Design of polyaniline encapsulated greigite(Fe3S4) microparticles for excellent microwave absorption performance with broad bandwidth and ultrahigh reflection loss

Abstract

Exploring microwave absorption materials with the advantages of wide effective absorption bandwidth, thin thickness, strong absorption capacity and light weight is significant to solving the problems of electromagnetic (EM) irradiation in both military and civil areas. Herein, to make up for the weaknesses of single component Fe3S4 or polyaniline in microwave absorption performance, the composites with extraordinary microwave absorption performance composed of Fe3S4 encapsulated in polyaniline was elaborately designed. The successful synthesis and the microwave absorption mechanisms of Fe3S4@PANI composites were demonstrated by several characterizations. The results indicated that the dielectric constant of the composites can easily be adjusted by the content of PANI in favor of the impedance matching within the frequency range. Therefore, the sample F–P-2 presented the optimum performance, the minimum reflection loss (RLmin) value and broadest effective absorption bandwidth (EAB) respectively reach −63.8 dB at 7.68 GHz and 5.04 GHz (ranging from 12.88 to 17.92 GHz) under 40 wt% loading. Such good performance could be dependent on multiple loss mechanisms, such as the interface and dipole polarization, conduction loss as well as the multiple reflection and scattering. Based on the excellent properties and simple preparation methods, the Fe3S4@PANI composites can be a potential candidate in military and civil microwave absorption field.