Graphite-reinforced plastic
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Graphite-reinforced plastic or carbon fibre reinforced plastic (CFRP or CRP), is a strong, light and very expensive composite material or fibre reinforced plastic. Like glass-reinforced plastic, the composite material is commonly referred to by the name of its reinforcing fibers (carbon fiber), an example of part-for-whole metonymy. The plastic is most often epoxy, but other plastics, like polyester or vinylester, are also sometimes used.
It has many applications in aerospace and automotive fields, as well as in sailboats, and notably in modern bicycles, where these qualities are of importance. It is becoming increasingly common in small consumer goods as well, such as laptops, tripods, and fishing rods.
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Composite
The choice of matrix can have a profound effect on the properties of the finished composite. One common plastic for this application is graphite epoxy, and materials produced with this methodology are generically referred to as composites. The material is produced by layering sheets of carbon fibre cloth into a mould in the shape of the final product. The alignment and weave of the cloth fibres is important for the strength of the resulting material. In professional applications all air is evacuated from the mould, however in applications where cost is more important than structural rigidity, this step is skipped. The mould is then filled with epoxy and is heated or air cured. The resulting stiff panel will not corrode in water and is very strong, especially for its weight. If the mould contains air, small air bubbles will be present in the material, reducing strength. For hobby or custom applications the cloth can instead be draped over a mould, and the epoxy is "painted" over it, however because of the resulting lack of strength, this is usually only used for cosmetic details.
The high amount of (often manual) work required to manufacture composites has hitherto limited their use in applications where a high number of complicated parts is required.
The chemistry and manufacturing techniques for thermosetting plastics like epoxy are often poorly-suited to mass-production. One potentially cost-saving and performance-enhancing measure involves replacing the epoxy matrix with a thermoplastic material such as Nylon or polyketone. Boeing's entry in the Joint Strike Fighter competition (http://en.wikipedia.org/wiki/Joint_Strike_Fighter#Program__History) included a Delta-shaped carbon fibre reinforced thermoplastic wing, but difficulties in fabrication of this part contributed to Lockheed Martin winning the competition.
Other materials can be used as the matrix for carbon fibres, as well. Due to the formation of metal carbides (i.e., water-soluble AlC) and corrosion considerations, carbon has seen limited success in metal matrix composite applications. Reinforced carbon-carbon (RCC) consists of carbon fibre-reinforced graphite, and is used structurally in high-temperature applications, such as the nose cone and leading edges of the space shuttle.
Automotive uses
Carbon fiber is used extensively in racing, most especially in Formula One and Indycar racing. The high cost of carbon fiber is mitigated by the material's unsurpassed strength-to-weight ratio, and low weight is essential for high-performance automobile racing.
Several supercars over the past few decades have used carbon fiber for various components. The most notable is the McLaren F1 which used the material extensively, even for the monocoque. Other supercars that make significant use of the material include the Bugatti EB110, Pagani Zonda and Ferrari Enzo.
Until now, the material has had limited use in mass-produced cars because of the expense involved - in terms of materials, equipment and the relatively limited pool of individuals with expertise in working with it.
BMW has begun studying and creating methods of producing carbon fibre reinforced plastics in its Landshut plant. To make the roof of the BMW M3 CSL, 5 layers of carbon fibre cloth are placed in an 1,800 ton press, where epoxy is resin transfer moulded and heat-cured in a robot-automated process. The resulting roof is half the weight of the equivalent steel roof.
Chevrolet is already using carbon fiber in its flagship sports car, the Corvette. A special option package for the Corvette, dubbed the Z06, includes carbon fiber front bodywork for reduced weight and added rigidity.
Use of the material has been more readily adopted by low-volume manufacturers like TVR who use it primarily for creating body-panels for some of their high-end cars due to its increased strength and decreased weight compared with the glass-reinforced plastic they use for the majority of their products.
See also
External links
- Japan Carbon Fibre Manufacturers Association (English) (http://www.carbonfibre.gr.jp/english/)
- Carbon fibre page from the Department of Polymer Science at USM (http://www.psrc.usm.edu/macrog/carfib.htm)
- BMW's use of carbon fibre reinforced plastics (http://www.germancarfans.com/News.cfm/NewsID/2030725.001)de:Kohlenstofffaser