Carbon fibre is literally a fibre made of carbon. The carbon content is 90% or more for carbon fibres of standard modulus elasticity and 100% for carbon fibres of high modulus elasticity. Nitrogen is the secondary element.
Carbon fibre is produced by baking PolyAcryloNitrile (PAN) fibre, pitch fibre or other organic fibre in an inert atmosphere to dissociate elements other than carbon.
The two key features of carbon fibre is strength and lightness in weight. Carbon fibre has various other characteristics such as, rust resistance, and chemical and thermal stability making it a highly reliable surface.
Unlike the other fibres which we designate by their linear density (denier), carbon fibres are designated by the number of filaments per fibre. In Stratis we use 6K and 12K ('K' is short for 1,000) so each fibre will have either 6,000 or 12,000 filaments per fibre.
Stratis uses Ultra High tenacity aerospace grade carbon fibres made in Japan and Korea.
1. The starting point is a high quality PolyAcryloNitrile (PAN) precursor fibre, which is specifically engineered for carbon fibre production.
2. The PAN precursor is then stretched and tensioned to optimize molecular and structural orientation.
3. In-line quality control of the PAN precursor ensures process continuity and efficiency.
4. The precursor is exposed to hot air, turning it into oxidized polyacrylonitrile fiber.
5. It is carbonized into carbon fibre by exposing it to progressively higher temperatures in a nitrogen-filled oven.
The carbon fibre undergoes final carbonization at more than 1,000-2,000 degrees celsius to establish strength and stiffness, and to ensure it's other material properties.
6. At 2,000-3,000 degrees celsius, graphitization for high modulus types occurs.
7. The carbon fibre is surface-treated or etched to create a surface that will bond effectively.
8. A polymer coating (sizing) is applied to promote fibre-handling characteristics, wet-out and bonding.
9. Continuous fibre is wound onto bobbins.
(Top Image: Carbon Process Table)
(Bottom Image: Close-up of Carbon fibre)