Showa Denko K.k.

Showa Denko Kabushiki Kaisha

Showa Denka K.k.

Hirohiko Ohtsubo

Eiji Ihara

Katsuyuki Tsuji

Eiichi Iizuka

Makoto Iizuka

Masakazu Maki

Takuya Okubo

Makoto Kasahara

Tatsuya Shimidzu

Tetsuro Sakurai

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

A method is provided for producing cubic boron nitride, in which a mixture containing hexagonal boron nitride and a catalyst is maintained under pressure and temperature conditions that thermodynamically favor the stable presence of cubic boron nitride, thereby forming composite lumps containing cubic boron nitride, which in turn are dissolved in an alkaline solution to recover cubic boron nitride. The method is characterized by including, prior to the dissolving step, a step of decreasing the ratio of low-pressure phase boron nitride to cubic boron nitride in the composite lumps down to 50% by mass or less.

Method for producing cubic boron nitride

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

An object of the present invention is to provide a method for producing diamond and cubic boron nitride crystals having excellent mechanical strength and high regularity in particle size with high productivity, wherein seed crystals are efficiently placed in a regular pattern on a supporting plate or a raw material plate. A method for growing diamond and cubic boron nitride crystals at a pressure and temperature within the stable region of diamond or cubic boron nitride, includes stacking a supporting plate and a raw material plate, and placing a plurality of seed crystals such that the crystals come in contact with the supporting plate, placing the seed crystals in a regular pattern on the supporting plate or the raw material plate by means of placing the seed crystals on an adhesive sheet through pores formed in a regular pattern, transferring the regularly-placed seed crystals on the adhesive sheet onto the surface of the supporting plate or the raw material plate and pressing the crystals against the surface. The supporting plate or the raw material plate is used for growing the crystals.

Method for growing diamond and cubic boron nitride crystals

CBN abrasive grains contain 0.01% by weight or more of Si and, the majority of the surfaces of its grains consist of {111} planes. In the method for producing CBN abrasive grains, a C source, an Si source, and at least one member selected from the group consisting of alkali hydride, alkali-earth hydride, and a synthetizing catalyst of CBN which may be the alkali hydride and alkali-earth hydride, are mixed together with HBN and are subjected to the treatment.

Growing community of inventors

Shiojiri, Japan

Hirohiko Ohtsubo