Methods and compositions for repair of composite materials

Patent metadata

Field	Value
Publication number	US-9512505-B2
Application number	US-201414522016-A
Country	US
Kind code	B2
Filing date	Oct 23, 2014
Priority date	Oct 23, 2014
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

A method for repair of composite materials includes applying a formulation to a ceramic matrix composite substrate. The formulation comprises a liquid carrier, a ceramic filler dispersed within the carrier, and a polymeric binder disposed in the carrier. The method further includes removing the carrier from the formulation to form a green composition; pyrolyzing the green composition to form a porous composition; disposing a liquid metal or metalloid within the pores of the porous composition to form an intermediate composite composition; and converting the liquid metal or metalloid to solid state to form a solid composite composition.

First claim

The invention claimed is:

1. A method comprising:
applying a formulation to a ceramic matrix composite substrate, wherein the formulation comprises
a liquid carrier,
a ceramic filler dispersed within the carrier, and
a polymeric binder disposed in the carrier;

removing the carrier from the formulation to form a green composition;
pyrolyzing the green composition to form a porous composition;
disposing a liquid metal or metalloid within the pores of the porous composition to form an intermediate composite composition; and
converting the liquid metal or metalloid to solid state to form a solid composite composition.

2. The method of claim 1 , wherein the formulation further comprises a shrinkage control agent.

3. The method of claim 2 , wherein the shrinkage control agent comprises carbon fiber.

4. The method of claim 3 , wherein the carbon fiber has a length less than about 250 micrometers.

5. The method of claim 3 , wherein the fiber has an aspect ratio of at least about 5.

6. The method of claim 2 , wherein the shrinkage control agent comprises a plurality of particles having a median diameter of at least about 10 micrometers.

7. The method of claim 6 , wherein the plurality of particles comprises silicon carbide particles.

8. The method of claim 1 , wherein the formulation further comprises a plasticizer.

9. The method of claim 1 , wherein the ceramic filler comprises a plurality of particles having a median diameter less than 10 micrometers.

10. The method of claim 9 , wherein the median diameter is less than 1 micrometer.

11. The method of claim 1 , wherein the ceramic filler comprises silicon carbide.

12. The method of claim 11 , wherein the ceramic filler further comprises elemental carbon.

13. The method of claim 1 , wherein the liquid carrier comprises an organic liquid.

14. The method of claim 1 , wherein the binder is at least partially dissolved in the carrier.

15. The method of claim 1 , wherein the binder comprises a phenolic resin, a furan or furanic-based resin, a petroleum-tar-based resin, a coal tar-based resin, a polyarylacetylene, or combinations thereof.

16. The method of claim 1 , wherein the binder comprises a phenolic resin and furfuryl alcohol.

17. The method of claim 1 , wherein the formulation further comprises a pore-forming agent disposed in the carrier.

18. The method of claim 17 , wherein the pore-forming agent comprises polyvinyl butyral resin, an acrylic resin, an acetate resin, a cellulosic resin, or combinations thereof.

19. The method of claim 1 , wherein applying comprises mechanically spreading or injecting the formulation onto the substrate.

20. The method of claim 1 , wherein removing the carrier comprises heating formulation in an autoclave under a pressure greater than 1 atmosphere.

21. The method of claim 1 , wherein pyrolyzing comprises heating the green composition to a temperature in a range from about 400 degrees Celsius to about 1000 degrees Celsius.

22. The method of claim 1 , wherein pyrolyzing comprises heating in a vacuum or in a substantially inert atmosphere.

23. The method of claim 1 , wherein the liquid metal or metalloid comprises silicon.

24. The method of claim 1 , wherein disposing the liquid metal or metalloid comprises disposing a silicon source in fluid communication with the pores of the porous composition, and infiltrating the pores with liquid silicon.

25. The method of claim 1 , wherein converting the liquid metal or metalloid to solid state comprises reacting the metal or metalloid with the porous composition.

26. The method of claim 1 , further comprising performing a machining operation on the solid composite composition.

27. The method of claim 1 , further comprising forming the formulation, wherein forming the formulation includes dispersing carbon fibers into a slurry comprising the carrier using a centrifugal planetary mixer.

28. A method comprising:
applying a formulation to a ceramic matrix composite substrate comprising silicon carbide, wherein the formulation comprises
an organic liquid carrier,
a ceramic filler dispersed within the carrier, the filler comprising (i) a plurality of silicon carbide particles, and (ii) carbon black,
a phenolic resin binder dissolved in the carrier,
a polyvinyl butyral resin pore-forming agent dissolved in the carrier,
a plasticizer, and
a shrinkage control agent comprising carbon fiber dispersed within the carrier;

autoclaving the formulation to form a green composition;
pyrolyzing the green composition to form a porous composition;
disposing a quantity of liquid silicon or silicon-bearing alloy within the pores of the porous composition to form an intermediate composite composition; and
converting the liquid silicon or silicon-bearing alloy to solid state to form a solid composite composition.

Assignees

• Gen Electric

Inventors

• Weaver Jared Hogg
• Dunn Daniel Gene

Classifications

• C04B41/52

  Multiple coating or impregnating {multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation} · CPC title

• C04B41/89

  for obtaining at least two superposed coatings having different compositions · CPC title

• F05D2300/6033

  Ceramic matrix composites [CMC] · CPC title

• F05D2230/80

  Repairing, retrofitting or upgrading methods · CPC title

• C04B41/009

  characterised by the material treated · CPC title