Single crystal diamond and tool provided with same

Abstract

A single crystal diamond comprising nitrogen atoms at a content rate of 1-2000 ppm based on the number of atoms, wherein the ratio (NALL-NC) / NC of the difference NALL-NC between the number NALL of all nitrogen atoms and the number NC of nitrogen atoms at C centers, with respect to the number NC of nitrogen atoms at C centers is 1-105.

Description

Single crystal diamond and tool including same

[0001] The present disclosure relates to single crystal diamonds and tools comprising the same.

[0002] Single crystal diamond is extremely hard and is therefore used industrially in a wide range of applications, including cutting tools such as precision cutting tools and woodworking cutters, as well as wear-resistant tools such as dressers for grinding wheels, wire drawing dies, scribing tools, orifices for water jets, and wire guides (Patent Documents 1 and 2).

[0003] International Publication No. WO2022 / 118461 International Publication No. WO2017 / 198662

[0004] The single crystal diamond of the present disclosure has a nitrogen atom content of 1 ppm or more and 2000 ppm or less based on the atomic number, and the number of nitrogen atoms in the C center (isolated N) is Ｃ The total number of nitrogen atoms, N ＡＬＬ and the number N of nitrogen atoms in the C center Ｃ Difference with N ＡＬＬ -N Ｃ The proportion of (N ＡＬＬ -N Ｃ ) / N Ｃ is 1 or more and 10 ５ The following is the result.

[0005] Figure 1 is a schematic cross-sectional view showing an example of a sample chamber configuration used in producing a synthetic single crystal diamond according to one embodiment of the present disclosure. Figure 2 is a schematic cross-sectional view of a single crystal diamond according to one embodiment of the present disclosure.

[0006] [Problems to be Solved by the Present Disclosure] In recent years, the demand for improving tool life has been increasing, and the wear resistance and chipping resistance of single crystal diamonds that can be used in tools are required to be improved.It is known that the wear resistance and chipping resistance of single crystal diamonds can be improved by facilitating the formation of agglomeration between nitrogen atoms, agglomeration between nitrogen atoms and vacancies, or both in single crystal diamonds (Patent Document 2).However, in the examples of Patent Documents 1 and 2, since the annealing temperature (in other words, the maximum temperature of heat treatment) is less than 1600 ° C, it is difficult to sufficiently form agglomeration between nitrogen atoms, agglomeration between nitrogen atoms and vacancies, or both.In addition, simply increasing the annealing temperature has the problem of easily progressing the reverse phase transformation from diamond to graphite.As a result, it is sometimes difficult to provide single crystal diamonds with both excellent wear resistance and excellent chipping resistance.

[0007] Therefore, an object of the present disclosure is to provide a single crystal diamond that has both excellent wear resistance and excellent chipping resistance, and a tool including the same.

[0008] Effect of the Present Disclosure According to the present disclosure, it is possible to provide a single crystal diamond that has both excellent wear resistance and excellent chipping resistance, and a tool including the same.

[0009] [Explanation of the embodiment of the present disclosure] First, the embodiment of the present disclosure will be listed and explained. (1) The single crystal diamond of the present disclosure has a nitrogen atom content based on the atomic number of 1 ppm or more and 2000 ppm or less, and the number of nitrogen atoms in the C center, N Ｃ The total number of nitrogen atoms, N ＡＬＬ and the number N of nitrogen atoms in the C center Ｃ Difference with N ＡＬＬ -N Ｃ The proportion of (N ＡＬＬ -N Ｃ ) / N Ｃ is 1 or more and 10 ５ The following is the result.

[0010] According to the present disclosure, it is possible to provide a single crystal diamond that combines excellent wear resistance and excellent chipping resistance, and a tool including the same.

[0011] (2) In the above (1), the single crystal diamond may contain an A center, thereby providing a single crystal diamond and a tool including the same that have both superior wear resistance and superior chipping resistance.

[0012] (3) In the above (1) or (2), the single crystal diamond may contain a B center, thereby providing a single crystal diamond and a tool including the same that have both superior wear resistance and superior chipping resistance.

[0013] (4) In any one of the above (1) to (3), the single crystal diamond is NV ０ The center may include a single crystal diamond, which has both superior wear resistance and superior chipping resistance, and a tool including the single crystal diamond.

