Carbon Fiber – Properties, Processing and Applications

Carbon fiber – also known as carbon fibre or graphite fiber – is one of the most high-performance reinforcement fibers in modern lightweight construction. With its exceptional combination of low weight, high tensile strength and stiffness, it has established itself as an indispensable material across numerous high-tech industries.

Whether in aerospace, automotive engineering, or sports equipment manufacturing – wherever weight reduction and maximum mechanical performance are required simultaneously, carbon fiber is the material of choice.

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Properties of Carbon Fiber

Carbon fibers consist of more than 90% carbon. Their exceptional strength and stiffness are attributed to the highly ordered alignment of carbon atoms along the fiber axis.

The carbon atoms are arranged in a graphite-like layered structure aligned along the fiber axis – this is precisely what gives the fiber its enormous tensile strength combined with very low density.

Processing

Carbon fibers are typically not processed as individual filaments, but rather as fiber bundles – known as rovings or tows. These can be further processed into carbon fiber fabric , non-crimp fabrics or nonwovens . Processing typically takes place in combination with matrix systems such as epoxy resins , using a variety of methods:

• Hand laminating – suitable for small series and prototypes
• Vacuum infusion – for large-area, uniform components
• Prepreg processing – for the highest quality requirements, e.g. in aerospace
• Filament winding – for rotationally symmetrical components such as tubes or pressure vessels

Caution is advised when cutting carbon fiber fabric: the fine fiber dust is hazardous to health and requires appropriate personal protective equipment (respiratory protection, gloves, safety goggles).

Applications

Carbon fiber is used almost exclusively as a reinforcement material in fiber-reinforced composites. When cured in combination with a resin matrix, the result is what is known as carbon fiber reinforced polymer (CFRP) , which is characterised by an exceptional strength-to-weight ratio. Typical application areas include structural components, body panels, sports equipment, and medical technology.

Manufacturing

The production of carbon fiber is an energy-intensive, multi-stage process. The primary precursor material is polyacrylonitrile (PAN), with pitch or rayon used less frequently.

The precursor is first spun into fibers, then oxidised (stabilised at approx. 200–300 °C), and finally carbonised or graphitised at temperatures between 1,000 and 3,000 °C under an inert gas atmosphere.

During this process, virtually all non-carbon atoms are expelled, and the characteristic crystalline structure is formed.

Colour

Carbon fiber is characteristically black to anthracite in colour – a property that results directly from the carbonisation process. In woven form, depending on the weave pattern (plain, twill, satin), a distinctive, visually appealing weave pattern is visible, which is deliberately used as a design feature in many applications.

Texture and Feel

In its raw state, carbon fiber fabric feels soft, lightweight, and silky – similar to a fine textile. Only after processing with resin and curing does the familiar hard, rigid CFRP component emerge.

The surface of cured CFRP parts is smooth and can be brought to a high-gloss finish by sanding and polishing.

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Use & Processing of Carbon Fiber

Fields of Application

Carbon fiber is used wherever lightweight construction and high mechanical load capacity are required:

• Aerospace – structural components, fuselage shells, rotor blades
• Automotive engineering – body panels, monocoques in motorsport, roof modules
• Wind energy – rotor blades for wind turbines
• Sports equipment – bicycle frames, tennis rackets, skis, paddle blades
• Medical technology – prostheses, orthoses, X-ray tables
• Shipbuilding & marine – masts, hulls, deck structures
• Architecture & design – facade elements, furniture, design objects

Application Examples

A classic example is the CFRP bicycle frame: by using carbon fiber fabric and epoxy resin, it is possible to manufacture frames that – at a weight of under 1 kg – withstand the highest mechanical loads.

In motorsport, the CFRP monocoque not only enables extreme weight savings, but also provides outstanding safety through the targeted orientation of the fibers.

For your own projects, we recommend high-quality carbon fiber fabric from R&G – precisely woven, available in various weave patterns and areal weights, and optimally matched for processing with epoxy resin systems.

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Alternative Terms for Carbon Fiber

In English-language technical literature and industry usage, carbon fiber is referred to by several terms – all describing the same material:

• Carbon fiber – the most common spelling in American English
• Carbon fibre – the standard spelling in British English
• Graphite fiber – used in some technical and aerospace contexts
• Carbon fiber fabric / carbon fiber cloth – refers to the woven textile made from carbon fibers
• Carbon – colloquial term, commonly used in DIY and design contexts

Abbreviation: CF and CFRP

The internationally recognised abbreviation for carbon fiber is CF. In combination with a polymer matrix, the abbreviation CFRP (Carbon Fiber Reinforced Polymer) is used – equivalent to the German CFK (kohlenstofffaserverstärkter Kunststoff). These abbreviations are standardised across industry, standards bodies, and technical literature and are used consistently worldwide.

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FAQ – Frequently Asked Questions About Carbon Fiber

What is carbon fiber?

Carbon fiber is a synthetic fiber consisting of more than 90% carbon. It is characterised by very high tensile strength, a high modulus of elasticity, and low density. Carbon fibers are used almost exclusively as a reinforcement material in fiber-reinforced composites – in combination with a resin matrix, they form carbon fiber reinforced polymers (CFRP), which rank among the most high-performance structural materials available.

Why is carbon fiber so expensive?

The high cost of carbon fiber is attributable to several factors: the manufacturing process is extremely energy-intensive and requires precisely controlled high-temperature processes over several hours. The precursor material PAN (polyacrylonitrile) is itself not an inexpensive raw material, and the production facilities are highly specialised and capital-intensive. In addition, further processing into fabrics, prepregs, or finished components places high demands on machinery and skilled personnel. Despite falling prices through scaling and process optimisation, carbon fiber remains a premium material compared to glass fiber or natural fibers.

How is carbon fiber made?

The production of carbon fiber takes place in a multi-stage thermal process. The starting material in most cases is polyacrylonitrile (PAN), which is first spun into fibers. These fibers are then stabilised in an oxidising atmosphere at approx. 200–300 °C (oxidation), before being carbonised in an inert gas furnace at 1,000–1,500 °C. Optionally, graphitisation at up to 3,000 °C follows for particularly high-modulus fibers. Finally, the fibers are surface-treated (sizing applied) to improve adhesion to the resin matrix, and further processed into rovings or woven fabrics.