Laser Irradiation Behavior of Plasma-Sprayed Y2SiO5 and Y2Si2O7 Coatings

With the rapid development of laser technology, laser protection for material surfaces has been a major concern. In this paper, Y2SiO5 and Y2Si2O7 coatings were applied to the surface of high-temperature alloy substrates by air plasma spraying and irradiated using high-energy laser. The phase structure, microstructure, element distribution, reflectivity, and chemical state of the coatings were characterized. During laser irradiation, Y2SiO5 and Y2Si2O7 coatings underwent melting and vaporization, and some areas also experienced mechanical spalling. Annealing can reduce the concentration of oxygen vacancy defects within the lattice, increase the reflectivity of the coating, and further enhance the laser protection capability of the coating. The annealed Y2Si2O7 coating showed no damage under 1000 W/cm(2) laser irradiation for 15 seconds, and provided excellent protection for the substrate. Compared to Y2SiO5 coating, Y2Si2O7 coating exhibits superior laser protective capability due to the higher reflectivity and better structural stability.