Method of manufacturing conductive film holes
A method for applying a coating to a substrate having a plurality of holes. The method comprises: applying a braze material to a substrate having a plurality of holes; heating the substrate to melt the braze material to form a melt; cooling the substrate to solidify the melt to form plugs in the respective holes; applying a coating to the substrate; and further heating the substrate to melt the plugs.
1. A method for applying a coating to a substrate having a plurality of holes, the method comprising:
applying a braze material to a substrate having a plurality of holes, the applying comprising applying the braze material aside the holes but not completely plugging the holes;
heating the substrate to melt the braze material to form a melt;
cooling the substrate to solidify the melt to form plugs in the respective holes, the heating and cooling causing the braze material to completely plug the holes;
after the cooling, applying a coating to the substrate; and
further heating the substrate to melt the plugs.
2. The method of claim 1 wherein:
evacuating the melted plug.
3. The method of claim 2 wherein:
the evacuation ruptures the coating.
4. The method of claim 1 wherein the applying the coating comprises:
applying a metallic bondcoat; and
applying a ceramic coating atop the bondcoat.
5. The method of claim 1 wherein:
the braze material is an Au—Cu braze material.
6. The method of claim 5 wherein:
the braze material is applied via a braze paste.
7. The method of claim 6 wherein:
the braze paste comprises a water-based gel binder.
8. The method of claim 7 wherein:
the braze paste comprises particles of an alloy having a by weight composition of Au, Cu, and no more than 5% all other elements total, if any.
9. The method of claim 8 wherein:
a ratio of Au to Cu in said alloy is between 67/33 and 56/44.
10. The method of claim 8 wherein:
said particles of said alloy form at least 95% of alloy in the braze paste.
11. The method of claim 7 wherein:
said water-based gel binder forms 8% to 25% by weight of the braze paste.
12. The method of claim 1 further comprising:
machining the holes.
13. The method of claim 1 further comprising:
using pressurized gas to evacuate molten material of the plugs.
14. The method of claim 1 further comprising:
vibrating to evacuate molten material of the plugs.
15. The method of claim 1 wherein:
during the applying, the coating preferentially deposits away from the plugs.
16. The method of claim 1 wherein:
the coating comprises a ceramic layer.
17. The method of claim 1 wherein:
the substrate is a nickel-based superalloy.
18. The method of claim 1 wherein:
the substrate is a combustor panel substrate having a body formed as a frustoconical segment.
19. The method of claim 18 wherein:
the holes are along the body.