Coating for internal surfaces of an airfoil and method of manufacture thereof

Patent metadata

Field	Value
Publication number	US-2018340265-A1
Application number	US-201715605720-A
Country	US
Kind code	A1
Filing date	May 25, 2017
Priority date	May 25, 2017
Publication date	Nov 29, 2018
Grant date	—

Abstract

Disclosed herein is a method of coating, comprising providing an article having an internal passage therein to be coated; electrolytically applying a first layer that comprises chromium or a chromium alloy onto a surface of the internal passage; electrolytically applying a second layer comprising aluminum or an aluminum alloy onto the first layer; and heat treating the article to promote interdiffusion between the first layer and the second layer.

First claim

1 . A method of coating, comprising:
providing an article having an internal passage therein to be coated; electrolytically applying a first layer that comprises chromium or a chromium alloy onto a surface of the internal passage; electrolytically applying a second layer comprising aluminum or an aluminum alloy onto the first layer; and heat treating the article to promote interdiffusion between the first layer and the second layer.

2 . The method of claim 1 , wherein the electrolytically applying of the first layer and/or the electrolytically applying of the second layer is conducted via electrodeposition.

3 . The method of claim 2 , where the electrodeposition is conducted via electroless deposition.

4 . The method of claim 2 , where the electrodeposition is conducted by using conforming electrodes that traverse internal passages of the component without contacting a surface of the article.

5 . The method of claim 4 , where the conforming electrode is an anode and where the article is a cathode.

6 . The method of claim 5 , where the conforming electrode is coated with a porous electrically insulating material.

7 . The method of claim 1 , where the electrolytically applying of the first layer comprises using an electrolyte that comprises a suspension of chromium or nickel-chromium.

8 . The method of claim 1 , where the electrolytically applying of the second layer comprises using an electrolyte that comprises a suspension of aluminum or an aluminum alloy.

9 . The method of claim 1 , where the first layer has a thickness of 50 to 100 micrometers.

10 . The method of claim 1 , where the second layer has a thickness of 25 to 75 micrometers.

11 . The method of claim 1 , where the heat treating is conducted at a temperature of 800 to 1600° C.

12 . The method of claim 1 , where the heat treating results in the formation of a layer of thermally grown oxides that comprise alumina and chromium oxide that is disposed on a layer of Ni—Cr/aluminide or a layer of Cr/aluminide.

13 . The method of claim 12 , where the Ni—Cr/aluminide layer or the Cr/aluminide layer contains aluminum and chromium that vary in amount inversely with one another with distance from a surface of the article or from a surface of the thermally grown oxide layer.

14 . The method of claim 1 , where the article is an airfoil.

15 . An airfoil comprising:
an internal surface having disposed thereon:
a thermally grown oxide layer that comprises alumina and chromium oxide; and
a layer comprising Ni—Cr/aluminide or Cr/aluminide disposed between the layer comprising alumina and chromium oxide and the internal surface of the airfoil.

16 . The airfoil of claim 15 , where the layer comprising Ni—Cr/aluminide or Cr/aluminide contains aluminum and chromium that vary in amount inversely with one another with distance from the internal surface of the airfoil or from a surface of the thermally grown oxide layer.

17 . The airfoil of claim 15 , where the thermally grown oxide layer has a thickness of 2 to 7 micrometers.

18 . The airfoil of claim 15 , where the layer comprising Ni—Cr/aluminide or Cr/aluminide has a thickness of 50 to 100 micrometers.

19 . The airfoil of claim 15 , where the layer comprising Ni—Cr/aluminide or Cr/aluminide is obtained by thermally treating:
a first layer comprising chromium or nickel-chromium that is disposed on the internal surface of the airfoil; and
a second layer that contains aluminum or an aluminum alloy that is disposed on the first layer.

20 . The airfoil of claim 15 , where the first layer and the second layer are deposited electrolytically.

Assignees

• United Technologies Corp

Inventors

• Chen Lei
• Protsailo Lesia V
• Task Michael N

Classifications

• C25D7/008

  Thermal barrier coatings · CPC title

• C23C18/1692

  Heat-treatment · CPC title

• F05D2230/90

  Coating; Surface treatment · CPC title

• F01D5/187

  Convection cooling · CPC title

• C25D3/56

  of alloys · CPC title