[0014] (5) In any one of the above (1) to (4), the single crystal diamond is NV ― The center may include a single crystal diamond, which has both superior wear resistance and superior chipping resistance, and a tool including the single crystal diamond.

[0015] (6) In any of the above (1) to (5), the single crystal diamond may contain an H center, thereby providing a single crystal diamond and a tool including the same that have both superior wear resistance and superior chipping resistance.

[0016] (7) In any of the above (1) to (6), the single crystal diamond may contain an H3 center, thereby providing a single crystal diamond and a tool including the same that have both superior wear resistance and superior chipping resistance.

[0017] (8) In any of the above (1) to (7), the single crystal diamond may contain an N3 center, thereby providing a single crystal diamond and a tool including the same that have both superior wear resistance and superior chipping resistance.

[0018] (9) In any of (1) to (8) above, the surface of the single crystal diamond may include a first region, the first region having an arithmetic mean height Sa of 3 nm or more as defined in JIS B 0681-2: 2018, and the first region having a maximum height Sz of 60 nm or more as defined in JIS B 0681-2: 2018. This makes it possible to provide a single crystal diamond and a tool including the same that have both superior wear resistance and superior chipping resistance.

[0019] (10) In any of the above (1) to (9), an altered portion is present on the outer periphery of the single crystal diamond, and in the core electron excitation spectrum of the altered portion obtained by electron energy loss spectroscopy using a transmission electron microscope, the amount of energy loss is in the range of 285 eV±5 eV. ＊ Maximum intensity of the peak Iπ ＊ and σ in the range of energy loss 291±5 eV. ＊ Maximum intensity of the peak Iσ ＊ The ratio Iπ ＊ / Iσ ＊ is 0.15 or more, and in the altered portion, the percentage of the number N1 of primary carbon atoms to the sum N1+N2 of the number N1 of primary carbon atoms constituting amorphous carbon and the number N2 of secondary carbon atoms constituting graphite, {N1 / (N1+N2)}×100, may be 90% or more. This makes it possible to provide a single crystal diamond and a tool including the same that have both superior wear resistance and superior chipping resistance.

[0020] (11) The tool of the present disclosure comprises the single crystal diamond described in (1) to (10) above.

[0021] According to the present disclosure, it is possible to provide a tool including a single crystal diamond that has both excellent wear resistance and excellent chipping resistance.

[0022] (12) In the above (11), the tool may be a cutting tool, a wear-resistant tool, or a grinding tool. This makes it possible to provide, as tools including single crystal diamond that have both excellent wear resistance and excellent chipping resistance, for example, wire drawing dies, injection molding nozzles, wire guides, etc.

[0023] [Details of the embodiment of the present disclosure] A single crystal diamond, its manufacturing method, tool, and specific examples of the manufacturing method of one embodiment of the present disclosure (hereinafter also referred to as "the present embodiment") will be described below with reference to the drawings. In the drawings of the present disclosure, the same reference symbols represent the same or corresponding parts. In addition, dimensional relationships such as length, width, thickness, and depth have been appropriately changed for the clarity and simplification of the drawings, and do not necessarily represent actual dimensional relationships.

[0024] In the present disclosure, the notation in the form of "A to B" means the upper and lower limits of a range (i.e., A or more and B or less), and when no unit is specified for A and a unit is specified only for B, the units of A and B are the same.

[0025] In the present disclosure, when a compound or the like is represented by a chemical formula, unless the atomic ratio is particularly limited, it is intended to include any conventionally known atomic ratio, and should not necessarily be limited to only those within the stoichiometric range.

[0026] [Embodiment 1: Single Crystal Diamond] A single crystal diamond according to one embodiment of the present disclosure will be described below. In one embodiment of the present disclosure (hereinafter also referred to as "this embodiment"), the content of nitrogen atoms based on the atomic number is 1 ppm or more and 2000 ppm or less, and the atomic number N of nitrogen atoms in the C center is Ｃ The total number of nitrogen atoms, N ＡＬＬ and the number N of nitrogen atoms in the C center Ｃ Difference with N ＡＬＬ -N Ｃ The proportion of (N ＡＬＬ -N Ｃ ) / NＣ is 1 or more and 10 ５ Below is a single crystal diamond.

