# US 5,705,008 A · Fiber-reinforced carbon and graphite articles and method for the production thereof

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- Number: US 5,705,008 A
- Document ID: US5705008A
- Status: Granted
- Kind: A
- Application number: 08/685,163
- Filed: 1996-07-23
- Granted: 1998-01-06
- Earliest claimed: 1994-08-05
- Assignees: Amoco Corporation
- Inventors: Daniel H. Hecht
- Web page: https://patentgrep.com/patent/US5705008A

## CPC

- C22C 49/14: characterised by the fibres or filaments
- C04B 35/80: Fibres, filaments, whiskers, platelets, or the like
- C04B 35/83: Carbon fibres in a carbon matrix
- C22C 47/00: Making alloys containing metallic or non-metallic fibres or filaments
- C22C 47/025: {Aligning or orienting the fibres}
- D04H 1/4242: Carbon fibres
- D04H 1/46: by needling or like operations to cause entanglement of fibres (D04H1/45 takes precedence; needling machines D04H18/00)
- F16D 69/023: {Composite materials containing carbon and carbon fibres or fibres made of carbonizable material}
- F16D 69/026: {containing fibres}
- B22F 2998/00: Supplementary information concerning processes or compositions relating to powder metallurgy
- C04B 2235/526: characterised by the length of the fibers
- C04B 2235/5268: Orientation of the fibers
- C04B 2235/608: Green bodies or pre-forms with well-defined density
- C04B 2235/614: Gas infiltration of green bodies or pre-forms
- C04B 2235/77: Density
- C04B 2235/95: Products characterised by their size, e.g. microceramics
- C04B 2235/96: Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
- C04B 2235/9607: Thermal properties, e.g. thermal expansion coefficient
- Y10T 428/24992: Density or compression of components
- Y10T 428/30: Self-sustaining carbon mass or layer with impregnant or other layer
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- 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
- D04H: MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL (weaving D03; knitting D04B; braiding D04C; net-making D04G; sewing D05B; tufting D05C; finishing non-woven fabrics D06); FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING {; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION}(non-woven fabrics having an intermediate or external layer of a different kind, e.g. of woven fabric, B32B)
- F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The present invention relates to the fabrication of thick, three-dimensional structures comprising discontinuous thermoset pitch fiber, and to composites comprising such structures embedded in a matrix material such as a thermoset resin, ceramic, metal or carbon. Carbon-carbon fiber composite articles produced from porous carbon preforms obtained by carbonizing such structures followed by infiltration with pyrolytic carbon using CVD processes exhibit surprisingly high through-thickness thermal conductivity and isotropic properties.

## Claims

### Claim 1

A method for producing a fibrous preform comprising the steps of forming a mat of discontinuous thermoset pitch fiber having a length greater than about 0.5 inch, said mat having a thickness in a range of from about 1/2 inch to about 4 inches and a density in a range of from 0.3 to about 0.6 g/cc; and needle punching said mat substantially normal to a surface to form filament bundles and re-orient a portion of said filament bundles in the needled direction.

### Claim 2 (depends on 1)

The method of claim 1 wherein said discontinuous thermoset pitch fiber is chopped multifilament tow having a nominal length in the range of from about 1 to about 4 inches.

### Claim 3 (depends on 1)

The method of claim 1 wherein said discontinuous thermoset pitch fiber is chopped multifilament tow having a nominal length of about 2 inches.

### Claim 4

A method for producing a fibrous preform comprising the steps of: providing shaping means for holding fiber; placing discontinuous thermoset pitch fiber having a length greater than about 0.5 inch into said shaping means and forming a mat having a thickness in a range of from about 1/2 inch to about 4 inches and a density of from about 0.3 to about 0.6 g/cc; needlepunching said mat substantially normal to a surface and at a needle density of from about 100 to about 10,000 per square inch to form filament bundles and re-orient a portion of said filament bundles in the needled direction, thereby providing a three-dimensional filamentary structure; and carbonizing said filamentary structure by heating in an inert atmosphere to a temperature greater than about 1000.degree. C. to provide a porous carbon preform.

### Claim 5 (depends on 4)

The method of claim 4 wherein said heating is conducted to a temperature in the range of from about 1200.degree. to about 2200.degree. C.

### Claim 6 (depends on 4)

The method of claim 4 wherein said heating is conducted to a final temperature in a range of between about 2600.degree. to about 3400.degree. C., thereby substantially graphitizing said filamentary structure.

### Claim 7 (depends on 4)

The method of claim 4 wherein said discontinuous thermoset pitch fiber is chopped, thermoset pitch fiber tow having a nominal length of from about 1 to about 4 inches, said tow being sized and having a moisture content of from about 20 to about 30 wt %.

### Claim 8 (depends on 4)

The method of claim 4 wherein said porous carbon preform has a bulk density in the range 0.4 to about 0.7 g/cc.

### Claim 9 (depends on 4)

The method of claim 4 wherein said preform has a bulk density greater than 0.5 g/cc and a unit flow resistance in the needled direction of less than about 0.2 psi/liters/min-cm.