Airfoil with improved coating system and methods of forming the same

Patent metadata

Field	Value
Publication number	US-2017350261-A1
Application number	US-201615171389-A
Country	US
Kind code	A1
Filing date	Jun 2, 2016
Priority date	Jun 2, 2016
Publication date	Dec 7, 2017
Grant date	—

Abstract

A coating system for a surface of a superalloy component is provided. The coating system includes a MCrAlY coating on the surface of the superalloy component, where M is Ni, Fe, Co, or a combination thereof. The MCrAlY coating generally has a higher chromium content than the superalloy component. The MCrAlY coating also includes a platinum-group metal aluminide diffusion layer. The MCrAlY coating includes Re, Ta, or a mixture thereof. Methods are also provided for forming a coating system on a surface of a superalloy component.

First claim

What is claimed is:

1 . A coating system on a surface of a superalloy component, the coating system comprising:
a MCrAlY coating on the surface of the superalloy component, wherein M is Ni, Fe, Co, or a combination thereof, wherein the MCrAlY coating has a higher chromium content than the superalloy component, and wherein the MCrAlY coating comprises a platinum-group metal aluminide diffusion layer, and further wherein the MCrAlY coating comprises Re, Ta, or a mixture thereof.

2 . The coating system as in claim 1 , wherein the MCrAlY coating includes an inner portion adjacent to the superalloy component, a middle portion on the inner portion, and an outer portion on the middle portion, and wherein the middle portion has a chromium content that this greater than, in terms of weight percent, than the inner portion and the outer portion.

3 . The coating system as in claim 2 , wherein the outer portion has a chromium content of about 3% to about 7.5% by weight, and wherein the middle portion has a chromium content of about 8% to about 20% by weight, and further wherein the inner portion has a chromium content of about 5% to about 12% by weight.

4 . The coating system as in claim 1 , wherein the MCrAlY coating includes an inner portion adjacent to the superalloy component, a middle portion on the inner portion, and an outer portion on the middle portion, and wherein the outer portion has a rhenium content that is less than, in terms of weight percent, than a rhenium content of the middle portion, and further wherein the middle portion has a rhenium content that is less than, in terms of weight percent, a rhenium content of the inner portion.

5 . The coating system as in claim 4 , wherein the outer portion has a rhenium content of 0% to about 0.1% by weight, and wherein the middle portion has a rhenium content of about 0.1% to about 4% by weight, and wherein the inner portion has a rhenium content of greater than about 3% by weight.

6 . The coating system as in claim 1 , wherein the MCrAlY coating includes an inner portion adjacent to the superalloy component, a middle portion on the inner portion, and an outer portion on the middle portion, and wherein the outer portion has a tantalum content that is lower, in terms of weight percent, than a tantalum content of the middle portion.

7 . The coating system as in claim 6 , wherein the outer portion has a tantalum content of about 0.1% to about 2.25% by weight, and wherein the middle portion has a tantalum content of about 2.5% to about 7.5% by weight.

8 . The coating system as in claim 6 , wherein the inner portion can have a tantalum content of about 3% to about 7.5% by weight.

9 . The coating system as in claim 1 , wherein the MCrAlY coating has a thickness of about 10 μm to about 100 μm.

10 . The coating system as in claim 9 , wherein the superalloy component defines film holes within the surface.

11 . The coating system as in claim 5 , wherein the MCrAlY coating defines an external surface having a surface roughness (Ra) of about 0.75 μm to about 2.75 μm.

12 . The coating system as in claim 1 , the MCrAlY coating comprises a MCrAlY layer and the platinum-group metal aluminide layer diffused together, and wherein the platinum-group metal aluminide layer comprises a platinum-group metal selected from the group consisting of platinum, rhodium, palladium, or a mixture thereof.

13 . The coating system as in claim 1 , wherein the MCrAlY coating is directly on the surface of the component, and wherein the coating system further comprises a thermal barrier coating directly on the MCrAlY coating.

14 . The coating system as in claim 1 , wherein the MCrAlY coating includes an inner portion adjacent to the superalloy component, a middle portion on the inner portion, and an outer portion on the middle portion, and wherein the inner portion has a hafnium content that is lower, in terms of weight percent, than the hafnium content of the middle portion, and further wherein the outer portion has a hafnium content that is lower, in terms of weight percent, than the hafnium content of the middle portion.

15 . A method of forming a coating system on a surface of a superalloy component, the method comprising:
forming a MCrAlY layer on the surface of the superalloy component, wherein the MCrAlY layer has a chromium content that is higher than the superalloy component, and wherein M is Ni, Fe, Co, or a combination thereof; forming a platinum-group metal layer on the MCrAlY layer; heating the platinum-group metal layer to a treatment temperature of about 900° C. to about 1200° C.; and forming an aluminide coating over platinum-group metal layer.

16 . The method as in claim 15 , further comprising:
heating the coating system to form a MCrAlY coating from the MCrAlY layer, the platinum-group metal layer, and the aluminide coating.

17 . The method as in claim 16 , wherein the surface of the superalloy component defines a plurality of film holes therein, and wherein the MCrAlY coating is deposited to a thickness of about 10 μm to about 100 μm while keeping the film holes defined within the surface of the superalloy component open

18 . The method as in claim 15 , wherein the MCrAlY layer, prior to forming the platinum-group metal layer, has a composition comprising up to about 25% Cr, about 6 to about 7% Al, up to about 1% Hf, up to about 0.5% Y, about 8% to about 12% Co, about 5% to about 7% Ta, about 1% to about 3% Re, about 0.5 to about 1.5% Si, up to about 0.5% Zr, and the balance Ni.

19 . The method as in claim 15 , wherein the aluminide coating is deposited to a thickness of about 25 μm to about 100 μm.

20 . The method as in claim 15 , further comprising:
after forming the aluminide coating, forming a thermal barrier coating over the bond coating.

Assignees

• Gen Electric

Inventors

• Nagaraj Bangalore Aswatha
• Clark Michael David
• Sheets Susan Lee

Classifications

• Y10T428/12611

  Oxide-containing component · CPC title

• Y10T428/12937

  Co- or Ni-base component next to Fe-base component · CPC title

• Y10T428/12958

  Next to Fe-base component · CPC title

• Y10T428/12896

  Ag-base component · CPC title

• F05D2300/177

  Ni - Si alloys · CPC title