BILAYER THERMAL BARRIER COATINGS WITH AN ADVANCED INTERFACE

Abstract

A component with a ceramic coating system wherein the component includes a substrate, especially a nickel- or cobalt-based superalloy, a metallic bond coat, especially based on a NiCoCrAl composition, a ceramic coating system with an lower ceramic coating and an upper ceramic coating. An intermediate coating is located between lower coating and upper coating, providing a rougher surface which has a maximum thickness of 25% of the thickness of the lower coating or of the upper coating. The bonding capacity of a ceramic coating system is improved by adapting the coating parameters such as size of the powder and changing of the parameters of the spraying system.

Claims

1. A ceramic coating system for a component comprising a substrate and a metallic bond coat, the coating system comprising: a lower ceramic coating and an upper ceramic coating, and an intermediate coating is located between the lower coating and the upper coating, providing a rougher surface which has a maximum thickness of 25% of the thickness of the lower coating or of the upper coating.

2. The Coating system according to claim 1, wherein the lower coating reveals a finer microstructure than the upper coating.

3. A Method to produce a ceramic coating system according to claim 1, comprising: spraying the lower ceramic coating in order to achieve maximum melting degree, depositing an intermediate coating: either by changing of spraying parameters of the ceramic lower coating during the last pass(es) by adopting colder parameters during the last pass(es) which reduces the melting degree of the particles significantly and particles are deposited semimolten and not as flattened pancakes, leading to an increase significantly in the roughness, or by changing powder for the last pass(es) of the ceramic lower coating by replacing it with coarser particles in order to deposit the last pass(es) on the intermediate coating onto the ceramic lower coating, and finally spraying a fully stabilized ceramic upper coating sprayed with fine powder.

4. The Coating system according to claim 1, wherein the ceramic lower coating is a partially stabilized Zirconia based coating.

5. The Coating system according to claim 1, wherein the ceramic intermediate coating is a partially stabilized Zirconia based coating.

6. The Coating system according to claim 1, wherein the ceramic upper coating is a fully stabilized Zirconia based coating.

7. A component, comprising: a substrate, a metallic bond coat, a ceramic coating system as claimed in claim 1.

8. The component of claim 7, wherein the substrate comprises a nickel- or cobalt-based superalloy.

9. The component of claim 7, wherein the metallic bond coat is based on a NiCoCrAl composition.

10. The method of claim 3, wherein spraying the lower ceramic coating comprises using a fine particles powder.

11. The method of claim 3, wherein the coarser particles are larger than 45 μm.

12. The coating system according to claim 4, wherein the ceramic lower coating is segmented.

13. The coating system according to claim 5, wherein the ceramic intermediate coating is segmented.

14. The coating system according to claim 6, wherein the ceramic upper coating is segmented.

15. The method of claim 3, wherein the ceramic lower coating is a partially stabilized Zirconia based coating; and/or wherein the ceramic intermediate coating is a partially stabilized Zirconia based coating; and/or wherein the ceramic upper coating is a partially stabilized Zirconia based coating.

16. The method of claim 15, wherein the ceramic lower coating is segmented; and/or wherein the ceramic intermediate coating is segmented; and/or wherein the ceramic upper coating is segmented.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The figure shows an inventive component 1.

DETAILED DESCRIPTION OF INVENTION

[0029] The component 1 has especially a metallic substrate 4, which is preferably a nickel or cobalt based superalloy.

[0030] On the metallic substrate 4 there is a metallic bond coat 7, especially on a NiCoCrAl base, means NiCoCrAlY, NiCoCrAlYSi, NiCoCrAlYRe, NiCoCrAlYTa, . . . .

[0031] On top of the metallic bond coat 7 there is the ceramic coating system 16 as described above: a PSZ segmented lower coating 10, a PSZ segmented intermediate coating 11, a FSZ segmented upper coating 13.