Carbon fiber is a highly processed material made from raw materials into a very lightweight but incredibly strong material. Production mainly starts with precursor materials, with the most common being polyacrylonitrile (PAN), which constitutes about 90% of the world’s carbon fiber production. The remainder usually comes from pitch or rayon. These materials are selected because of their high carbon content, an important factor in producing fibers that are strong.
First comes stabilization-the precursor is oxidized between 200°C and 300°C for hours. This process changes the chemical structure to fix the material in a state that will make subsequent processing stages possible. It is followed by carbonization, which is normally carried out in a furnace heated to a temperature from 1,000°C to 3,000°C, and during which all atoms bar carbon are removed, thus leaving behind fibers that have more than 90% carbon.
Next, surface treatment is done to enhance bonding properties with resins. It consists of an acid or gas treatment to the fibers, which makes the surface rough. Lastly, sizing involves coating the fibers with material, such as epoxy, for protection during handling, and the fibers are spooled onto large reels. The entire process can take several days and involves meticulous control to ensure consistency and quality.
Carbon fiber boasts a strength-to-weight ratio five times higher than steel, with about 30% less weight. This turns it into something invaluable for industries like aerospace, wherein a reduction in an aircraft’s weight by 1% can slash its fuel costs by a similar percentage annually. The Boeing 787 Dreamliner of 2019 featured over 50% of its build using carbon fiber, which showed how advanced materials could really make a difference.
If you can get lightweight materials right, you unlock a cascade of benefits in efficiency,” famously said Elon Musk, the CEO of Tesla and SpaceX, indicating the ever-increasing importance of carbon fiber in decreasing energy consumption and emission from all sectors.
The cost of carbon fiber remains high, between $5 and $25 per pound, depending on quality. This is mainly because of the energy-intensive manufacturing process. However, innovations such as automated fiber placement are expected to cut costs by up to 30% over the next decade.
For more information about carbon fiber and its uses, check out carbon fiber to learn why this material is revolutionizing modern engineering and design.