Editing Carbon fibers

{{short description|Material fibers about 5–10 μm in diameter composed of carbon}}
{{About|loose or woven carbon filament|the rigid composite material made from carbon fiber used in aerospace and other applications|Carbon fiber reinforced polymer}}
{{Use American English|date=September 2020}}<!-- IUPAC spelling for chemical elements (aluminium, sulfur, caesium, etc.). -->

[[File:Kohlenstofffasermatte.jpg|thumb|right|Fabric made of woven carbon filaments]]
<!-- Please do not change the spelling of fiber to fibre. Wikipedia policy is to retain the English dialect used in the first nonstub version of an article. This prevents needless "spelling wars". Changing the spelling also breaks links and categories. Changing the spelling will be treated as vandalism, and for this reason will be swiftly reverted. Please see the discussion page if you want to comment. -->
{{Fibre sidebar}}

'''Carbon fibers''' [[American and British English spelling differences|or]] '''carbon fibres''' (alternatively CF, graphite fiber or graphite fibre) are [[fiber]]s about {{convert|5|to(-)|10|μm|in|sp=us}} in diameter and composed mostly of [[carbon]] atoms.<ref>{{Citation|last1=Chaudhary|first1=Anisha|title=Electromagnetic Shielding Capabilities of Metal Matrix Composites|date=2021-01-01|url=https://www.sciencedirect.com/science/article/pii/B9780128035818118284|encyclopedia=Encyclopedia of Materials: Composites|pages=428–441|editor-last=Brabazon|editor-first=Dermot|place=Oxford|publisher=Elsevier|language=en|isbn=978-0-12-819731-8|access-date=2022-02-14|last2=Gupta|first2=Vinay|last3=Teotia|first3=Satish|last4=Nimanpure|first4=Subhash|last5=Rajak|first5=Dipen K.}}</ref> Carbon fibers have several advantages: high stiffness, high tensile strength, high strength to weight ratio, high chemical resistance, high-temperature tolerance, and low thermal expansion.<ref>{{cite thesis |url=https://www.materialsciencejournal.org/vol14no1/carbon-fibres-production-properties-and-potential-use/ |title=Carbon Fibres: Production, Properties and Potential Use |first=Pooja |last=Bhatt |date=2017 |access-date=2021-07-25 |url-status=live |archive-url=https://web.archive.org/web/20210430225305/https://www.materialsciencejournal.org/vol14no1/carbon-fibres-production-properties-and-potential-use/ |archive-date=2021-04-30}}</ref> These properties have made carbon fiber very popular in aerospace, civil engineering, military, motorsports, and other competition sports.<ref>{{Cite web |url=https://www.clarco.com/what-is-carbon-fiber-plate-in-shoes.html |title=What is the Carbon Fiber Plate in Shoes? Let's Make It All Clear Here! |date=19 November 2022 |publisher=clarco.com |access-date=2022-11-19}}</ref> However, they are relatively expensive compared to similar fibers, such as [[glass fiber]], [[basalt fiber]]s, or plastic fibers.<ref>{{cite journal |url=https://www.sv-jme.eu/?ns_articles_pdf=/ns_articles/files/ojs/43/submission/copyedit/43-130-1-CE.pdf&id=2847 |title=Application of Ultrasonic C-Scan Techniques for Tracing Defects in Laminated Composite Materials |first1=Theodoros |last1=Hasiotis |first2=Efstratios |last2=Badogiannis |first3=Nicolaos Georgios |last3=Tsouvalis |journal=Strojniški vestnik – Journal of Mechanical Engineering |volume=57 |issue=3 |pages=192–203 |year=2011 |doi=10.5545/sv-jme.2010.170 |access-date=2023-02-21 |issn=2536-3948|doi-access=free }}</ref>

To produce a carbon fiber, the carbon atoms are bonded together in crystals that are more or less aligned parallel to the fiber's long axis as the crystal alignment gives the fiber a high strength-to-volume ratio (in other words, it is strong for its size). Several thousand carbon fibers are bundled together to form a [[tow (fibre)|tow]], which may be used by itself or [[woven]] into a fabric. 

