SURFACE-AIDED MELT INFILTRATION FOR PRODUCING A CERAMIC MATRIX COMPOSITE

• US 20160326064A1
• Filed: 05/05/2016
• Published: 11/10/2016
• Est. Priority Date: 05/08/2015
• Status: Active Grant

• Current Assignee: Rolls-Royce High Temperature Composites, Inc. (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce High Temperature Composites, Inc. (Rolls-Royce Holdings Plc)
• Inventors: Lazur, Andrew, Shim, Sungbo, Shinavski, Robert
• Granted Patent: US 10,150,708 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3463 Alumino-silicates other than clay, e.g. mullite
• 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 2235/404 Refractory metals
• CPC Class Codes: C04B 2235/424 Carbon black
• CPC Class Codes: C04B 2235/425 Graphite
• CPC Class Codes: C04B 2235/427 Diamond
• 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 2235/524 Non-oxidic, e.g. borides, carbides, silicides or nitrides
• CPC Class Codes: C04B 2235/5244 Silicon carbide
• CPC Class Codes: C04B 2235/616 Liquid infiltration of green bodies or pre-forms
• CPC Class Codes: C04B 35/565 based on silicon carbide
• CPC Class Codes: C04B 35/573 obtained by reaction sintering or recrystallisation
• 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: F05D 2240/11 Shroud seal segments
• CPC Class Codes: F05D 2300/6033 : Ceramic matrix composites [CMC]
• CPC Class Codes: F23R 3/007 : constructed mainly of ceramic components

Abstract

A method of melt infiltration for producing a ceramic matrix composite comprises applying a surface slurry onto one or more outer surfaces of an impregnated porous preform. The surface slurry comprises a solvent and particulate solids, and the preform comprises a framework of ceramic fibers loaded with particulate matter. The surface slurry is dried to form a porous layer comprising the particulate solids on the one or more outer surfaces of the impregnated porous preform. After forming the porous layer, an end portion of the impregnated porous preform that includes at least part of the porous layer is immersed in a molten material, and the molten material is infiltrated into the impregnated porous preform from the end portion. The porous layer serves as a wick to transport the molten material over the one or more outer surfaces, thereby enabling melt infiltration of the impregnated porous preform from other portions thereof.

Claims

1. A method of melt infiltration for producing a ceramic matrix composite, the method comprising:

applying a surface slurry onto one or more outer surfaces of an impregnated porous preform comprising a framework of ceramic fibers loaded with particulate matter, the surface slurry comprising a solvent and particulate solids;

drying the surface slurry to form a porous layer comprising the particulate solids on the one or more outer surfaces; and

after forming the porous layer, immersing an end portion of the impregnated porous preform into a molten material, the end portion including at least part of the porous layer, the molten material being infiltrated into the impregnated porous preform from the end portion,

wherein the porous layer serves as a wick to transport the molten material over the one or more outer surfaces, thereby enabling melt infiltration of the impregnated porous preform from other portions thereof.

2. The method of claim 1, wherein applying the surface slurry comprises dip coating, solution casting, spray coating and/or brushing on.

3. The method of claim 1, wherein the surface slurry covers only a portion of the one or more outer surfaces.

4. The method of claim 1, wherein the surface slurry covers an entirety of the one or more outer surfaces.

5. The method of claim 1, wherein the porous layer comprises a thickness of from about 0.1 mm to about 1 mm.

6. The method of claim 1, further comprising incorporating one or more reinforcement structures into the surface slurry prior to application to the one or more outer surfaces.

7. The method of claim 6, wherein the one or more reinforcement structures comprises a woven fabric comprising a polymer.

8. The method of claim 1, wherein, prior to infiltration of the molten material, the porous layer comprises a loading of the particulate solids of from about 30 vol. % to about 60 vol. %, the particulate solids including ceramic particles comprising a ceramic selected from the group consisting of:

silicon carbide, silicon nitride, alumina and aluminosilicate.

9. The method of claim 8, wherein the particulate solids further comprise one or more reactive elements selected from the group consisting of carbon, molybdenum, tungsten and titanium.

10. The method of claim 1, wherein, prior to infiltration of the molten material, the impregnated porous preform comprises a loading of the particulate matter of from about 40 vol. % to about 60 vol. %, the particulate matter including ceramic particles selected from the group consisting of silicon carbide, silicon nitride, alumina and aluminosilicate, and the particulate matter further comprising one or more reactive elements in an amount from about 2 wt. % to about 12 wt. %.

11. The method of claim 1, further comprising, prior to infiltrating the molten material, machining the porous layer.

12. The method of claim 1, further comprising, after infiltration of the molten material, cooling the molten material to form a composite body including a ceramic coating thereon,

wherein the ceramic fibers comprise a ceramic selected from the group consisting of:

silicon carbide, silicon nitride, alumina, and aluminosilicate.

13. The method of claim 12, further comprising, after cooling, machining the ceramic coating.

14. The method of claim 12, wherein the ceramic coating comprises a ceramic selected from the group consisting of:

carbide, nitride, silicide and boride.

15. The method of claim 12, wherein the ceramic coating further comprises silicon.

16. A ceramic matrix composite (CMC) component comprising:

a composite body having a ceramic coating on one or more surfaces thereof, the composite body comprising ceramic fibers dispersed in a ceramic matrix and further containing an amount of residual metal of about 5 vol. % or less, and the ceramic coating having a surface finish comprising an average surface roughness (R_a) of about 200 micro-inches or less.

17. The CMC component of claim 16, wherein the ceramic fibers, the ceramic matrix and the ceramic coating comprise silicon carbide, and wherein the residual metal comprises silicon.

18. The CMC component of claim 16, wherein the ceramic coating further comprises some amount of the residual metal.

19. The CMC component of claim 16, wherein the ceramic coating has a thickness of from about 1 mil to about 20 mils.

20. The CMC component of claim 16 comprising a seal segment, a blade, a vane or a combustor liner of a gas turbine engine.