# US 12,180,591 B2 · Ceramic matrix composite surface roughness

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- Number: US 12,180,591 B2
- Document ID: US12180591B2
- Status: Granted
- Kind: B2
- Application number: 17/587,354
- Filed: 2022-01-28
- Published: 2023-08-03
- Granted: 2024-12-31
- Earliest claimed: 2022-01-28
- Assignees: Rtx Corporation
- Applicants: RTX Corporation
- Inventors: Ashley A. Smith; Andrew J. Lazur; Howard J. Liles
- Web page: https://patentgrep.com/patent/US12180591B2

## CPC

- C04B 41/91: involving the removal of part of the materials of the treated articles, e.g. etching
- C23C 16/52: Controlling or regulating the coating process {(C23C16/45557, C23C16/279 take precedence)}
- C04B 35/80: Fibres, filaments, whiskers, platelets, or the like
- C04B 41/009: {characterised by the material treated}
- C04B 41/53: involving the removal of at least part of the materials of the treated article, {e.g. etching, drying of hardened concrete (C04B41/0036 - C04B41/0054 take precedence)}
- C23C 16/0272: {Deposition of sub-layers, e.g. to promote the adhesion of the main coating}
- C23C 16/045: {Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates}
- C23C 16/56: After-treatment
- C04B 2235/5252: having a specific pre-form
- C04B 2235/5256: Two-dimensional, e.g. woven structures
- C04B 2235/614: Gas infiltration of green bodies or pre-forms
- C04B 2235/963: Surface properties, e.g. surface roughness
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A method of improving surface roughness of ceramic matrix composites (CMCs) is provided. The method includes completing a formation of the CMCs and a chemical vapor infiltration (CVI) process to initially coat the CMCs, inspecting a CMC surface, identifying, from a result of the inspecting, a defect in the CMC surface that negatively impacts a surface roughness characteristic thereof, locally targeting and ablating the defect and re-inspecting the CMC surface to ensure that the defect is correct.

## Claims

### Claim 1

A method of improving surface roughness of ceramic matrix composites (CMCs), the method comprising:
completing a formation of the CMCs and a chemical vapor infiltration (CVI) process to initially coat the CMCs;
inspecting a CMC surface;
identifying, from a result of the inspecting, a defect in the CMC surface in a form of a deviation of a fiber of the CMC surface from a nominal shape of the fiber that negatively impacts a surface roughness characteristic thereof;
locally targeting and ablating the defect by smoothing the fiber of the CMC surface; and
re-inspecting the CMC surface to ensure that the defect is corrected,
wherein the ablating comprises one of laser machining and an abrasive process to smooth the fiber of the CMC surface at and around a location of the defect without smoothing neighboring fibers.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the inspecting, the locally targeting and ablating and the reinspecting comprises programing tooling to follow a macroscopic contour of the CMC surface and to follow a microscopic contour of the fiber and other fibers of the CMCs of the CMC surface.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the inspecting comprises one of a structured light inspection and a digital inspection.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the inspecting is executed at a resolution of about 2/10000″.

### Claim 5 (depends on 1)

The method according to claim 1, further comprising repeating the CVI process at and around a location of the defect to re-initially coat the CMCs at and around the location of the defect.

### Claim 6 (depends on 1)

The method according to claim 1, further comprising:
applying an environmental barrier coating (EBC) comprising a bond coat and a top coat to the CMC surface; and
repeating the inspecting, the identifying, the locally targeting and ablating and the re-inspecting with respect to defects in the EBC.

### Claim 7

A method of improving surface roughness of an aerodynamic component formed of ceramic matrix composites (CMCs), the method comprising:
completing a formation of the aerodynamic component formed of the CMCs and a chemical vapor infiltration (CVI) process to initially coat the CMCs;
inspecting a CMC surface of the aerodynamic component;
identifying, from a result of the inspecting, a defect in the CMC surface in a form of a deviation of a fiber of the CMC surface from a nominal shape of the fiber that negatively impacts a surface roughness characteristic thereof;
locally targeting and ablating the defect by smoothing the fiber of the CMC surface; and
re-inspecting the surface to ensure that the defect is corrected,
wherein the ablating comprises one of laser machining and an abrasive process to smooth the fiber of the CMC surface at and around a location of the defect without smoothing neighboring fibers.

### Claim 8 (depends on 7)

The method according to claim 7, wherein the aerodynamic component comprises one of a vane, an airfoil and a blade outer air seal (BOAS) of a gas turbine engine.

### Claim 9 (depends on 7)

The method according to claim 7, wherein the inspecting, the locally targeting and ablating and the reinspecting comprises programing tooling to follow a macroscopic contour of the CMC surface and to follow a microscopic contour of the fiber and other fibers of the CMCs of the CMC surface.

### Claim 10 (depends on 7)

The method according to claim 7, wherein the inspecting comprises one of a structured light inspection and a digital inspection.

### Claim 11 (depends on 7)

The method according to claim 7, wherein the inspecting is executed at a resolution of about 2/10000″.

### Claim 12 (depends on 7)

The method according to claim 7, further comprising repeating the CVI process at and around a location of the defect to re-initially coat the CMCs at and around the location of the defect.

### Claim 13 (depends on 7)

The method according to claim 7, further comprising:
applying an environmental barrier coating (EBC) comprising a bond coat and a top coat to the CMC surface; and
repeating the inspecting, the identifying, the locally targeting and ablating and the re-inspecting with respect to defects in the EBC.