The term carbon fiber (alternatively referred to as Graphite Fiber) is mostly used to refer to a composite material made of carbon fibers and a polymer resin, cured into the desired shape. When people say that a car body panel or a bicycle frame is “made of carbon fiber,” they are typically referring to this composite.
A second use of the term points to carbon fiber fabric — the woven or unidirectional textiles produced from bundles of carbon filaments, before being combined with resin.
Carbon fiber filaments are much thinner than a human hair—around 5 to 7 microns in diameter—yet far stronger, which explains their crucial role in high-performance composites
Finally, carbon fiber filaments may also be referred to as carbon fiber. These are extremely thin strands, typically around 5 to 7 micrometers in diameter, much finer than a human hair. They are composed of long chains of carbon atoms arranged in a highly ordered structure, giving them exceptional tensile strength and stiffness.
Filaments are usually bundled together into tows containing thousands of fibers, which then serve as the basis for producing fabrics and composites.
How is carbon fiber made?
Carbon fiber is produced from organic polymers known as precursors, most commonly polyacrylonitrile (PAN). About 90% of all carbon fibers are made through the PAN process, while the rest originate from rayon or petroleum pitch. Not all carbon fiber is identical and different qualities and grades are achieved depending on the manufacturing method and the gases, liquids, and other materials used.
Carbon fiber production begins with PAN precursor, which undergoes stretching, oxidation, carbonization, and graphitization before surface treatment, sizing, and winding into tows ready for composite manufacturing.
The production of carbon fiber involves several controlled stages:
- Spinning – the precursor is mixed with other ingredients, spun into fibers, washed, and stretched.
- Stabilizing – chemical treatment alters the fibers to make them thermally stable.
- Carbonizing – the stabilized fibers are heated at very high temperatures, forming tightly bonded carbon crystals.
- Surface treatment – oxidation of the fiber surface improves bonding with resins.
- Sizing – a protective coating is applied, and fibers are wound into tows or yarns for further use.
What resins are used for carbon fiber composites?
In the vast majority of cases, when people talk about carbon fiber composites, they are referring to carbon fiber combined with an epoxy resin. Epoxies dominate because they offer excellent mechanical strength, chemical resistance, and fatigue performance, making them the default choice for aerospace, automotive, and high-performance applications.
Epoxy resin is the most common polymer matrix for carbon fiber composites, delivering high strength, durability, and chemical resistance in aerospace, automotive, and advanced engineering.
Other resins can be used, but much less frequently.
Polyester resins are cheaper, though they provide lower performance. For this reason, they are more commonly paired with glass fiber, which is also more economical, rather than with carbon fiber.
Vinyl ester resins sit somewhere in between, offering greater toughness and chemical resistance than polyester but not quite matching epoxy, which explains why the most common combination remains carbon fiber with epoxy resin.
There are also special-purpose resins. Phenolic resins are valued for their fire resistance and low smoke emission, making them suitable for specific applications.
Another example is the resin we used at Managing Composites in the European research project MC4, focused on circularity in composite materials. For this project, we built a kayak in composite materiales which can be reshaped and reused at the end of life of the product thanks to a vitrimer resin developed by CIDETEC. This resin is a thermosetting polymer that behaves like a thermoset at service temperatures but can be healed or partially reprocessed by applying heat and pressure.
Key characteristics of carbon fiber
- High strength-to-weight ratio. Carbon fiber composites can achieve the strength of steel at a fraction of the weight.
- High stiffness. The ordered atomic structure of carbon filaments provides exceptional rigidity.
- Anisotropy. The properties of carbon fiber composites depend strongly on the orientation of the fibers, which allows engineers to tailor stiffness and strength in specific directions.
- Fatigue resistance. Properly designed carbon composites maintain their properties under repeated stress cycles better than many metals.
- Corrosion resistance. Unlike metals, carbon fiber does not rust and shows good resistance to chemical attack, although galvanic corrosion may occur in direct contact with aluminum.
- Thermal properties. Carbon fibers withstand high service temperatures depending on the specific resin matrix.
Common Applications of Carbon Fiber
Carbon fiber has steadily expanded from its origins in aerospace and defense into a wide range of industries. As manufacturing methods improve and costs gradually decrease, it continues to gain prominence in new sectors, where its strength, lightness, and durability unlock performance advantages that traditional materials cannot match. Today, it is found not only in high-tech engineering but also in products that are part of everyday life.
The Airbus A350-1000 is built with over 50% carbon fiber reinforced polymer composites, reducing weight while boosting fuel efficiency and performance.
Some of the most common applications include:
- Aerospace: Aircraft structures, helicopters, turbine parts, aircraft interiors, and space components.
- Automotive: High-performance cars, electric vehicles, body panels, motorbike parts, and structural reinforcement.
- Sporting goods: Bicycle frames, tennis rackets, surfboards, skis, and helmets.
- Marine: High-performance boat hulls, masts, and kayaks.
