Cost effective Fe/NG/PMMA nanocomposites for high-performance microwave absorbing applications

The microwave (MW) absorbing properties of melt-blended iron nanoparticles/exfoliated nanographites/polymethylmethacrylate (Fe/NG/PMMA) nanocomposites (with 1, 2, 3 and 5 wt% of NG) were investigated in 2–18 GHz frequency range. Le Bail refinement of XRD patterns confirmed the formation of α-Fe (bcc) phase in Fe nanoparticles. The average Fe nanoparticle sizes estimated from transmission electron microscopy (TEM) were found to be ∼29 nm. Scanning electron micrographs (SEM) show homogeneous dispersion of NG and Fe nanoparticles in PMMA matrix. The room temperature M-H hysteresis curves of Fe nanoparticles noted the saturation magnetization (Ms) and coercivity (Hc) of ∼196.4 emu g−1 and ∼630 Oe, respectively. The reflection loss (RL), calculated using transmission line theory, reaches −38.8 dB (MW absorption of 99.98%) at 12.6 GHz frequency in Fe/NG(2)/PMMA (with 2 wt% of NG) nanocomposite sample. In addition, the wide-bandwidth of ∼6.3 GHz (in X- and Ku-bands), for RL ≤ −10 dB (90% MW absorption), was attained in Fe/NG(2)/PMMA nanocomposite sample. These results suggested that the excellent MW absorbing properties of as-prepared Fe/NG/PMMA nanocomposites are mainly controlled by dielectric losses, which are introduced through optimized loading of NG in nanocomposite samples.