Abstract: A producing method of a carbon fiber by spraying a raw material solution containing a carbon source and a transition metallic compound into a reaction zone and subjecting the raw material solution to thermal decomposition, which is characterized in (1) spraying the raw material solution at a spray angle of 3° to 30° and (2) feeding a carrier gas through at least one site other than an inlet through which the raw material solution is sprayed. A composite material comprising a vapor grown carbon fiber, each fiber filament of the carbon fiber having a branching degree of at least 0.15 occurrences/?m and a bulk density of 0.025 g/cm3 or less.

Abstract: (1) A carbonaceous material for forming an electrically conductive composition, comprising a vapor grown carbon fiber, each fiber filament of the carbon fiber having an outer diameter of 2 to 500 nm and an aspect ratio of 10 to 15,000, or the carbon fiber containing boron in an amount of 0.01 to 5 mass %, and graphitic particles and/or amorphous carbon particles, wherein the amount of the vapor grown carbon fiber is 10 to 90 mass %, the amount of the graphitic particles is 0 to 65 mass %, and the amount of the amorphous carbon particles is 0 to 35 mass %; (2) an electrically conductive composition comprising the carbonaceous material for forming an electrically conductive composition, and a producing method thereof; (3) an electrically conductive coating material comprising, as an electrically conductive material, the electrically conductive composition, and an electrically conductive coating film and electric device using the electrically conductive coating material.

Abstract: A vapor grown carbon fiber, each fiber filament of the carbonfiber having a branching degree of at least 0.15 occurrences/?m and a bulk density of 0.025 g/cm3 or less and a producing method of the carbon fiber by spraying a raw material solution containing a carbon source and a transition metallic compound into a reaction zone and subjecting the raw material solution to thermal decomposition, which is characterized in (1) spraying the raw material solution at a spray angle of 3° to 30° and (2) feeding a carrier gas through at least one site other than an inlet through which the raw material solution is sprayed, and a composite material comprising the carbon fiber.

Abstract: A vapor grown carbon fiber, each fiber filament of the carbonfiber having a branching degree of at least 0.15 occurrences/?m and a bulk density of 0.025 g/cm3 or less and a producing method of the carbon fiber by spraying a raw material solution containing a carbon source and a transition metallic compound into a reaction zone and subjecting the raw material solution to thermal decomposition, which is characterized in (1) spraying the raw material solution at a spray angle of 3° to 30° and (2) feeding a carrier gas through at least one site other than an inlet through which the raw material solution is sprayed, and a composite material comprising the carbon fiber.

Abstract: (1) A carbonaceous material for forming an electrically conductive composition, comprising a vapor grown carbon fiber, each fiber filament of the carbon fiber having an outer diameter of 2 to 500 nm and an aspect ratio of 10 to 15,000, or the carbon fiber containing boron in an amount of 0.01 to 5 mass %, and graphitic particles and/or amorphous carbon particles, wherein the amount of the vapor grown carbon fiber is 10 to 90 mass %, the amount of the graphitic particles is 0 to 65 mass %, and the amount of the amorphous carbon particles is 0 to 35 mass %; (2) an electrically conductive composition comprising the carbonaceous material for forming an electrically conductive composition, and a producing method thereof; (3) an electrically conductive coating material comprising, as an electrically conductive material, the electrically conductive composition, and an electrically conductive coating film and electric device using the electrically conductive coating material.

Abstract: An abrasive composite material containing a matrix, abrasive grains, and carbon fiber having a multi-layer structure, each fiber filament of the carbon fiber having an outer diameter of about 2 to about 500 nm and an aspect ratio of about 5 to about 15,000, and including a hollow space extending along its center axis. Preferably, the carbon fiber has a BET specific surface area of about 4 m2/g or more; the carbon fiber has, at a carbon (002) plane, an interlayer distance (d002) of about 0.345 nm or less as measured by means of X-ray diffractometry; and the ratio of the peak height (Id) of the band at 1,341 to 1,349 cm−1 in a Raman scattering spectrum of the carbon fiber to the peak height (Ig) of the band at 1,570 to 1,578 cm−1 in the spectrum; i.e., Id/Ig, is about 1.5 or less. More preferably, the carbon fiber contains branched vapor grown carbon fiber; boron is contained, in an amount of about 0.