[0027] According to the present disclosure, it is possible to provide a single crystal diamond that combines excellent wear resistance and excellent chipping resistance, and a tool including the same. The reasons for this are presumably as follows.

[0028] The single crystal diamond of this embodiment has a nitrogen atom content of 1 ppm or more and 2000 ppm or less based on the atomic number of nitrogen atoms, and the atomic number N of the nitrogen atoms in the C center is Ｃ The total number of nitrogen atoms, N ＡＬＬ and the number of nitrogen atoms in the C center, N Ｃ Difference with N ＡＬＬ -N Ｃ The proportion of (N ＡＬＬ -N Ｃ ) / N Ｃ is 1 or more and 10 ５ As a result, agglomeration of nitrogen atoms, agglomeration of nitrogen atoms and vacancies, or both, is likely to occur in the single crystal diamond, improving the wear resistance and chipping resistance of the single crystal diamond. As a result, it is possible to provide a single crystal diamond that has both excellent wear resistance and excellent chipping resistance, and a tool including the same.

[0029] The "C center" is a diamond crystal in which a nitrogen atom replaces a carbon atom on an atomic basis. Diamonds containing the "C center" include type Ib. Single crystal diamonds containing the C center have a wavenumber of 1130 cm in the infrared absorption spectrum measured by Fourier transform infrared spectroscopy. －１ (e.g., wave number 1130±2 cm －１ ) shows the absorption peak.

[0030] The "A center" described below is an aggregate consisting of two nitrogen atoms, which are covalently bonded and each nitrogen atom is substituted for a carbon atom constituting the diamond crystal. Diamonds containing the A center are called IaA type. Single crystal diamonds containing the A center have a wave number of 1282 cm in the infrared absorption spectrum measured by Fourier transform infrared spectroscopy. －１ (e.g., wave number 1282±2 cm －１ ) shows the absorption peak.

[0031] The "B center" described below is an aggregate consisting of four nitrogen atoms and one atomic vacancy, and each nitrogen atom is substituted for a carbon atom that constitutes the diamond crystal. Diamonds containing the B center are called IaB type. Single crystal diamonds containing the B center have a wavenumber of 1175 cm in the infrared absorption spectrum measured by Fourier transform infrared spectroscopy. －１ (e.g., wave number 1175±2 cm －１ ) shows the absorption peak.

[0032] The "NV" ０ The "NV center" is a complex defect consisting of one vacancy and one nitrogen atom adjacent to the vacancy. ０ A single crystal diamond containing a center exhibits an emission peak around a fluorescence wavelength of 575 nm (for example, a fluorescence wavelength of 575±2 nm) in a fluorescence spectrum obtained by irradiating it with excitation light shorter than approximately 575 nm, for example, excitation light with a wavelength of 514 nm.

[0033] The "NV" － The "vacancy center" is a complex defect consisting of one negatively charged vacancy and one nitrogen atom adjacent to the vacancy. － A single crystal diamond containing a center exhibits an emission peak around a fluorescence wavelength of 637 nm (for example, a fluorescence wavelength of 637±2 nm) in a fluorescence spectrum obtained by irradiating it with excitation light shorter than approximately 637 nm, for example, excitation light with a wavelength of 514 nm.

[0034] The "H2 center" described below is an aggregate consisting of one negatively charged vacancy and two nitrogen atoms adjacent to the vacancy, and each nitrogen atom is substituted for a carbon atom constituting the diamond crystal. Single crystal diamond containing the H2 center shows an emission peak at a fluorescence wavelength of around 986 nm (for example, a fluorescence wavelength of 986±2 nm) in the fluorescence spectrum obtained by irradiating it with excitation light shorter than about 986 nm, for example, excitation light with a wavelength of 830 nm.

[0035] The "H3 center" described below is an aggregate consisting of one vacancy and two nitrogen atoms adjacent to the vacancy, and each nitrogen atom is substituted for a carbon atom constituting the diamond crystal. Single crystal diamond containing the H3 center shows an emission peak at a fluorescence wavelength of around 503 nm (for example, a fluorescence wavelength of 503±2 nm) in the fluorescence spectrum obtained by irradiating it with excitation light shorter than approximately 503 nm, for example, excitation light with a wavelength of 457 nm.

