Protective coating for protecting a component from corrosion, oxidation and excessive thermal stress, process for producing the coating and gas turbine component

• US 5,993,980 A
• Filed: 04/14/1997
• Issued: 11/30/1999
• Est. Priority Date: 10/14/1994
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Schmitz, Friedheim, Czech, Norbert
• Primary Examiner(s): Zimmerman, John J.
• Application Number:
  US08/839,462
• Time in Patent Office: 960 Days
• Field of Search: 428/621, 428/623, 428/633, 428/632, 428/678, 428/680, 428/668, 428/937, 428/938, 427/250, 427/456, 427/454, 427/255.7, 416/241 R, 416/241 B, 204/192.15, 204/192.16
• US Class Current: 428/633
• CPC Class Codes: C23C 28/00 Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
• CPC Class Codes: C23C 28/321 with at least one metal alloy layer
• CPC Class Codes: C23C 28/3455 with a refractory ceramic layer, e.g. refractory metal oxide, ZrO2, rare earth oxides or a thermal barrier system comprising at least one refractory oxide layer
• CPC Class Codes: C23C 4/02 Pretreatment of the material to be coated, e.g. for coating on selected surface areas
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft
• CPC Class Codes: Y10S 428/937 Sprayed metal
• CPC Class Codes: Y10S 428/938 Vapor deposition or gas diffusion
• CPC Class Codes: Y10T 428/12618 Plural oxides
• CPC Class Codes: Y10T 428/12931 Co-, Fe-, or Ni-base components, alternative to each other

Abstract

A protective coating for protecting a component from corrosion and oxidation at a high temperature and from excessive thermal stress, has a heat insulation layer including a ceramic material and an adhesion-promoting layer including a rhenium containing metal alloy. The metal alloy belongs to the alloys covered by the general term MCrAlY, where M represents cobalt and/or nickel and Y represents yttrium and/or at least one equivalent metal from the group including scandium and the rare earth elements. The protective coating is distinguished by high oxidation resistance and corrosion resistance of the alloy, by outstanding thermal fatigue properties and an effective and permanent bond between the alloy and the ceramic heat insulation layer. As a result of the heat insulation, the temperature at the outer surface of the protective coating can be considerably higher than with purely metallic protective coatings, without an increased thermal load being exerted on the component. The protective coating is therefore particularly suitable for a gas turbine component exposed to a hot combustion gas, for example a guide vane, a rotor blade or a heat shield.

Claims

1. A protective coating for protecting a component from corrosion and oxidation at a high temperature and from excessive thermal stress, comprising:

a insulation layer of a ceramic material having a thickness in a range from 50 μ

m to 3000 μ

m; and

an adhesion-promoting layer binding said heat insulation layer to a component and including an alloy with the following composition in percent by weight;

5to 20% rhenium,

15 to 35% chromium,

7 to 18% aluminum,

0.3 to 2% of at least one element selected from the group consisting of yttrium, scandium, and the rare earth elements,

0 to 3% silicon,

0 to 5% hafnium,

0 to 5% tantalum,

0 to 2% zirconium,

0 to 12% tungsten,

0 to 10% manganese,

0 to 4% niobium, and

remainder including at least one of cobalt and nickel and impurities associated with the preparation.

2. The protective coating according to claim 1, including:

7 to 15% aluminum,

15 to 30% chromium and

5 to 11% rhenium.

4. The protective coating according to claim 1, wherein said insulation layer contains zirconium oxide (ZrO₂).

6. The protective coating according to claim 4, wherein said zirconium oxide is stabilized with 5 to 20% yttrium oxide (Y₂ O₃).

7. The protective coating according to claim 4, wherein said zirconium oxide is stabilized with 6 to 8% yttrium oxide (Y₂ O₃).

18. The protective coating according to claim 1, wherein said heat insulation layer is 50 μ

m to 300 μ

m thick.

20. The protective layer according to claim 1, wherein said heat insulation layer is 200 μ

m to 3000 μ

m thick.

22. The protective layer according to claim 1, wherein said adhesion promoting layer is 50 μ

m to 300 μ

m thick.

