METHODS OF REPAIRING A THERMAL BARRIER COATING OF A GAS TURBINE COMPONENT AND THE RESULTING COMPONENTS

• US 20170122561A1
• Filed: 10/28/2015
• Published: 05/04/2017
• Est. Priority Date: 10/28/2015
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Nagaraj, Bangalore Aswatha
• Application Number:
  US14/925,288
• Publication Number:
  US 20170122561A1
• Time in Patent Office: Days
• CPC Class Codes: C23C 16/44 characterised by the method of coating C23C16/04 takes precedence
• CPC Class Codes: C23C 28/022 with at least one MCrAlX layer
• CPC Class Codes: C23C 28/028 Including graded layers in composition or in physical properties, e.g. density, porosity, grain size
• CPC Class Codes: C23C 28/3215 at least one MCrAlX layer
• CPC Class Codes: C23C 28/325 with layers graded in composition or in physical properties
• CPC Class Codes: C23C 28/36 including layers graded in composition or physical properties
• CPC Class Codes: C23C 4/073 containing MCrAl or MCrAlY alloys, where M is nickel, cobalt or iron, with or without non-metal elements
• CPC Class Codes: C23C 4/10 Oxides, borides, carbides, nitrides or silicides; Mixtures thereof
• CPC Class Codes: C23C 4/12 characterised by the method of spraying
• CPC Class Codes: C23C 4/134 Plasma spraying
• CPC Class Codes: F01D 5/005 Repairing methods or devices
• CPC Class Codes: F01D 5/288 Protective coatings for blades
• CPC Class Codes: F02C 7/24 Heat or noise insulation air intakes having provisions for noise suppression F02C7/045; turbine exhaust heads, chambers, or the like F01D25/30; silencing nozzles of jet-propulsion plants F02K1/00
• CPC Class Codes: F05D 2220/32 in gas turbines
• CPC Class Codes: F05D 2230/80 Repairing, retrofitting or upgrading methods
• CPC Class Codes: F05D 2240/35 Combustors or associated equipment
• CPC Class Codes: F05D 2260/231 Preventing heat transfer
• CPC Class Codes: F05D 2300/1723 Nickel-Copper alloy, e.g. Monel
• CPC Class Codes: F05D 2300/177 Ni - Si alloys
• CPC Class Codes: F23R 3/002 Wall structures F23R3/02 and F23R3/007 take precedence
• CPC Class Codes: Y02T 50/60 : Efficient propulsion technologies, e.g. for aircraft

Abstract

Turbine engine components are provided that have a repaired thermal barrier coating, along with their methods of formation and repair. The turbine engine component includes a thermal barrier coating on a first portion of a surface of a substrate; a repaired thermal barrier coating on a second portion of the surface of the substrate; and a ceramic coat on the outer bond coat. The thermal barrier coating includes an inner bonding layer and a first ceramic layer, with the inner bonding layer being positioned between the substrate and the first ceramic layer. The repaired thermal barrier coating generally includes an inner bond coat on the surface of the substrate and an outer bond coat on the inner bond coat. The inner bond coat is formed from a cobalt-containing material, while the outer bond coat is substantially free from cobalt.

Claims

1. A turbine engine component having a repaired thermal barrier coating, the turbine engine component comprising:

a substrate defining a surface;

a thermal barrier coating on a first portion of the surface of the substrate, wherein the thermal barrier coating comprises an inner bonding layer and a first ceramic layer, and wherein the inner bonding layer is positioned between the substrate and the first ceramic layer;

a repaired thermal barrier coating on a second portion of the surface of the substrate, wherein the repaired thermal barrier coating comprises;

an inner bond coat on the surface of the substrate, wherein the inner bond coat comprises a cobalt-containing material;

an outer bond coat on the inner bond coat, wherein the outer bond coat is substantially free from cobalt; and

a ceramic coat on the outer bond coat.

2. The turbine engine component as in claim 1, wherein the repaired thermal barrier coating further comprises:

an inner bonding layer positioned between the surface of the substrate and the inner bond coat.

