Abstract Scope |
Rare-earth silicates are excellent candidate materials for environmental barrier coatings in next generation aero turbine engines. Siliceous debris, such as ash and dust, can be ingested into engines and deposits as molten calcium-magnesium aluminosilicate (CMAS) glass on hot section components, degrading them. Single-cation rare-earth monosilicates were exposed to CMAS for 24h at 1300°C in a stagnant air box furnace, and their reactions characterized by SEM and EDS. Monosilicates containing the largest and the smallest rare-earth cations formed the thinnest, most protective reaction product layers, while the middle of the rare-earth series produced thick, low density reaction layers. These results are important for the selection of constituents used in multicomponent silicate coatings, which are designed for enhanced thermal properties in addition to thermochemical stability. |