# US 2017/0283330 A1 · High density carbon-carbon friction materials

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- Number: US 2017/0283330 A1
- Document ID: US20170283330A1
- Status: Published application
- Kind: A1
- Application number: 15/088,941
- Filed: 2016-04-01
- Published: 2017-10-05
- Earliest claimed: 2016-04-01
- Assignees: Honeywell International Inc.
- Applicants: Honeywell International Inc.
- Inventors: Slawomir T. Fryska; Neil Murdie; Mark L. La Forest
- Web page: https://patentgrep.com/patent/US20170283330A1

## CPC

- C04B 35/83: Carbon fibres in a carbon matrix
- C04B 35/62272: {based on non-oxide ceramics (carbon nanotubes C01B32/15; carbon fibers D01F9/12)}
- C04B 35/6455: {Hot isostatic pressing}
- C23C 16/26: Deposition of carbon only
- F16D 69/023: {Composite materials containing carbon and carbon fibres or fibres made of carbonizable material}
- C04B 2235/3418: Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
- C04B 2235/422: Carbon
- C04B 2235/424: Carbon black
- C04B 2235/425: Graphite
- C04B 2235/428: Silicon
- C04B 2235/48: Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins
- C04B 2235/5248: Carbon, e.g. graphite
- C04B 2235/5252: having a specific pre-form
- C04B 2235/5436: micrometer sized, i.e. from 1 to 100 micron
- C04B 2235/612: Machining
- C04B 2235/616: Liquid infiltration of green bodies or pre-forms
- C04B 2235/6562: Heating rate
- C04B 2235/658: Atmosphere during thermal treatment
- C04B 2235/661: Multi-step sintering
- 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)
- F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES

## Abstract

A technique of forming a carbon-carbon composite that includes infiltrating a preform comprising carbon fibers or carbon-precursor fibers with a pitch and pyrolyzing the pitch using a controlled pressure and temperature ramp rate to control a growth of optical textures as the pitch is pyrolyzed to a coke matrix. Pyrolyzing the pitch may include initiating pyrolysis of at least some of the pitch at a first pressure less than about 2000 psi and a first temperature ramp rate between about 5 ° C./hr and about 50 ° C./hr to a first target temperature, and pyrolyzing at least some of the pitch at a second pressure greater than 2000 psi and a second temperature ramp rate between about 5 ° C./hr and about 50 ° C./hr to a second target temperature, where the second target temperature is greater than the first target temperature.

## Claims

### Claim 1

A method of forming a carbon-carbon composite comprising:
infiltrating a preform comprising carbon fibers or carbon-precursor fibers with a pitch to form an infiltrated preform;
pyrolyzing the pitch in the infiltrated preform using a controlled pressure and temperature ramp rate to control a growth of optical textures as the pitch is pyrolyzed to a coke matrix, wherein pyrolyzing the pitch using the controlled pressure and temperature ramp rate comprises:
initiating pyrolysis of at least some of the pitch at a first pressure and a first temperature ramp rate to a first target temperature, wherein the first pressure is less than about 2000 pounds per square inch (psi), wherein the first temperature ramp is between about 5 degrees Celsius per hour (5° C./hr) and about 50° C./hr; and
pyrolyzing at least some of the pitch at a second pressure and a second temperature ramp rate to a second target temperature, wherein the second pressure is greater than 2000 psi, wherein the second temperature ramp rate is between about 5° C./hr and about 50° C./hr, and wherein the second target temperature is greater than the first target temperature.

### Claim 2 (depends on 1)

The method of claim 1, wherein the coke matrix comprises at least about 80% by volume, large-sized optical textures that define a major dimension of at least 10 microns.

### Claim 3 (depends on 1)

The method of claim 1, wherein the pitch comprises an isotropic pitch.

### Claim 4 (depends on 1)

The method of claim 1, wherein pyrolyzing the pitch using a controlled pressure and controlled temperature, further comprises, increasing the pressure from the first pressure to the second pressure.

### Claim 5 (depends on 1)

The method of claim 1, wherein the first temperature ramp rate is less than second temperature ramp rate.

### Claim 6 (depends on 1)

The method of claim 1, wherein initiating pyrolysis comprises heating the preform and the pitch over a first range of temperatures at the first temperature ramp rate, wherein the first temperature range comprises a range of temperatures between an initial temperature below a pyrolysis temperature of the pitch and the first target temperature.