3. The turbine engine component as in claim 1, wherein the inner bond coat has a porosity that is about 5% or less, and wherein the outer bond coat has a porosity that is greater than about 5%

4. The turbine engine component as in claim 1, wherein the inner bond coat has a sulfur diffusion rate that is at least 10 times slower than the sulfur diffusion rate of the outer bond coat.

5. The turbine engine component as in claim 1, wherein the inner bond coat comprises CoNiCrAlY, and wherein the outer bond coat comprises NiCrAlY.

6. The turbine engine component as in claim 1, wherein the inner layer coating has an average thickness of about 200 μ

m to about 350 μ

m, and wherein the outer layer coating has an average thickness of about 100 μ

m to about 400 μ

m.

7. The turbine engine component as in claim 1, further comprising:

an intermediate bond coat positioned between the outer bond coat and the ceramic coat, and wherein the intermediate bond coat has a porosity that is greater than a porosity of the inner bond coat, and further wherein the intermediate bond coat has a porosity that is less than a porosity of the outer bond coat.

8. A turbine engine component having a repaired thermal barrier coating, the turbine engine component comprising:

a substrate defining a surface;

an inner bonding layer on the surface of the substrate;

an inner bond coat on the inner bonding layer, wherein the inner bond coat comprises a cobalt-containing material;

an outer bond coat on the inner bond coat, wherein the outer bond coat is substantially free from cobalt; and

a ceramic coat on the outer bond coat.

9. The turbine engine component as in claim 8, wherein the inner bond coat has a porosity that is about 5% or less, and wherein the outer bond coat has a porosity that is greater than about 5%

10. The turbine engine component as in claim 8, wherein the inner bond coat has a sulfur diffusion rate that is at least 10 times slower than the sulfur diffusion rate of the outer bond coat.

11. The turbine engine component as in claim 8, wherein the inner bond coat comprises CoNiCrAlY, and wherein the outer bond coat comprises NiCrAlY.

12. The turbine engine component as in claim 8, wherein the inner layer coating has an average thickness of about 200 μ

m to about 350 μ

m, and wherein the outer layer coating has an average thickness of about 100 μ

m to about 400 μ

m.

13. The turbine engine component as in claim 8, further comprising:

an intermediate bond coat positioned between the outer bond coat and the ceramic coat, and wherein the intermediate bond coat has a porosity that is greater than a porosity of the inner bond coat, and further wherein the intermediate bond coat has a porosity that is less than a porosity of the outer bond coat.

14. A method of repairing a thermal barrier coating on a turbine engine component, the method comprising:

removing any ceramic coating from an area of a surface of a substrate;

forming an inner bond coat over the area of the surface of the substrate, wherein the inner bond coat comprises a cobalt-containing material;

forming an outer bond coat over the inner bond coat, wherein the outer bond coat is substantially free from cobalt; and

forming a ceramic coat on the outer bond coat.

15. The method as in claim 14, wherein forming the inner bond coat comprises high velocity oxy-fuel coating spraying a plurality of first particles onto the area of the substrate to form an inner bond coat, wherein the plurality of first particles comprises a cobalt-containing material and have an average particle size that is less than about 45 μ

m.

16. The method as in claim 15, wherein the plurality of first particles comprises CoNiCrAlY.

17. The method as in claim 15, wherein the outer bond coat is formed via high velocity oxy-fuel coating spraying a plurality of second particles having an average diameter that is about 50 μ

m to about 150 μ

m, and wherein the plurality of second particles comprises NiCrAlY.

18. The method as in claim 14, further comprising:

prior to forming the outer bond coat, forming an intermediate bond coat on the inner bond coat, wherein the intermediate bond coat is substantially free from cobalt, and wherein the intermediate bond coat has a porosity that is greater than a porosity of the inner bond coat, and further wherein the intermediate bond coat has a porosity that is less than a porosity of the outer bond coat.

19. The method as in claim 14, wherein removing any ceramic coating from the surface of the substrate comprising:

removing all material from the surface of the substrate to expose the surface of the substrate.

20. The method as in claim 14, wherein removing any ceramic coating from the surface of the substrate comprises:

removing all ceramic coating material from the area of the surface of the substrate while leaving a portion of an existing bond coating on the surface of the substrate.