Information about Carbon Fiber

Carbon fibre or carbon fiber can refer to carbon filament thread, or to felt or woven cloth made from those carbon filaments. By extension, the term is also used informally to mean any composite material made with carbon filament, such as carbon fiber reinforced plastic. Carbon fibers find many uses because of their strength and light weight. Carbon fiber was invented in the early 1960's at the Royal Aircraft Establishment at Farnborough, Hampshire (England).

Structure and properties

Each carbon filament thread is a bundle of many thousand carbon filaments. A single such filament is a thin tube with a diameter of 5–8 micrometers and consists almost exclusively of carbon.

The atomic structure of carbon fiber is similar to that of graphite, consisting of sheets of carbon atoms arranged in a regular hexagonal pattern. The difference lies in the way these sheets interlock. Graphite is a crystalline material in which the sheets are stacked parallel to one another in regular fashion. The chemical bonds between the sheets are relatively weak, giving graphite its soft and brittle characteristics. Carbon fiber is an amorphous material: the sheets of carbon atoms are haphazardly folded, or crumpled, together. This interlocks the sheets, preventing slippage and greatly increasing the strength of the material.

The density of carbon fiber is 1750 kg/m³. It has high electrical and low thermal conductivity. When heated, a carbon filament becomes thicker and shorter. Carbon fiber is naturally a glossy black color. Recently, however, colored carbon fiber has become available.

Carbon fiber thread or yarn is rated by either linear density (mass per unit length, with the unit 1 tex = 1 g/1000 m), or by the number of filaments per yarn, in thousands.

Synthesis

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, the non-carbon constituents evaporate away, the chains bond side-to-side (ladder polymers) and form 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 fiber can become further enhanced 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 fiber 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.

Uses

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, sports equipment such as racing bikes, radio controlled vehicles, 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 1980s.

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, e.g., 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 (e.g. Montblanc), [pen|pens]] (e.g. Caran d'Ache), and watches (e.g. TAG Heuer).

Musical instruments

Some string instruments, such as guitars and members of the violin family are being fabricated of carbon fiber reinforced composite. One revolutionary company, XOX Audio Tools, makes a Monocoque carbon fiber electric guitar, the Handle. There is also a company specializing in Carbon Fiber wind instruments offering bagpipe chanters, tin whistles and flutes currently manufacturing product.

For over a decade, a number of drum companies such as Tempus and Rocket Shells have been using carbon fiber in their kits and individual snare drums. Carbon fiber solves a number of problems inherent to wood drums and is especially beneficial when used in drums used by drum corps and marching bands, which are typically worn while played. There is also a company called Carbonlite making a lightweight drum rack and cymbal boom arms out of carbon fiber.

Utensils

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.

Vehicles

Many high-end frames for road bikes and mountain bikes are made of carbon fiber reinforced composite. 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.

Newer designs of aircraft are beginning to make increased use of carbon fiber composities. For example, the Airbus A380 uses many CFRP components. The even newer Boeing 787 Dreamliner will be the first passenger jet with a main wing and fuselage (body) made entirely out of carbon fiber. This is one of the main causes of the current worldwide shortage as Boeing have bought up most of the world's output for the new 787.

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.

Sports equipment

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. As well as these water sports, carbon fiber is also used in the construction of water skis from Goode Ski Technologies of Ogden, Utah.

Carbon fiber is a prime material for use in archery. Many modern-day arrows are made as either aluminium-carbon composites or entirely of carbon fiber. Limbs can also have a laminate system, consisting of carbon fiber sheets alternated 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 1992 Olympic Games in Barcelona 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.

Fishing rods are often made of carbon fiber: this started during the 1970s. Prior to that, heavier glassfiber rods were used.

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 events, 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 stick 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.

In sailing and yacht racing, traditionally wood, and then aluminum, were used to form components such as spars. Newer sailboat designs incorporate carbon fibre materials for these parts to reduce weight. An example of this is the Pixel, which sports a carbon-fibre mast.^[2]

Photography equipment

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 large format 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.

See also

• Carbon nanotube
• Tenax

References

External links

• Working with Carbon fiber for Robotics and R/C Aircraft
• Carbon Fiber in Formula One
• The Chemistry of Carbon Fiber
• Making Carbon Fiber
• Carbon Fiber Examples
• Luis and Clark Carbon Fiber Musical Instruments
• Carbon Fiber Musical Instruments XOX Audio Tools

•  • [ e] Fibers
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