Abstract: A single-crystal diamond, wherein the single-crystal diamond has an average of a phase difference per unit thickness of 10 nm/mm or less, and the phase difference has a standard deviation of 5 nm/mm or less.

Abstract: A single-crystal diamond having an X-ray diffraction rocking curve with a half-width of 20 seconds or less, wherein the half-width of the X-ray diffraction rocking curve is measured with CuK? radiation in a (004) plane parallel arrangement using a diamond crystal as a first crystal in X-ray diffraction by a double-crystal method, a peak at a Raman shift in the range of 1332 cm?1 to 1333 cm?1 in a Raman spectrum has a half-width of 2.0 cm?1 or less, the single-crystal diamond has an etch-pit density of 10,000/cm2 or less, the etch-pit density is measured in an etching test, and the single-crystal diamond has a nitrogen content of more than 0.1 ppm and 50 ppm or less based on the number of atoms.

Abstract: A synthetic single crystal diamond containing 100 ppm or more and 1500 ppm or less of nitrogen atoms, in which the synthetic single crystal diamond contains aggregates each composed of one vacancy and two to four nitrogen atoms present adjacent to the vacancy, a ratio b/a of a length b of a short diagonal line to a length a of a long diagonal line of diagonal lines of a Knoop indentation in a <110> direction in a {001} plane of the synthetic single crystal diamond is 0.08 or less, and the Knoop indentation is formed by measuring Knoop hardness in the <100> direction in the {001} plane of the synthetic single crystal diamond according to JIS Z 2251: 2009 under conditions of a temperature of 23° C.±5° C. and a test load of 4.9 N.

Abstract: A synthetic single crystal diamond containing nitrogen atoms at a concentration of 100 ppm or more and 1500 ppm or less based on atom numbers, in which the synthetic single crystal diamond contains aggregates each composed of one vacancy and three substitutional nitrogen atoms present adjacent to the vacancy, and a Raman shift ?? cm?1 of a peak in a first-order Raman scattering spectrum of the synthetic single crystal diamond and a Raman shift ? cm?1 of a peak in a first-order Raman scattering spectrum of a synthetic type IIa single crystal diamond containing nitrogen atoms at a concentration of 1 ppm or less based on atom numbers show a relationship of the following formula 1, ?????0??Formula 1.

Abstract: Provided is a synthetic single crystal diamond containing nitrogen atoms at a concentration of more than 600 ppm and 1500 ppm or less. The Raman shift ?? (cm?1) of a peak in a primary Raman scattering spectrum of the synthetic single crystal diamond and the Raman shift ? (cm?1) of a peak in a primary Raman scattering spectrum of a synthetic type IIa single crystal diamond containing nitrogen atoms at a content of 1 ppm or less satisfy the following expression (1): ??????0.10??(1).

Abstract: Provided is a synthetic single-crystal diamond containing nitrogen. In an X-ray absorption fine structure thereof, a ratio I405/I412 between an intensity I405 of a peak which appears at an energy of 405±1 eV and has a full width at ¾ maximum of 3 eV or more and an intensity I412 of a peak which appears at an energy of 412±2 eV is less than 1.

Abstract: A synthetic single crystal diamond contains nitrogen atoms at a concentration of more than 600 ppm and 1500 ppm or less, and the nitrogen atoms do not include any isolated substitutional nitrogen atom.

Abstract: Provided is a synthetic single crystal diamond containing nitrogen atoms at a concentration of more than 600 ppm and 1500 ppm or less. The Raman shift ?? (cm?1) of a peak in a primary Raman scattering spectrum of the synthetic single crystal diamond and the Raman shift ? (cm?1) of a peak in a primary Raman scattering spectrum of a synthetic type IIa single crystal diamond containing nitrogen atoms at a content of 1 ppm or less satisfy the following expression (1): ??????0.10??(1).

Abstract: The composite sintered body of the invention is a composite sintered body, containing 20 volume % or more and 80 volume % or less of cubic boron nitride particles, and a binder; wherein the binder contains at least one selected from the group consisting of nitrides, carbides, borides, and oxides of elements in the group 4a, elements in the group 5a, and elements in the group 6a in the periodic table, and solid solutions thereof, at least one selected from the group consisting of simple substances of Zr, Si, Hf, Ge, W and Co, compounds thereof, and solid solutions thereof, and a compound of Al; and when the composite sintered body contains therein W and/or Co, the total weight of the W and/or Co is less than 2.0 weight % and further the composite sintered body contains therein one or more of the Zr, Si, Hf and Ge (hereinafter referred to as “X”), and when the composite sintered body contains the X, the amount of each of the X is 0.005 weight % or more and less than 2.0 weight %, X/(X+W+Co) is 0.

Abstract: A cBN sintered body excellent in chipping resistance and wear resistance in working difficult-to-machine centrifugally cast iron is provided. The present invention is directed to a cBN sintered body composed of a cBN component not lower than 50 volume % and not higher than 90 volume % or not lower than 40 volume % and not higher than 85 volume %, characterized in that the cBN sintered body contains alumina and zirconia not lower than 9 volume % and not higher than 50 volume % and a weight ratio of zirconia/alumina is not lower than 0.1 and not higher than 4. A tool including the cBN sintered body according to the present invention in a portion involved with cutting achieves improved performance in working difficult-to-machine centrifugally cast iron as compared with a conventional tool made of a cBN sintered body, because the cBN sintered body is excellent in strength, hardness and toughness.

Abstract: The composite sintered body of the invention is a composite sintered body, containing 20 volume % or more and 80 volume % or less of cubic boron nitride particles, and a binder; wherein the binder contains at least one selected from the group consisting of nitrides, carbides, borides, and oxides of elements in the group 4a, elements in the group 5a, and elements in the group 6a in the periodic table, and solid solutions thereof, at least one selected from the group consisting of simple substances of Zr, Si, Hf, Ge, W and Co, compounds thereof, and solid solutions thereof, and a compound of Al; and when the composite sintered body contains therein W and/or Co, the total weight of the W and/or Co is less than 2.0 weight % and further the composite sintered body contains therein one or more of the Zr, Si, Hf and Ge (hereinafter referred to as “X”), and when the composite sintered body contains the X, the amount of each of the X is 0.005 weight % or more and less than 2.0 weight %, X/(X+W+Co) is 0.