Laser ablation protection of polymer matrix composites by adhesive inorganic coatings

Further utilization of polymer matrix composites (PMCs) in the aerospace industry is threatened by the development of laser weapons, resulting from weak oxidation resistance, low operation temperature and poor anti-laser ablation performance of the PMCs. Preparing an adhesive inorganic coating on the surface of components is an effective method to improve the laser irradiation resistance. Anti-laser ablation coatings composed of ZrO₂ as pigment and sodium silicate as binder with different curing agents (including SiO₂ and Na₂SiF₆) are fabricated on the PMCs substrate with brush painting. Influence of the different curing agents on anti-laser ablation of the coatings at the laser wavelength of 1064 nm is investigated. The rear surface temperature of substrate with coatings, containing SiO₂ and Na₂SiF₆, decreases from 240 to 60 and 70 °C, respectively, when testing at 1000 W for 5 s. After irradiation test at 1000 W for 10 s, the coating with SiO₂ as curing agent shows slight molten state on the surface, while the coating with Na₂SiF₆ is broke down, because coating containing SiO₂ possesses more compact microstructure and fewer cracks than that with Na₂SiF₆.