The Importance of Manufacturing and Spray Process Methods in the Design and Development of Environmental Barrier Coatings:

The ability to design and develop advanced Environmental Barrier Coating (EBC) systems is related to several material and processing related variables. Key requirements for an EBC are the microstructural uniformity and consistency of the coating. This is strongly dependent on material chemistry, manufacturing route and selection of the appropriate thermal spray equipment and parameters. Factors which govern the quality of an EBC are minimal loss of constituent elements and reduced oxidation and phase transformation during coating deposition. In order to produce a state-of-the-art and functional EBC coating, the optimal powder design for each thermal spray process is vital. Coatings with similar feedstock (powder) chemistry can result in significantly different microstructure and properties depending on the selected powder manufacturing method. This study focuses on properties and performance evaluation of various EBC materials using two different processing technologies: Atmospheric Plasma Spray (APS) and Low Pressure Plasma Spray (LPPS). Coating materials to be investigated include: Silicon, Mullite, Ytterbium Disilicate and other emerging EBC bond coats.