Abstract: Provided are a valve guide made of an iron-based sintered alloy excellent in wear resistance and thermal conductivity, and a method of producing the same. Specifically, provided are a method of producing a valve guide made of an iron-based sintered alloy, the method including the steps of: molding raw material powder including diffusion-alloyed powder including core iron powder and Cu bonded to the core iron powder through diffusion to obtain a molded body; and sintering the molded body, to thereby produce a valve guide made of an iron-based sintered alloy, and a valve guide produced by the production method.

Abstract: Applicability to a composite material with high purity and high strength, and a material requiring high conductivity or high thermal conductivity is enhanced. The present invention relates to a multi-walled carbon nanotube having two or more tubes of a graphene sheet where carbon atoms are arranged in a hexagonal honeycomb form, coaxially, wherein a diameter of an outermost wall based on observation of an image by a transmission electron microscope is 3 nm or more and 15 nm or less, and a length based on observation of an image of a scanning electron microscope is 1.0 mm or more, an aggregate of multi-walled carbon nanotubes and a method for preparing the multi-walled carbon nanotube.

Abstract: Applicability to a composite material with high purity and high strength, and a material requiring high conductivity or high thermal conductivity is enhanced. The present invention relates to a multi-walled carbon nanotube having two or more tubes of a graphene sheet where carbon atoms are arranged in a hexagonal honeycomb form, coaxially, wherein a diameter of an outermost wall based on observation of an image by a transmission electron microscope is 3 nm or more and 15 nm or less, and a length based on observation of an image of a scanning electron microscope is 1.0 mm or more, an aggregate of multi-walled carbon nanotubes and a method for preparing the multi-walled carbon nanotube.

Abstract: Provided are a valve guide made of an iron-based sintered alloy excellent in wear resistance and thermal conductivity, and a method of producing the same. Specifically, provided are a method of producing a valve guide made of an iron-based sintered alloy, the method including the steps of: molding raw material powder including diffusion-alloyed powder including core iron powder and Cu bonded to the core iron powder through diffusion to obtain a molded body; and sintering the molded body, to thereby produce a valve guide made of an iron-based sintered alloy, and a valve guide produced by the production method.

Abstract: A method of producing a spherical boron nitride fine particle includes reacting ammonia with an alkoxide borate at an ammonia/alkoxide borate molar ratio of 1 to 10 in an inert gas stream at 750° C. or higher within 30 seconds, then applying heat treatment to a reaction product in an atmosphere of ammonia gas or a mixed gas of ammonia gas and an inert gas at 1,000 to 1,600° C. for at least 1 hour, and further firing the reaction product in an inert gas atmosphere at 1,800 to 2,200° C. for at least 0.5 hour.

Abstract: A spherical boron nitride fine particle suited for use as a highly thermoconductive filler or the like has an average particle diameter of 0.01 to 1.0 ?m, an orientation index of 1 to 15, a boron nitride purity of 98.0% by mass or greater, and an average circularity of 0.80 or greater. A method of producing a spherical boron nitride fine particle includes reacting ammonia with an alkoxide borate at an ammonia/alkoxide borate molar ratio of 1 to 10 in an inert gas stream at 750° C. or higher within 30 seconds, then applying heat treatment to a reaction product in an atmosphere of ammonia gas or a mixed gas of ammonia gas and an inert gas at 1,000 to 1,600° C. for at least 1 hour, and further firing the reaction product in an inert gas atmosphere at 1,800 to 2,200° C. for at least 0.5 hour.

Abstract: A boron nitride fine particle has low major diameter/thickness (aspect) ratio, high purity and high crystallinity, and also has an average particle diameter of 0.05 to 2.0 ?m, a graphitization index of 3 or less, and a total oxygen content of 0.20% by mass or less, with an average value of a major diameter/thickness ratio of scaly particles being 6.0 or less. A method of producing a boron nitride fine particle includes introducing ammonia and an alkoxide borate at an ammonia/alkoxide borate molar ratio of 1 to 5 in a reaction vessel in an inert gas atmosphere for heating at 800 to 1,350° C. within 30 seconds thereby obtaining a boron nitride precursor, and then heating the boron nitride precursor at 1,650 to 2,200° C. for at least 0.5 hour in an inert gas atmosphere.

Abstract: A boron nitride fine particle has low major diameter/thickness (aspect) ratio, high purity and high crystallinity, and also has an average particle diameter of 0.05 to 2.0 ?m, a graphitization index of 3 or less, and a total oxygen content of 0.20% by mass or less, with an average value of a major diameter/thickness ratio of scaly particles being 6.0 or less. A method of producing a boron nitride fine particle includes introducing ammonia and an alkoxide borate at an ammonia/alkoxide borate molar ratio of 1 to 5 in a reaction vessel in an inert gas atmosphere for heating at 800 to 1,350° C. within 30 seconds thereby obtaining a boron nitride precursor, and then heating the boron nitride precursor at 1,650 to 2,200° C. for at least 0.5 hour in an inert gas atmosphere.

