Showa Denko K.k.

Showa Denko Kabushiki Kaisha

Eiji Ihara

Hirohiko Ohtsubo

Kousuke Shioi

Katsuyuki Tsuji

Makoto Iizuka

Taishu Yanagisawa

Takuya Okubo

Makoto Kasahara

Tatsuya Shimidzu

A method for producing cubic boron nitride in which hBN is held in the presence of a catalyst substance under conditions in which cBN remains thermodynamically stable, to thereby cause hBN to undergo a phase transition to form cBN, wherein the catalyst substance contains a lithium source, a magnesium source, and a carbon source. The performance of cBN is improved even though phase transition ratio from hBN to cBN is increased.

Cubic boron nitride, method for producing cubic boron nitride, grinding wheel with cubic boron nitride, and sintered cubic boron nitride compact

The present invention relates to a method for producing cubic boron nitride abrasive grains used for producing a grinding wheel, etc., and to cubic boron nitride abrasive grains. The method comprises maintaining a mixture containing hexagonal boron nitride and seed crystals of cubic boron nitride under pressure and temperature conditions where cubic boron nitride remains thermodynamically stable, characterized in that the seed crystals contain cubic boron nitride twin crystals.

Method for producing cubic boron nitride abrasive grains

By using a CBN synthesis catalyst containing a CBN synthesis catalyst component coated with an organic substance for producing cubic boron nitride (CBN), the CBN can be produced at a high transformation ration and a high yield ratio. Each of the CBN grains produced through this method has a sharp shape with a highly developed (111) plane, exhibits high strength, and exhibits a small reduction in strength due to heating. The amount of catalyst component contained in the CBN is 7.5&#xd7;10mol or less per 1 mol of CBN.

Cubic boron nitride, catalyst for synthesizing cubic boron nitride, and method for producing cubic boron nitride

A metal-coated cubic boron nitride abrasive grain obtained by forming grooves, in which the ratio (w/d) of the width (w) to the depth (d) is less than 1, and the ratio (w/L) of the width (w) to the length (L) is less than 0.1, on the surface of a cubic boron nitride abrasive grain. In this cubic boron nitride abrasive grain, the retention force (bonding strength) between the metallic coating and the cubic boron nitride abrasive grain is improved; therefore, it is possible to fabricate a resin bonded grinding wheel, in which a high grinding ratio (long life) and a low grinding power (superior grinding performance) are achieved, using such cubic boron nitride abrasive grains.

Metal-coated cubic boron nitride abrasive grain, production method thereof, and resin bonded grinding wheel

hBN is converted to cBN by keeping it under temperature and pressure conditions within the range of stability of cubic boron nitride, in the presence of at least one compound selected from amides, imides and carbides of alkali metals and alkaline earth metals, as well as a silicon source and/or a boron source.

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Shiojiri, Japan

Eiji Ihara