Development and Evaluation of Environmental Barrier Coatings for Si-based Ceramics

摘要

Environmental barrier coatings (EBCs) are being developed for silicon carbide (SiC) based composites and monolithic silicon nitride (Si_3N_4) to protect against the accelerated oxidation and subsequent silica volatilization in high temperature, high-pressure steam environments encountered in gas turbine engines. While EBCs for silicon carbide (EBC_(SiC)) have been demonstrated in combustor liner applications, efforts are ongoing in the development of EBC systems for silicon nitride (EBC_(SiN))- The challenges of adapting EBC_(SiC) to monolithic Si_3N_4 are discussed in this paper. Progress in the area of EBC_(SiN) including development and performance during field tests and tests simulating engine conditions are reviewed.