Verification of an EBC’s Protective Capability by First-Stage Evaluation in a High Temperature, High-Pressure Furnace

High-temperature, high-pressure exposure furnaces (commonly referred to as Keiser Rigs) have been used successfully to evaluate the ability of environmental barrier coatings (EBCs) on continuous fiber-reinforced ceramic matrix composites and monolithic Si3N4 to protect the underlying substrate at high temperatures and H2O pressures. The ORNL rig provides for a relatively inexpensive way to conduct high sample throughput, first-stage evaluation of an EBCs protective capability on small ceramic specimens under a range of temperatures, pressures, and H2O contents. The exposure of the EBCs in the Keiser Rig is coupled with extensive microstructural analysis to evaluate EBC failure and degradation mechanisms.