Thermal insulation system employing oxide ceramic matrix composites

• US 6,969,546 B2
• Filed: 10/20/2003
• Issued: 11/29/2005
• Est. Priority Date: 10/20/2003
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: DiChiara, Robert A. Jr.
• Primary Examiner(s): XU, LING X
• Application Number:
  US10/689,809
• Publication Number:
  US 20050084665A1
• Time in Patent Office: 771 Days
• Field of Search: 428/46, 428/49, 428/76, 428/121, 428/293.4, 428/375, 428/378, 428701-702, 428/428, 428/697, 428/699, 427180-181, 427202-203, 427/205, 427/206, 427/314, 427/376.3, 427/376.2, 442/178, 244/158.A, 501/35, 501/53, 501/133
• US Class Current: 428/49
• CPC Class Codes: B28B 19/0053 to tiles, bricks or the like
• CPC Class Codes: B64G 1/58 Thermal protection, e.g. heat shields
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3804 Borides
• CPC Class Codes: C04B 2235/3834 Beta silicon carbide
• CPC Class Codes: C04B 2235/3891 Silicides, e.g. molybdenum disilicide, iron silicide
• CPC Class Codes: C04B 2235/5224 Alumina or aluminates
• CPC Class Codes: C04B 2235/5228 Silica and alumina, including aluminosilicates, e.g. mullite
• CPC Class Codes: C04B 2235/5232 Silica or silicates other than aluminosilicates, e.g. quartz
• CPC Class Codes: C04B 35/117 Composites
• CPC Class Codes: C04B 35/18 rich in aluminium oxide
• CPC Class Codes: C04B 35/195 Alkaline earth aluminosilicates, e.g. cordierite or anorthite
• CPC Class Codes: C04B 35/447 based on phosphates , e.g. hydroxyapatite
• CPC Class Codes: C04B 35/6263 characterised by their solids loadings, i.e. the percentage of solids
• CPC Class Codes: C04B 35/80 Fibres, filaments, whiskers, platelets, or the like
• CPC Class Codes: Y10T 428/162 Transparent or translucent layer or section
• CPC Class Codes: Y10T 428/166 Glass, ceramic, or metal sections [e.g., floor or wall tile, etc.]
• CPC Class Codes: Y10T 428/239 Complete cover or casing
• CPC Class Codes: Y10T 428/2419 Fold at edge
• CPC Class Codes: Y10T 428/249928 Fiber embedded in a ceramic, glass, or carbon matrix
• CPC Class Codes: Y10T 428/2933 : Coated or with bond, impregnation or core
• CPC Class Codes: Y10T 428/2938 : Coating on discrete and individual rods, strands or filaments
• CPC Class Codes: Y10T 442/2975 : Coated or impregnated ceramic fiber fabric

Abstract

A ceramic tile includes a ceramic core material and an oxide ceramic matrix composite (CMC), where the ceramic core material has at least one surface covered by the oxide CMC. The oxide CMC includes a ceramic fiber, with a cured metal oxide ceramic material impregnating the ceramic fiber. An exemplary embodiment of the ceramic tile provided as part of the invention further includes a tough low temperature cure coating (TLTC) which infiltrates the ceramic core surface before it is covered by the oxide CMC. The TLTC includes a cured ceramic powder together with a binder. The metal oxide ceramic material impregnating the ceramic fiber, and the TLTC are co-cured, meaning that neither is cured when the CMC is wrapped around a surface of the TLTC-infiltrated ceramic core, and a curing step is performed on both uncured ceramic materials at the same time.

Claims

1. A ceramic tile, which comprises:

a ceramic core material;

having a surface;

a tough low temperature cure coating (TLTC) infiltrating the surface, the TLTC comprising a cured ceramic powder combined with a binder; and

an oxide ceramic matrix composite (CMC), covering the surface infiltrated with the TLTC, the oxide CMC comprising;

a ceramic fiber; and

a cured metal oxide ceramic material impregnating said ceramic fiber.

2. A ceramic tile according to claim 1, wherein said cured metal oxide ceramic material impregnating said ceramic fiber and said TLTC are co-cured.

3. A ceramic tile according to claim 1, wherein said ceramic core material has a coefficient of thermal expansion, and said TLTC raises said coefficient of thermal expansion of said ceramic core material.

