ABSTRACT
Carbon is a truly remarkable element existing in three allotropic forms, namely, diamond, graphite, and fullerenes, and each allotrope is having signicant scientic and technological importance. Its most abundant allotrope, graphite, can be produced in different forms: from amorphous to highly crystalline, from highly dense (ρ = 2.2) to highly porous (ρ = 0.5), and different shapes. Examples include coke, glassy carbon, carbon black, porous carbon, activated charcoal, graphite powder, graphite electrodes, and carbon bers. Carbon is a preferred material for structural applications, where extreme environmental conditions such as high temperature and corrosive liquids or gases are encountered. This is mainly due to its high strength, chemical inertness, and ability to retain the strength at high temperatures, even above 1500°C. Theoretically, carbon materials with covalently bonded atoms should possess very high strengths in the range of 40-50 GPa. However, the bulk synthetic graphite has less than 2% of the theoretical strength. Therefore, for long there has been a quest by scientists to explore the ways to achieve the maximum possible strength. This, coupled with the search for high-performance reinforcing bers to produce advanced composites, had led to the development of carbon bers. The judicious incorporation of these carbon bers into carbon matrix has led to the birth of carbon-carbon (C/C) composite materials with improved properties.
