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Carbon fibre or carbon fiber (See spelling differences) can refer to carbon filament thread, or to felt or woven cloth made from those carbon filaments. By extension, it is also used informally to mean any composite material made with carbon filament; for more on that application, see Carbon fibre reinforced plastic.
Each carbon filament is made out of long, thin filaments of carbon sometimes transferred to graphite. A common method of making carbon filaments is the oxidation and thermal pyrolysis of polyacrylonitrile (PAN), a polymer based on acrylonitrile used in the creation of synthetic materials. Like all polymers, polyacrylonitrile molecules are long chains, which are aligned in the process of drawing continuous filaments. When heated in the correct conditions, these chains bond side-to-side (ladder polymers), forming narrow graphene sheets which eventually merge to form a single, jelly roll-shaped or round filament. The result is usually 93-95% carbon. Lower-quality fiber can be manufactured using pitch or rayon as the precursor instead of PAN. The carbon can become further enhanced, as high modulus, or high strength carbon, by heat treatment processes. Carbon heated in the range of 1500-2000 °C (carbonization) exhibits the highest tensile strength (820,000 psi or 5,650 MPa or 5,650 N/mm²), while carbon fibre heated from 2500 to 3000 °C (graphitizing) exhibits a higher modulus of elasticity (77,000,000 psi or 531 GPa or 531 kN/mm²). For further literature see Rose, Ziegmann and Hillermeier.
There are several categories of carbon fibres: standard modulus (250 GPa) , intermediate modulus (300 GPa), and high modulus (> 300 GPa). The tensile strength of different yarn types varies between 2000 and 7000 MPa. The density of carbon fiber is 1750 kg/m<sup>3</sup>.
Precursors for carbon fibres are PAN, rayon and pitch. In former times rayon was more used as a precursor and still is for certain specialized applications (rockets). Carbon fiber filament yarns are used in several processing techniques: the direct uses are for prepregging, filament winding, pultrusion, weaving, braiding etc.
These filaments are stranded into a yarn. Carbon fiber yarn is rated by the linear density (weight per unit length = 1 g/1000 m = tex) or by number of filaments per yarn count, in thousands. For example 200 tex for 3,000 filaments of carbon fiber is 3 times as strong as 1,000 carbon fibers, but is also 3 times as heavy. This thread can then be used to weave a carbon fiber filament fabric or cloth. The appearance of this fabric generally depends on the linear density of the yarn and the weave chosen. Carbon fiber is naturally a glossy black but recently colored carbon fiber has become available.
Within the end-consumer carbon fiber textile industry, there is an increasing demand, along with an apparent decreasing supply. The result is an increased premium and moderate scarcity of small to medium amounts of carbon fiber fabrics, since approximately mid-2005. This declining supply is due to the large orders placed by priority customers such as militaries and aviation companies. The increasing demand is attributed to the widening realization of the viability of this material for use in high-tensile strength, low-weight applications.
Carbon fiber is most notably used to reinforce composite materials, particularly the class of materials known as carbon fiber reinforced plastics. This class of materials is used in aircraft parts, high-performance vehicles, tuner cars, sporting equipment such as racing bikes, wind generator blades and gears and other demanding mechanical applications; a more thorough discussion of these uses, including composite lay-up techniques, can be found in the carbon fiber reinforced plastic article.
Carbon fiber is one of the leading materials used in Formula One car production since the introduction of the fiber into common commercial use in the early 1980's.
Non-polymer materials can also be used as the matrix for carbon fibers. Due to the formation of metal carbides (i.e., water-soluble AlC), bad wetting by some metals, and corrosion considerations, carbon has seen limited success in metal matrix composite applications; however, this can be improved by proper surface treatment, eg. for carbon-aluminium MMCs a vapor deposition of titanium boride on the fibers is often employed. Reinforced carbon-carbon (RCC) consists of carbon fiber-reinforced graphite, and is used structurally in high-temperature applications, such as the nose cone and leading edges of the space shuttle.
The fiber also finds use in filtration of high-temperature gases, as an electrode with high surface area and impeccable corrosion resistance, and as an anti-static component in high-performance clothing.
Generally, within the realm of design and marketing there is a trend toward use of carbon fiber to imply a technical construction (for the given item) or associate it with traditional uses (i.e. military, or high performance) to attract a certain demographic. This is best noted in the increasing prevalence of carbon fiber in jewelery (i.e. Montblanc), pens (i.e. Caran d'Ache), and watches (i.e. TAG Heuer).
Some string instruments, such as violins and cellos, use carbon fiber reinforced composite bows. This is an alternative to the more common wooden bows. There are also several companies which make entire instruments, such as cellos, guitars, and mandolins out of carbon fiber.