Carbon fibers are usually combined with other materials to form a [[composite material|composite]]. For example, when permeated with a [[Plastic|plastic resin]] and [[autoclave (industrial)|baked]], it forms [[carbon-fiber-reinforced polymer]] (often referred to as carbon fiber), which has a very high [[strength-to-weight ratio]] and is extremely rigid although somewhat brittle. Carbon fibers are also composited with other materials, such as [[graphite]], to form [[reinforced carbon-carbon]] composites, which have a very high heat tolerance.

Carbon fiber-reinforced materials are used to make aircraft and spacecraft parts, racing car bodies, golf club shafts, bicycle frames, fishing rods, automobile springs, sailboat masts, and many other components where light weight and high strength are needed.

==History==
[[File:Carbon fibers from silk cocoon.tif|thumb|Carbon fibers produced by [[pyrolysis]] of a silk cocoon. Electron micrograph—scale bar at bottom left shows 100 [[micrometre|μm]].]]

In 1860, [[Joseph Swan]] produced carbon fibers for the first time, for use in light bulbs.<ref>{{cite thesis |url=https://drum.lib.umd.edu/bitstream/handle/1903/6997/umi-umd-4508.pdf |title=Carbon Fiber Electronic Interconnects |first=Yuliang |last=Deng |date=2007 |access-date=2017-03-02 |url-status=live |archive-url=https://web.archive.org/web/20190404201211/https://drum.lib.umd.edu/bitstream/handle/1903/6997/umi-umd-4508.pdf |archive-date=2019-04-04}}</ref> In 1879, [[Thomas Edison]] baked cotton threads or bamboo slivers at high temperatures carbonizing them into an all-carbon fiber filament used in one of the first incandescent light bulbs to be heated by electricity.<ref>{{cite web |url=http://www.acs.org/content/acs/en/education/whatischemistry/landmarks/carbonfibers.html |title=High Performance Carbon Fibers |publisher=American Chemical Society |work=National Historic Chemical Landmarks |date=2003 |access-date=2014-04-26 |url-status=live |archive-url=https://web.archive.org/web/20140427100035/http://www.acs.org/content/acs/en/education/whatischemistry/landmarks/carbonfibers.html |archive-date=2014-04-27}}</ref> In 1880, [[Lewis Howard Latimer|Lewis Latimer]] developed a reliable carbon wire filament for the incandescent light bulb, heated by electricity.<ref>{{cite web |url=http://www.nps.gov/edis/forkids/the-gifted-men-who-worked-for-edison.htm |title=The Gifted Men Who Worked for Edison |publisher=National Park Service |access-date=2014-12-01 |url-status=live |archive-url=https://web.archive.org/web/20150207003814/http://www.nps.gov/edis/forkids/the-gifted-men-who-worked-for-edison.htm |archive-date=2015-02-07}}</ref>

In 1958, [[Roger Bacon (physicist)|Roger Bacon]] created high-performance carbon fibers at the [[Union Carbide]] Parma Technical Center located outside of [[Cleveland]], [[Ohio]].<ref>{{cite patent |inventor=Bacon, Roger |title=Filamentary graphite and method for producing the same |country=US |number=2957756 |gdate=1960-10-25 |fdate=1958-03-18}}</ref> Those fibers were manufactured by heating strands of [[rayon]] until they [[carbonization|carbonized]]. This process proved to be inefficient, as the resulting fibers contained only about 20% carbon. In the early 1960s, a process was developed by Dr. Akio Shindo at [[National Institute of Advanced Industrial Science and Technology|Agency of Industrial Science and Technology]] of Japan, using [[polyacrylonitrile]] (PAN) as a raw material. This had produced a carbon fiber that contained about 55% carbon. In 1960 Richard Millington of H.I. Thompson Fiberglas Co. developed a process (US Patent No. 3,294,489) for producing a high carbon content (99%) fiber using rayon as a precursor. These carbon fibers had sufficient strength (modulus of elasticity and tensile strength) to be used as a reinforcement for composites having high strength to weight properties and for high temperature resistant applications.

