCl/KCl molten salt using Ti powders, Al powders, and starch as reaction precursors, and then they were selectively etched with Lewis acid molten salt (CuCl2) to prepare Ti2AlC/Cu/Ti2C hybrids. The results indicated that when the mass fraction of porous lamellar Ti2AlC powder in paraffin was 40 %, the maximum RL and EAB were −44.15 dB and 2.68 GHz, respectively. After Lewis acid molten salt etching, the RL and EAB of Ti2AlC/Cu/Ti2C hybrids increased to −54.88 dB and 4.48 GHz, respectively. The improvement of microwave absorption property could be attributed to the enhancement of polarization and conductivity losses caused by the formation of Ti2C MXene and copper nanoparticles. This study provides a simple way to tune the microstructure and microwave absorption capability of Ti2AlC.