Abstract: A method of modifying the surface of carbon materials such as vapor grown carbon nanofibers is provided in which silicon is deposited on vapor grown carbon nanofibers using a chemical vapor deposition process. The resulting silicon-carbon alloy may be used as an anode in a rechargeable lithium ion battery.

Abstract: A method of depositing silicon on carbon nanomaterials such as vapor grown carbon nanofibers, nanomats, or nanofiber powder is provided. The method includes flowing a silicon-containing precursor gas in contact with the carbon nanomaterial such that silicon is deposited on the exterior surface and within the hollow core of the carbon nanomaterials. A protective carbon coating may be deposited on the silicon-coated nanomaterials. The resulting nanocomposite materials may be used as anodes in lithium ion batteries.

Abstract: A method of making a polymer composite from a mixture of a polymeric material, carbon nanofibers, and nano-scale particles is provided. The carbon nanofibers are less than about 1 micrometer in diameter, and the nano-scale particles are shorter in length than the carbon nanofibers. The nano-scale particles are selected from nano-scale carbon additives, non-conductive nano-clays, nano-scale conductive metallic additives, or combinations thereof. The components are mixed to form a polymer composite. A polymer composite having a resistivity of less than about 107 ohm-cm is also described.

Abstract: A method of making a polymer composite from a mixture of a polymeric material, carbon nanofibers, and nano-scale particles is provided. The carbon nanofibers are less than about 1 micrometer in diameter, and the nano-scale particles are shorter in length than the carbon nanofibers. The nano-scale particles are selected from nano-scale carbon additives, non-conductive nano-clays, nano-scale conductive metallic additives, or combinations thereof. The components are mixed to form a polymer composite. A polymer composite having a resistivity of less than about 107 ohm-cm is also described.

Abstract: A method and apparatus are provided for separating carbon fibers from gaseous effluent which fibers have been formed in a continuous gas phase reaction. The apparatus is a collection chamber including top and bottom portions and including exit tubes attached to the bottom portion. Carbon fibers enter the top portion of the chamber from a reactor and are collected in the bottom portion where they are forced into the exit tubes by a piston and then collected in bundles. As the fibers are compressed into the tubes, they form an airtight seal which prevents air from entering the chamber and prevents gas from exiting the chamber. The remaining gaseous effluent may then be removed from the chamber and processed for reuse.

Abstract: High surface energy vapor grown carbon fibers and methods of making such fibers. The high surface energy vapor grown carbon fibers of the present invention have a surface energy greater than about 75 mJ/m2 without post-manufacture treatment.

Abstract: A process for forming carbon nanofibers by means of pyrolyzation with plasma in a reactor is disclosed. The process includes the steps of: providing, in a reactor, a first catalyst in the form of solid catalytic particles; applying a vacuum to the reactor to create a reduced pressure in the reactor; feeding a first mixture of gases including a carbon-based gas into the reactor; forming, from the carbon-based gas, a plasma containing carbon free-radical species; and forming, in the presence of the catalytic particles, carbon nanofibers.

Abstract: A method of producing vapor grown carbon fibers is provided in which coal is utilized as a source of an iron catalyst, as a source of hydrocarbon and sulfur, or both. The method includes the steps of introducing pulverized coal into a furnace containing a gas selected from the group consisting of hydrogen, hydrocarbon, nitrogen, ammonia, helium, or mixtures thereof, and maintaining the gas at a temperature from about 1000.degree.-1175.degree. C. to form the fibers. The coal has a sulfur content of from 1 to 6% by weight and may comprise high volatile bituminous coal. The use of coal to produce vapor grown carbon fibers provides a significant cost advantage over other starting materials and also provides an environmentally safe use for high sulfur content coal.

Abstract: A carbon-carbon composite is provided comprising a preform containing interwoven mats of graphitized vapor grown carbon fibers. The mat comprises semi-aligned, semi-continuous vapor grown carbon fibers which have been interwoven in situ during growth. The preferred method of producing the carbon-carbon composite includes the steps of densifying the preform by depositing pyrolytic carbon into the interstices of the preform by chemical vapor infiltration or pitch infiltration. The resulting carbon-carbon composite has a thermal conductivity of between about 900 W/m-K and 1000 W/m-K and is useful as a component in electronic devices, aircraft, spacecraft, and other thermal management applications.

Abstract: An aluminum matrix composite is provided comprising a preform formed from interwoven mats of graphitized vapor grown carbon fibers. The mats comprise semi-aligned, semi-continuous vapor grown carbon fibers which have been interwoven in situ during growth. The preferred method of producing the composite includes the steps of providing a vapor grown carbon preform and infiltrating molten aluminum into the interstices of the preform by a pressure casting process. The resulting aluminum matrix composite has a thermal conductivity of between about 600 W/m-K and 700 W/m-K and is useful as a component in electronic devices, aircraft, spacecraft, and other thermal management applications.

Abstract: A diamond/carbon/carbon composite is provided comprising a carbon/carbon composite having a polycrystalline diamond film deposited thereon. The carbon/carbon composite comprises a preform of interwoven carbon fibers comprising vapor grown carbon fibers. The preferred method of producing the composite involves chemical vapor infiltration of the pyrolytic carbon into the interstices of the preform, followed by microwave plasma enhanced chemical vapor deposition of the diamond film on the carbon/carbon composite. The resulting diamond/carbon/carbon composite is useful as an integral dielectric heat sink for electronic systems in spacecraft, aircraft and supercomputers due to its thermal management properties. Such a heat sink can be made by depositing metallic circuits on the diamond layer of the diamond/carbon/carbon composite.

Abstract: Carbon fiber with increased bulk density comprising vapor grown carbon fiber is provided. The preferred method of increasing the carbon fiber bulk density comprises mixing a vapor grown carbon fiber with a diameter of less than about 1 .mu.m and an initial bulk density of less than about 0.2 lb/ft.sup.3 with an aqueous-based solution, blending the mixture under high shear conditions, and drying the blended mixture. Upon drying, the mixture forms a carbon fiber mass with an increased bulk density having a final bulk density of at least about 3 lb/ft.sup.3. The increased bulk density carbon fiber pellets are ideally suited for use as reinforcing materials in rubber, plastic and the like. Preferably, the aqueous-based solution is a latex containing solution and latex is deposited on the fibers.

Abstract: A method for producing a diamond/carbon/carbon composite is provided which includes the steps of densifying a preform of interwoven vapor grown carbon fibers form a carbon/carbon composite, and then depositing a polycrystalline diamond film on the carbon/carbon composite. The preform may be densified by depositing pyrolyric carbon into the interstices of the preform, either by a chemical vapor infiltration process or by a pitch infiltration process. The polycrystalline diamond film is deposited on the carbon/carbon composite by a microwave plasma enhanced chemical vapor deposition process. The resulting diamond/carbon/carbon composite can be utilized as an integral dielectric heat sink by depositing metallic circuits on the diamond layer of the diamond/carbon/carbon composite.