The high potential strength of carbon fiber was realized in 1963 in a process developed by W. Watt, L. N. Phillips, and W. Johnson at the [[Royal Aircraft Establishment]] at [[Farnborough, Hampshire]]. The process was patented by the UK [[Ministry of Defence (United Kingdom)|Ministry of Defence]], then licensed by the British [[National Research Development Corporation]] to three companies: [[Rolls-Royce Limited|Rolls-Royce]], who were already making carbon fiber; Morganite; and [[Courtaulds]]. Within a few years, after successful use in 1968 of a ''Hyfil'' [[Carbon-fiber-reinforced polymer|carbon-fiber]] fan assembly in the [[Rolls-Royce Conway]] jet engines of the [[Vickers VC10]],<ref>{{cite journal |url=http://www.flightglobal.com/pdfarchive/view/1968/1968%20-%202107.html?search=rolls-royce%20rb211%20hyfil |title=Stand Points |journal=Flight International |via=Flight Global Archive |page=481 |date=1968-09-26 |access-date=2014-08-14 |archive-url=https://web.archive.org/web/20140814123711/http://www.flightglobal.com/pdfarchive/view/1968/1968%20-%202107.html?search=rolls-royce%20rb211%20hyfil |archive-date=2014-08-14}}</ref> Rolls-Royce took advantage of the new material's properties to break into the American market with its [[Rolls-Royce RB211|RB-211]] aero-engine with carbon-fiber compressor blades. Unfortunately, the blades proved vulnerable to damage from [[Bird strike|bird impact]]. This problem and others caused Rolls-Royce such setbacks that the company was nationalized in 1971. The carbon-fiber production plant was sold off to form ''Bristol Composite Materials Engineering Ltd''<ref>{{Cite web|title=Rolls-Royce - Graces Guide|url=https://www.gracesguide.co.uk/Rolls-Royce#cite_note-16|access-date=2020-09-22|website=www.gracesguide.co.uk}}</ref> (often referred to as Bristol Composites).

In the late 1960s, the Japanese took the lead in manufacturing PAN-based carbon fibers. A 1970 joint technology agreement allowed [[Union Carbide]] to manufacture Japan's [[Toray Industries]] product. Morganite decided that carbon-fiber production was peripheral to its core business, leaving Courtaulds as the only big UK manufacturer. Courtaulds's water-based inorganic process made the product susceptible to impurities that did not affect the organic process used by other carbon-fiber manufacturers, leading Courtaulds ceasing carbon-fiber production in 1991.

[[File:Ready to use carbon fiber sheet.jpg|thumb|Ready-to-use carbon fiber sheet in the factory before molding]]

During the 1960s, experimental work to find alternative raw materials led to the introduction of carbon fibers made from a petroleum pitch derived from oil processing. These fibers contained about 85% carbon and had excellent flexural strength. Also, during this period, the Japanese Government heavily supported carbon fiber development at home and several Japanese companies such as Toray, Nippon Carbon, Toho Rayon and [[Mitsubishi]] started their own development and production. Since the late 1970s, further types of carbon fiber yarn entered the global market, offering higher tensile strength and higher elastic modulus. For example, T400 from Toray with a [[tensile strength]] of 4,000 [[pascal (unit)|MPa]] and M40, a modulus of 400 GPa. Intermediate carbon fibers, such as IM 600 from Toho Rayon with up to 6,000 MPa were developed. Carbon fibers from Toray, Celanese and Akzo found their way to aerospace application from secondary to primary parts first in military and later in civil aircraft as in McDonnell Douglas, Boeing, Airbus, and [[Irkut MC-21|United Aircraft Corporation]] planes. In 1988, Dr. [[Jacob Lahijani]] invented balanced ultra-high Young's modulus (greater than 100 Mpsi) and high tensile strength pitch carbon fiber (greater than 500 kpsi) used extensively in automotive and aerospace applications. In March 2006, the patent was assigned to the [[University of Tennessee]] Research Foundation.<ref>{{cite patent |country=US |number=4915926 |title=Balanced ultra-high modulus and high tensile strength carbon fibers |invent1=Lahijani, Jacob |pubdate=1990-04-10}}<!-- See legal events tab for assignee --></ref>

==Structure and properties==
[[File:Cfaser haarrp.jpg|thumb|right|200px|A 6 μm diameter carbon filament (running from bottom left to top right) compared to a human hair]]

