Using soft magnetic alloys as the matrix, the structural diversity of rare-earth metal-organic frameworks (RE-MOFs) provide a versatile platform for developing advanced electromagnetic wave (EMW) absorbing materials. In this study, an annealing-induced amorphous-nanocrystalline transformation in FeSiB alloys effectively relieves internal stress and stabilizes the magnetic matrix. Subsequently, a low-conductivity, wrinkled RE-MOF layer is constructed on the alloy surface to regulate dielectric behavior and optimize impedance matching. The abundant heterogeneous interfaces and defect sites introduced by the RE-MOF architecture facilitate interfacial polarization by providing charge accumulation centers at phase boundaries. Meanwhile, the hierarchical and rigid framework of the RE-MOF layer contributes to multiple internal reflections and scattering of incident electromagnetic waves, thereby extending the propagation path and enhancing energy dissipation. At a La-MOF loading of 5 wt%, the composite exhibits a minimum reflection loss (RLmin) of -63.72 dB (13.58 GHz, 1.82 mm), with a bandwidth of 2.93 GHz at RL ≤ -20 dB for a thickness of 1.8 mm. Increasing the La-MOF content to 10 wt%, yielding an RLmin of -56.16 dB (8.565 GHz, 2.63 mm), while the corresponding absorption bandwidth decreases to 1.93 GHz (1.8 mm). These results indicate that the incorporation of rare-earth MOF into the amorphous-nanocrystalline FeSiB matrix effectively enhances microwave attenuation, which is closely associated with the folded MOF microstructure that facilitates repeated scattering and prolongs the propagation path of incident electromagnetic waves.
Dong et al. (Sun,) studied this question.