Magnetic-dielectric synergistic construction of Ni-doped Ti3AlC2 achieving efficient microwave absorption

Doping can introduce diverse interfaces and optimize impedance matching, making it a significant approach for enhancing the substrate's microwave absorption performance (MAP). Herein, a novel Ni-doped Ti3AlC2 composite (xNi-Ti3AlC2; x = 0, 0.1, 0.2, 0.3) is successfully fabricated using pressureless sintering method. Partial replacement of Al atoms with doped Ni atoms leads to an improvement in permeability. Simultaneously, the substitution of Ni for Al and the formation of metal oxides (such as Al2O3, NiO, etc.) weaken the construction of conductive network, resulting in reduced conductivity and permittivity. The magnetic-dielectric synergistic effect significantly improves the impedance matching of Ti3AlC2. Furthermore, the presence of multiphase interfaces and heightened defects results in an augmentation of both interfacial polarization and dipole polarization. Consequently, the 0.2Ni-Ti3AlC2 demonstrates an outstanding MAP, with a minimum reflection loss (RLmin) of -48.73 dB at 14.33 GHz and an effective absorption bandwidth (reflection loss < -10 dB) of 4.38 GHz (11.43-15.81 GHz) at a thickness of 1.72 mm, surpassing that of Ti3AlC2. Moreover, the 0.1Ni-Ti3AlC2 achieves a RLmin of -65.07 dB, which is 4.24 times that of Ti3AlC2. This study provides a valuable reference for assisting in the design and development of an absorber that capitalizes on magnetic-dielectric synergistic effect.