Preparation and infrared/millimeter wave attenuation properties of magnetic expanded graphite by explosive combustion

A composite based on magnetic iron particles and expanded graphite was prepared by an explosive combustion and blending method. It was then introduced into a smoke canister, and colloidal silicone rubber (RTV-615) was used as an infrared and millimeter wave absorber. The infrared shielding effectiveness was investigated by measuring the thermal extinction using the smoke canister for dynamic testing with a thermal imager in the 8-12 μm range. The millimeter wave absorbing properties were investigated by measuring the transmission loss in the 32-38 GHz microwave frequency range with a network analyzer using the free space method. The effects of structure, media material type (carbonyl iron powder and Fe3O4 and weight ratio on the infrared/millimeter wave attenuation properties of magnetic expanded graphite were also studied. The results showed that the magnetic expanded graphite had excellent infrared (8-12 μm) and millimeter wave (35 GHz) interference abilities and could be used as a new material for obscuring infrared and millimeter waves. For magnetic expanded graphite with a concentration of 2 mg/cm3, the thermal extinction reached 31 °C, and at a weight ratio (expanded graphite:magnetic iron particles) of 2:1 (3 mg/cm3 and a thickness of 1.5 mm, the minimum transmission loss value was -10.8 dB in the 32-38 GHz range.