- Wind energy: Reinforcement of specific parts of turbines.
- Civil engineering: Strengthening and retrofitting of concrete and infrastructure.
- Medical devices: Prosthetics, surgical instruments, and imaging equipment.
- Drones, robotics, armors, etc.
Why is carbon fiber the best material for hypercars?
In 1980 McLaren built the MP4/1, the first Formula 1 car with a carbon fiber monocoque chassis. Its success transformed motorsport, with every F1 team quickly adopting the technology — a standard that remains today.
Hypercars and supercars borrowed directly from this racing heritage and beyond body panels, carbon fiber is now used in monocoques, interiors, wheels, small components, and many more parts.
From Bugatti to McLaren and Koenigsegg, today’s hypercars rely on carbon fiber composites to achieve unmatched lightness, strength, and performance.
Strength to weight ratio
The performance of a car depends less on its absolute power than on its power-to-weight ratio. Since carbon fiber enables the necessary strength to be achieved at lower weight, it makes cars lighter and their power results in higher performance.
Rigidity and safety
Carbon fiber provides extreme stiffness while also offering excellent crash protection. Composite structures offer wide design possibilities to create tailor-made architectures that dissipate energy in a precisely calculated manner, offering outstanding protection for the occupants of the vehicle.
Prestige and exclusivity
Beyond performance, carbon fiber has become a symbol of cutting-edge technology and craftsmanship. Its distinctive woven look is instantly associated with hypercars, reinforcing their status as the pinnacle of automotive engineering.
Design optimization
Carbon fiber is anisotropic, meaning its strength varies depending on the orientation of the fibers. Additional layers can be added or removed to achieve higher or lower strength, and reinforcement can be applied only in the specific areas of a part where it is required. These variables, among many others, make it possible to optimize components in ways that are unattainable with other materials.
PROS & CONS of Carbon Fiber
| High strength-to-weight ratio.
The strength of steel or aluminum at a fraction of the weight. |
Complex manufacturing.
Requires controlled processes (autoclaves, molds, curing) that increase production time. |
| Corrosion resistance.
Does not rust and resists most chemicals. |
High cost.
Raw materials and processing are significantly more expensive than metals. |
| Fatigue resistance.
Maintains performance under repeated stress cycles. |
Recycling challenges.
Conventional carbon fiber composites are difficult to recycle at scale. |
| Thermal stability.
Fibers may withstand high service temperatures with low thermal expansion. |
Difficult repair.
Damage is often not easily detectable and repairs can be more complex than with metals. |
| Customization.
Fiber type, orientation, and resin allow tailoring of stiffness, strength, and weight. |
Production rate limitations.
Slower production cycles compared to stamping or casting metals. |
Q&A
- Why is carbon fiber so expensive?
Because its production involves costly precursors and complex processing, although for certain applications it is the more cost-effective option.
- Is FRP carbon fiber?
Not always. FRP means Fiber Reinforced Polymer; carbon fiber reinforced polymer (CFRP) is just one type.
- Is carbon fiber a thermoplastic or a thermoset?
The fibers are neither. Most composites use thermoset resins (epoxy), but thermoplastic versions also exist.
- Is carbon fiber stronger than steel?
Yes. It can be as strong as steel while being about five times lighter.
- Can carbon fiber be recycled?
Traditional composites are difficult to recycle, but new resins such as vitrimers allow reprocessing.
- What is a carbon fiber monocoque?
A one-piece chassis made of carbon fiber composite, combining stiffness, lightness, and crash protection.
- Can carbon fiber parts be repaired?
Yes, but repairs can be complex and require specialized techniques.
- Is carbon fiber always black?
Usually, yes — but resins or hybrid fibers can add color.
- What is better, a fiberglass or a carbon fiber paddle?
Carbon fiber is lighter and stiffer; fiberglass is cheaper and more flexible.
- Who invented carbon fiber?
Edison made the first fibers in 1879, but modern high-strength fibers came in the 1960s.
- What is carbon fiber prepreg?
Carbon fabric pre-impregnated with resin, ensuring quality and consistency, cured under heat and pressure.
Carbon fiber components, like this aerodynamic detail on a supercar, combine lightness, strength, and design precision to enhance performance.
TL;DR
- Carbon fiber can mean composite, fabric, or filaments. The most common meaning is composite: carbon fiber + resin.
- Epoxy resin + carbon fiber is the most common combination. Other resins like vinyl ester, phenolic or vitrimers are for very specific uses.
- Mostly made from PAN (polyacrylonitrile) via multi-stage process.
- Key properties: strength-to-weight ratio, stiffness, anisotropy, fatigue resistance, corrosion resistance, thermal stability, design flexibility.
- Applications: aerospace, automotive, marine, wind energy, sports, medical.
- All hypercars use a carbon fiber monocoque and body panels.
- Pros: performance, design freedom, prestige. Cons: high cost, recycling challenges, complex manufacturing.