Method for nitride free vapor deposition of chromium coating

Patent metadata

Field	Value
Publication number	US-10023749-B2
Application number	US-201514597263-A
Country	US
Kind code	B2
Filing date	Jan 15, 2015
Priority date	Jan 15, 2015
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

A process for applying a chromium layer on a substrate, specifically a turbine engine airfoil, by contacting at least a portion of the substrate with a gaseous chromium wherein the gaseous chromium is generated from a substantially nitrogen free source.

First claim

The invention claimed is:

1. A process for applying a chromium layer on a substrate comprising: contacting at least a portion of the substrate with a vapor comprising a gaseous chromium wherein the gaseous chromium is generated from a mixture comprising a chromium source and a substantially nitrogen free activator, wherein the activator is selected from the group consisting of chromium III chloride and chromium II chloride.

2. A process according to claim 1 wherein the chromium diffuses into the portion of the substrate to define the chromium layer.

3. A process according to claim 1 wherein the mixture comprises a chromium solid.

4. A process according to claim 3 wherein the mixture is heated to produce gaseous chromium.

5. A process according to claim 1 wherein the contacting step takes place in an enclosed space.

6. A process according to claim 5 wherein conditions inside the enclosed space are between 1900° F. and 2000° F.

7. A process according to claim 5 wherein conditions inside the enclosed space are held between 4 and 20 hours.

8. A process according to claim 1 wherein the substrate is an aircraft engine airfoil.

9. A process according to claim 8 wherein the airfoil is a high pressure turbine stage airfoil.

10. A process according to claim 8 wherein the airfoil is a low pressure turbine stage airfoil.

11. A process according to claim 1 wherein the chromium layer has a thickness of between 7.62-33.02 microns.

12. A process according to claim 1 wherein the activator is a halide compound.

13. A process according to claim 1 wherein the activator source is a nitrogen free chloride compound.

14. A process according to claim 1 wherein the activator source is chromium III chloride.

15. A process according to claim 1 wherein the ratio of chromium to activator is between 120:1 and 160:1.

16. A process according to claim 1 wherein the substrate has internal passageways.

17. A process according to claim 16 wherein the portion includes the internal passageways.

18. A process according to claim 17 wherein the chromium layer covers the internal passageways.

19. A process according to claim 1 wherein the substrate is made of a nickel-based superalloy.

20. A process according to claim 19 wherein relative to a total combined weight of the chromium and the activator, the mixture has 98-99% by weight of the chromium, and 1-2% by weight of the chromium(III) chloride.

21. A process according to claim 1 wherein the mixture further comprises chromium (III) chloride.

22. A process according to claim 1 , wherein the mixture consists essentially of the chromium source, the activator and a carrier material, wherein the carrier material is an inert gas.

Assignees

• United Technologies Corp

Inventors

• Collins Kevin L
• Minor Michael J

Classifications

• C23C16/06

  characterised by the deposition of metallic material · CPC title

• C23C10/32

  Chromising · CPC title

• C09D5/08 Primary

  Anti-corrosive paints · CPC title

• C23C10/10 Primary

  Chromising · CPC title

• C23C16/44

  characterised by the method of coating (C23C16/04 takes precedence) · CPC title