Abstract: A diamond polycrystal is a diamond polycrystal basically composed of a diamond single phase, wherein the diamond polycrystal is composed of a plurality of diamond grains having an average grain size of less than or equal to 30 nm, and the diamond polycrystal has a carbon dangling bond density of more than or equal to 10 ppm.

Abstract: A cemented carbide includes a first hard phase and a binder phase. The first hard phase is composed of tungsten carbide grains. The binder phase includes cobalt and nickel as constituent elements. An arbitrary surface or arbitrary cross section of the cemented carbide has: a region R1 interposed between an interface between the tungsten carbide grains and the binder phase and an imaginary line A; a region R2 interposed between the imaginary line A and an imaginary line B; and a region R3 other than the region R1 and R2. When a line analysis is performed in a range including the region R1 and the region R3 adjacent to the region R1 with the region R2, a ratio C5/C20 of a maximum atomic concentration C5 at % of cobalt in the region R1 and a maximum atomic concentration C20 at % of cobalt in the region R3 is more than 1.

Abstract: This method for producing a body obtained by processing a solid carbon-containing material includes: a step of preparing the solid carbon-containing material having at least a surface composed of solid carbon; and a step of processing the solid carbon-containing material. The step of processing the solid carbon-containing material includes: a sub-step of forming non-diamond carbon by heat-treating the solid carbon in the surface of the solid carbon-containing material; and a sub-step of removing at least a part of the non-diamond carbon.

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: A method for producing a body obtained by processing a solid carbon-containing material, the method includes: preparing the solid carbon-containing material composed of a material having at least a surface containing solid carbon; forming a gas phase fluid containing at least one of an active gas or an active plasma which are active against the solid carbon; and processing the solid carbon-containing material by injecting the gas phase fluid onto at least a part of the surface of the solid carbon-containing material.

Abstract: A cemented carbide includes a first hard phase and a binder phase. The first hard phase is composed of tungsten carbide grains. The binder phase includes cobalt and nickel as constituent elements. An arbitrary surface or arbitrary cross section of the cemented carbide has: a region R1 interposed between an interface between the tungsten carbide grains and the binder phase and an imaginary line A; a region R2 interposed between the imaginary line A and an imaginary line B; and a region R3 other than the region R1 and R2. When a line analysis is performed in a range including the region R1 and the region R3 adjacent to the region R1 with the region R2, a ratio C5/C20 of a maximum atomic concentration C5 at % of cobalt in the region R1 and a maximum atomic concentration C20 at % of cobalt in the region R3 is more than 1.

Abstract: An indenter is made of polycrystalline diamond and has a tip having a spherical surface with a radius of 10 to 2000 ?m.

Abstract: A method for producing a body obtained by processing a solid carbon-containing material, the method includes: preparing the solid carbon-containing material composed of a material having at least a surface containing solid carbon; forming a gas phase fluid containing at least one of an active gas or an active plasma which are active against the solid carbon; and processing the solid carbon-containing material by injecting the gas phase fluid onto at least a part of the surface of the solid carbon-containing material.

Abstract: This method for producing a body obtained by processing a solid carbon-containing material includes: a step of preparing the solid carbon-containing material having at least a surface composed of solid carbon; and a step of processing the solid carbon-containing material. The step of processing the solid carbon-containing material includes: a sub-step of forming non-diamond carbon by heat-treating the solid carbon in the surface of the solid carbon-containing material; and a sub-step of removing at least a part of the non-diamond carbon.

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: A diamond polycrystal is a diamond polycrystal basically composed of a diamond single phase, wherein the diamond polycrystal is composed of a plurality of diamond grains having an average grain size of less than or equal to 30 nm, and the diamond polycrystal has a carbon dangling bond density of more than or equal to 10 ppm.

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: An indenter is made of polycrystalline diamond and has a tip having a spherical surface with a radius of 10 to 2000 ?m.