Knife manufacturers sometimes use carbon fiber for functional purposes, such as creating lightweight handles and scales. Some also use carbon fiber inserts for decorative purposes. An entire knife can be constructed from carbon fiber.
Many high-end frames for road bikes and mountain bikes are made of carbon fiber reinforced composite. Also, many road bikes made of aluminum have carbon fiber reinforced composite seat posts and seat stays. Additionally, handlebars and forks use carbon fiber for reduced weight, improved rider comfort and stiffness. Carbon fiber has also found its way into the sole of high end cycling shoes made for road racing because of their stiffness.
Some velomobiles use a monocoque body constructed with carbon fiber.
It is also widely used to enhance the look of automobiles and reduce weight. Many of the "tuner" style cars have carbon fiber hoods or other components to reduce weight. Another use is in the increasingly popular hobby of RC cars, many high-end kits come with many carbon fiber parts due to their light weight and attractive appearance.
In motorsports, carbon fiber is often used to construct bodywork or a monocoque chassis. This trend started in Formula 1 and has gradually been adopted in other forms of motor racing.
Carbon fiber is commonly used in aftermarket motorcycle accessories because of its high rigidity and low weight. These parts range from small covers and panel replacements, to entire frames and wheels. Much of the demand for carbon fiber in the motorcycle community is made by the professional racers and factory race teams who exhaustively utilize carbon fiber for the above mentioned reasons. Reducing the weight and increasing the strength of motorcycle parts can allow for vast improvements in the power-to-weight ratio and suspension response of the vehicle.
Newer designs of Aircraft are beginning to make increased use of carbon fiber composities. For example, the Airbus A380 uses many CFRP components.
Carbon fiber is also used by skateboard companies to make strong lightweight skateboards for all types of skating, mainly downhill speedboarding. It is also used in many composite longboards to stiffen an otherwise very flexible board.
In surfing, carbon fiber is emerging as a very high-end (and very expensive) board construction material, exhibiting even higher strength and lighter weight than epoxy boards.
Carbon fiber is used on racing yachts, rowing boats, kayaks and canoes, as well as on the paddles and oars used with them. Its use has allowed boat builders to produce stiffer and lighter boats. Carbon, along with other artificial fibers, has replaced more traditional laminated wooden or fiberglass constructions.
Carbon fiber is a prime material for use in archery. Many modern day arrows are made as either aluminium-carbon composites, or entirely carbon fiber. Limbs can also have a laminate system consisting of carbon fiber sheets with materials such as foam. This makes the bow faster and smoother to shoot. Another use in archery is in the bow's riser, for both recurve and compound bows. More risers nowadays are beginning to have carbon fiber parts, which makes them lighter, and there are several companies that have made full carbon fiber risers (including Carbofast and KG), with at least 3 currently in production (Win&Win, FiberBow the first in total carbon, and High Country Archery[compound]).
In cycling, the use of carbon fiber for both frames and different components became commonplace in the late 90s/early 2000s, a notable early example being Chris Boardman's full-carbon monocoque Lotus frame which he rode in the 1996 Olympic Games in Atlanta in track events. This so-called 'carbon revolution' resulted in the production of bicycles with weight-to-stiffness characteristics that had never been seen before, eventually leading to the almost-exclusive use of carbon as a material of choice in high-end competition bicycles in all disciplines of the sport. Today, carbon fiber frames are quite common even in the non-sponsored amateur ranks (nevertheless they are still quite expensive), along with many types of components, e.g. wheels, handlebars, seat pillars etc.
High-end sports kites are framed using carbon fibre spars, taking advantage of the low weight and high rigidity of the material. Cheaper pultruded spars are still popular but "wrapped" and conical spars are now standard in high-end kites. Manufacturers include Skyshark, Aerostuff and Avia.
In Track and Field, carbon fiber has been used in newer designs of pole vault poles, to add rigidity while reducing weight, javelins for the same purpose, and the discus, to increase the percentage of rim weight for higher spin.
Carbon fiber is used in lacrosse and hockey shafts and curling brooms. Pure carbon fibre sticks are rare due to the brittleness of carbon fiber. In these sticks carbon fibre is often found in composites. [1]
Carbon fiber is also used in many paintball products. Carbon fiber barrels, tanks, and triggers are not uncommon in aftermarket paintball parts.
Carbon fiber can also be found in shoes. Nike, in particular, uses foot-length carbon fiber spring plates in high-end basketball shoes like the Air Jordan XI. These plates are found between the outsole and the midsole, usually partially exposed along some stretches of the sole.
Several photographic tripod manufacturers, including Manfrotto and Gitzo, employ carbon fiber in their professional range tripods, due in large part to its lightweight properties and its comparable strength to aluminum, the material most consumer tripods are made from.
Toyo View also produces a 4x5 view camera made partially from carbon fiber, mostly used in this case to cut down on the high weight of a standard large format camera.