ABRADABLE LAYER INCLUDING A RARE EARTH SILICATE

• US 20100129636A1
• Filed: 11/24/2009
• Published: 05/27/2010
• Est. Priority Date: 11/25/2008
• Status: Active Grant

• Current Assignee: Rolls-Royce Corporation (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce Corporation (Rolls-Royce Holdings Plc)
• Inventors: Sinatra, Raymond J., Cybulsky, Michael, Lee, Kang N.
• Granted Patent: US 8,124,252 B2
• Time in Patent Office: Days
• US Class Current: 428/310.500
• CPC Class Codes: C04B 35/00 Shaped ceramic products characterised by their composition porous ceramic products C04B38/00; ceramic articles characterised by particular shape, see the relevant classes, e.g. linings for casting ladles, tundishes, cups or the like B22D41/02; ceramic substrates for microelectronic semi-conductors H01L23/15; Ceramics compositions containing free metal bonded to carbides, diamond, oxides, borides, nitrides, silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides or sulfides other than as macroscopic reinforcing agents C22C; shaping of ceramics B28B; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products chemical preparation of powders of inorganic compounds C01; infiltration of sintered ceramic preforms with molten metal C04B41/51
• CPC Class Codes: C04B 35/565 based on silicon carbide
• CPC Class Codes: C04B 35/584 based on silicon nitride
• CPC Class Codes: C04B 35/806 The matrix of the ceramic products consisting of non-oxides only
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4527 Plasma spraying deposition from the gas phase using plasma C04B41/4533
• CPC Class Codes: C04B 41/5024 Silicates C04B41/5022 takes precedence; silico-fluorides C04B41/5018
• CPC Class Codes: C04B 41/5042 Zirconium oxides or zirconates; Hafnium oxides or hafnates
• CPC Class Codes: C04B 41/5096 Silicon C04B35/573 takes precedence
• CPC Class Codes: C04B 41/52 Multiple coating or impregnating multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation
• CPC Class Codes: C04B 41/89 for obtaining at least two superposed coatings having different compositions
• CPC Class Codes: C23C 28/042 including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides
• CPC Class Codes: C23C 28/42 characterized by the composition of the alternating layers
• CPC Class Codes: C23C 30/00 Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process C23C26/00, C23C28/00 take precedence
• CPC Class Codes: C23C 4/11 Oxides
• CPC Class Codes: F01D 11/122 with erodable or abradable material blades having cutting or grinding tips F01D5/20
• CPC Class Codes: F01D 5/288 Protective coatings for blades
• CPC Class Codes: F05D 2230/31 Layer deposition
• CPC Class Codes: F05D 2300/211 Silica
• CPC Class Codes: Y10T 428/249953 Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/249961 : With gradual property change within a component

Abstract

An abradable coating may include a rare earth silicate. The abradable coating may be deposited over a substrate, an environmental barrier coating, or a thermal barrier coating. The abradable coating may be deposited on a gas turbine blade track or a gas turbine blade shroud to form a seal between the gas turbine blade track or gas turbine blade shroud and a gas turbine blade. The abradable coating may also include a plurality of layers, such as alternating first and second layers including, respectively, a rare earth silicate and stabilized zirconia or stabilized hafnia.

Claims

1. A multilayer environmental barrier coating and abradable system comprising:

an environmental barrier coating (EBC); and

an abradable coating deposited over the EBC, wherein the abradable coating comprises a rare earth silicate.

2. The multilayer environmental barrier coating and abradable system of claim 1, wherein the EBC comprises a rare earth silicate.

3. The multilayer environmental barrier coating and abradable system of claim 1, wherein the abradable coating comprises at least one of RE₂SiO₅ and RE₂Si₂O₇, and wherein RE is a rare earth element.

4. The multilayer environmental barrier coating and abradable system of claim 3, wherein the rare earth element comprises at least one of Lu, Yb, Tm, Er, Ho, Dy, Tb, Gd, Eu, Sm, Pm, Nd, Pr, Ce, La, Y, and Sc.

5. The multilayer environmental barrier coating and abradable system of claim 1, wherein the rare earth silicate comprises a silicate of at least one of Lu, Yb, Tm, Er, Ho, Dy, Tb, Gd, Eu, Sm, Pm, Nd, Pr, Ce, La, Y, and Sc.

6. The multilayer environmental barrier coating and abradable system of claim 1, wherein the abradable coating further comprises an oxide of at least one of Lu, Yb, Tm, Er, Ho, Dy, Tb, Gd, Eu, Sm, Pm, Nd, Pr, Ce, La, Y, and Sc.

7. The multilayer environmental barrier coating and abradable system of claim 1, wherein the abradable coating further comprises silica.

8. The multilayer environmental barrier coating and abradable system of claim 1, wherein the abradable coating further comprises at least one of alumina, Ta₂O₅, HfSiO₄, an alkali oxide, and an alkali earth oxide.

9. The multilayer environmental barrier coating and abradable system of claim 1, wherein the abradable coating comprises pores.

10. The multilayer environmental barrier coating and abradable system of claim 9, wherein the abradable coating comprises a first surface adjacent the EBC and a second surface opposite the EBC, and wherein a first porosity of the abradable coating proximate the first surface is different from a second porosity of the abradable coating proximate the second surface.

11. The multilayer environmental barrier coating and abradable system of claim 1, wherein the abradable coating comprises a first layer and a second layer.