3. A protective coating for protecting a component from corrosion and oxidation at a high temperature and from excessive thermal stress, comprising:

a heat insulation layer of a ceramic material having a thickness in a range from 50 μ

m to 3000 μ

m; and

an adhesion-promoting layer including a metal alloy of the composition MCrAlY where M represents at least one of cobalt and nickel and Y represents at least one element selected from the group consisting of yttrium, scandium, and the rare earth elements, and a portion of at least 5% rhenium in percent by weight.

5. The protective coating according to claim 3, wherein said insulation layer contains zirconium oxide (ZrO₂).

8. The protective coating according to claim 5, wherein said zirconium oxide is stabilized with 5 to 20% yttrium oxide (Y₂ O₃).

9. The protective coating according to claim 5, wherein said zirconium oxide is stabilized with 6 to 8% yttrium oxide (Y₂ O₃).

19. The protective coating according to claim 3, wherein said heat insulation layer is 50 μ

m to 300 μ

m thick.

21. The protective layer according to claim 3, wherein said heat insulation layer is 200 μ

m to 3000 μ

m thick.

23. The protective layer according to claim 3, wherein said adhesion promoting layer is 50 μ

m to 300 μ

m thick.

10. A gas turbine component, comprising:

a component body; and

a protective coating for protecting said component body from corrosion and oxidation at a high temperature and from excessive thermal stress, said protective coating including;

a heat insulation layer of a ceramic material having a thickness in a range from 50 μ

m to 3000 μ

m; and

an adhesion-promoting layer binding said heat insulation layer to said component body and including an alloy with the following composition in percent by weight;

5to 20%rhenium,

15 to 35% chromium,

7 to 18% aluminum,

0.3 to 2% of at least one element selected from the group consisting of yttrium, scandium, and the rare earth elements,

0 to 3% silicon,

0 to 5% hafnium,

0 to 5% tantalum,

0 to 2% zirconium,

0 to 12% tungsten,

0 to 10% manganese,

0 to 4% niobium, and

a remainder including at least one of cobalt and nickel and impurities associated with the preparation.

11. The component according to claim 10, wherein said component body is a rotor blade body.

12. The component according to claim 10, wherein said component body is a guide vane body.

13. The component according to claim 10, wherein said component body is a heat shield body.

14. A gas turbine component, comprising:

a component body; and

a protective coating for protecting said component body from corrosion and oxidation at a high temperature and from excessive thermal stress, said protective coating including;

a heat insulation layer of a ceramic material having a thickness in a range from 50 μ

m to 3000 μ

m; and

an adhesion-promoting layer including a metal alloy of the composition MCrAlY where M represents at least one of cobalt and nickel and Y represents at least one element selected from the group consisting of yttrium, scandium, and the rare earth elements, and a portion of at least 5% rhenium in percent by weight.

15. The component according to claim 14, wherein said component body is a rotor blade body.

16. The component according to claim 14, wherein said component body is a guide vane body.

17. The component according to claim 14, wherein said component body is a heat shield body.

24. A process for coating a component with a protective coating, which comprises:

applying an adhesion-promoting layer including an alloy with the following composition in percent by weight;

5 to 20% rhenium,

15 to 35% chromium,

7 to 18% aluminum,

25. 3 to 2% of at least one element selected from the group consisting of yttrium, scandium, and the rare earth elements,

0 to 3% silicon,

0 to 5% hafnium,

0 to 5% tantalum,

0 to 2% zirconium,

0 to 12% tungsten,

0 to 10% manganese,

0 to 4% niobium, and

a remainder including at least one of cobalt and nickel and impurities associated with the preparation, to a component by thermal spraying or physical vapor deposition (PVD);

and

applying a heat insulation layer of a ceramic material to the adhesion-promoting layer by atmospheric plasma spraying (APS) or physical vapor deposition (PVD).

26. A process for coating a component with a protective coating, which comprises:

applying an adhesion-promoting layer including a metal alloy of the composition MCrAlY where M represents at least one of cobalt and nickel and Y represents at least one element selected from the group consisting of yttrium, scandium, and the rare earth elements, and a portion of at least 5% rhenium in percent by weight, to a component by thermal spraying or physical vapor deposition (PVD); and

applying a heat insulation layer of a ceramic material to the adhesion-promoting layer by atmospheric plasma spraying (APS) or physical vapor deposition (PVD).