Environmental barrier coatings for improved temperature capabilities and longevity
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorsKang N. Lee, Deborah L. Waters
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Abstract
Slurry EBC systems and method for fabricating slurry EBC systems for protecting component substrates and extending the longevity of such components are disclosed. The slurry EBC systems include a bond coat having a temperature capability of up to 1482° C. (2700° F.). Example bond coats include a mullite-based bond coat and a rare earth disilicate-based bond coat.
Claims18
A method of fabricating a slurry environmental barrier coating system comprising:
- fabricating a bond coat comprising:
- preparing a mixture comprising:
- a bond-coat coating material comprising 70 wt %-99 wt % mullite,
- a primary sintering aid comprising 0.1 wt % to 30 wt % Si,
- at least one secondary sintering aid selected from 0.1 wt % to 20 wt % RE2Si2O7, 0.1 wt % to 20 wt % Yb2Si2O7, 0.1 wt % to 20 wt % YAG (Y3Al5O12), 0.1 wt % to 20 wt % YbAG (Yb3Al5O12), 0.1 wt % to 20 wt % Al2O3, and 0.1 wt % to 20 wt % TiO2, or any combination of two or more thereof, and
- a first solvent;
- milling the mixture in a milling media to form a first slurry;
- filtering and drying the first slurry to form a powder of the bond-coat coating material, the primary sintering aid, and the at least one secondary sintering aid;
- mixing the powder with a solution comprising a second solvent and an organic processing aid and milling the resulting mixture to form a second slurry;
- and
- applying the second slurry to a substrate to form the bond coat layer.
A method of fabricating a slurry environmental barrier coating system comprising:
- fabricating a bond coat comprising:
- preparing a mixture comprising:
- a bond-coat coating material comprising 70 wt %-99 wt % RE2Si2O7, a primary sintering aid comprising 1 wt % to 30 wt % Si,
- at least one secondary sintering aid selected from 0.1 to 20 wt % mullite, 0.1 wt % to 20 wt % YAG (Y3Al5O12), 0.1 wt % to 20 wt % YbAG (Yb3Al5O12), 0.1 wt % to 20 wt % Al2O3, and 0.1 wt % to 20 wt % TiO2, or any combination of two or more thereof, and
- a first solvent;
- milling the mixture in a milling media to form a first slurry;
- filtering and drying the first slurry to form a powder of the bond-coat coating material and the primary sintering aid;
- mixing the powder with a solution comprising a second solvent and an organic processing aid and milling the resulting mixture to form a second slurry;
- and
- applying the second slurry to a substrate to form the bond coat layer.
Dependencies are inferred from the claim text.