Structural Modifications and Electromagnetic Property Regulations of Ti3AlC2 MAX for Enhancing Microwave Absorption through the Strategy of Fe Doping

Microwave absorption enhancements through atomic doping in traditional materials remain a significant challenge. Herein, the MAX phase materials of Fe-doped Ti3AlC2 (xFe-Ti3AlC2, abbreviated as TFAC-x, x = 0, 0.2, 0.3, 0.4) are synthesized via solid-phase reaction method. The X-ray diffraction, Raman, and scanning electron microscopy confirm that the TFAC-x samples are of high quality with multiphase coexistence structure and abundant interfaces. Relying on the improved impedance matching originating from structural modulation, the synergistic effects of dielectric loss and magnetic loss, as well as the enhanced interfacial polarization and defect dipole polarization, both the microwave absorption intensity and bandwidth are greatly strengthened. Accordingly, the minimum reflection loss of TFAC-3 sample can achieve -33.3 dB and the absorption bandwidth could reach 3.9 GHz with the thickness of only 1.5 mm. Moreover, the investigated frequency can cover 86% through regulating their thickness from 1.5 to 5 mm, showing the excellent frequency modulation effect. The revealed improvements in both the microwave absorption performance and properties of TFAC-x may enlighten the designing of microwave absorption materials and have potentials for widespread applications.