Preparation of magnetic iron particle doped expanded graphite and its interaction with millimeter wavelength radiation

Magnetic iron particle-doped expanded graphite was prepared by dipping, stirring and standing an expandable graphite for 5-8 h in ferrocene then expanding at 500°C. The surface morphology and composition of the expanded graphite were characterized by SEM and elemental analysis while the magnetization curves, magnetic susceptibility and the attenuation properties for an 8 mm wavelength electromagnetic signal were characterized by a vibration magnetometer. Results showed that ferric oxide was deposited on the surface of the expanded graphite. The average magnetic intensity of the expanded graphite prepared is higher than 8 emu/g under a magnetic field intensity of 0-7.958 × 10⁵ A/m. The largest attenuation is over -10 dB and its mass extinction coefficient is over 1.0 g/m² in the wave length of military radar, which is better than a current millimeter wave radar shielding material.