### Claim 7 (depends on 6)

The method of claim 6, wherein the first temperature ramp rate comprises about 5° C./hr to about 25° C./hr.

### Claim 8 (depends on 1)

The method of claim 1, wherein the first target temperature is less than about 450 degrees Celsius (° C.), and wherein the second target comprises a temperature less than about 700° C.

### Claim 9 (depends on 8)

The method of claim 8, wherein the second temperature ramp rate comprises about 10° C./hr to about 50° C./hr.

### Claim 10 (depends on 1)

The method of claim 1, further comprising cooling the infiltrated preform after infiltrating the preform with the pitch and before pyrolyzing the pitch in the infiltrated preform to allow at least some of the pitch to solidify in the preform.

### Claim 11

A method for making a carbon-carbon composite brake disc, the method comprising:
pyrolyzing a pitch in a preform using a controlled pressure and temperature ramp rate to control a growth of optical textures formed as the pitch is pyrolyzed to a coke matrix, wherein the preform comprises carbon fibers or carbon-precursor fibers, wherein the pitch comprises at least one isotropic pitch, and wherein pyrolyzing the pitch using the controlled pressure and temperature ramp rate comprises:
heating the pitch and the preform in a vessel at a first pressure less than about 2000 pounds per square inch (psi) at a first temperature ramp rate between about 5 degrees Celsius per hour (5° C./hr) and about 50° C./hr to a first target temperature less than about 450 degrees Celsius (° C.) to convert at least some of the pitch to the coke matrix, wherein the coke matrix includes at least one optical texture;
increasing a pressure in the vessel from the first pressure to a second pressure between 2000 psi and about 15,000 psi; and
heating the pitch and the preform in the vessel at the second pressure, at a second temperature ramp rate between about 5° C./hr and about 50° C./hr to covert the remaining pitch to the coke matrix.

### Claim 12 (depends on 11)

The method of claim 11, wherein the coke matrix comprises large-sized optical textures that each define a major dimension of at least 10 micrometers (μm).

### Claim 13 (depends on 12)

The method of claim 12, wherein large-sized optical textures comprise at least about 80% by volume of the coke matrix.

### Claim 14 (depends on 11)

The method of claim 11, further comprising holding the pitch and the preform at the first target temperature for a predetermined period of time to convert at least some of the pitch to the coke matrix,

### Claim 15 (depends on 11)

The method of claim 11, wherein and the first temperature ramp rate comprises about 5° C./hr to about 25° C./hr and the second temperature ramp rate comprises about 10° C./hr to about 25° C./hr.

### Claim 16 (depends on 11)

The method of claim 11, wherein the pitch consists of isotropic pitch.

### Claim 17

An assembly for making a carbon-carbon composite comprising:
a vessel;
a pitch-infiltrated preform in the shape of the carbon-carbon composite disposed in the vessel, wherein the pitch-infiltrated preform comprises:
an isotropic pitch, and
a preform derived from:
a plurality of layers comprising carbon fibers or carbon-precursor fibers, and
needled fibers comprising carbon fibers or carbon-precursor fibers; and
a pressure and heat source, wherein the pressure and heat source are configured to apply a first pressure less than about 500 pounds per square inch (psi) to the pitch-infiltrated preform deposited in the vessel and heat the pitch-infiltrated preform over a first range of temperatures at a first temperature ramp rate between about 5 degrees Celsius per hour (5° C./hr) and about 50° C./hr to initiate pyrolysis of the isotropic pitch to a coke matrix, and then apply a second pressure greater than about 10,000 psi to the pitch-infiltrated preform deposited in the vessel and heat the pitch-infiltrated preform over a second range of temperatures at a second temperature ramp rate between about 5° C./hr and about 50° C./hr to complete pyrolyze the isotropic pitch to coke matrix.

### Claim 18 (depends on 17)

The assembly of claim 17, wherein the first range of temperatures comprises a range less than about 450 degrees Celsius (° C.) and the second range of temperatures comprises a range greater than the first range of temperature and less than about 700° C.

### Claim 19 (depends on 17)

The assembly of claim 17, wherein and the first temperature ramp rate comprises about 5° C./hr to about 15° C./hr and the second temperature ramp rate comprises about 10° C./hr to about 25° C./hr.

### Claim 20 (depends on 17)

The assembly of claim 17, wherein the coke matrix comprises large-sized optical textures that define a major dimension of at least 10 micrometers (μm), wherein the large-sized optical textures comprise at least about 80% by volume of the coke matrix.