Enhanced microwave absorption of flaky FeSiAl/ZnO composites fabricated via precipitation

In this study, we investigated the effects of ZnO loading on flaky FeSiAl alloys and assessed their material structure, morphology, magnetism, and microwave absorption characteristics. The structure and morphology indicated a ZnO precipitation limit on the flaky FeSiAl alloy surfaces, and the surface precipitation and mixture were tunable via precipitation technology. The results also indicated that the surface deposition weight ratio of ZnO to FeSiAl should not exceed 2:5, as excessive ZnO deposition resulted in the formation of large ZnO nanoparticles. In addition, nonmagnetic ZnO caused a steady decrease in saturation magnetization from 89.3 to 48.2 emu/g. Following the ideal impedance matching and high dielectric loss, we obtained a minimum reflection loss of −47.85 dB and bandwidth of 3.24 GHz. Compared to conventional oxides coated with flaky FeSiAl, the low density and semiconductor ZnO composites exhibited greatly improved microwave absorption performance for future lightweight and microwave absorption applications.