Method for thermal barrier coating and a liner made using said method

• US 6,620,457 B2
• Filed: 07/13/2001
• Issued: 09/16/2003
• Est. Priority Date: 07/13/2001
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Tomlinson, Thomas John, Imhoff, William Lee, Farmer, Gilbert, Heidorn, Raymond William, Fehrenbach, Jeffrey Arnold, Rutherford, Myron Edward
• Primary Examiner(s): Chen, Bret
• Assistant Examiner(s): FLETCHER III, WILLIAM P
• Application Number:
  US09/905,798
• Publication Number:
  US 20030010035A1
• Time in Patent Office: 795 Days
• Field of Search: 427/421, 427/424, 427/427, 427/446, 427/455, 427/456, 427/235, 427/236, 427/271, 427/270, 427/273
• US Class Current: 427/235
• CPC Class Codes: B23P 2700/06 Cooling passages of turbine components, e.g. unblocking or preventing blocking of cooling passages of turbine components
• CPC Class Codes: C23C 4/00 Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge build-up welding B23K, e.g. B23K5/18, B23K9/04
• CPC Class Codes: C23C 4/02 Pretreatment of the material to be coated, e.g. for coating on selected surface areas
• CPC Class Codes: C23C 4/18 After-treatment
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A method of applying a thermal barrier coating system to a metal piece having cooling holes angled in a first direction and cooling holes angled in a second direction. The method includes spraying a bond coat on a first surface of the piece at angles with respect to the first and second directions and to a thickness selected in combination with the angles to prevent the bond coat from entirely filling any of the holes. A thermal barrier coating is sprayed on the bond coat at angles with respect to the first and second directions and to a thickness selected in combination with the angles to prevent the thermal barrier coating from entirely filling any of the holes. The method also includes spraying a high pressure fluid jet from a nozzle assembly through each hole generally parallel to the respective cooling hole.

Claims

1. A method of applying a thermal barrier coating system to a metal piece having a first plurality of cooling holes angled in a first direction through the piece from a first surface of the piece to a second surface of the piece opposite the first surface, and a second plurality of cooling holes angled in a second direction different than said first direction through the piece from the first surface to the second surface, said method comprising the steps of:

spraying a bond coat on said first surface of the piece at angles with respect to said first direction and said second direction and to a thickness selected in combination with the angles to prevent the bond coat from entirely filling any hole within said first plurality of cooling holes or any hole within said second plurality of cooling holes;

spraying a thermal barrier coating on the bond coat at angles with respect to said first direction and said second direction and to a thickness selected in combination with the angles to prevent the thermal barrier coating from entirely filling any hole within said first plurality of coding holes or any hole within said second plurality of cooling holes; and

spraying a high pressure fluid jet from a nozzle assembly through at least one hole within said first plurality of cooling holes in a direction generally parallel to said first direction to remove at least one of said band coat and said thermal barrier coating from said at least one hole within said first plurality of cooling holes.

2. A method as set forth in claim 1 wherein the step of spraying the high pressure fluid jet from the nozzle assembly is performed at least twice, once after the step of spraying the bond coat but before the step of spraying the thermal barrier coating to remove the bond coat from said first plurality of holes and said second plurality of holes, and again after the step of spraying the thermal barrier coating to remove the thermal barrier coating from said first plurality of holes and said second plurality of holes.

3. A method as set forth in claim 1 wherein the thermal barrier coating is sprayed on said first surface in at least two coats and the step of spraying the fluid from the nozzle assembly is performed at least twice, once after spraying a first coat of said coats of thermal barrier coating and again after spraying a second coat of said coats of thermal barrier coating.

4. A method as set forth in claim 1 wherein the fluid jet is sprayed from the nozzle assembly toward the second surface of the metal piece.

5. A method as set forth in claim 1 wherein the fluid jet is sprayed from the nozzle assembly at a pressure of between about 5000 pounds per square inch and about 50,000 pounds per square inch.

7. A method as set forth in claim 1 wherein the nozzle assembly is spaced from the metal piece by a distance of between about 0.8 inches and about 1.6 inches while the jet is sprayed from the assembly.

8. A method as set forth in claim 1 further comprising the step of moving the nozzle assembly relative to the metal piece at a speed of between about 20 inches per minute and about 480 inches per minute as the fluid jet is sprayed from the nozzle assembly.

