The element carbon is widely distributed in nature. It is found in the earth’s crust in the ratio of 180 ppm, most of it in the form of compounds. Many of these natural compounds are essential to the production of synthetic carbon materials and include various coals, hydrocarbons complexes and the gaseous hydrocarbons.
Only two polymorphs of carbon are found on earth as minerals: natural graphite and diamond.
The element carbon is detected in abundance in the universe, in the sun, stars, comets, and in the atmosphere of the planets. It is the fourth most abundant element in the solar system, after hydrogen, helium, and oxygen, and is found mostly in form of hydrocarbons and other compounds. The spontaneous generation of fullerene molecules may also play an important role in the process of stellar dust formation. Carbon polymorphs, such as microscopic diamond and lonsdaleite, a form similar to diamond, have been discovered in some meteorites.
Carbon, in the form of charcoal, is an element of prehistoric discovery and was familiar to many ancient civilizations. As diamond, it has been known since the early history of mankind. A historical perspective of carbon and its allotropes and the important dates in the development of carbon technology are given in Table 1.1. Additional notes of historical interest will be presented in the relevant chapters.
Table 1.1 Chronology of Carbon
First “lead ” pencils 1600’s
Discovery of the carbon composition of diamond 1797
First carbon electrode for electric arc 1800
Graphite recognized as a carbon polymorph 1855
First carbon filament 1879
Chemical vapor deposition (CVD) of carbon patented 1880
Production of first molded graphite (Acheson process) 1896
Carbon dating with 14C isotope 1946
Industrial production of carbon fibers from rayon 1950’s
Development and production of vitreous carbon 1960’s
Development of PAN-based carbon fibers 1960’s
Development of pitch-based carbon fibers late 1960’s
Discovery of low-pressure diamond synthesis 1970’s
Production of synthetic diamond suitable for gem trade 1985
Development of diamond-like carbon (DLC) 1980’s
Discovery of fullerene molecules late 1980’s
Industrial production of CVD diamond 1992