12. The multilayer environmental barrier coating and abradable system of claim 11, wherein the first layer comprises a silicate of at least one of Lu, Yb, Tm, Er, Ho, Dy, Tb, Gd, Eu, Sm, Pm, Nd, Pr, Ce, La, Y, and Sc, and wherein the second layer comprises at least one of stabilized zirconia and stabilized hafnia.

13. An article comprising:

a substrate; and

an abradable coating deposited over the substrate, wherein the abradable coating comprises a rare earth silicate.

14. The article of claim 13, wherein the abradable coating is deposited directly on the substrate.

15. The article of claim 13, further comprising a bond coat, and wherein the abradable coating is deposited over the bond coat.

16. The article of claim 13, wherein the substrate comprises a ceramic matrix composite (CMC).

17. The article of claim 16, further comprising an environmental barrier coating (EBC) deposited over the substrate.

18. The article of claim 17, wherein the EBC comprises a rare earth silicate.

19. The article of claim 13, further comprising a thermal barrier coating deposited over the substrate.

20. The article of claim 19, wherein the substrate comprises a superalloy.

21. The article of claim 13, wherein the substrate comprises a superalloy.

22. The article of claim 13, further comprising a thermal barrier coating deposited over the substrate and an environmental barrier coating deposited over the substrate, wherein the abradable coating is deposited over the thermal barrier coating and the environmental barrier coating.

23. The article of claim 22, wherein the thermal barrier coating is deposited over the environmental barrier coating and wherein the abradable coating is deposited over the thermal barrier coating.

24. The article of claim 13, wherein the abradable coating comprises at least one of RE₂SiO₅ and RE₂Si₂O₇, and wherein RE is a rare earth element.

25. The article of claim 24, wherein the rare earth element comprises at least one of Lu, Yb, Tm, Er, Ho, Dy, Tb, Gd, Eu, Sm, Pm, Nd, Pr, Ce, La, Y, and Sc.

26. The article of claim 13, wherein the rare earth silicate comprises a silicate of at least one of Lu, Yb, Tm, Er, Ho, Dy, Tb, Gd, Eu, Sm, Pm, Nd, Pr, Ce, La, Y, and Sc.

27. The article of claim 13, wherein the abradable coating further comprises an oxide of at least one of Lu, Yb, Tm, Er, Ho, Dy, Tb, Gd, Eu, Sm, Pm, Nd, Pr, Ce, La, Y, and Sc.

28. The article of claim 13, wherein the abradable coating further comprises silica.

29. The article of claim 13, wherein the abradable coating further comprises at least one of alumina, Ta₂O₅, HfSiO₄, an alkali oxide, and an alkali earth oxide.

30. The article of claim 13, wherein the abradable coating comprises pores.

31. The article of claim 30, wherein the abradable coating comprises a first surface adjacent the EBC and a second surface opposite the EBC, and wherein a first porosity of the abradable coating proximate the first surface is different from a second porosity of the abradable coating proximate the second surface.

32. The article of claim 13, wherein the abradable coating comprises a first layer and a second layer.

33. The article of claim 13, wherein the first layer comprises a silicate of at least one of Lu, Yb, Tm, Er, Ho, Dy, Tb, Gd, Eu, Sm, Pm, Nd, Pr, Ce, La, Y, and Sc, and wherein the second layer comprises at least one of stabilized zirconia and stabilized hafnia.

34. The article of claim 13, wherein the article comprises a turbine blade track.

35. The article of claim 13, wherein the article comprises a turbine shroud.

36. A method comprising:

depositing over a substrate an abradable coating comprising a rare earth silicate.

37. The method of claim 36, wherein depositing over the substrate the abradable coating comprises depositing over the substrate a porous abradable coating.

38. The method of claim 37, wherein the porous abradable coating comprises a first surface adjacent the substrate and a second surface opposite the substrate, and wherein a first porosity of the porous abradable coating proximate the first surface is different from a second porosity of the porous abradable coating proximate the second surface.

39. The method of claim 36, wherein depositing over the substrate the abradable coating comprises thermal spraying over the substrate the abradable coating comprising a rare earth silicate and a coating material additive.

40. The method of claim 39, wherein the coating material additive comprises at least one of graphite, hexagonal boron nitride, and a polymer.

41. The method of claim 40, wherein the coating material additive comprises polyester.

42. The method of claim 39, further comprising subjecting the abradable coating to a heat treatment.

43. The method of claim 42, wherein subjecting the abradable coating to the heat treatment at least one of burns and melts the coating material additive to form pores in the abradable coating.

44. The method of claim 36, further comprising depositing over the substrate an environmental barrier coating (EBC), and wherein depositing over the substrate the abradable layer comprises depositing over the EBC the abradable layer.

45. The method of claim 44, further comprising depositing over the substrate a bond coat, and wherein depositing over the substrate the EBC comprises depositing the EBC over the bond coat.

46. The method of claim 36, further comprising depositing over the substrate a thermal barrier coating (TBC), and wherein depositing over the substrate the abradable layer comprises depositing over the TBC the abradable layer.

47. The method of claim 46, further comprising depositing over the substrate a bond coat, and wherein depositing over the substrate the TBC comprises depositing over the bond coat the EBC.

48. The method of claim 36, further comprising depositing over the substrate a bond coat, and wherein depositing over the substrate the abradable layer comprises depositing over the bond coat the abradable layer.