What do the space shuttle, airplane brakes, rocket nozzles and hip prosthetics have in common? These examples demonstrate the versatility of carbon-carbon composites in a wide variety of extreme situations where their unique combination of mechanical, thermal, electrical, microstructural and chemical properties has opened up new possibilities. Carbon-carbon composites are becoming increasingly used in engineering applications today and are considered by some to be the definitive development in carbon science. There are three characteristics of carbon-carbon composites that make them superior to many other material selections available. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get Original Essay One of the most important characteristics of CC composites is superior strength and the ability to maintain its strength at high temperatures. Carbon fibers are responsible for the excellent strength found in carbon-carbon composites. The most important properties of carbon-carbon composites are their thermal properties. CC composites have very low coefficients of thermal expansion and have high thermal conductivity. The main reason why carbon-carbon composites are used as a material is their ability to maintain these strength levels at temperatures above 2000°C. At this high temperature, the strength is almost the same as room temperature. A third characteristic of carbon-carbon composites is the inertness to many chemical agents such as strong acids, alkalis and reducing agents. These chemical characteristics make CC composites an excellent choice for surgical implants and prosthetics. They are also resistant to thermal shock due to rapid and extreme changes in temperature. Other properties include low weight, high abrasion resistance, high electrical conductivity, non-brittle failure, and resistance to biological rejection and chemical corrosion. Carbon-carbon composites are very workable and can be formed into many different shapes. PAN fibers have existed as fabrics for almost 50 years, they are more commonly known as acrylics. Acrylics are basically carbon atoms, surrounded by cyanides. Carbon fiber manufacturing involves heat treating PAN fibers to remove cyanides, leaving carbon fiber, which is stronger than steel and lighter. The conversion of PAN into carbon fibers occurs in 4 continuous steps: oxidation, carbonization, surface treatment and sizing. Oxidation involves heating the fibers to approximately 300 degrees C in air. The polymer changes from a ladder structure to a stable ring structure and the fiber changes color from white through brown to black. Carbonization involves heating the fibers up to 3000. C in an inert atmosphere, the fibers are now made up of almost 100% carbon. The temperature will determine the grade of fiber produced. The surface treatment forms chemical bonds with the carbon surface, which gives better bonding to the composite resin system. The sizing is a neutral finishing agent (usually epoxy) to protect the fibers during further processing. The main disadvantage of carbon-carbon composites is that they oxidize easily at temperatures between 600 and 700 °C, especially in the presence of oxygen. A protective coating (usually silicon carbide) must be applied to prevent high-temperature oxidation. Carbon-carbon composites are currently very expensive and complicated to produce, which limits their use mainly to aerospace and defense applications. Carbon fiber was,