Simple and efficient preparation high-performance magnetic carbon-based nanocomposites as electromagnetic wave-absorbing materials is a research hotspot. Here, employing a straightforward, ecologically friendly, and effective solid-state technique, FeCo/graphene nanocomposites with good electromagnetic wave absorption capabilities were successfully fabricated without the use of any external carbon sources. m-NaCl powder is combined with Co(acac)2 and Fe(acac)3 and then annealed at a particular temperature. During the annealing process, FeCo nanoparticles were synthesized and supported on graphene nanocomposites. Following annealing at 700 °C, the material showed an ideal reflection loss of −71.63 dB at 10.8 GHz, an effective bandwidth of 4.24 GHz, and a thickness of 2.68 mm. The radar cross section (RCS) of FeCo/C-700 is less than −10 dB m2, which provides evidence that the samples have good radar wave attenuation capabilities when the scattering angle is between 0 and 60°. The approach for creating graphene composites with FeCo nanoparticles suggested in this study serves as a crucial source of inspiration for the later development of new magnetic carbon nanocomposite systems.

L10 ordered FePt and FePtCu nanoparticles (NPs) with a good dispersion were successfully fabricated by a simple, green, one-step solid-phase reduction method. Fe (acac)3, Pt (acac)2, and CuO as the precursors were dispersed in NaCl and annealed at different temperatures with an H2-containing atmosphere. As the annealing temperature increased, the chemical order parameter (S), average particle size (D), coercivity (Hc), and saturation magnetization (Ms) of FePt and FePtCu NPs increased and the size distribution range of the particles became wider. The ordered degree, D, Hc, and Ms of FePt NPs were greatly improved by adding 5% Cu. The highest S, D, Hc, and Ms were obtained when FePtCu NPs annealed at 750 °C, which were 0.91, 4.87 nm, 12,200 Oe, and 23.38 emu/g, respectively. The structure and magnetic properties of FePt and FePtCu NPs at different annealing temperatures were investigated and the formation mechanism of FePt and FePtCu NPs were discussed in detail.