Fabrication and Electromagnetic Properties of Fe Nanofibers Composites

In order to develop electromagnetic (EM) wave absorbing materials in the giga-hertz (GHz) frequency range, Fe nanofibers have been prepared by multi-nozzle electrospinning process (ESP) and heat treatments. The effects of applied voltage and feed rate on the morphology of electrospun PVP/Fe salt nanofibers have been studied in the electrospinning process. The average diameter and the standard deviation of electrospun nanofibers tend to decrease with the increase of the applied voltage and the decrease of the feed rate, respectively. Through the heat treatments of calcination and H-2 reduction, as-spun PVP/Fe salt has been stepwise transformed into Fe2O3, Fe3O4, and Fe phases. To evaluate the EM characteristic of the prepared Fe nanofibers, epoxy matrix composites containing Fe nanofibers of 10 and 30 wt% have been fabricated. The Fe nanofibers have improved the EM characteristics of composites as compared to those of nano-sized metallic particles.