What are carbon fiber composites

Carbon fiber is a long, thin chain of material, about 0.0002-0.0004 inches (0.005-0.010 mm) in diameter, composed primarily of carbon atoms. The carbon atoms are bound together in microcrystals that are aligned more or less parallel to the long axis of the fiber. The arrangement of the crystals gives the fibers incredible strength for their size.

Carbon fiber composites come in many forms and can be manipulated to meet the needs of unique applications. For example, thousands of carbon fibers are bonded together to form a yarn, which can be used alone or woven into a fabric. The yarns or fabrics are combined with epoxy resins and wrapped around a mold to form a variety of composites, such as carbon fiber cloth, carbon fiber tubes, and carbon fiber sheets as the most basic raw materials.

Carbon fiber reinforced composites are used in the manufacture of aircraft and spacecraft components, racing car bodies, golf club bodies, bicycle frames, fishing rods, automotive springs, sailboat masts, and many other components that require light weight and high strength. The only limit to what carbon fiber can be used for and create something new is people's imagination for carbon fiber composites.

Carbon fibers are classified according to the fiber's tensile modulus: the imperial unit of measurement is pounds of force per square inch of cross-sectional area, or psi. Carbon fibers classified as "low modulus" have a tensile modulus of less than 34.8 million psi (240 million kPa). Other classifications, in ascending order of tensile modulus, include "standard modulus," "intermediate modulus," "high modulus," and "ultra-high modulus". ". Ultra-high modulus carbon fibers have a tensile modulus of 72.5 to 145.0 million psi (500 million to 1 billion kPa). For comparison, steel has a tensile modulus of about 29 million psi (200 million kPa). Thus, the strongest carbon fibers are 10 times stronger than steel, and aluminum is 8 times stronger, not to mention being much lighter than both materials, by a factor of 5 and 1.5, respectively. In addition, their fatigue properties are superior to all known metallic structures and, when combined with suitable resins, they are among the most corrosion-resistant materials available.

History of Carbon Fiber Composites

In 1860, Joseph Swan first invented carbon fiber for use in light bulbs.

In 1879, Thomas Edison baked cotton threads or bamboo strips at high temperatures to carbonize them into all-carbon fiber filaments for one of the first incandescent light bulbs, which were heated electrically.

In 1880, Lewis Latimer developed a reliable carbon filament for use in incandescent light bulbs, heated by electricity.

In 1958, Roger Bacon manufactured high-performance carbon fibers at the Union Carbide Par-ma Technology Center outside Cleveland, Ohio. These fibers were made by heating rayon strands until they carbonized. The method later proved to be inefficient because the resulting carbon fibers contained only about 20 percent carbon and had low strength and stiffness properties.

In the early 1960s, Dr. Akimbo Shinto of the Japan Industrial Science and Technology Agency developed a method using polyacrylonitrile (PAN) as a raw material. This produced carbon fibers containing about 55% carbon.

In 1960, Richard. Milling-ton of HI Thompson Fiberglas Co. developed a method for producing fibers with high carbon content (99%) using rayon as a precursor (U.S. Patent No. 3,294,489). These carbon fibers have sufficient strength (modulus of elasticity and tensile strength) to be used as reinforcing materials for composites with high-strength weight properties and high-temperature resistant applications.

The high potential of carbon fibers was realized in 1963 by a process developed by W. Watt.LN Phillips and W. Johnson at the Royal Aircraft Corporation in Farnborough, Hampshire. The process was patented by the UK Ministry of Defense and then licensed to three companies by the UK National Research and Development Corporation. A few years later, the first successful application of carbon fiber sheet fan assemblies in an aircraft on top was made in the Rolls-Royce Conway jet engine in the Vickers VC10. Within a few years, Rolls-Royce took advantage of the properties of the new material to penetrate the U.S. market with its RB-211 aero-engine equipped with carbon fiber compressor blades. Unfortunately, the blades were vulnerable to damage caused by bird strikes. This and other problems led to the setback of Rolls-Royce being nationalized in 1971. The carbon fiber production plant was sold to form Bristol Composites .

In the late 1960s, the Japanese pioneered the production of PAN-based carbon fibers.A joint technology agreement in 1970 allowed Union Carbide to produce Japanese Toray Industries products.Morganatic considered carbon fiber production to be peripheral to its core business, leaving Courtyards as the only large manufacturer in the U.K. Courteous' water-based inorganic process made the product susceptible to impurities that would not interfere with the organic process used by other carbon fiber manufacturers, leading Courtyards to stop producing carbon fiber in 1991.

In the 1960s, experimental work to find alternative raw materials led to the introduction of carbon fiber composites made from petroleum pitch derived from petroleum processing. These fibers contain about 85% carbon and have excellent flexural strength. In addition, during this period, the Japanese government strongly supported the development of carbon fibers domestically, and several Japanese companies such as Toray, Toho Ren and Mitsubishi began their own development and production.

Since the late 1970s, more types of carbon fiber yarns have entered the global market, offering higher tensile strength and higher modulus of elasticity. For example, T400 has a tensile strength of 4,000 MPa and a modulus of 400 GPa. Intermediate carbon fibers were developed, such as IM 600 with up to 6,000 MPa. Carbon fiber composites were first used in aerospace applications ranging from secondary to primary components in military and later civil aircraft, such as those of McDonnell Douglas, Boeing, Airbus and United Aircraft Corporation.