Carbon fiber is frequently supplied in the form of a continuous tow wound onto a reel. The tow is a bundle of thousands of continuous individual carbon filaments held together and protected by an organic coating, or size, such as [[polyethylene oxide]] (PEO) or [[polyvinyl alcohol]] (PVA).  The tow can be conveniently unwound from the reel for use.  Each carbon filament in the tow is a continuous cylinder with a diameter of 5–10 [[micrometre|micrometer]]s and consists almost exclusively of [[carbon]]. The earliest generation (e.g. T300, HTA and AS4) had diameters of 16–22 [[micrometre|micrometers]].<ref name=cantwell>{{cite journal |first1=W.J. |last1=Cantwell |first2=J. |last2=Morton |title=The impact resistance of composite materials – a review |journal=Composites |year=1991 |volume=22 |issue=5 |pages=347–362 |doi=10.1016/0010-4361(91)90549-V}}</ref> Later fibers (e.g. IM6 or IM600) have diameters that are approximately 5 micrometers.<ref name=cantwell/>

The atomic structure of carbon fiber is similar to that of [[graphite]], consisting of sheets of carbon [[atoms]] arranged in a regular [[hexagon]]al pattern ([[graphene]] sheets), the difference being 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 intermolecular forces between the sheets are relatively weak [[Van der Waals force]]s, giving graphite its soft and brittle characteristics.

Depending upon the precursor to make the fiber, carbon fiber may be turbostratic or graphitic, or have a hybrid structure with both graphitic and turbostratic parts present. In turbostratic carbon fiber the sheets of carbon atoms are haphazardly folded, or crumpled, together. Carbon fibers derived from [[Polyacrylonitrile|polyacrylonitrile (PAN)]] are turbostratic, whereas carbon fibers derived from [[mesophase]] [[Pitch (resin)|pitch]] are graphitic after heat treatment at temperatures exceeding 2200&nbsp;°C. Turbostratic carbon fibers tend to have high ultimate [[tensile strength]], whereas heat-treated mesophase-pitch-derived carbon fibers have high [[Young's modulus]] (i.e., high stiffness or resistance to extension under load) and high [[thermal conductivity]].

==Applications==
[[File:Ray Ban Giant.jpg|thumb|Carbon fiber sunglasses temples and carbon fiber bicycle frame tube]]

Carbon fiber can have higher cost than other materials which has been one of the limiting factors of adoption. In a comparison between [[steel]] and carbon fiber materials for [[Automotive industry|automotive materials]], carbon fiber may be 10-12x more expensive. However, this cost premium has come down over the past decade from estimates of 35x more expensive than steel in the early 2000s.<ref>{{Cite news|url=http://www.plasticsnews.com/article/20140805/NEWS/140809971/price-keeping-carbon-fiber-from-mass-adoption|title=Price keeping carbon fiber from mass adoption - Plastics News|last=Bregar|first=Bill|work=Plastics News|date=5 August 2014|publisher=Crain Communications, Inc. |location=Atlanta |access-date=2017-05-25|url-status=dead|archive-url=https://web.archive.org/web/20161209082227/http://www.plasticsnews.com/article/20140805/NEWS/140809971/price-keeping-carbon-fiber-from-mass-adoption|archive-date=2016-12-09}}</ref>

===Composite materials===
Carbon fiber is most notably used to reinforce [[composite material]]s, particularly the class of materials known as [[Carbon fiber reinforced polymer|carbon fiber or graphite reinforced polymers]]. Non-polymer materials can also be used as the matrix for carbon fibers. Due to the formation of metal [[carbide]]s and [[corrosion]] considerations, carbon has seen limited success in [[metal matrix composite]] applications.  [[Reinforced carbon-carbon]] (RCC) consists of carbon fiber-reinforced graphite, and is used structurally in high-temperature applications. 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-[[Triboelectric effect|static]] component. Molding a thin layer of carbon fibers significantly improves fire resistance of polymers or thermoset composites because a dense, compact layer of carbon fibers efficiently reflects heat.<ref>{{cite journal |last1=Zhao |first1=Z. |last2=Gou |first2=J. |title=Improved fire retardancy of thermoset composites modified with carbon nanofibers|journal= Sci. Technol. Adv. Mater. |volume=10 |issue=1 |year=2009|page=015005 |doi=10.1088/1468-6996/10/1/015005|bibcode = 2009STAdM..10a5005Z |pmid=27877268 |pmc=5109595}}</ref>

