Coating for improved surface finish
A ceramic matrix composite (CMC) component includes at least one seal surface, the at least one seal surface disposed adjacent an interfacing surface for providing a seal therebetween; and a coating disposed on the seal surface. The coating includes an aluminum oxide and/or a silicon dioxide.
1. A ceramic matrix composite (CMC) component comprising:
at least one seal surface, the at least one seal surface disposed adjacent an interfacing surface for providing a seal therebetween; and
a coating disposed on the at least one seal surface,
wherein the coating comprises an aluminum oxide, a silicon dioxide, and at least 10% by mass of yttrium oxide, wherein the coating comprises by mass at least 10% of the aluminum oxide and at least 50% of the silicon dioxide.
2. The ceramic matrix composite (CMC) component of claim 1 , wherein the coating comprises a surface finish with a roughness average between about 10 microinches and about 150 microinches.
3. The ceramic matrix composite (CMC) component of claim 1 , wherein the coating comprises a softening point greater than about 1200° C.
4. The ceramic matrix composite (CMC) component of claim 1 , wherein the coating comprises a coefficient of thermal expansion equal to or less than about 8.0 (×10{circumflex over ( )}−6/(° C.)).
5. The ceramic matrix composite (CMC) component of claim 1 , wherein the CMC component further comprises a coefficient of thermal expansion equal to or less than about 8.0 (×10{circumflex over ( )}−6/(° C.)).
6. The ceramic matrix composite (CMC) component of claim 1 , wherein the CMC component further comprises a coefficient of thermal expansion that is within about 50% of a coefficient of thermal expansion of the coating.
7. The ceramic matrix composite (CMC) component of claim 6 , wherein the CMC component further comprises a coefficient of thermal expansion that is within about 20% of a coefficient of thermal expansion of the coating.
8. The ceramic matrix composite (CMC) component of claim 1 , wherein the coating comprises by mass at least 15% yttrium oxide.
9. The ceramic matrix composite (CMC) component of claim 1 , wherein the coating further comprises barium oxide.
10. The CMC component of claim 8 , wherein the coating comprises by mass about 20% yttrium oxide.
11. The CMC component of claim 1 , wherein the coating comprises by mass:
from about 12% to about 22% of the aluminum oxide;
from about 51% to about 63% of the silicon dioxide; and
from about 14% to about 28% yttrium oxide.
12. The CMC component of claim 11 , wherein the coating further comprises barium oxide.
13. The CMC component of claim 12 , wherein the coating further comprises by mass from about 3% to about 7% barium oxide.
14. The CMC component of claim 1 , wherein the aluminum oxide and the silicon dioxide are each included in:
a first material system including by mass from about 50% to about 59% of the silicon dioxide, from about 13% to about 23% of the aluminum oxide, and from about 22% to about 33% yttrium oxide, and
a second material system including by mass from about 10% to about 18% of the aluminum oxide, from about 61% to about 72% of the silicon dioxide, and further including from about 15% to about 25% barium oxide.
15. The CMC component of claim 14 , wherein the coating comprises the first material system in a range of from about 65% to about 85% and the second material system in a range of from about 15% to about 35%.
16. The CMC component of claim 15 , wherein the coating comprises by mass about 70% of the first material system and about 30% of the second material system.
17. The CMC component of claim 15 , wherein the coating comprises by mass about 80% of the first material system and about 20% of the second material system.
18. A gas turbine comprising:
a compressor section;
a combustor section fluidly coupled downstream of the compressor section;
a turbine section fluidly coupled downstream of the combustor section; and
a ceramic matrix composite (CMC) component, the CMC component comprising:
at least one seal surface, the at least one seal surface disposed adjacent an interfacing surface for providing a seal therebetween; and
a coating disposed on the at least one seal surface,
wherein the coating comprises an aluminum oxide and a silicon dioxide each included in:
a first material system including by mass from about 49% to about 59% of the silicon dioxide, from about 13% to about 23% of the aluminum oxide, and at least 20% yttrium oxide; and
a second material system including by mass from about 8% to about 18% of the aluminum oxide, from about 61% to about 72% of the silicon dioxide, and at least 15% barium oxide.
19. The gas turbine of claim 18 , wherein the ceramic matrix composite (CMC) component is a component of the hot section of the gas turbine.
20. The gas turbine of claim 18 , wherein the at least one surface of the ceramic matrix composite (CMC) component is at least one of a transition piece, a combustor liner, a first stage turbine nozzle, a second stage turbine nozzle, a flow-path duct, a shroud slash face, a shroud segment forward edge, a shroud segment aft edge, a shroud hot gas surface, an airfoil platform forward edge, an airfoil platform aft edge, and an airfoil platform circumferential edge.
21. The gas turbine of claim 18 , wherein the second material system includes by mass about 20% barium oxide.
22. The gas turbine of claim 18 , wherein the first material system includes about 28% yttrium oxide.