Ablation Behavior of Plasma-Sprayed La_1-xSr_xTiO_3+δ Coating Irradiated by High-Intensity Continuous Laser

Laser protection for optical components, particularly those in high-power laser systems, has been a major concern. La_1-xSr_xTiO_3+δ with its good optical and thermal properties can be potentially applied as a high-temperature optical protective coating or high-reflectivity material for optical components. However, the high-power laser ablation behavior of plasma-sprayed La_1-xSr_xTiO_3+δ (x = 0.1) coatings has rarely been investigated. Thus, in this study, laser irradiation experiments were performed to study the effect of high-intensity continuous laser on the ablation behavior of the La_1-xSr_xTiO_3+δ coating. The results show that the La_1-xSr_xTiO_3+δ coating undergoes three ablation stages during laser irradiation: coating oxidation, formation and growth of new structures (columnar and dendritic crystals), and mechanical failure. A finite-element simulation was also conducted to explore the mechanism of the ablation damage to the La_1-xSr_xTiO_3+δ coating and provided a good understanding of the ablation behavior. The apparent ablation characteristics are attributed to the different temperature gradients determined by the reflectivity and thermal diffusivity of the La_1-xSr_xTiO_3+δ coating material, which are critical factors for improving the antilaser ablation property. Now, the stainless steel substrate deposited by it can effectively work as a protective shield layer against ablation by laser irradiation.