The increasing use of carbon fiber composites is displacing aluminum from aerospace applications in favor of other metals because of [[galvanic corrosion]] issues.<ref>{{cite magazine |url=http://www.boeing.com/commercial/aeromagazine/aero_07/corrosn.html |title=Design for Corrosion |magazine=Aero |publisher=Boeing |issue=7 |date=July 1999 |last1=Banis |first1=David |last2=Marceau |first2=J. Arthur |last3=Mohaghegh |first3=Michael |access-date=2018-05-07 |archive-url=https://web.archive.org/web/20130902081013/http://www.boeing.com/commercial/aeromagazine/aero_07/corrosn.html |archive-date=2013-09-02 |url-status=live}}</ref><ref>{{cite journal |url=http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_05_06_2013_p42-574844.xml&p=2 |first1=Graham |last1=Warwick |first2=Guy |last2=Norris |title=Metallics Make Comeback With Manufacturing Advances |journal=Aviation Week & Space Technology |date=2013-05-06 |archive-url=https://web.archive.org/web/20150427133615/http://www.aviationweek.com/Article.aspx?id=%2Farticle-xml%2FAW_05_06_2013_p42-574844.xml&p=2 |archive-date=2015-04-27}}</ref> Note, however, that carbon fiber does not eliminate the risk of galvanic corrosion.<ref>{{cite magazine |url=http://www.boeing.com/commercial/aeromagazine/aero_07/corrosn.html |title=Design for Corrosion |magazine=Aero |publisher=Boeing |issue=7 |date=July 1999 |last1=Banis |first1=David |last2=Marceau |first2=J. Arthur |last3=Mohaghegh |first3=Michael |access-date=2018-05-07 |archive-url=https://web.archive.org/web/20130902081013/http://www.boeing.com/commercial/aeromagazine/aero_07/corrosn.html |archive-date=2013-09-02 |url-status=live}}</ref> In contact with metal, it forms "a perfect galvanic corrosion cell ..., and the metal will be subjected to galvanic corrosion attack" unless a sealant is applied between the metal and the carbon fiber.<ref>{{cite magazine |url=https://www.sciencedirect.com/science/article/pii/S2667266921000037 |title=Galvanic activity of carbon fiber reinforced polymers and electrochemical behavior of carbon fiber |magazine=Corrosion Communications |publisher=Elsevier B.V. |issue=1 |date=March 2021 |last1=Song |first1=Guang-Ling |last2=Chi |first2=Zhang |last3=Xiaodong |first3=Chen |volume=1 |pages=26–39 |doi=10.1016/j.corcom.2021.05.003 |access-date=2023-01-22 }}</ref>

Carbon fiber can be used as an additive to asphalt to make electrically conductive asphalt concrete.<ref>{{cite journal |title=Effect of Carbon-Fiber Properties on Volumetrics and Ohmic Heating of Electrically Conductive Asphalt Concrete |first1=Mohammad Ali |last1=Notani |first2=Ali |last2=Arabzadeh |first3=Halil |last3=Ceylan |first4=Sunghwan |last4=Kim |journal=Journal of Materials in Civil Engineering |location=US |volume=31 |issue=9 |pages=04019200 |date=June 2019 |doi= 10.1061/(ASCE)MT.1943-5533.0002868|s2cid=198395022 }}</ref> Using this composite material in the transportation infrastructure, especially for airport pavement, decreases some winter maintenance problems that lead to flight cancellation or delay due to the presence of ice and snow. Passing current through the composite material 3D network of carbon fibers dissipates thermal energy that increases the surface temperature of the asphalt, which is able to melt ice and snow above it.<ref>{{cite journal |title=Electrically conductive asphalt concrete: An alternative for automating the winter maintenance operations of transportation infrastructure |first1=Ali |last1=Arabzadeh |first2=Mohammad Ali |last2=Notani |first3=Ayoub Kazemiyan |last3=Zadeh |first4=Ali |last4=Nahvi |first5=Alireza |last5=Sassani |first6=Halil |last6=Ceylan |journal=Composites Part B: Engineering |location=US |volume=173 |pages=106985 |date=2019-09-15 |doi=10.1016/j.compositesb.2019.106985|s2cid=189994116 |url=https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1233&context=ccee_pubs }}</ref>

