Ceramic matrix composite utilizing partially stabilized fibers

• US 20060211564A1
• Filed: 03/16/2005
• Published: 09/21/2006
• Est. Priority Date: 03/16/2005
• Status: Active Grant

• Current Assignee: Siemens Energy Incorporated (Siemens AG)
• Original Assignee: Siemens Westinghouse Power Corporation
• Inventors: Merrill, Gary Brian
• Granted Patent: US 7,300,621 B2
• Time in Patent Office: Days
• US Class Current: 501/95.200
• CPC Class Codes: C04B 2235/5228 Silica and alumina, including aluminosilicates, e.g. mullite
• CPC Class Codes: C04B 35/117 Composites
• CPC Class Codes: C04B 35/80 Fibres, filaments, whiskers, platelets, or the like
• CPC Class Codes: F01D 5/282 Selecting composite materials, e.g. blades with reinforcing filaments
• CPC Class Codes: F01D 5/284 Selection of ceramic materials
• CPC Class Codes: F23R 3/007 constructed mainly of ceramic components

Abstract

A green body ceramic matrix composite material (30) is formed using ceramic fibers (32) in an intermediate state disposed in a green body ceramic matrix material (34). The fibers may be in either a dry but unfired (green) condition or in a partially fired condition. Selective control of the degree of pre-firing (pre-shrinkage) of the fibers may be used to control the level of residual stresses within the resulting refractory material resulting from differential shrinkage of the fibers and the matrix material during processing of the composite material.

Claims

1. A method of making a ceramic matrix composite refractory material, the method comprising:

surrounding ceramic fibers while in an intermediate state with a ceramic matrix material in a green body state to form a green body ceramic matrix composite material; and

firing the green body ceramic matrix composite material to form a refractory material.

2. The method of claim 1, further comprising partially pre-shrinking the fibers prior to the step of surrounding to a degree necessary to achieve a ratio of matrix shrinkage to fiber shrinkage during the steps of surrounding and firing of less than 5:

1.

3. The method of claim 1, further comprising partially pre-shrinking the fibers prior to the step of surrounding to a degree necessary to achieve a ratio of matrix shrinkage to fiber shrinkage during the steps of surrounding and firing of less than 3:

1.

4. The method of claim 1, further comprising partially pre-shrinking the fibers prior to the step of surrounding to a degree necessary to achieve a ratio of matrix shrinkage to fiber shrinkage during the steps of surrounding and firing of less than 2:

1.

5. The method of claim 1, further comprising partially pre-shrinking the fibers prior to the step of surrounding to a degree necessary to achieve a ratio of matrix shrinkage to fiber shrinkage during the steps of surrounding and firing of approximately 1:

1.

6. The method of claim 1, further comprising surrounding the ceramic fibers with the matrix material while the fibers are in a green state.

7. The method of claim 1, further comprising surrounding the ceramic fibers with the matrix material while the fibers are in a partially fired state.

8. The method of claim 1, further comprising partially firing the ceramic fibers to a predetermined degree prior to the step of surrounding the fibers with a matrix material in order to achieve a predicted degree of shrinkage of the fibers during the step of firing.

10. The method of claim 1, further comprising selecting the fibers to comprise alumina-silica.

11. The method of claim 1, further comprising selecting the matrix material to comprise alumina.

12. A part for a gas turbine engine manufactured using the method of claim 1.

13. A green body ceramic matrix composite material comprising:

a plurality of ceramic fibers in an intermediate state; and

a ceramic matrix material in a green body state surrounding the fibers.

14. The material of claim 13, wherein the fibers comprise alumina-silica fibers.

15. The material of claim 13, wherein the matrix material comprises alumina.

16. The material of claim 13, wherein the fibers comprise alumina-silica fibers and the matrix material comprises alumina.

17. The material of claim 13, wherein the fibers are in a green state.

18. The material of claim 13, wherein the fibers are in a partially fired state.

19. A part for a gas turbine engine comprising the material of claim 13.