Abstract: A spherical boron nitride fine particle suited for use as a highly thermoconductive filler or the like has an average particle diameter of 0.01 to 1.0 ?m, an orientation index of 1 to 15, a boron nitride purity of 98.0% by mass or greater, and an average circularity of 0.80 or greater. A method of producing a spherical boron nitride fine particle includes reacting ammonia with an alkoxide borate at an ammonia/alkoxide borate molar ratio of 1 to 10 in an inert gas stream at 750° C. or higher within 30 seconds, then applying heat treatment to a reaction product in an atmosphere of ammonia gas or a mixed gas of ammonia gas and an inert gas at 1,000 to 1,600° C. for at least 1 hour, and further firing the reaction product in an inert gas atmosphere at 1,800 to 2,200° C. for at least 0.5 hour.

Abstract: A boron nitride fiber paper having a very small fiber diameter and exhibiting excellent heat resistance, mechanical properties and heat conductivity. The fiber paper is composed of a fiber assembly which contains boron nitride fibers having a fiber diameter of not more than 1 ?m in an amount of not less than 40 wt %.

Abstract: A boron nitride nanosheet containing three-layered hexagonal boron nitride, which is in a form of multi-layered hexagonal boron nitride with some its layers peeled, can be produced by dispersing pristine hexagonal boron nitride powder in an organic solvent and by subjecting the fluid dispersion to ultrasonication.

Abstract: A boron nitride fiber paper having a very small fiber diameter and exhibiting excellent heat resistance, mechanical properties and heat conductivity. The fiber paper is composed of a fiber assembly which contains boron nitride fibers having a fiber diameter of not more than 1 ?m in an amount of not less than 40 wt %.

Abstract: The object of this invention is to provide a polyamide resin composition excellent in insulating properties, mechanical properties and dimensional stability. This invention is a resin composition containing 100 parts by weight of a polyamide resin and 0.01 to 50 parts by weight of boron nitride nanotubes. The invention also includes a formed article from the resin composition and processes for the production of the resin composition and the formed article.

Abstract: By preliminarily measuring the gallium temperature and the length change of a temperature sensing element comprising a carbon nanotube having a continuous column of gallium contained therein, then heating the temperature sensing element installed in a subject to increase the temperature thereof in air, removing the temperature sensing element subjecting to measure the gallium length, and substituting the measured gallium length in a formula, the temperature is measured accurately over a wide temperature range in a micrometer size or less environment.

Abstract: A novel nano thermometer, which can be used for temperature measurement of a wide temperature range, in a micrometer size environment, and a method for producing the same. The nano thermometer is a carbon nanotube filled with a continuous columnar gallium, which enables measurement of environmental temperature by length change of the columnar gallium, and is produced by mixing Ga2O3 powder and carbon powder uniformly, and performing heat treatment for this mixed powder at a temperature range of 1200 to 1400° C. under an inert gas flow.

Abstract: A novel nano thermometer, which can be used for temperature measurement of a wide temperature range, in a micrometer size environment, and a method for producing the same. The nano thermometer is a carbon nanotube filled with a continuous columnar gallium, which enables measurement of environmental temperature by length change of the columnar gallium, and is produced by mixing Ga2O3 powder and carbon powder uniformly, and performing heat treatment for this mixed powder at a temperature range of 1200 to 1400° C. under an inert gas flow.

Abstract: A new nanothermometer comprises, as a temperature sensitive element, a carbon nanotube in which continuous and columnar indium is included, and comprises a temperature-measuring section for measuring the temperature of an environment by measuring the length in the axial direction of the columnar indium, in the temperature sensitive element, which can be changed with a change in the environment temperature. The nanothermometer can be used to measure temperatures in a wide temperature range in an environment having a size of micrometers or less.

Abstract: By preliminarily measuring the gallium temperature and the length change of a temperature sensing element comprising a carbon nano tube having a continuous columnar gallium contained, then heating the temperature sensing element installed in a subject to have the temperature measure in the air, taking out the temperature sensing element subjecting to measure the gallium length, and substituting the measured gallium length in the formula, the temperature is measured accurately in a wide temperature range in a micrometer size or less environment.

Abstract: In order to provide a novel nano thermometer, which can use for temperature measurement of a wide temperature range, in a micrometer size environment, and a method for producing the same, the nano thermometer, comprising a carbon nanotube filled with a continuous columnar gallium, which enables measurement of environmental temperature by length change of the columnar gallium is produced by the method comprising mixing Ga2O3 powder and carbon powder uniformly, and performing heat treatment for this mixed powder at a temperature range of 1200 to 1400° C. under an inert gas flow.