Non-Line-of-Sight Coating Of Turbine Airfoils

Advanced thermal barrier coating (TBC) systems are desired for naval gas turbine engines. These coatings will increase the durability of hot-section engine components to significantly improve the time “on-wing”, safety and readiness of these engines. Currently, TBC top coats are applied onto gas turbine engine components primarily using an electron beam physical vapor deposition (EB-PVD) process. This approach is an effective means for applying high quality TBC coatings, however, a key drawback of the process it that it can only effectively coat surfaces that are in the line-of-sight of the component surface. The advent of advanced engine designs containing complex components with many hidden and partially hidden surfaces have resulted in a growing need for TBC deposition techniques which can effectively deposit high quality coatings onto the non line-of-sight regions of these components. The objective of this work is to explore the use of a novel physical vapor deposition coating technique that increases the growth rate of TBC coatings in non light-of-sight (NLOS) regions over that found in the EB-PVD technique and also results in the required coating microstructure.