Repair of combustion turbine components

1. A method of repairing a combustion turbine component having damage located at or near a cooling hole or hollow or geometrically complex portion of the component, comprising:

forming a preparatory groove that extends from a surface of the component to the damaged area but does not extend to the cooling hole or hollow or geometrically complex portion of the component, the groove extending 40–90% the distance from the surface of the component to a portion of the damaged area that is closest to the cooling hole or geometrically complex portion of the component;

spraying a filler material into the groove with a micro-plasma torch at a current of less than 50 ampers; and

filling the groove with the filler material such that the heated filler material substantially extends from the cooling hole or hollow or geometrically complex portion of the component to a surface of the component.

2. The method of claim 1 , wherein the damage is located at a cooling hole.

3. The method of claim 1 , wherein the damage is located near an area of spallation.

4. The method of claim 1 , wherein the damage is located near a geometrically complex area of the component.

5. The method of claim 1 , wherein the damage is a crack.

6. The method of claim 1 , wherein the damage is a chip.

7. The method of claim 1 , wherein the damage is caused by oxidation or corrosion.

8. The method of claim 1 , wherein the component is a transition duct.

9. The method of claim 1 , wherein the preparatory groove extends 60–70% the distance from the component to the damaged area.

10. The method of claim 1 , wherein the preparatory groove is formed by hand grinding or machining.

11. The method of claim 1 , wherein the filler material is provided in a powder form or a wire feeder form.

12. The method of claim 1 , wherein the filler material comprises a ytrria stabilized zirconia composition.

13. The method of claim 1 , wherein the micro-plasma torch has a nozzle orifice of about 1–2 mm which spreads the powder at an angle of about 10 degrees.

14. The method of claim 1 , wherein the micro-plasma torch has a heat input of about 2–5 kJ/cm.

15. The method of claim 1 , wherein the groove is completely filled with the filler material.

16. The method of claim 1 , further comprising smoothing the filler material so that it is substantially planar with the component surface.

17. The method of claim 1 , wherein the crack has a width of about 0.01–4 mm, a length of greater than 1 mm, and a depth of 0.5–10 mm.

18. The method of claim 17 , wherein the width of the preparatory groove is substantially constant along the entire length of the groove.

19. A method of repairing a combustion turbine component having damage located at or near a cooling hole, comprising:

forming a preparatory groove that extends from a surface of the component to the damaged area but does not extend to the cooling hole, the groove extending 40–90% the distance from a surface of the component to a portion of the damaged area that is closest to the cooling hole;

placing a filler material into the groove with a spray torch at a current of less than 50 amperes; and

filling the groove with the filler material such that the heated filler material substantially extends from the cooling hole to a surface of the component.

20. The method of claim 19 , wherein a width of the preparatory groove is substantially constant along a length of the groove.