Porous Fe@Fe₃O₄-C Nanocomposite Using Polyvinyl Alcohol Sponge as Template for Microwave Absorption

In order to obtain a material with excellent microwave absorption performance, polyvinyl alcohol (PVA) sponge was employed as the template. The porous structure of the sponge can facilitate faster and more uniform diffusion of the ferric nitrate liquid during the dipping and obtain a uniform distribution of the ferromagnetic particles, which serves as a functional phase to enhance the microwave absorption properties. The Fe@Fe3O4-C nanocomposite can then be fabricated through a dipping/carbonization process. The special core-shell structure effectively improves the dielectric and magnetic loss and provides proper impedance matching. The results indicate that the prepared samples show excellent microwave absorption performance, with maximum effective absorption bandwidth up to 7.9 GHz at a thickness of 2.27 mm. The maximum reflection loss can reach -48.36 dB at 9.6 GHz. Therefore, it is feasible to use PVA sponge as a template to fabricate porous Fe@Fe3O4-C nanocomposite with excellent microwave absorption performance.