Method for forming an improved thermal barrier coating (TBC), thermal-barrier-coated article and method for the repair thereof

Patent metadata

Field	Value
Publication number	US-9429035-B2
Application number	US-201214237255-A
Country	US
Kind code	B2
Filing date	Aug 3, 2012
Priority date	Aug 5, 2011
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

The invention refers to a process for the formation of a thermal barrier coating on a substrate, comprising the steps of:
a) applying a bond coat on the substrate; b) subjecting the bond coat to a low activity aluminizing process, thus obtaining, above the bond coat, a temporary intermediate diffusion layer; c) applying, on the temporary intermediate diffusion layer, aluminum powder in suspension with a solvent or aqueous base, said aluminum powder having size distribution from 15 to 150 μm; d) performing a thermal treatment in a vacuum at a pressure from 10 −3 to 10 −5 bars, at a temperature from 800° C. to 1050° C. and with an active phase having duration in the range of 60 minutes to 4 hours, thus obtaining above the bond coat an enriched intermediate diffusion layer; and e) applying a definitive barrier layer on said enriched intermediate diffusion layer.

First claim

The invention claimed is:

1. A method for forming a thermal barrier coating ( 102 ) on a substrate ( 101 ), comprising the steps of:
a) applying a bond coat ( 103 ) on said substrate ( 101 );
b) subjecting said bond coat ( 103 ) to a low activity aluminizing process, thus obtaining a temporary intermediate diffusion layer on said bond coat ( 103 );
characterized in that it comprises the steps of
c) applying on said temporary intermediate diffusion layer obtained from said phase b) aluminium powder in suspension with a solvent or aqueous base, said aluminium powder having a size distribution from 15 to 150 μm;
d) carrying out a vacuum heat treatment on the substrate, bond coat and temporary intermediate diffusion layer as a whole, at a pressure from 10 − 3 to 10 − 5 bar, at a temperature from 800° C. to 1050° C. and with an active phase in the range of 60 min-4 h, thus obtaining an enriched intermediate diffusion layer ( 105 ) on said bond coat ( 103 ); and
e) applying a definitive barrier layer ( 104 ) on said enriched intermediate diffusion layer ( 105 ).

2. A method according to claim 1 , wherein said aluminium powder has a size distribution from 30 to 100 μm.

3. A method according to claim 1 , wherein said step c) of applying said aluminium powder is repeated 1-4 times.

4. A method according to claim 1 , wherein said step d) of heat treatment is carried out at a temperature from 850° C. to 1000° C.

5. A method according to claim 1 , wherein said step d) of heat treatment has an active phase with a duration in the range of 90-180 min.

6. A method according to claim 1 , wherein said step d) of heat treatment is repeatedly carried out 1-6 times.

7. An article ( 100 ) comprising a substrate ( 101 ) and a thermal barrier coating ( 102 ) applied on said substrate, characterized in that said thermal barrier coating ( 102 ) is formed by means of a method according to claim 1 .

8. A method for repairing an article ( 100 ) comprising a substrate ( 101 ) coated with a thermal barrier coating comprising a bond coat ( 103 ); characterized in that it comprises the steps of:
i) subjecting said bond coat ( 103 ) to a low activity aluminizing process, thus obtaining a temporary intermediate diffusion layer on said bond coat ( 103 );
j) applying, on said temporary intermediate diffusion layer, aluminium powder in suspension with a solvent or aqueous base, said aluminium powder having a size distribution from 15 to 150 μm;
k) carrying out a thermal vacuum treatment on the substrate, bond coat and temporary intermediate diffusion layer as a whole, at a pressure from 10 − 3 to 10 − 5 bar, at a temperature from 800° C. to 1050° C. and with an active phase in the range of 60 min-4 h, thus obtaining an enriched intermediate diffusion layer ( 105 ) on said bond coat ( 103 ); and
l) applying a definitive barrier layer ( 104 ) on said enriched intermediate diffusion layer ( 105 ).

9. A method for repairing an article ( 100 ) comprising a substrate ( 101 ) coated with a thermal barrier coating comprising a bond coat ( 103 ) and a temporary intermediate diffusion layer arranged on said bond coat; characterized in that it comprises the steps of:
j) applying, on said temporary intermediate diffusion layer, aluminium powder in suspension with a solvent or aqueous base, said aluminium powder having a size distribution from 15 to 150 μm;
k) carrying out a thermal vacuum treatment on the substrate, bond coat and temporary intermediate diffusion layer as a whole, at a pressure from 10-3 to 10-5 bar, at a temperature from 800° C. to 1050° C. and with an active phase in the range of 60 min-4 h, thus obtaining an enriched intermediate diffusion layer ( 105 ) on said bond coat ( 103 ); and
l) applying a definitive barrier layer ( 104 ) on said enriched intermediate diffusion layer ( 105 ).

Assignees

• Della Femina Maurizio
• Rossi Marco
• Casillo Raffaele
• Silvestro Carlo
• Ge Avio Srl

Inventors

• Della Femina Maurizio
• Rossi Marco
• Casillo Raffaele
• Silvestro Carlo

Classifications

• F01D25/007 Primary

  Preventing corrosion · CPC title

• C23C10/18

  using liquids, e.g. salt baths, liquid suspensions · CPC title

• C23C10/48

  Aluminising · CPC title

• C23C24/087

  Coating with metal alloys or metal elements only · CPC title

• C23C4/06

  Metallic material · CPC title