Effect of the Dynamic Porous Structure Generation in Laser Irradiated Multi-Functional Coatings

Focusing on solving the adverse laser-inducing damage problem, high-power laser-resistant strategies have attracted more attention. In order to improve the laser-resistant property, a novel dynamic porous structure generation idea for laser irradiation was presented in this study, both of high-reflection and reaction endothermic effects. A detailed investigation on phase structure change, optical properties variation, micro-structure evolution, and substrate temperature development during laser irradiation was performed. The initial reflectivity of two coatings at 1064 nm was high, around 80-90%. During laser irradiation, the reflectivity grew continuously, reaching a maximum of 93%. During laser irradiation, a skeleton porous structure formed, promoted by the endothermic reaction of aluminum tri-hydroxide, whose structure contributes to the heat insulation from surface to interior. Thus, the prepared coating showed excellent anti-laser ablation performance, being dependent on its thermal insulation by the reaction-generated porous structure; high reflectivity by surface; and heat dissipation by endothermic reaction. Under 2000 W/cm², 10 s laser irradiation (spot area is 10 mm × 10 mm), the back-surface temperature is just 159 °C, which is far away from the melting point of aluminum substrate. The coatings and strategy mentioned in this study have a great potential to be applied in the anti-laser field.