CORE-Materials
Carbon-carbon composite
DoITPoMS, University of Cambridge
Carbon-carbon composites are manufactured from continuous carbon fibres which are woven in a two or three dimensional pattern. The fibres are then impregnated with a polymeric resin. After the component has been shaped and cured the matrix is pyrolysed by heating in an inert atmosphere. This converts the matrix to carbon chain molecules which are densified by further heat treatments. The resulting composite consists of the original carbon fibres in a carbon matrix. Carbon-carbon composites have low density, high strength and high modulus. These properties are retained to temperatures above 2000ºC. Creep resistance and toughness are also high, and the high thermal conductivity and low thermal expansion coefficient provide thermal shock resistance. The woven structure of this composite can be seen in the low magnification micrograph. At high magnification, the fibres can be resolved. The fibres are continuous, but appear to be discontinuous as they are not parallel to the section plane of the sample.
System
CCcomposite
Composition
Not specified
Reaction
Processing
Woven, continuous carbon fibres, impregnated with a polymeric resin. Composite is then shaped, cured, and matrix is pyrolised by heat in an inert atmosphere
Applications
Typical applications include braking materials in aircraft and high performance cars, ablative shields for aerospace vehicles such as the nose cap and wing leading edges of the Space Shuttle orbiter and hot-pressing moulds. A SiC coating is used to protect the composite from high temperature oxidation.
Sample preparation
Technique
Reflected light microscopy
Contributor
Dr J Marrow
Organisation
Department of Materials Science, University of Manchester and UMIST
Carbon-carbon composite
DoITPoMS, University of Cambridge
Carbon-carbon composites are manufactured from continuous carbon fibres which are woven in a two or three dimensional pattern. The fibres are then impregnated with a polymeric resin. After the component has been shaped and cured the matrix is pyrolysed by heating in an inert atmosphere. This converts the matrix to carbon chain molecules which are densified by further heat treatments. The resulting composite consists of the original carbon fibres in a carbon matrix. Carbon-carbon composites have low density, high strength and high modulus. These properties are retained to temperatures above 2000ºC. Creep resistance and toughness are also high, and the high thermal conductivity and low thermal expansion coefficient provide thermal shock resistance. The woven structure of this composite can be seen in the low magnification micrograph. At high magnification, the fibres can be resolved. The fibres are continuous, but appear to be discontinuous as they are not parallel to the section plane of the sample.
System
CCcomposite
Composition
Not specified
Reaction
Processing
Woven, continuous carbon fibres, impregnated with a polymeric resin. Composite is then shaped, cured, and matrix is pyrolised by heat in an inert atmosphere
Applications
Typical applications include braking materials in aircraft and high performance cars, ablative shields for aerospace vehicles such as the nose cap and wing leading edges of the Space Shuttle orbiter and hot-pressing moulds. A SiC coating is used to protect the composite from high temperature oxidation.
Sample preparation
Technique
Reflected light microscopy
Contributor
Dr J Marrow
Organisation
Department of Materials Science, University of Manchester and UMIST