Low-infrared-emissivity Al@SiO2/EPDM composite coating compatible with low dielectric loss and antistatic property

Abstract

Low infrared emissivity coatings have been widely used in many fields. At present, there are few researches on coatings that are compatible with low infrared emissivity and high radar wave transmittance. In this paper, floating aluminum (Al) powdercoated with SiO2 was prepared using tetraethyl orthosilicate (TEOS) as raw material by sol-gel method. The composite coating was prepared using modified Al powder and antistatic carbonaceous fiber (CF) as filler, EPDM as binder. The surface morphology, infrared absorption properties of the modified Al powder and the infrared emissivity, surface resistivity, electromagnetic properties and mechanical properties of the composite coating were analyzed. The results show that with the increase of TEOS addition amount, more SiO2 was covered to the surface of floating Al powder. By adjusting the thickness of the surface modification layer of floating Al powder,the dielectric constant (ε) and dielectric loss tangent values (tanδ) of the composite coating were significantly reduced. When the addition amount of TEOS is 1 g for Al@SiO2, the ε and tanδ can be significantly reduced, and the infrared emissivity was less than 0.6, the tensile strength (σb) and elongation rate at break (e) decreased slightly. This suggests that the composite coating has low infrared emissivity compatible with high radar wave transmittance was obtained, which is expected to be applied to the surface of aircraft radome.