National Institute for Materials Science

Denka Company Limited

Seitaro Kobayashi

Takashi Kawasaki

Go Takeda

Yoshio Bando

Dmitri Golberg

Fumihiro Kurokawa

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 &#x3bc;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&#xb0; C. within 30 seconds thereby obtaining a boron nitride precursor, and then heating the boron nitride precursor at 1,650 to 2,200&#xb0; C. for at least 0.5 hour in an inert gas atmosphere.

Boron nitride fine particles and production method thereof

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 &#x3bc;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&#xb0; 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&#xb0; C. for at least 1 hour, and further firing the reaction product in an inert gas atmosphere at 1,800 to 2,200&#xb0; C. for at least 0.5 hour.

Spherical boron nitride fine particles and production method thereof

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Omuta, Japan

Seitaro Kobayashi