Carbon fiber is a fiber that is about 5 to 10 microns in diameter and is composed mainly of carbon atoms. Carbon fiber has several advantages: high stiffness, high tensile strength, high strength-to-weight ratio, high chemical tolerance, high temperature tolerance, and low thermal expansion. These properties make carbon fiber very popular in aerospace, civil engineering, military, racing cars, and various competitive sports equipment. However, the price of carbon fiber is relatively high compared to similar fibers such as glass fiber, basalt fiber or plastic fiber.
To produce carbon fibers, carbon atoms are bonded together in crystals that are aligned parallel to the long axis of the fiber. This arrangement gives carbon fibers a high strength-to-volume ratio, with five to ten times the tensile strength of steel but only one-quarter the density. Thousands of carbon fiber filaments are bundled together to form a carbon fiber bundle, which can be used individually or woven into a carbon fiber cloth.
Carbon fibers are often combined with other materials to make a composite material (CFRP). For example, when impregnated with plastic resin and heated, a carbon fiber reinforced polymer is formed, which has a very high strength-to-weight ratio and is extremely rigid. Carbon fibers can also be compounded with other materials such as graphite to form enhanced carbon-carbon composites, which have very high heat resistance.
