The BISFA definition of a carbon fibre is "fibre containing at least 90% by mass of carbon obtained by thermal carbonisation of organic fibre precursors".
The common precursors used to make carbon fibres are specifically made polyacrylonitrile(PAN) and pitch. If pitch is used the process consists of extrusion, oxidation and graphitisation. If PAN is used, a tow is oxidised, then carbonised followed by graphitisation.
Properties and End-Uses
Carbon fibres are characterised by having high moduli and high strength, especially when embedded in a matrix such as epoxy resin. They are also brittle and have a low density. The main end-uses are as reinforcement fibres in composites for the aircraft and aerospace industries and sports goods.