Abstract: 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.

Abstract: 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.

Abstract: 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 7.5×10?4 mol or less per 1 mol of CBN.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Cubic boron nitride abrasive grains which are substantially mono-crystalline and assume a black color. Such abrasive grains preferably have a specific packing ratio. Such abrasive grains are obtained by adding a boron source during synthesizing cubic boron nitride. By using such abrasive grains, a grinding wheel or a coated abrasive, which can improve surface roughness of ground workpieces while maintaining reduced grinding power, is formed.

Abstract: A CBN synthesis catalyst containing a CBN synthesis catalyst component coated with an organic substance is used for producing cubic boron nitride (CBN). The amount by mass of the organic substance is preferably contained 0.01 to 50 parts by mass based on 100 parts by mass of the CBN synthesis catalyst component. The organic substance is preferably stearic acid and/or lauric acid. By use of such a CBN synthesis catalyst, a CBN crystal which has a sharp shape, with the (111) place being developed, and which contains a small amount of a catalyst component(s) incorporated into CBN can be produced at high productivity (percent transformation (high yield)) in a simple manner and operation.

Abstract: 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.

Abstract: 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.

Abstract: 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.