===Textiles===
[[File:Before heated.jpg|thumb|The look of the product before the heating process]]
[[File:Cfk heli slw.jpg|120px|thumb|Tail of a [[radio-controlled helicopter]], made of [[carbon fiber reinforced polymer]]]][[File:MotorcycleRacingGlove.jpg|thumb|Motorcycle racing gloves with carbon fiber protectors for ligaments in fingers]]

Precursors for carbon fibers are [[polyacrylonitrile]] (PAN), [[rayon]] and [[pitch (resin)|pitch]]. Carbon fiber filament yarns are used in several processing techniques: the direct uses are for prepregging, filament winding, pultrusion, weaving, braiding, etc. Carbon fiber yarn is rated by the linear density (weight per unit length; i.e., 1&nbsp;g/1000&nbsp;m = 1&nbsp;[[tex (unit)#Tex|tex]]) or by number of filaments per yarn count, in thousands. For example, 200&nbsp;tex for 3,000&nbsp;filaments of carbon fiber is three times as strong as 1,000&nbsp;carbon filament yarn, but is also three times as heavy. This thread can then be used to [[weaving|weave]] a carbon fiber filament [[textile|fabric]] or [[cloth]]. The appearance of this fabric generally depends on the linear density of the yarn and the weave chosen. Some commonly used types of weave are [[twill]], [[satin weave|satin]] and [[plain weave|plain]]. Carbon filament yarns can also be [[knitting|knitted]] or [[braiding|braided]]. [[Carbon-fiber reinforced polymer|Dry fabric carbon fiber composites (CFRP)]] are typically cut using [[CNC router|CNC digital cutting systems]] equipped with rotating machine knives and [[ultrasonic]] cutting method.<ref>{{Cite web |date=2025-03-06 |title=Cutting of Fiber-Reinforced Composites: Overview |url=https://www.sollex.se/en/blog/post/industrial-cutting-of-fiber-reinforced-composites-textiles-prepregs |access-date=2025-03-31 |website=Sollex |language=en}}</ref>

===Microelectrodes===

Carbon fibers are used for fabrication of carbon-fiber [[microelectrodes]]. In this application typically a single carbon fiber with diameter of 5–7 μm is sealed in a glass capillary.<ref>{{cite journal |last1=Pike |first1=Carolyn M. |last2=Grabner |first2=Chad P. |last3=Harkins |first3=Amy B. |title=Fabrication of Amperometric Electrodes |journal=Journal of Visualized Experiments |date=2009-05-04 |issue=27 |pages=1040 |doi=10.3791/1040|pmid=19415069 |pmc=2762914 }}</ref> At the tip the capillary is either sealed with epoxy and polished to make a carbon-fiber disk microelectrode, or the fiber is cut to a length of 75–150 μm to make a carbon-fiber cylinder electrode. Carbon-fiber [[microelectrodes]] are used either in [[amperometry]] or [[fast-scan cyclic voltammetry]] for detection of biochemical signaling.

===Flexible heating===
[[File:Heated jacket.jpg|thumb|right|A DIY carbon fiber heated jacket]]

Despite being known for their electrical conductivity, carbon fibers can carry only very low currents on their own.  When woven into larger fabrics, they can be used to reliably provide (infrared) heating in applications requiring flexible electrical heating elements and can easily sustain temperatures past 100&nbsp;°C.  Many examples of this type of application can be seen in [[DIY]] heated articles of clothing and blankets.  Due to its chemical inertness, it can be used relatively safely amongst most fabrics and materials; however, shorts caused by the material folding back on itself will lead to increased heat production and can lead to a fire.

==Synthesis==

[[File:PAN stabilization.PNG|thumb|Synthesis of carbon fiber from [[polyacrylonitrile]] (PAN): {{ordered list
| Polymerization of [[acrylonitrile]] to PAN, 
| Cyclization during the low-temperature process, 
| High-temperature oxidative treatment of carbonization (hydrogen is removed). 
After this process of [[graphitization]] starts where nitrogen is removed and chains are joined into graphite planes.
}}]]

