Carbon Fiber Carbon fiber is defined as a fiber containing at least 92 wt % carbon, while the fiber containing at least 99 wt % carbon is usually called a graphite fiber. It is a material consisting of several fibers and composed mostly of carbon atoms. Each fiber is about 5 – 10 μm thick in diameter.
Carbon Fibero The crystal alignment gives the fiber high strength- to-volume ratio.o Carbon fibers are usually combined with other materials to form a composite.o When combined with a plastic resin and wound or molded it forms carbon fiber reinforced plastic.
Carbon Fibero Carbon Fiber Reinforced Plastic has a very high strength-to-weight ratio, and is extremely rigid and brittle.o Carbon Fibers are also composed with other materials, such as with graphite to form carbon- carbon composites, which have a very high heat tolerance.
Historyo Carbon fibers were developed in the 1950s as a reinforcement for high-temperature molded plastic components on missiles.o Firstly manufactured by Dr. Roger Bacon.o The first fibers were manufactured by heating strands of rayon until they carbonized.
History This process proved to be inefficient, as the resulting fibers contained only about 20% carbon and had low strength and stiffness properties.
Carbon Fiber Vs Steel Carbon Fiber is actually 5 times stronger than steel. It is also 2 times more stiff. This material has a really very strength-to- weight ratio, which makes it great for almost anything that requires high strength and low weight.
Manufacturing ChallengesThe manufacturing of carbon fibers carriesa number of challenges, including: The need for more cost effective recovery and repair. Close control required to ensure consistent quality. Health and safety issues Skin irritation Breathing irritation.
Manufacturing of Carbon Fibers Carbon fiber is currently produced in relatively limited quantities mostly via two manufacturing processes: Based on pitch (coal tar and petroleum products) Based on Polyacrylonitrile (PAN)o Current global capacity for pitch-based carbon fiber is estimated at about 3,500 metric tons per year. Global use for PAN-based carbon fiber is increasing rapidly, and total production capacity currently does not meet the demand. PAN-based carbon fiber is more expensive to produce, hence, limiting its use to high end applications, (used primarily by aerospace and sporting equipment industries).
Manufacturing Process In the manufacturing process, the raw material, which is called precursor, is drawn into long strands or fibers. The fibers are woven into fabric or combined with other materials that are molded into desired shapes and sizes. There are typically five segments in the manufacturing of carbon fibers from the PAN1)Spinning: process. These are: PAN mixed with other ingredients and spun into fibers, which are washed and stretched.
Stabilizing:Chemical alteration to stabilize bonding.Carbonizing:Stabilized fibers heated to very hightemperature forming tightly bonded carboncrystals.Treating the Surface:Surface of fibers oxidized to improve bondingproperties.
Sizing: Fibers are coated and wound onto bobbins, which are loaded onto spinning machines that twist the fibers into different size yarns. Instead of being woven into fabrics, fibers may be formed into composites. To form composite materials, heat, pressure, or a vacuum binds fibers together with a plastic polymer.
Structure The atomic structure of carbon fiber is similar to that of graphite, consisting of sheets of carbon atoms arranged in a regular hexagonal pattern. Graphite is a crystalline material in which the sheets are stacked parallel to one another in regular fashion.
o A 6 μm diameter carbon filament compared to ahuman hair.
Properties High tensile strength. Low thermal expansion. Electrically and thermally conductive. Light weight and low density. High abrasion and wear resistance.
Advantages It has the greatest compressive strength of all reinforcing materials. Long service life. Low coefficient of thermal expansion. Its density is much lower than the density of steel. Exhibit properties better than any other metal. Insensitive to temperature changes
Disadvantages The main disadvantage of carbon fiber is its cost. This fiber will cause some forms of cancer of the lungs.
Carbon Fiber’s Future The future efforts on carbon fiber research will be focused on cost reduction and property improvement. The mechanical property of carbon fiber heavily relies on its microstructure. The improvement on the tensile, flexural, and shear strength of pitch carbon fibers has been observed by randomizing the graphite distribution in the fiber transverse direction.
Carbon Fiber’s Future Alternate Energy: Wind turbines, compressed natural gas storage and transportation fuel cells. Fuel Efficient Automobiles: Moving towards large production series cars.
Carbon Fiber’s Future Construction Infrastructure: Light weight pre-cast concrete, earthquake protection. Oil Exploration: Deep sea drilling platforms, choke and drill pipes.
Conclusion It revolutionized the field of light weight materials. The new substitute for metals. In short it is the future manufacturing material.