Oxide based ceramic matrix composites

• US 20050218565A1
• Filed: 05/23/2005
• Published: 10/06/2005
• Est. Priority Date: 07/30/2001
• Status: Abandoned Application

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: DiChiara, Robert A. Jr.
• Application Number:
  US11/134,876
• Publication Number:
  US 20050218565A1
• Time in Patent Office: Days
• US Class Current: 264/621
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3418 Silicon oxide, silicic acids, or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint glass constituents C04B2235/36
• CPC Class Codes: C04B 2235/3463 Alumino-silicates other than clay, e.g. mullite
• CPC Class Codes: C04B 2235/5252 having a specific pre-form
• CPC Class Codes: C04B 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/5454 nanometer sized, i.e. below 100 nm
• CPC Class Codes: C04B 2235/616 Liquid infiltration of green bodies or pre-forms
• CPC Class Codes: C04B 35/111 Fine ceramics
• CPC Class Codes: C04B 35/117 Composites
• CPC Class Codes: C04B 35/14 based on silica
• CPC Class Codes: C04B 35/16 based on silicates other than clay zircon C04B35/48
• CPC Class Codes: C04B 35/6261 Milling
• CPC Class Codes: C04B 35/62813 Alumina or aluminates
• CPC Class Codes: C04B 35/80 Fibres, filaments, whiskers, platelets, or the like

Abstract

A method of making a ceramic matrix composites (CMC) having superior properties at high temperatures. The CMC can include a sol gel mixture mixed or blended metal oxide particles. The sol-gel mixture can be an aqueous colloidal suspension of a metal oxide, preferably from about 10 wt % to about 25 wt % of the metal oxide, containing a metal oxide such as alumina (Al₂O₃), silica (SiO₂) or alumina-coated silica. The mixture can be infiltrated into a ceramic fiber, gelled, dried and sintered to form the CMC of the present teachings.

Claims

1. A method of preparing an oxide-based ceramic matrix comprising the steps of:

providing a sol-gel matrix, wherein the sol-gel matrix comprises from about 10 wt % to about 60 wt % of solids;

mixing alumina particles into the sol-gel to form a ceramic matrix wherein the alumina particles comprise from about 30 wt % to about 60 wt % of the ceramic matrix; and

if necessary, adjusting the pH to prevent gelling of the ceramic matrix.

2. The method of claim 1 wherein the sol-gel includes at least one of an alumina sol, a silica sol an alumina-coated silica sol, or combinations thereof.

3. The method of claim 1 wherein the alumina particles have a size of from about 0.1 μ

m to about 1.5 μ

m.

4. The method of claim 1 wherein adjusting the pH of the matrix includes the addition of an acid.

5. The method of claim 4 wherein the addition of the acid includes selecting at least one of a nitric acid, a hydrochloric acid, a sulfuric acid, or combinations thereof.

6. The method of claim 1 further comprising:

treating the mixture to form a homogeneous suspension.

7. The method of claim 6 wherein treating the mixture includes ball milling, attritor milling, planetory milling, high-shear mixing, or combinations thereof.

8. The method of claim 1 further comprising:

selecting a ceramic fiber.

9. The method of claim 8 wherein selecting a ceramic fiber includes selecting at least one of a continuous fiber, a cut fiber, or combinations thereof.

10. The method of claim 8 further comprising:

weaving the fiber into a fabric.

11. The method of claim 8 further comprising:

forming a composite by mixing the ceramic matrix with the ceramic fiber.

12. The method of claim 8 further comprising selecting the ceramic fiber to include at least one of quartz, silicon carbide, alumina, alumina-silicate, or combinations thereof.

13. The method of claim 8, further comprising infiltrating the ceramic matrix into the ceramic fiber.

14. A method of making a fiber-reinforced oxide based ceramic matrix composite comprising the steps of:

providing a sol-gel matrix, wherein the sol-gel matrix comprises about 10 wt % to about 60 wt % of metal oxide solids;

mixing alumina particles into the sol-gel to form a ceramic matrix wherein the alumina particles comprise about 30 wt % to about 60 wt % of the ceramic matrix;

obtaining a pH to prevent gelling of the ceramic matrix;

treating the ceramic matrix to form a homogenous suspension; and

infiltrating the homogeneous suspension into a ceramic fiber.

15. The method of claim 14 wherein the sol-gel matrix includes at least one of an alumina sol, a silica sol an alumina-coated silica sol, or combinations thereof.

16. The method of claim 14 wherein the alumina particles have a size of about 0.1 μ

m to about 1.5 μ

m.

17. The method of claim 14 which obtains a pH including adding at least one of a nitric acid, a hydrochloric acid a sulfuric acid or combinations thereof.

18. The method of claim 14, wherein obtaining a pH to prevent gelling of the ceramic matrix includes adjusting the pH by addition of at least one of an acid, a base, or combinations thereof.

19. The method of claim 14, wherein obtaining a pH to prevent gelling of the ceramic matrix includes substantially mixing the alumina particles into the sol gel.

20. The method of claim 14, wherein treating the ceramic matrix to form a homogeneous suspension includes at least one of ball milling the ceramic matrix, attritor milling the ceramic matrix, planetary milling the ceramic matrix, high shear mixing of the ceramic matrix, or combinations thereof.

21. The method of claim 14, wherein the ceramic fiber includes a ceramic fiber fabric;

wherein infiltrating the homogeneous suspension into the ceramic fiber fabric includes forming a pre-form of the infiltrated ceramic fiber fabric.

22. The method of claim 21, further comprising:

calcining the infiltrated perform; and

sintering the infiltrated preform.

23. The method of claim 14, further comprising:

calcining the infiltrated ceramic fiber;

infiltrating the ceramic fiber with the homogeneous suspension after calcining; and

repeating at least one of the calcining, the infiltrating, or combinations thereof.

24. The method of claim 14, wherein the ceramic fiber includes at least one of quartz, silicon carbide, alumina, alumina silicate, or combinations thereof.

25. A method of forming a ceramic composite comprising:

selecting a ceramic fiber;

selecting a sol gel comprising about 10 wt % to about 60 wt % of solids;

selecting an alumina particle;

mixing the alumina particle with the sol gel wherein the mixture includes about 40 wt % to about 70 wt % of the sol gel and about 30 wt % to about 60 wt % of the alumina particle; and

surrounding the selected ceramic fiber with the mixture of the sol gel and the alumina particles.

26. The method of claim 25, further comprising:

selecting a sol gel including silica sol having a solids content of about 0 wt % to about 60 wt %.

27. The method of claim 25, further comprising:

adding a filler material to the mixture.

28. The method of claim 25, wherein selecting the sol gel includes selecting an alumina sol, having a solids content up about 10 wt % to about 25 wt %.

29. The method of claim 25, wherein selecting a ceramic fiber includes forming a fabric of the selected ceramic fiber.

30. The method of claim 29, wherein the fabric of the selected fiber includes substantially continuous fibers, cut fibers, or combinations thereof.