9. A method as set forth in claim 1 wherein the step of spraying the high pressure fluid jet further comprises spraying the high pressure fluid jet from the nozzle assembly through at least one hole within said second plurality of cooling holes in a direction generally parallel to said second direction to remove at least one of said bond coat and said thermal barrier coating from said at least one hole within said second plurality of cooling holes.

10. A method as set forth in claim 9 wherein the high pressure fluid jet is sprayed through each hole within the first plurality of cooling holes and through each hole with the second plurality of cooling holes during the step of spraying the high pressure fluid jet.

11. A method as set forth in claim 10 wherein the nozzle assembly sprays the high pressure fluid jet through each hole in said first plurality of cooling holes generally parallel to said first direction and through each hole in said second plurality of cooling holes generally parallel to said second direction.

6. A method as set forth in claim 6 wherein the fluid jet is sprayed from the nozzle assembly at a pressure of about 45,000 pounds per square inch.

12. A method of applying a thermal barrier coating system to an annular liner surrounding an axial centerline and extending between an upstream end and a downstream end, said liner having a first plurality of cooling holes angled in a first hole direction through the liner from an outer surface to an inner surface, and a second plurality of cooling holes angled in a second hole direction through the liner from the outer surface to the inner surface, said second hole direction having a circumferential component opposite that of said first hole direction, said method comprising the steps of:

spraying a bond coat on the inner surface in a first spray direction having an axial component to a thickness selected in combination with the first spray direction to prevent the bond coat from entirely filling any hole within said first plurality of cooling holes or any hole within said second plurality of cooling holes;

spraying a thermal barrier coating on the bond coat in a second spray direction having an axial component to a thickness selected in combination with the second spray direction to prevent the thermal barrier coating from entirely filling any hole within said first plurality of cooling holes or any hole within said second plurality of cooling holes; and

spraying a high pressure fluid jet from a nozzle assembly through at least one hole within said first plurality of cooling holes in a direction generally parallel to said first direction to remove at least one of said bond coat and said thermal barrier coating from said at least one hole with in said first plurality of cooling holes.

13. A method as set forth in claim 12 wherein said first plurality of cooling holes and said second plurality of cooling holes are angled axially downstream from the outer surface to the inner surface, and the bond coat and the thermal barrier coating are sprayed axially upstream toward the inner surface of the liner.

14. A method as set forth in claim 12 wherein the liner has a third plurality of coaling holes angled axially downstream through the liner from the outer surface to the inner surface, and the bond coat and the thermal barrier coating are sprayed axially downstream toward the inner surface of the liner.

15. A method as set forth in claim 12 wherein the step of spraying the high pressure fluid jet from the nozzle assembly is performed at least twice, once after the step of spraying the bond coat but before the step of spraying the thermal barrier coating to remove the bond coat from said first plurality of holes and said second plurality of holes, and again after the step of spraying the thermal barrier coating to remove the thermal barrier coating from said first plurality of holes and said second plurality of holes.

16. A method as set forth in claim 12 wherein the thermal barrier coating is sprayed on the inner surface in at least two coats and the step of spraying the fluid from the nozzle assembly is performed at least twice, once after spraying a first coat of said coats of thermal barrier coating and again after spraying a second coat of said coats of thermal barrier coating.

17. A method as set forth in claim 12 wherein the fluid jet is sprayed from the nozzle assembly toward the outer surface of the liner.

18. A method as set forth in claim 12 wherein the step of spraying the high pressure fluid jet further comprises spraying the high pressure fluid jet from the nozzle assembly through at least one hole within said second plurality of cooling holes in a direction generally parallel to said second spray direction to remove at least one of said bond coat and said thermal barrier coating from said at least one hole within said second plurality of cooling holes.

19. A method as set forth in claim 18 wherein the high pressure fluid jet is sprayed through each hole within the first plurality of cooling holes and through each hole with the second plurality of cooling holes during the step of spraying the high pressure fluid jet.

20. A method as set forth in claim 19 wherein the nozzle assembly sprays the high pressure fluid jet through each hole in said first plurality of cooling holes generally parallel to said first spray direction and through each hole in said second plurality of cooling holes generally parallel to said second direction.