Electromagnetic wave absorption and infrared camouflage of ordered mesoporous carbon–alumina nanocomposites

Ordered mesoporous C–Al2O3 nanocomposites with different alumina contents were prepared via evaporation-induced triconstituent co-assembly method. As shown by X-ray diffraction (XRD), N2 adsorption–desorption and transmission electron microscopy (TEM), the C–Al2O3 nanocomposites exhibit ordered mesoporous structures, and the results indicate that the carbon as amorphous components in the mesostructured framework can stabilize the ordered mesostructures of the nanocomposites. Furthermore, the electromagnetic wave absorption properties and infrared emissivities of the ordered mesoporous C–Al2O3 nanocomposites were examined systematically. It was observed that the mesoporous nanocomposites have excellent electromagnetic wave absorption properties and low infrared emissivities. For example, the sample with 50 wt.% Al2O3 achieves a maximum reflection loss of −15.3 dB and the bandwidths being lower than −10 dB is 7.4 GHz with a thickness of 3 mm in 0.5–18 GHz, whereas its infrared emissivity can reach 0.46 in the wavelength range from 8 to 14 μm.