Bond coat including metal oxides and oxygen getters
Coated components and their methods of formation are provided. The coated component includes: a ceramic matrix composite substrate comprising silicon carbide and having a surface; a bond coat on the surface of the substrate; and an environmental barrier coating on the bond coat. The bond coat includes a plurality of discrete particles dispersed within a matrix phase that includes mullite. The plurality of discrete particles includes an oxygen getter and a transition metal oxide.
1. A coated component, comprising:
a ceramic matrix composite substrate comprising silicon carbide and having a surface;
a bond coat on the surface of the ceramic matrix composite substrate, wherein the bond coat comprises a plurality of discrete particles dispersed within a matrix phase, wherein the plurality of discrete particles comprises an oxygen getter and a transition metal oxide in the form of an aluminate-transition metal oxide complex, and wherein the matrix phase comprises mullite; and
an environmental barrier coating on the bond coat.
2. The coated component as in claim 1 , wherein the transition metal oxide comprises Y 2 O 3 , Lu 2 O 3 , Sc 2 O 3 , TiO 2 , Ta 2 O 5 , La 2 O 3 , CeO 2 , or mixtures thereof.
3. The coated component as in claim 1 , wherein the bond coat includes 0.1% by weight to 10% by weight of the transition metal oxide.
4. The coated component as in claim 1 , wherein the bond coat has a porosity that is less than 15%.
5. The coated component as in claim 1 , wherein the oxygen getter forms first discrete particles in the plurality of discrete particles and the transition metal oxide forms second discrete particles in the plurality of discrete particles.
6. The coated component as in claim 1 , wherein the oxygen getter comprises elemental silicon, a silicon alloy, a silicide, or a mixture thereof.
7. The coated component as in claim 1 , wherein the oxygen getter comprises elemental silicon.
8. The coated component as in claim 1 , wherein the bond coat includes 1% by weight to 30% by weight of the oxygen getter.
9. The coated component as in claim 1 , wherein the matrix phase is a continuous phase, and wherein the matrix phase spans the bond coat and bonds directly to the surface of the ceramic matrix composite substrate and to an inner surface of the environmental barrier coating.
10. The coated component as in claim 1 , wherein the matrix phase defines 60% to 98% by volume of the bond coat.
11. The coated component as in claim 1 , wherein the matrix phase defines 65% to 96% by volume of the bond coat.
12. The coated component as in claim 1 , wherein the matrix phase defines 75% to 95% by volume of the bond coat.
13. The coated component as in claim 1 , wherein the matrix phase consists essentially of mullite.
14. The coated component as in claim 1 , wherein the environmental barrier coating comprises a plurality of layers with at least one of the layers of the environmental barrier coating comprises a hermetic layer.
15. The coated component as in claim 14 , wherein the hermetic layer is adjacent to the bond coat such that the hermetic layer defines an inner surface of the environmental barrier coating.
16. The coated component as in claim 1 , wherein the bond coat is configured to withstand exposure to operating temperatures of 1475° C. to 1650° C.
17. The coated component as in claim 1 , wherein the environmental barrier coating comprises a hafnia layer, an alumina layer, or both.
18. The coated component as in claim 1 , wherein the environmental barrier coating comprises a rare earth disilicate layer, a rare earth monosilicate layer, or both.
19. A method of forming a coated component, the method comprising:
forming a bond coat on a surface of a substrate, wherein the bond coat comprises a plurality of discrete particles dispersed within a matrix phase, wherein the plurality of discrete particles comprises an oxygen getter and a transition metal oxide in the form of an aluminate-transition metal oxide complex, and wherein the matrix phase comprises mullite; and
forming an environmental barrier coating on the bond coat such that the plurality of discrete particles, when melted, are contained within matrix phase between the surface of the substrate and an inner surface of the environmental barrier coating.
20. The method as in claim 19 , wherein the transition metal oxide comprises Y 2 O 3 , Lu 2 O 3 , Sc 2 O 3 , TiO 2 , Ta 2 O 5 , La 2 O 3 , CeO 2 , or mixtures thereof.