Abstract: A cubic boron nitride polycrystal includes cubic boron nitride, the cubic boron nitride having an average grain size of not more than 150 nm, the cubic boron nitride polycrystal having a crack generation load of not less than 25 N in a breaking strength test in which an R200 ?m diamond indenter is used to apply a load at a rate of 100 N/min.

Abstract: Nano polycrystalline diamond is composed of carbon, an element of different type which is an element other than carbon and is added to be dispersed in carbon at an atomic level, and an inevitable impurity. The polycrystalline diamond has a crystal grain size not greater than 500 nm. The polycrystalline diamond can be fabricated by subjecting graphite in which the element of different type which is an element other than carbon has been added to be dispersed in carbon at an atomic level to heat treatment within high-pressure press equipment.

Abstract: Nano polycrystalline diamond is composed of carbon and a plurality of impurities other than carbon. A concentration of each of the plurality of impurities is not higher than 0.01 mass %, and the nano polycrystalline diamond has a crystal grain size (a maximum length) not greater than 500 nm. The nano polycrystalline diamond can be fabricated by preparing graphite in which a concentration of an impurity is not higher than 0.01 mass % and converting graphite to diamond by applying an ultra-high pressure and a high temperature to graphite.

Abstract: A composite polycrystal contains polycrystalline diamond formed of diamond grains that are directly bonded mutually, and compressed graphite dispersed in the polycrystalline diamond.

Abstract: Nano polycrystalline diamond is composed of carbon and a plurality of impurities other than carbon. A concentration of each of the plurality of impurities is not higher than 0.01 mass %, and the nano polycrystalline diamond has a crystal grain size (a maximum length) not greater than 500 nm. The nano polycrystalline diamond can be fabricated by preparing graphite in which a concentration of an impurity is not higher than 0.01 mass % and converting graphite to diamond by applying an ultra-high pressure and a high temperature to graphite.

Abstract: A composite polycrystal includes: a polycrystalline diamond phase including a plurality of diamond particles; and non-diamond phases composed of non-diamond carbon. The non-diamond phases are distributed in the polycrystalline diamond phase. An average value of projected area equivalent circle diameters of the non-diamond phases is not more than 1000 nm.

Abstract: A composite polycrystal contains polycrystalline diamond formed of diamond grains that are directly bonded mutually, and non-diamond carbon dispersed in the polycrystalline diamond, and has a concentration of contained hydrogen of greater than 1000 ppm and less than or equal to 20000 ppm.

Abstract: A composite polycrystal contains polycrystalline diamond formed of diamond grains that are directly bonded mutually, and non-diamond carbon dispersed in the polycrystalline diamond, and has a concentration of contained hydrogen of less than or equal to 1000 ppm.

Abstract: In a single-crystal diamond material, a concentration of non-substitutional nitrogen atoms is not more than 200 ppm, a concentration of substitutional nitrogen atoms is lower than the concentration of the non-substitutional nitrogen atoms, and the single-crystal diamond material has a crystal growth main surface having an off angle of not more than 20°. A perforated tool includes a single-crystal diamond die, wherein in the single-crystal diamond die, a concentration of non-substitutional nitrogen atoms is not more than 200 ppm, a concentration of substitutional nitrogen atoms is lower than the concentration of the non-substitutional nitrogen atoms, and the single-crystal diamond die has a low-index plane represented by a Miller index of not less than ?5 and not more than 5 in an integer, a perpendicular line of the low-index plane having an off angle of not more than 20° relative to an orientation of a hole for wire drawing.

Abstract: Provided are a diamond composite body capable of shortening a separation time for separating a substrate and a diamond layer, the substrate, and a method for manufacturing a diamond, as well as a diamond obtained from the diamond composite body and a tool including the diamond. The diamond composite body includes a substrate including a diamond seed crystal and having grooves in a main surface, a diamond layer formed on the main surface of the substrate, and a non-diamond layer formed on a substrate side at a constant depth from an interface between the substrate and the diamond layer.

Abstract: A method of manufacturing a diamond by a vapor phase synthesis method includes: preparing a substrate including a diamond seed crystal; forming a light absorbing layer lower in optical transparency than the substrate by performing ion implantation into the substrate, the light absorbing layer being formed at a predetermined depth from a main surface of the substrate; growing a diamond layer on the main surface of the substrate by the vapor phase synthesis method; and separating the diamond layer from the substrate by applying light from a main surface of at least one of the diamond layer and the substrate to allow the light absorbing layer to absorb the light and cause the light absorbing layer to be broken up.

