Laser irradiation behavior of plasma-sprayed tantalum oxide coatings

With the repaid development of laser manufacturing industry, laser protection for optical components, especially high power continuous laser, has been a major concern. Optical coatings should have a good anti-laser ablation property. However, the high-power laser ablation behavior of plasma-sprayed Ta₂O₅ coatings is rarely investigated. In this paper, tantalum oxide coatings were prepared by plasma spraying technique and irradiated using continuous laser with 1070 nm wavelength. The phase structure, ablation surface morphology and reflectivity of the coating were characterized by XRD, SEM, and UV–Visible-near Infrared Spectroscopy. During laser irradiation, the tantalum oxide coatings experience three stages: coating oxidation, micro-cracks occurrence and mechanical failure. A finite-element simulation was also conducted to explore the change of temperature field during irradiation. The simulation results show that the change of reflectivity of tantalum oxide coating during laser irradiation is of great benefit in improving its laser protection ability.