carbon black

Refers to any of a group of intensely black, finely divided forms of amorphous carbon, usually obtained as soot from partial combustion of hydrocarbons, used to produce extremely black pigments of high hiding power in printing ink, paint, and carbon paper, as reinforcing agents in rubber products, and to create protective coatings, plastics, and resistors for electronic circuits. Carbon black particles are usually spherical in shape and less regularly crystalline than graphite. Carbon black changes into graphite if heated at 3,000 degrees Celsius for a prolonged period. Among the most finely divided materials known, carbon blacks vary widely in particle size and color intensity depending upon the process by which they are made.