4. A ceramic tile according to claim 1, wherein said ceramic powder comprises cordierite.

5. A ceramic tile according to claim 1, wherein said binder comprises silica sol.

6. A ceramic tile according to claim 1, wherein said TLTC infiltrates every surface of said ceramic core material, and said oxide CMC entirely surrounds said ceramic core material.

7. A ceramic tile according to claim 1, wherein substantially none of said TLTC lies on said surface of said ceramic core material.

8. A ceramic tile according to claim 1, wherein said TLTC further comprises an emissivity-modifying agent that modifies the emissivity of a region of said ceramic core material surrounding said surface.

9. A ceramic tile according to claim 1, wherein said oxide CMC entirely surrounds said ceramic core material.

10. A ceramic tile according to claim 1, wherein said ceramic core material comprises a sintered mat pf ceramic fibers.

11. A ceramic tile according to claim 9, wherein said ceramic fibers comprise silica fibers, aluminoborosilicate fibers, and alumina fibers.

12. A method of forming a ceramic tile, which comprises the steps of:

infiltrating a surface of a ceramic core material with a tough low temperature cure coating (TLTC) comprising a cured ceramic powder combined with a binder; and

covering the TLTC-infiltrated surface of the ceramic core material with an oxide ceramic matrix composite (CMC), said oxide CMC comprising;

a ceramic fiber, and

a cured metal oxide ceramic material impregnating said ceramic fiber.

13. A method according to claim 12, which further comprises the step of:

pre-shrinking said ceramic fiber prior to impregnating said ceramic fiber with said metal oxide ceramic material.

14. A method according to claim 13, wherein said pre-shrinking step comprises heating said ceramic fiber.

15. A method according to claim 14, wherein said ceramic fiber is heated to about 1800°

F. during said pre-shrinking step.

16. A method according to claim 12, which further comprises the step of:

co-curing said cured metal oxide ceramic material impregnating said ceramic fiber and said TLTC.

17. A method according to claim 16, wherein no curing process has been performed for either said cured metal oxide ceramic material impregnating said ceramic fiber or said TLTC prior to said co-curing step.

18. A method according to claim 16, wherein said co-curing step is performed using an autoclave between about 25 and about 100 psi.

19. A method according to claim 18, wherein said co-curing step is performed between about 50 and about 80 psi.

20. A method according to claim 18, wherein said co-curing step is performed at a temperature ranging between ambient temperature and about 500°

F.

21. A method according to claim 12, wherein said ceramic core material has a coefficient of thermal expansion, and said TLTC raises said coefficient of thermal expansion of said ceramic core material.

22. A method according to claim 12, wherein said ceramic powder comprises cordierite.

23. A method according to claim 12, wherein said binder comprises silica sol.

24. A method according to claim 12, wherein said infiltrating step comprises infiltrating every surface of said ceramic core material, and said covering step comprises entirely surrounding said ceramic core material.

25. A method according to claim 12, wherein upon completion of said infiltrating step substantially none of said TLTC lies on said surface of said ceramic core material.

26. A method according to claim 12, wherein said TLTC further comprises an emissivity-modifying agent that modifies the emissivity of a region of said ceramic core material surrounding said surface.

27. A method according to claim 12, wherein said covering step comprises entirely surrounding said ceramic core material.

28. A method according to claim 12, wherein said ceramic core material comprises a sintered mat of ceramic fibers.

29. A method according to claim 28, wherein said ceramic fibers comprise silica fibers, aluminoborosilicate fibers, and alumina fibers.

30. A ceramic tile produced by a method which comprises the steps of:

infiltrating a surface of a ceramic core material with a tough low temperature cure coating (TLTC) comprising a cured ceramic powder combined with a binder; and

covering the TLTC-infiltrated surface of the ceramic core material with an oxide ceramic matrix composite (CMC), said oxide CMC comprising;

a ceramic fiber, and

a cured metal oxide ceramic material impregnating said ceramic fiber.

31. A ceramic tile according to claim 30, wherein said method further comprises the step of:

co-curing said cured metal oxide ceramic material impregnating said ceramic fiber and said TLTC.

32. A ceramic tile according to claim 30, wherein said method further comprises the step of:

pre-shrinking said ceramic fiber prior to impregnating said ceramic fiber with said metal oxide ceramic material.

33. A ceramic tile according to claim 32, wherein said pre-shrinking step comprises heating said ceramic fiber.

34. A method according to claim 33, wherein said ceramic fiber is heated to about 1800°

F. during said pre-shrinking step.