Claims
- 1. An article having a metallic substrate and a ceramic thermal barrier layer including a mixed metal oxide system comprising a compound selected from the group consisting of (i) a lanthanum aluminate and (ii) a calcium zirconate, the calcium in which is partially replaced by at least one calcium-substitute element.
- 2. An article according to claim 1, wherein the lanthanum in said lanthanum aluminate is partially replaced by at least one lanthanum-substitute element.
- 3. An article according to claim 2, wherein said lanthanum-substitute element is from the lanthanide group.
- 4. An article according to claim 2, wherein said lanthanum-substitute element is gadolinium (Gd).
- 5. An article according to claim 1, wherein said lanthanum aluminate has the formula La1−xMxAl1−yNyO3, M being a substitute element for lanthanum in said lanthanum aluminate, x being a substitution factor for M, N being a substitute element for aluminum in said lanthanum aluminate, and y being a substitution factor for N.
- 6. An article according to claim 5, wherein M is from the lanthanide group and x is between 0 and 0.8.
- 7. An article according to claim 5, wherein M is gadolinium (Gd) and x is about 0.5.
- 8. An article according to claim 1, wherein said calcium-substitute element is one of strontium (Sr) and barium (Ba).
- 9. An article according to claim 1, wherein said calcium zirconate has the formula Ca1−xSrxZr1−yMyO3, x being a substitute factor for calcium in said calcium zirconate, M being a substitute element for zirconium in said calcium zirconate, and y being a substitution factor for M.
- 10. An article according to claim 9, wherein x is between 0 and 0.8.
- 11. An article according to claim 10, wherein x is about 0.5.
- 12. An article according to claim 11, wherein M is selected from the group comprising titanium (Ti) and hafnium (Hf).
- 13. An article according to any one of claims 1 to 4 and 8, wherein said mixed metal oxide system includes an additional oxide.
- 14. An article according to claim 1, further including an adhesion promotion layer forming a bonding oxide between said substrate and said ceramic thermal barrier layer.
- 15. An article according to claim 1, wherein said adhesion promotion layer comprises an alloy including at least one element in said mixed metal oxide system.
- 16. An article according to claim 1, wherein said metallic substrate comprises one of a nickel-based superalloy, a cobalt-based superalloy and a chromium-based superalloy.
- 17. An article according to claim 16, wherein said article is a component of an internal combustion engine.
- 18. An article according to claim 17, wherein said article is a one of a turbine blade, a guide vane and a heat shield element for a gas turbine engine.
- 19. An article according to claim 18, wherein the lanthanum in said lanthanum aluminate is partially replaced by gadolinium (Gd) and said calcium-substitute element is one of strontium (Sr) and barium (Ba).
- 20. An article according claim 19, wherein a coefficient of thermal expansion of said ceramic thermal barrier layer is between 7×10−6/K and 17×10−6/K.
- 21. An article according claim 19, wherein a thermal conductivity of said ceramic thermal barrier layer is between 1.0 W/mK and 4.0 W/mK.
- 22. A process for producing a thermal barrier layer on an article comprising a substrate for accepting said thermal barrier layer, said process comprising the steps of:
providing a pre-reacted mixed metal oxide system comprising a compound selected from the group consisting of (i) a lanthanum aluminate and (ii) a calcium zirconate, the calcium in which is partially replaced by at least one calcium-substitute element; and applying said pre-reacted metal oxide system to said substrate by one of plasma spraying and an evaporation coating process.
- 23. A process according to claim 22, wherein said calcium-substitute element is strontium (Sr).
Priority Claims (1)
Number |
Date |
Country |
Kind |
197 48 508.1 |
Nov 1997 |
DE |
|
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International Application PCT/DE98/03205, with an international filing date of Nov. 3, 1998, now abandoned.
Divisions (1)
|
Number |
Date |
Country |
Parent |
09562877 |
May 2000 |
US |
Child |
10187504 |
Jul 2002 |
US |
Continuations (1)
|
Number |
Date |
Country |
Parent |
PCT/DE98/03205 |
Nov 1998 |
US |
Child |
09562877 |
May 2000 |
US |