Abstract: A precursor of an alumina sintered compact including aluminum, yttrium, and at least one metal selected from iron, zinc, cobalt, manganese, copper, niobium, antimony, tungsten, silver, and gallium. The aluminum content is 98.0% by mass or more as an oxide (Al2O3) in 100% by mass of the precursor of an alumina sintered compact; the yttrium content is 0.01 to 1.35 parts by mass as an oxide (Y2O3) based on 100 parts by mass of the content of the aluminum as an oxide; the total content of the metals selected from the foregoing group is 0.02 to 1.55 parts by mass as an oxide based on 100 parts by mass of the content of aluminum as an oxide; and the aluminum is contained as ?-alumina. Also disclosed is an alumina sintered compact, and a method for producing an alumina sintered compact and for producing abrasive grains.

Abstract: A precursor of an alumina sintered compact including aluminum, yttrium, and at least one metal selected from iron, zinc, cobalt, manganese, copper, niobium, antimony, tungsten, silver, and gallium. The aluminum content is 98.0% by mass or more as an oxide (Al2O3) in 100% by mass of the precursor of an alumina sintered compact; the yttrium content is 0.01 to 1.35 parts by mass as an oxide (Y2O3) based on 100 parts by mass of the content of the aluminum as an oxide; the total content of the metals selected from the foregoing group is 0.02 to 1.55 parts by mass as an oxide based on 100 parts by mass of the content of aluminum as an oxide; and the aluminum is contained as ?-alumina. Also disclosed is an alumina sintered compact, and a method for producing an alumina sintered compact and for producing abrasive grains.

Abstract: A precursor of an alumina sintered compact including aluminum, yttrium, and at least one metal selected from iron, zinc, cobalt, manganese, copper, niobium, antimony, tungsten, silver, and gallium. The aluminum content is 98.0% by mass or more as an oxide (Al2O3) in 100% by mass of the precursor of an alumina sintered compact; the yttrium content is 0.01 to 1.35 parts by mass as an oxide (Y2O3) based on 100 parts by mass of the content of the aluminum as an oxide; the total content of the metals selected from the foregoing group is 0.02 to 1.55 parts by mass as an oxide based on 100 parts by mass of the content of aluminum as an oxide; and the aluminum is contained as ?-alumina. Also disclosed is an alumina sintered compact, and a method for producing an alumina sintered compact and for producing abrasive grains.

Abstract: A carbon fiber composite material comprising 100 parts by mass of an elastomer, and 20 to 100 parts by mass of carbon nanofibers that have been oxidized and reduced in number of branch points. The carbon fiber composite material has a dynamic modulus of elasticity (E?) at 200° C. and 10 Hz of 10 to 1000 MPa, and a volume resistivity of 106 to 1018 ohms·cm.

Abstract: A carbon fiber composite material comprising 100 parts by mass of an elastomer, and 20 to 100 parts by mass of carbon nanofibers that have been oxidized and reduced in number of branch points. The carbon fiber composite material has a dynamic modulus of elasticity (E?) at 200° C. and 10 Hz of 10 to 1000 MPa, and a volume resistivity of 106 to 1018 ohms·cm.

Abstract: An electrode material comprising a particle containing at least one member selected from the particles containing silicon, tin, silicon compound and tin compound, and fibrous carbon. The particle includes: (1) a particle comprising at least one member of a silicon particle, tin particle, particle containing a lithium-ion-intercalatable/releasable silicon compound and particle containing a lithium-ion-intercalatable/releasable tin compound; or (2) a particle comprising a silicon and/or silicon compound-containing carbonaceous material deposited onto at least a portion of the surfaces of a carbon particle having a graphite structure. The lithium secondary battery using the electrode material as a negative electrode has high discharging capacity and is excellent in cycle characteristics and characteristics under a load of large current.

Abstract: A seal member includes a hydrogenated acrylonitrile-butadiene rubber (HNBR) and carbon nanofibers. The seal member has a number of cycles to fracture of 7000 or more when subjected to a tensile fatigue test at a temperature of 70° C., a maximum tensile stress of 4 N/mm, and a frequency of 1 Hz. The seal member exhibits excellent abrasion resistance.

Abstract: A method of producing carbon nanofibers includes grinding untreated carbon nanofibers produced by a vapor growth method. The untreated carbon nanofibers are ground so that the ground carbon nanofibers have a tap density 1.5 to 10 times higher than that of the untreated carbon nanofibers. A method of producing a carbon fiber composite material includes mixing carbon nanofibers into an elastomer, and uniformly dispersing the carbon nanofibers in the elastomer by applying a shear force to obtain a carbon fiber composite material.

Abstract: A method of producing a carbon fiber composite material includes a first step and a second step. The first step includes oxidizing first carbon nanofibers produced by a vapor growth method to obtain second carbon nanofibers having an oxidized surface. The second step includes mixing the second carbon nanofibers into an elastomer, and uniformly dispersing the carbon nanofibers in the elastomer by applying a shear force to obtain the carbon fiber composite material. The second carbon nanofibers obtained by the first step have a surface oxygen concentration measured by X-ray photoelectron spectroscopy (XPS) of 2.6 to 4.6 atm %.

Abstract: The seal member includes a tetrafluoroethylene-propylene copolymer (FEPM) and carbon nanofibers. The seal member has a number of cycles to fracture of 10 or more when subjected to a tension fatigue test at a temperature of 150° C., a maximum tensile stress of 2 N/mm, and a frequency of 1 Hz. The seal member exhibits excellent heat resistance and abrasion resistance.

