What do the space shuttle, airplane brakes, rocket nozzles and hip prostheses 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 increasingly used in today's engineering applications and are considered by some to be the ultimate development in carbon science. Carbon-carbon composites have three characteristics that make them superior to many other materials available. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essay One of the most important characteristics of CC composites is their superior strength and their ability to maintain their strength at high temperatures. Carbon fibers are responsible for the excellent strength of carbon-carbon composites. The most important properties of carbon-carbon composites are their thermal properties. CC composites have very low thermal expansion coefficients and high thermal conductivity. The main reason 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 resistance is close to that at room temperature. A third characteristic of carbon-carbon composites is their 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 temperature changes. Other properties include low weight, high abrasion resistance, high electrical conductivity, non-brittle failure, and resistance to biological release and chemical corrosion. Carbon-carbon composites are very easy to work with and can take many different shapes. PAN fibers have existed as textiles for almost 50 years, they are more commonly known as acrylics. Acrylics are essentially carbon atoms surrounded by cyanides. Manufacturing carbon fiber 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 is done in 4 continuous steps: oxidation, carbonization, surface treatment and sizing. Oxidation involves heating the fibers to around 300°C in air. The polymer changes from a ladder structure to a stable ring structure and the fiber changes color from white to brown to black. Carbonization involves heating the fibers up to 3,000°C. C under an inert atmosphere, the fibers are now almost 100% carbon. The temperature will determine the quality of the fiber produced. The surface treatment forms chemical bonds on the surface of the carbon, which gives better attachment to the resin system of the composite. 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 oxidation at high temperatures. Carbon-carbon composites are,