DENSIFIED POLYMER INFILTRATED AND PYROLYSIS-BASED CMC ARTICLES

• US 20160229757A1
• Filed: 09/12/2014
• Published: 08/11/2016
• Est. Priority Date: 09/19/2013
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Rtx Corporation)
• Inventors: McCaffrey, Michael G., Berczik, Douglas M.
• Granted Patent: US 10,294,166 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B05D 3/007 After-treatment
• CPC Class Codes: C04B 2235/3821 Boron carbides
• CPC Class Codes: C04B 2235/3826 Silicon carbides
• CPC Class Codes: C04B 2235/3873 Silicon nitrides, e.g. silicon carbonitride, silicon oxynitride
• CPC Class Codes: C04B 2235/428 Silicon
• CPC Class Codes: C04B 2235/5248 Carbon, e.g. graphite
• CPC Class Codes: C04B 2235/5252 having a specific pre-form
• CPC Class Codes: C04B 2235/5256 Two-dimensional, e.g. woven structures
• CPC Class Codes: C04B 2235/614 Gas infiltration of green bodies or pre-forms
• CPC Class Codes: C04B 2235/616 Liquid infiltration of green bodies or pre-forms
• CPC Class Codes: C04B 35/52 based on carbon, e.g. graphite
• CPC Class Codes: C04B 35/573 obtained by reaction sintering or recrystallisation
• CPC Class Codes: C04B 35/6267 Pyrolysis, carbonisation or auto-combustion reactions
• CPC Class Codes: C04B 35/80 Fibres, filaments, whiskers, platelets, or the like
• CPC Class Codes: C04B 38/0096 Pores with coated inner walls
• CPC Class Codes: C04B 38/0615 the burned-out substance being a monolitic element having approximately the same dimensions as the final article, e.g. a porous polyurethane sheet or a prepreg obtained by bonding together resin particles C04B38/0022 takes precedence
• CPC Class Codes: C04B 41/89 for obtaining at least two superposed coatings having different compositions

Abstract

A method of densifying a CMC article includes the steps of pyrolyzing a CMC article until a desired initial porosity is achieved, coating CMC pores within the CMC article with carbon, pyrolyzing the carbon to form carbon pores, coating the carbon pores with silicon, and heat treating the CMC article to create a silicon carbide filled pore integrated with silicon carbide of the CMC article to densify the CMC article.

Claims

1. A method of densifying a CMC article comprising the steps of:

pyrolyzing a CMC article until a desired initial porosity is achieved;

coating CMC pores within the CMC article with carbon;

pyrolyzing the carbon to form carbon pores;

coating the carbon pores with silicon; and

heat treat the CMC article to create a silicon carbide filled pore integrated with silicon carbide of the CMC article to densify the CMC article.

2. The method according to claim 1, wherein the CMC article is pyrolyzed more than once to achieve the initial porosity.

3. The method according to claim 2, wherein the CMC article is pyrolyzed less than six times to achieve the initial porosity.

4. The method according to claim 1, wherein the CMC article is pyrolyzed at a temperature of 1000-1400°

C. to achieve the initial porosity.

5. The method according to claim 1, wherein the CMC pore coating step includes infiltrating the CMC pores with a carbon precursor resin.

6. The method according to claim 5, wherein the carbon precursor resin includes fillers selected from the group including silicon, silicon carbide, boron carbide and silicon nitride.

7. The method according to claim 1, wherein the carbon is pyrolyzed at a temperature of 1000-1800°

C.

8. The method according to claim 7, wherein the silicon enters the carbon pores by capillary action.

9. The method according to claim 1, wherein the densified article is machined to a desired shape.

10. The method according to claim 9, wherein a seal coat is applied to the machine shape.

11. The method according to claim 10, wherein an environmental barrier coating is applied to the seal coating.

12. The method according to claim 1, wherein the CMC article is densified by infiltrating the article with a silicon carbide precursor resin.

13. The method according to claim 12, wherein the CMC article is pyrolyzed at 1200-1800°

C.

14. The method according to claim 12, wherein the silicon carbide precursor resin includes a filler selected from the group including silicon, silicon carbide, boron carbide and silicon nitride.

15. The method according to claim 1, wherein CMC fibers are arranged about a form and a silicon carbide precursor resin is injected into a mold to provide the CMC article.

16. The method according to claim 15, wherein the CMC fibers are wrapped about the form.

17. The method according to claim 15, wherein the silicon carbide precursor resin includes a filler selected from the group including silicon, silicon carbide, boron carbide and silicon nitride.

18. The method according to claim 15, wherein the CMC fibers are provided as a prepreg.

19. The method according to claim 15, wherein the CMC article in the mold is heated to a temperature of 100-600°

C. and is removed from the mold.

20. The method according to claim 15, wherein the CMC article is placed in a fixture and pyrolyzed to a temperature of 1000-1400°

C.