Abstract: A method of producing a carbon fiber composite material includes a first step and a second step. The first step includes oxidizing first carbon nanofibers produced by a vapor growth method to obtain second carbon nanofibers having an oxidized surface. The second step includes mixing the second carbon nanofibers into an elastomer, and uniformly dispersing the carbon nanofibers in the elastomer by applying a shear force to obtain the carbon fiber composite material. The second carbon nanofibers obtained by the first step have a surface oxygen concentration measured by X-ray photoelectron spectroscopy (XPS) of 2.6 to 4.6 atm %.

Abstract: A method of producing a carbon fiber composite material includes a first step and a second step. The first step includes oxidizing first carbon nanofibers produced by a vapor growth method to obtain second carbon nanofibers having an oxidized surface. The second step includes mixing the second carbon nanofibers into an elastomer, and uniformly dispersing the carbon nanofibers in the elastomer by applying a shear force to obtain the carbon fiber composite material. The second carbon nanofibers obtained by the first step have a surface oxygen concentration measured by X-ray photoelectron spectroscopy (XPS) of 2.6 to 4.6 atm %.

Abstract: A seal member includes a hydrogenated acrylonitrile-butadiene rubber (HNBR) and carbon nanofibers. The seal member has a number of cycles to fracture of 7000 or more when subjected to a tensile fatigue test at a temperature of 70° C., a maximum tensile stress of 4 N/mm, and a frequency of 1 Hz. The seal member exhibits excellent abrasion resistance.

Abstract: A dynamic seal member includes a ternary fluoroelastomer (FKM) and carbon nanofibers. The carbon nanofibers are carbon nanofibers having an average diameter of 10 to 20 nm, or carbon nanofibers having an average diameter of 60 to 110 nm and subjected to a low-temperature heat treatment. The carbon nanofibers having an average diameter of 60 to 110 nm and subjected to the low-temperature heat treatment have a ratio (D/G) of a peak intensity D at around 1300 cm?1 to a peak intensity G at around 1600 cm?1 measured by Raman scattering spectroscopy of more than 0.9 and less than 1.6. The dynamic seal member has a number of cycles to fracture of 10 or more when subjected to a tension fatigue test at a temperature of 200° C., a maximum tensile stress of 2.5 N/mm, and a frequency of 1 Hz. The dynamic seal member exhibits excellent heat resistance and abrasion resistance.

Abstract: A carbon fiber composite material comprising 100 parts by mass of an elastomer, and 20 to 100 parts by mass of carbon nanofibers that have been oxidized and reduced in number of branch points. The carbon fiber composite material has a dynamic modulus of elasticity (E?) at 200° C. and 10 Hz of 10 to 1000 MPa, and a volume resistivity of 106 to 1018 ohms·cm.

Abstract: The seal member includes a tetrafluoroethylene-propylene copolymer (FEPM) and carbon nanofibers. The seal member has a number of cycles to fracture of 10 or more when subjected to a tension fatigue test at a temperature of 150° C., a maximum tensile stress of 2 N/mm, and a frequency of 1 Hz. The seal member exhibits excellent heat resistance and abrasion resistance.

Abstract: A catalyst carrier, being characterized in that a catalyst metal for promoting an oxidation-reduction reaction is carried on a vapor-grown carbon fiber having an average outer diameter of from 2 nm to 500 nm, which has been subjected to a crushing treatment so as to have a BET specific surface area of from 4 m2/g to 100 m2/g and an aspect ratio of from 1 to 200, and exhibiting high activity per unit amount of a catalyst metal, a low reaction resistance and an improved output density, and is useful for a fuel cell; a production method thereof and a fuel cell using the catalyst carrier.

Abstract: A method of producing a carbon fiber composite material includes a first step and a second step. The first step includes oxidizing first carbon nanofibers produced by a vapor growth method to obtain second carbon nanofibers having an oxidized surface. The second step includes mixing the second carbon nanofibers into an elastomer, and uniformly dispersing the carbon nanofibers in the elastomer by applying a shear force to obtain the carbon fiber composite material. The second carbon nanofibers obtained by the first step have a surface oxygen concentration measured by X-ray photoelectron spectroscopy (XPS) of 2.6 to 4.6 atm %.

Abstract: A catalyst carrier, being characterized in that a catalyst metal for promoting an oxidation-reduction reaction is carried on a vapor-grown carbon fiber having an average outer diameter of from 2 nm to 500 nm, which has been subjected to a crushing treatment so as to have a BET specific surface area of from 4 m2/g to 100 m2/g and an aspect ratio of from 1 to 200, and exhibiting high activity per unit amount of a catalyst metal, a low reaction resistance and an improved output density, and is useful for a fuel cell; a production method thereof and a fuel cell using the catalyst carrier.

Abstract: An electrode material comprising a particle containing at least one member selected from the particles containing silicon, tin, silicon compound and tin compound, and fibrous carbon. The particle includes: (1) a particle comprising at least one member of a silicon particle, tin particle, particle containing a lithium-ion-intercalatable/releasable silicon compound and particle containing a lithium-ion-intercalatable/releasable tin compound; or (2) a particle comprising a silicon and/or silicon compound-containing carbonaceous material deposited onto at least a portion of the surfaces of a carbon particle having a graphite structure. The lithium secondary battery using the electrode material as a negative electrode has high discharging capacity and is excellent in cycle characteristics and characteristics under a load of large current.