Each carbon filament is produced from a [[polymer]] such as [[polyacrylonitrile]] (PAN), [[rayon]], or petroleum [[Pitch (resin)|pitch]]. All these polymers are known as a [[Precursor (manufacturing)|precursor]]. For synthetic polymers such as PAN or rayon, the precursor is first [[Spinning (polymers)|spun]] into filament yarns, using chemical and mechanical processes to initially align the polymer molecules in a way to enhance the final physical properties of the completed carbon fiber. Precursor compositions and mechanical processes used during spinning filament yarns may vary among manufacturers. After drawing or spinning, the polymer filament yarns are then heated to drive off non-carbon atoms ([[carbonization]]), producing the final carbon fiber. The carbon fibers filament yarns may be further treated to improve handling qualities, then wound on to [[bobbin]]s.<ref>{{cite web |url=http://www.zoltek.com/carbonfiber/how-is-it-made/ |title=How is Carbon Fiber Made? |publisher=Zoltek |url-status=live |archive-url=https://web.archive.org/web/20150319182214/http://www.zoltek.com/carbonfiber/how-is-it-made/ |archive-date=2015-03-19 |date=2017-08-10 }}</ref>

[[File:Diagram carbon fiber preperation.svg|center|500px|Carbon fiber preparation]]
[[File:Carbon Knitted fabric made by SOHIM.jpg|thumb|Flexibility of Carbon rayon based fabric]]

A common method of manufacture involves heating the spun PAN filaments to approximately 300&nbsp;°C in air, which breaks many of the hydrogen bonds and oxidizes the material. During this process, fibers tend to shrink. The resulting chemical composition and mechanical properties of the fiber are dependent on the time and temperature of the process, as well as on the tension applied to the fiber during oxidation.<ref>{{Cite journal |last=Zoli |first=Luca |last2=Servadei |first2=Francesca |last3=Cicogna |first3=Francesca |last4=Coiai |first4=Serena |last5=Calucci |first5=Lucia |last6=Forte |first6=Claudia |last7=Sciti |first7=Diletta |last8=Passaglia |first8=Elisa |date=2023-12-01 |title=Enhancing PANox fiber properties through controlled oxidation and tensioning: A study on shrinkage inhibition and structural analysis |url=https://www.sciencedirect.com/science/article/pii/S0141391023003014 |journal=Polymer Degradation and Stability |volume=218 |pages=110551 |doi=10.1016/j.polymdegradstab.2023.110551 |issn=0141-3910|doi-access=free }}</ref> The [[oxidized]] PAN is then placed into a furnace having an inert atmosphere of a gas such as [[argon]], and heated to approximately 2000&nbsp;°C, which induces [[graphitization]] of the material, changing the molecular bond structure. 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, columnar filament. The result is usually 93–95% carbon. Lower-quality fiber can be manufactured using [[Pitch (resin)|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&nbsp;°C (carbonization) exhibits the highest [[tensile strength]] (5,650{{nbsp}}[[MPa]], or 820,000{{nbsp}}[[pound force per square inch|psi]]), while carbon fiber heated from 2500 to 3000&nbsp;°C (graphitizing) exhibits a higher [[modulus of elasticity]] (531{{nbsp}}GPa, or 77,000,000{{nbsp}}psi).

==See also==
* [[Basalt fiber]]
* [[Carbon fiber reinforced polymer]]
* [[Ceramic matrix composite|Carbon fiber reinforced ceramic material]]
* [[Carbon nanotube]]
* [[ESD materials]]
* [[Graphene]]

==References==
{{Reflist|30em}}

==External links==
{{Commons category|Carbon_fibres|Carbon fibres}}
*[http://pslc.ws/macrog/carfsyn.htm Making Carbon Fiber]
*[http://www.madehow.com/Volume-4/Carbon-Fiber.html How carbon fiber is made]
*{{cite magazine |url=http://www.flightglobal.com/pdfarchive/view/1971/1971%20-%201784.html |title=Carbon Fibres – the First 5 naked years |magazine=Flight International |page=406 |date=1971-09-09 |archive-date=2012-02-04 |archive-url=https://web.archive.org/web/20120204235345/http://www.flightglobal.com/pdfarchive/view/1971/1971%20-%201784.html}}

{{Textile}}
{{fibers}}
{{Allotropes of carbon}}
{{Authority control}}

{{DEFAULTSORT:Carbon Fiber}}
[[Category:British inventions]]
[[Category:Allotropes of carbon]]
[[Category:Synthetic fibers]]
[[Category:Woven fabrics]]
[[Category:Nonwoven fabrics]]
[[Category:Net fabrics]]