THERMAL BARRIER COATING SYSTEM AND PROCESSES FOR FORMING A THERMAL BARRIER COATING SYSTEM

• US 20170081753A1
• Filed: 09/21/2015
• Published: 03/23/2017
• Est. Priority Date: 09/21/2015
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Zhang, Liming, Thompson, Christopher Edward, Connor, James Ryan, Ward, John D., DePalma, Michael Anthony
• Application Number:
  US14/859,587
• Publication Number:
  US 20170081753A1
• Time in Patent Office: Days
• CPC Class Codes: C23C 10/18 using liquids, e.g. salt baths, liquid suspensions
• CPC Class Codes: C23C 10/20 only one element being diffused
• CPC Class Codes: C23C 10/30 using a layer of powder or paste on the surface using liquid suspensions of solids C23C10/18
• CPC Class Codes: C23C 10/60 After-treatment
• CPC Class Codes: C23C 14/221 Ion beam deposition C23C14/46, C23C14/48 take precedence
• CPC Class Codes: C23C 28/321 with at least one metal alloy layer
• CPC Class Codes: C23C 28/3455 with a refractory ceramic layer, e.g. refractory metal oxide, ZrO2, rare earth oxides or a thermal barrier system comprising at least one refractory oxide layer
• CPC Class Codes: C23C 4/134 Plasma spraying
• CPC Class Codes: F01D 5/288 Protective coatings for blades
• CPC Class Codes: F05D 2300/134 Zirconium
• CPC Class Codes: F23R 3/002 Wall structures F23R3/02 and F23R3/007 take precedence

Abstract

A process for forming a thermal barrier coating system on a substrate is disclosed including preparing a slurry including a donor powder, an activator powder, and a binder. The donor powder includes a metallic aluminum alloy having a melting temperature higher than aluminum, and the binder includes at least one organic polymer gel. The process further includes applying the slurry to the substrate, heating the slurry to form an aluminide bond coating including an additive aluminide layer and an aluminide interdiffusion zone disposed between the substrate and the additive aluminide layer, and applying a thermal barrier coating to the aluminide bond coating. The thermal barrier coating may be a dense vertically-cracked thermal barrier coating, and the substrate may be a gas turbine component. Thermal barrier coating systems formed by the process are also disclosed.

Claims

1. :

A process for forming a thermal barrier coating system on a substrate, the process comprising;

preparing a slurry including, by weight, about 35 to about 65% of a donor powder, about 1 to about 25% of an activator powder, and about 25 to about 60% of a binder, the donor powder including a metallic aluminum alloy having a melting temperature higher than aluminum, and the binder including at least one organic polymer gel;

applying the slurry to the substrate;

heating the slurry to form an aluminide bond coating including an additive aluminide layer and an aluminide interdiffusion zone disposed between the substrate and the additive aluminide layer; and

applying a thermal barrier coating to the aluminide bond coating.

2. :

The process of claim 1, wherein the slurry is applied directly to the substrate, the thermal barrier coating is applied directly to the additive aluminide layer of the aluminide bond coating, and the thermal barrier coating system is formed free from any MCrAlY bond coating.

3. :

The process of claim 1, wherein the donor powder includes a chromium-aluminum alloy.

4. :

The process of claim 1, wherein the donor powder has a particle size of up to 100 mesh.

5. :

The process of claim 1, wherein the activator powder is selected from the group consisting of ammonium chloride, ammonium fluoride, ammonium bromide, and combinations thereof.

6. :

The process of claim 1, wherein applying the slurry coating includes applying the slurry coating with a maximum thickness of about 25 mm.

7. :

The process of claim 1, wherein the slurry is heated on the substrate to a temperature within a range of about 815°

C. to about 1150°

C.

8. :

The process of claim 1, wherein forming the aluminide bond coating includes forming the aluminide bond coating as an outward-type coating.

9. :

The process of claim 1, wherein the substrate is a gas turbine component.

10. :

The process of claim 9, wherein the gas turbine component is selected from the group consisting of a bucket, a nozzle, a shroud, a combustor, a hot gas path component, and combinations thereof.

11. :

The process of claim 1, wherein the substrate includes a nickel-based superalloy.

12. :

The process of claim 1, wherein heating the slurry forms a residue which is removed by a technique selected from the group consisting of directing forced gas flow at the aluminide bond coating, grit blasting the aluminide bond coating, and combinations thereof.

13. :

The process of claim 1, wherein applying the slurry to substrate forms a slurry coating having a non-uniform thickness with a minimum thickness of about 0.25 mm and a maximum thickness of about 6 mm or more, and the aluminide bond coating has a thickness which varies by about 0.01 mm or less and is therefore essentially independent of the thickness of the slurry coating.

14. :

The process of claim 1, wherein applying the thermal barrier coating includes applying a dense vertically-cracked thermal barrier coating.

15. :

A process for forming a dense vertically-cracked thermal barrier coating system on a gas turbine component, the process comprising;

providing the gas turbine component having a substrate;

preparing a slurry including a donor powder, an activator powder, and a binder, the donor powder including a metallic aluminum alloy having a melting temperature higher than aluminum, and the binder including at least one organic polymer gel;

applying the slurry directly to the substrate;

heating the slurry to form an aluminide bond coating including an additive aluminide layer and an aluminide interdiffusion zone disposed between the substrate and the additive aluminide layer; and

applying a dense vertically-cracked thermal barrier coating directly to the additive aluminide layer of the aluminide bond coating.

16. :

A thermal barrier coating system on a substrate, comprising;

a thermal barrier coating; and

an aluminide bond coating disposed between the substrate and the thermal barrier coating, the aluminide bond coating including an additive aluminide layer and an aluminide interdiffusion zone disposed between the substrate and the additive aluminide layer.

17. :

The thermal barrier coating system of claim 16, wherein the aluminide bond coating directly contacts the substrate, the thermal barrier coating directly contacts the additive aluminide layer of the aluminide bond coating, and the thermal barrier coating system is free from any MCrAlY bond coating.

18. :

The thermal barrier coating system of claim 16, wherein the aluminide bond coating is an outward-type coating.

19. :

The thermal barrier coating system of claim 16, wherein the substrate is a gas turbine component selected from the group consisting of a bucket, a nozzle, a shroud, a combustor, a hot gas path component, and combinations thereof.

20. :

The thermal barrier coating system of claim 16, wherein the substrate includes a nickel-based superalloy.