Fabrication of Yttrium-Aluminum-Garnet:Dysprosium Phosphorescent Coating Using the Aerosol Deposition Technique

Yttrium-Aluminum-Garnet doped with Dysprosium (YAG:Dy) powders and coatings have been used for non-contact, 2-dimensional temperature sensing coatings in extreme environments. The fast response time and thermal/environmental stability of the doped ceramic powder allow for measurements up to 2000K on surfaces such as rapidly rotating turbine components. Current fabrication of YAG:Dy coatings are limited to using paints/epoxies (which reduce maximum temperature due to pyrolysis), or deposition through plasma spray processes (which causes phase change and large tensile stresses/cracking through the coating). Aerosol Deposition (AD) is a relatively new coating process, which mimics the cold spray process, but is conducted in vacuum. The lack of bow shock due to the vacuum allows the use of nano-sized powder, which creates highly dense ceramic coatings. YAG:Dy coatings have been successfully demonstrated on a variety of materials, and preliminary characterization has been conducted. Coatings prepared by AD resulted in better performance compared to standard paint/epoxy methods.