Protective CMAS Coatings for SiC CMCs

TA&T proposes to develop and demonstrate a multi-layer based EBC that exhibits exceptional resistance to both the water vapor laded combustion environment of turbine engines and the external operational environments of molten sand ingestion at 1400oC.Several variants of experimental EBC compositions will be explored based on magnetron sputtered, multilayer hafnium oxide systems with excellent phase stability. Chemical resistance top coats will also be applied.A systematic approach includes the following: deposition on SiC CMC substrates, comprehensive characterization methods-XRD, SEM, EDS-to optimize deposition conditions, coating chemistry and microstructure; elevated isothermal and thermal cycling tests of EBC coated SiC CMC coupons in a 50/50 air/water vapor environment with sand; hot combustion tests of EBC coated SiC CMC bars with sand ingestion to determine and compare their potential for an accelerated Phase 2 program.