Carbon fibrils and method for producing same

A plurality of substantially discrete carbon fibrils characterized by a substantially constant diameter, length greater than about 5 times the diameter, an ordered outer region of multiple, substantially continuous layers of ordered carbon atoms having an outside diameter between about 3.5 and 70 nanometers which are catalytically grown from a gaseous carbon compound, said ordered carbon atoms having c-axes that are substantially perpendicular to the cylindrical axis of the fibril, and a distinct inner core region, each of the layers and the core being disposed substantially concentrically around the cylindrical axis of the fibrils, wherein said fibrils are substantially free of pyrolytically deposited thermal carbon formed by thermal decomposition of the gaseous carbon-containing compound, with the diameter of said fibrils being equal to the outside diameter of said ordered outer region.

A method for continuously producing carbon fibrils which comprises continuously contacting fibril-forming metal-containing particles with a gaseous, carbon-containing compound to catalytically grow substantially cylindrical carbon fibrils of substantially constant diameter, length greater than about 5 times the diameter, an ordered outer region of catalytically grown, multiple, substantially continuous layers of ordered carbon atoms having an outside diameter between about 3.5 and 70 nanometers, said ordered carbon atoms having c-axes that are substantially perpendicular to the cylindrical axis of the fibril, and a distinct inner core region, each of the layers and the core being disposed substantially concentrically about the cylindrical axis of the fibril, at a temperature below the thermal decomposition temperature of said carbon-containing compound to avoid significant formation of pyrolytic carbon formed by thermal decomposition of the gaseous carbon-containing compound on the catalytically grown outer region of said fibrils, and recovering the fibrils in a condition substantially free of pyrolytically deposited thermal carbon, with the diameter of said fibrils equal to the outer diameter of said ordered outer region.

A method for producing a substantially uniform plurality of carbon fibrils which comprises continuously contacting fibril-forming metal-containing particles with a gaseous, carbon-containing compound to catalytically grow substantially cylindrical carbon fibrils of substantially constant diameter, length greater than about 5 times the diameter, an ordered outer region of catalytically grown, multiple, substantially continuous layers of ordered carbon atoms having an outside diameter between about 3.5 and b 70 nanometers, said ordered carbon atoms comprising graphitic domains whose c-axes are substantially perpendicular to the cylindrical axis of the fibril, and a distinct inner core region, each of the layers and the core being disposed substantially concentrically about the cylindrical axis of the fibril, at a temperature below the thermal decomposition temperature of said carbon-containing compound to avoid significant formation of pyrolytic carbon on the catalytically grown outer region of said fibrils, and recovering the fibrils in a condition substantially free of pyrolytically deposited thermal carbon, with the diameter of said fibrils equal to the outer diameter of said ordered outer region.

A method for producing a carbon fibril which comprises the steps of

• contacting a fibril-forming metal-containing particle with a gaseous, carbon-containing compound to catalytically grow a substantially cylindrical carbon fibril of substantially constant diameter, length greater than about 5 times the diameter, an ordered outer region of multiple, substantially continuous layers of ordered carbon atoms having an outside diameter between about 3.5 and 70 nanometers which are catalytically grown from a gaseous carbon-containing compound, said ordered carbon atoms having c-axes that are substantially perpendicular to the cylindrical axis of the fibril, and a distinct inner core region, each of the layers and the core being disposed substantially concentrically about the cylindrical axis of the fibril, the temperature during said contacting being below the thermal decomposition temperature of the gaseous carbon-containing compound to avoid significant formation of pyrolytically deposited thermal carbon formed by thermal decomposition of the gaseous carbon-containing compound on said catalytically grown outer region;
• and
• recovering said fibril in a condition substantially free of pyrolytically deposited thermal carbon, with the diameter of said fibril equal to the outside diameter of said ordered outer region.