Oxidation-resistant layer for TiAl materials and method for the production thereof

Patent metadata

Field	Value
Publication number	US-9657395-B2
Application number	US-201514927849-A
Country	US
Kind code	B2
Filing date	Oct 30, 2015
Priority date	Nov 11, 2014
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

The present invention relates to a protective layer for TiAl materials for affording protection against oxidation, said protective layer having a layer sequence which, proceeding from the inner side facing toward the TiAl material ( 1 ), has an inner aluminum oxide layer ( 5 ), a first gradient layer ( 6 ) comprising aluminum and a base metal with a base metal content increasing outward toward the surface side, a base metal layer ( 7 ), a second gradient layer ( 8 ) comprising aluminum and a base metal with an aluminum content increasing outward toward the surface side, and an outer aluminum oxide layer ( 9 ), and also to a method for the production thereof.

First claim

What is claimed is:

1. A protective layer for protecting a TiAl material against oxidation, wherein the protective layer has a layer sequence which, proceeding from an inner side facing toward the TiAl material, comprises an inner aluminum oxide layer, a first gradient layer comprising aluminum and a base metal with a base metal content increasing outward toward a surface side, a base metal layer, a second gradient layer comprising aluminum and a base metal with an aluminum content increasing outward toward the surface side, and an outer aluminum oxide layer.

2. The protective layer of claim 1 , wherein a transition from the inner aluminum oxide layer to the first gradient layer is continuous, with an aluminum oxide content which decreases outward from the inner side and an aluminum content which increases outward from the inner side, and/or wherein a transition from the second gradient layer to the outer aluminum oxide layer is continuous, with an aluminum oxide content which increases outward from the inner side and an aluminum content which decreases outward from the inner side.

3. The protective layer of claim 1 , wherein the base metal of the first and second gradient layers and the base metal of the base metal layer are selected from metals which are oxidation-resistant at temperatures of up to 900° C.

4. The protective layer of claim 1 , wherein the base metal of the first and second gradient layers and the base metal of the base metal layer comprise one or more elements selected from iron, cobalt, nickel, chromium, gold, platinum, iridium, palladium, osmium, silver, rhodium, ruthenium.

5. The protective layer of claim 1 , wherein the protective layer further comprises a thermal barrier layer and/or an abrasion-resistant layer at the surface.

6. The protective layer of claim 5 , wherein the thermal barrier layer or the abrasion-resistant layer comprise zirconium oxide or zirconium oxide partially stabilized with yttrium oxide.

7. The protective layer of claim 5 , wherein the abrasion-resistant layer has a thickness of from 5 μm to 50 μm.

8. The protective layer of claim 5 , wherein the thermal barrier layer has a thickness of greater than or equal to about 150 μm.

9. The protective layer of claim 1 , wherein the protective layer further comprises a diffusion barrier layer with respect to the base metal or other constituents of the layer arranged between the TiAl material and the inner aluminum oxide layer.

10. The protective layer of claim 9 , wherein the diffusion barrier layer is formed from coarse-grained aluminum oxide, a grain size of the aluminum oxide being ranging from 10 nm to 1 μm.

11. The protective layer of claim 1 , wherein the protective layer further comprises an adhesion promoter layer arranged between the TiAl material and the inner aluminum oxide layer.

12. The protective layer of claim 11 , wherein the adhesion promoter layer is formed from initially amorphous aluminum oxide which crystallizes during a subsequent heat treatment and/or at elevated temperatures of more than 400° C. during use.

13. The protective layer of claim 11 , wherein the adhesion promoter layer is arranged on the inside, facing toward the TiAl material, and a diffusion barrier layer is arranged between the adhesion promoter layer and the inner aluminum oxide layer.

14. The protective layer of claim 13 , wherein the adhesion promoter layer and the diffusion barrier layer are formed as a graduated layer with a proportion of crystalline aluminum oxide which increases from the inside outward.

15. A TiAl material, wherein the material comprises the protective layer of claim 1 .

16. The material of claim 15 , wherein the material is a component of a stationary gas turbine or an aero engine.

17. The material of claim 15 , wherein the material is a component of a turbomachine.

18. A method for producing a protective layer on a TiAl material, wherein the method comprises applying by physical vapor deposition (PVD) or chemical vapor deposition (CVD) and proceeding from an inner side facing toward the TiAl material, an inner aluminum oxide layer, a first gradient layer comprising aluminum and a base metal with a base metal content increasing outward toward the surface side, a base metal layer, a second gradient layer comprising aluminum and a base metal with an aluminum content increasing outward toward the surface side, and an outer aluminum oxide layer.

19. The method of claim 18 , wherein additionally an outer thermal barrier layer or an abrasion-resistant layer is deposited by electron beam evaporation or by being sprayed on and/or an inner diffusion barrier layer and/or adhesion promoter layer are deposited by physical vapor deposition (PVD) or chemical vapor deposition (CVD).

20. The method of claim 18 , wherein a pre-oxidation layer is applied to the TiAl material by targeted oxidation at a temperature of less than 600° C. and for a period of time of less than 15 minutes, or is formed by an electrolytic process in a thickness of less than 500 nm.

Assignees

• MTU Aero Engines AG

Inventors

• Schloffer Martin
• Zheng Nanxi

Classifications

• C23C28/321

  with at least one metal alloy layer · CPC title

• C23C14/025

  Metallic sublayers · CPC title

• C23C14/34

  Sputtering · CPC title

• C23C16/06

  characterised by the deposition of metallic material · CPC title

• C23C28/347

  with layers adapted for cutting tools or wear applications · CPC title