Abstract: Single-crystal diamond is composed of carbon in which a concentration of a carbon isotope 12C is not lower than 99.9 mass % and a plurality of inevitable impurities other than carbon. The inevitable impurities include nitrogen, boron, hydrogen, and nickel, and a total content of nitrogen, boron, and hydrogen of the plurality of inevitable impurities is not higher than 0.01 mass %. In order to manufacture single-crystal diamond, initially, a hydrocarbon gas in which a concentration of the carbon isotope 12C is not lower than 99.9 mass % is subjected to denitrification.

Abstract: Nano polycrystalline diamond is composed of carbon, an element of different type which is an element other than carbon and is added to be dispersed in carbon at an atomic level, and an inevitable impurity. The polycrystalline diamond has a crystal grain size not greater than 500 nm. The polycrystalline diamond can be fabricated by subjecting graphite in which the element of different type which is an element other than carbon has been added to be dispersed in carbon at an atomic level to heat treatment within high-pressure press equipment.

Abstract: In an X-ray topography image for a crystal growth main surface of a single-crystal diamond, a group of crystal defect points are gathered, each of the crystal defect points being a tip point of a crystal defect line reaching the crystal growth main surface, the crystal defect line representing a line in which a crystal defect exists. Further, in the single-crystal diamond, a plurality of crystal defect line-like gathered regions exist in parallel. In the plurality of crystal defect line-like gathered regions, groups of crystal defect points are gathered to extend in the form of lines in a direction angled by not more than 30° relative to one arbitrarily specified direction. Accordingly, a single-crystal diamond is provided which is used suitably for a cutting tool, a polishing tool, an optical component, an electronic component, a semiconductor material, and the like.

Abstract: A polycrystalline diamond body contains diamond particles. The diamond particles have a mean particle size of 50 nm or less. As a result of measurement of a knoop hardness under a test load of 4.9 N at 23° C.±5° C., the polycrystalline diamond body has a ratio of a length B of a shorter diagonal line with respect to a length A of a longer diagonal line of diagonal lines of a knoop indentation, expressed as a B/A ratio, of 0.080 or less. This polycrystalline diamond body is tough and has a small particle size.

Abstract: Single crystal diamond of which hardness and chipping resistance have been improved in a balanced manner, a method for manufacturing the single crystal diamond, and a tool containing the diamond are provided. Single crystal diamond contains nitrogen atoms, and a ratio of the number of isolated substitutional nitrogen atoms in the single crystal diamond to the total number of nitrogen atoms in the single crystal diamond is not lower than 0.02% and lower than 40%.

Abstract: An object is to provide polycrystalline diamond applicable to diverse applications; and a water jet orifice, a stylus for gravure printing, a scriber, a diamond cutting tool, and a scribing wheel that include such polycrystalline diamond. This object is achieved by polycrystalline diamond obtained by converting and sintering non-diamond carbon under an ultrahigh pressure and at a high temperature without addition of a sintering aid or a catalyst, wherein sintered diamond grains constituting the polycrystalline diamond have an average grain diameter of more than 50 nm and less than 2500 nm and a purity of 99% or more, and the diamond has a D90 grain diameter of (average grain diameter+average grain diameter×0.9) or less.

Abstract: A composite sintered body includes a diamond phase and a non-diamond carbon phase. A non-diamond carbon phase occupancy rate is higher than 0% and not higher than 30%. The non-diamond carbon phase occupancy rate is a percentage of an area of the non-diamond carbon phase to a total area of one arbitrarily specified cross section of the composite sintered body. As a result, there is provided a high wear-resistant, high local wear-resistant and high chipping-resistant diamond-containing composite sintered body suitably used as a material for a wear-resistant tool, a cutting tool and the like.

Abstract: A composite sintered body includes a first phase and a second phase. The first phase is a diamond phase, and the second phase is a phase formed of one or more types of elements or compounds or both thereof and applying strain to the first phase. A contained amount of the second phase is larger than 0 ppm and not larger than 1000 ppm. As a result, there is provided a high wear-resistant, high local wear-resistant, and high chipping-resistant diamond-containing composite sintered body.

Abstract: A method for producing a diamond single crystal includes implanting an ion other than carbon into a surface of a diamond single crystal seed substrate and thereby decreasing the transmittance of light having a wavelength of 800 nm, the surface having an off-angle of 7 degrees or less with respect to a {100} plane, and homoepitaxially growing a diamond single crystal on the ion-implanted surface of the seed substrate using a chemical vapor synthesis under synthesis conditions where the ratio NC/NH of the number of carbon-containing molecules NC to the number of hydrogen molecules NH in a gas phase is 10% or more and 40% or less, the ratio NN/NC of the number of nitrogen molecules NN to the number of carbon-containing molecules NC in the gas phase is 0.1% or more and 10% or less, and the seed substrate temperature T is 850° C. or more and less than 1000° C.