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

Patent metadata

Field	Value
Publication number	US-11873569-B2
Application number	US-202016927417-A
Country	US
Kind code	B2
Filing date	Jul 13, 2020
Priority date	May 25, 2017
Publication date	Jan 16, 2024
Grant date	Jan 16, 2024

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

What is claimed is:

1. 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; 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.

2. The airfoil of claim 1 , where the thermally grown oxide layer has a thickness of 2 to 7 micrometers.

3. The airfoil of claim 1 , where the layer comprising Ni—Cr/aluminide or Cr/aluminide has a thickness of 50 to 100 micrometers.

4. The airfoil of claim 1 , 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.

5. The airfoil of claim 1 , where the first layer and the second layer are deposited electrolytically.

6. The airfoil of claim 1 , prepared by a method comprising:
providing the airfoil to be coated; wherein the internal surface comprises a convoluted internal passage;
electrolytically applying a first layer that comprises chromium or a chromium alloy onto the inner surface;
electrolytically applying a second layer comprising aluminum or an aluminum alloy onto the first layer; and
heat treating the airfoil to promote interdiffusion between the first layer and the second layer to form the thermally grown oxide layer that comprises alumina and chromium oxide; and the layer comprising Ni—Cr/aluminide or Cr/aluminide disposed between the layer comprising alumina and chromium oxide and the internal surface of the airfoil.

7. The airfoil of claim 6 , wherein the electrolytically applying of the first layer and/or the electrolytically applying of the second layer is conducted via electrodeposition.

8. The airfoil of claim 6 , where the electrodeposition is conducted by using a conforming electrode that traverses the convoluted internal passage of the component without contacting a surface of the airfoil.

9. The airfoil of claim 8 , where the conforming electrode is an anode and where the article is a cathode.

10. The airfoil of claim 9 , where the conforming electrode is coated with a porous electrically insulating material.

11. The airfoil of claim 6 , where the electrolytically applying of the first layer comprises using an electrolyte that comprises a suspension of chromium or nickel-chromium.

12. The airfoil of claim 6 , where the electrolytically applying of the second layer comprises using an electrolyte that comprises a suspension of aluminum or an aluminum alloy.

13. The airfoil of claim 6 , where the first layer has a thickness of 50 to 100 micrometers.

14. The airfoil of claim 6 , where the second layer has a thickness of 25 to 75 micrometers.

15. The airfoil of claim 6 , where the heat treating is conducted at a temperature of 800 to 1600° C.

Assignees

• Rtx Corp

Inventors

• Chen Lei
• Protsailo Lesia V
• Task Michael N

Classifications

• C25D5/12 Primary

  at least one layer being of nickel or chromium · CPC title

• B32B15/04

  comprising metal as the main or only constituent of a layer, {which is} next to another layer of {the same or of} a {different material (next to a bituminous or tarry layer B32B11/08; next to a water-setting substance layer B32B13/06; next to a glass layer B32B17/061; next to a cellulosic plastic layer B32B23/042)} · CPC title

• C22C27/06

  Alloys based on chromium · CPC title

• C23C18/165

  Multilayered product (layered product B32B) · CPC title

• C23C18/1616

  interior or inner surface · CPC title