Abstract: A diamond joined body is a diamond joined body including a hard substrate and a polycrystalline diamond layer arranged on the hard substrate, wherein an area ratio of carbon grains in a region of the hard substrate is less than 0.03%, the region being a region enclosed by an interface between the hard substrate and the polycrystalline diamond layer and an imaginary line x in a cross section parallel to a normal direction of the interface, the imaginary line x being parallel to the interface on the hard substrate side and having a distance of 500 ?m from the interface.

Abstract: A cutting tool includes: a base metal provided with a seat portion; a blade edge member that is a polycrystalline diamond sintered material containing polycrystalline diamond and a binder; and a brazing material that fixes the blade edge member to the seat portion of the base metal. The blade edge member has a thickness of greater than or equal to 0.3 mm. The brazing material is disposed between a blade edge bottom face of the blade edge member and a seat bottom face of the seat portion and is in contact with the blade edge bottom face and the seat bottom face. The flank face is located outside of the base metal with respect to the lateral face of the base metal.

Abstract: A sintered material includes diamond grains and a binder. A boron concentration in the diamond grains is more than or equal to 0.001 mass % and less than or equal to 0.9 mass %. A boron concentration in the binder is more than or equal to 0.5 mass % and less than or equal to 40 mass %.

Abstract: A cutting tool includes a rake face, a flank face, and a cutting edge ridge line connecting the rake face and the flank face. A portion of the rake face and a portion of the flank face adjacent to the cutting edge ridge line are made of a diamond sintered body including diamond grains. A dislocation density in the portion of the flank face is 8×1015/m2 or less. The diamond grains have an average grain size of 0.1 ?m to 50 ?m. A content ratio of the diamond grains in the diamond sintered body is 80% by volume to 99% by volume.

Abstract: A diamond sintered material includes diamond grains, wherein a content ratio of the diamond grains is more than or equal to 80 volume % and less than or equal to 99 volume % with respect to the diamond sintered material, an average grain size of the diamond grains is more than or equal to 0.1 ?m and less than or equal to 50 ?m, and a dislocation density of the diamond grains is more than or equal to 8.1×1013 m?2 and less than 1.0×1016 m?2.

Abstract: A diamond sintered material includes diamond grains, wherein a content ratio of the diamond grains is more than or equal to 80 volume % and less than or equal to 99 volume % with respect to the diamond sintered material, an average grain size of the diamond grains is more than or equal to 0.1 ?m and less than or equal to 50 ?m, and a dislocation density of the diamond grains is more than or equal to 1.2×1016 m?2 and less than or equal to 5.4×1019 m?2.

Abstract: A cutting tool includes: a base metal provided with a seat portion; a blade edge member that is a polycrystalline diamond sintered material containing polycrystalline diamond and a binder; and a brazing material that fixes the blade edge member to the seat portion of the base metal. The blade edge member has a thickness of greater than or equal to 0.3 mm. The brazing material is disposed between a blade edge bottom face of the blade edge member and the a seat bottom face of the seat portion and is in contact with the blade edge bottom face and the seat bottom face. The flank face is located outside of the base metal with respect to the lateral face of the base metal.

Abstract: A diamond joined body is a diamond joined body including a hard substrate and a polycrystalline diamond layer arranged on the hard substrate, wherein an area ratio of carbon grains in a region of the hard substrate is less than 0.03%, the region being a region enclosed by an interface between the hard substrate and the polycrystalline diamond layer and an imaginary line x in a cross section parallel to a normal direction of the interface, the imaginary line x being parallel to the interface on the hard substrate side and having a distance of 500 ?m from the interface.

Abstract: A method for reducing the caking property of coal, by contacting coal with sulfur dioxide in an amount at least 0.5 times the amount of the coal on a weight basis, at a temperature of at least 120.degree. C. under a pressure of at least 10 Kg/cm.sup.2, and separating the treated coal from the sulfur dioxide, whereby to reduce the caking property of the coal and to render the coal more easily pulverizable.