Silver-modified chromium(III) oxide as multi-band compatible stealth materials for visual/ infrared stealth and radar wave transmission

Here we proposed a strategy of modifying colored pigments with low emissivity materials to develop multi-band compatible stealth materials. The silver-modified Cr2O3 particles were first prepared for achieving visual/infrared stealth and radar wave transmission simultaneously. The electrical conductivity increased significantly and the emissivity reduced effectively of Cr2O3@Ag hybrid powders with the increase of Ag content. By employing silicone resin as the binder, and Cr2O3@Ag (X mol·L−1) as the filler, coatings were prepared to investigate the stealth performance. The coating with 65 wt% Cr2O3@Ag (0.2 mol⋅L−1) content achieved the lowest emissivity of 0.760. Particularly, the complex permittivity increased slowly and the transmittance was over 90% at the coating thickness within 0.3 mm. The high transmittance of radar waves is attributed to the good impedance matching between Cr2O3 and free space, along with the space between the Ag particles. Additionally, the brownish-green Cr2O3@Ag pigment showed a lower visible-near infrared reflectance than pure Cr2O3. The proposed method provides an idea for the design of colored coating with low emissivity and high radar wave transmission for application in stealth technology.