[0036] " N3 center " as described later is an aggregate that consists of one vacancy and three nitrogen atoms that exist adjacent to this vacancy, and each nitrogen atom substitutes for the carbon atom that constitutes diamond crystal.The single crystal diamond that contains N3 center shows emission peaks at either or both of the fluorescence wavelength of about 415nm (for example, fluorescence wavelength of 415±2nm) and the fluorescence wavelength of 420nm or more and 470nm or less in the fluorescence spectrum that is obtained by irradiating excitation light that is shorter than about 410nm, for example, excitation light that has a wavelength of 325nm.

[0037] <<(N ＡＬＬ -N Ｃ ) / N Ｃ ≫ Number of nitrogen atoms in the C center Ｃ The total number of nitrogen atoms, N ＡＬＬ and the number of nitrogen atoms in the C center, N Ｃ Difference with N ＡＬＬ -N Ｃ The proportion of (N ＡＬＬ -N Ｃ ) / N Ｃ is 1 or more and 10 ５This makes it possible to improve the wear resistance and chipping resistance of the single crystal diamond. (N ＡＬＬ -N Ｃ ) / N Ｃ The lower limit of N may be 1.5 or more, or may be 2.0 or more. ＡＬＬ -N Ｃ ) / N Ｃ The upper limit is 2.0 × 10 ４ It may be 19890 or less, or 10 ４ It may be 10 or less, ３ It may be 10 or less, ２ (N ＡＬＬ -N Ｃ ) / N Ｃ is 1.5 or more 10 ４ It may be 2.0 or more and 10 ３ It may be the following:

[0038] In the present disclosure, (N ＡＬＬ -N Ｃ ) / N Ｃ can be determined in the following way: Ｃ is the 1130 cm －１ Based on the integrated intensity of the absorption peak of N, it was calculated using the method described in the literature "I. Kiflawi, A. E. Mayer, P. M. Spear, J. A. van Wyk, G. S. Woods, Philos. Mag. B 69 (1994) 1141. and G. S. Woods, J. A. van Wyk, A. T. Collins, Philos. Mag. B 62 (1990) 589." ＡＬＬ was determined by performing measurements using secondary ion mass spectrometry (SIMS) under the following conditions. Ｃ and N ＡＬＬ Based on this, (N ＡＬＬ -N Ｃ ) / N Ｃ(Conditions) Measurement device: Product name (product number): "IMS-7f", manufactured by CAMECA Primary ion species: Cesium (Cs+) Primary acceleration voltage: 15 kV Detection area: 30 (μmφ) Measurement accuracy: ±40% (2σ)

[0039] <> The single crystal diamond may contain an A center (2N), which can further improve the wear resistance and chipping resistance of the single crystal diamond.

[0040] In the present disclosure, "single crystal diamond contains an A center" means that the A center has a wave number of 1282 cm in the infrared absorption spectrum measured by Fourier transform infrared spectroscopy. －１ (e.g., wave number 1282±2 cm －１ ) can be identified by confirming the presence of an absorption peak.

[0041] The single crystal diamond may contain a B center (4NV), which can further improve the wear resistance and chipping resistance of the single crystal diamond.

[0042] In the present disclosure, "single crystal diamond contains a B center" means that the B center has a wave number of 1175 cm in the infrared absorption spectrum measured by Fourier transform infrared spectroscopy. －１ (e.g., wave number 1175±2 cm －１ ) can be identified by confirming the presence of an absorption peak.

[0043] <NV ０ Center≫ Single crystal diamond is NV ０ The single crystal diamond may contain a center, which can further improve the wear resistance and chipping resistance of the single crystal diamond.

[0044] In this disclosure, "single crystal diamond" refers to NV ０The fact that a compound contains a center can be identified by confirming that an emission peak exists at a fluorescence wavelength of about 575 nm (e.g., a fluorescence wavelength of 575±2 nm) in a fluorescence spectrum obtained by irradiating the compound with excitation light having a wavelength shorter than about 575 nm, for example, excitation light having a wavelength of 514 nm.

[0045] <NV ― Center≫ Single crystal diamond is NV ― The single crystal diamond may contain a center, which can further improve the wear resistance and chipping resistance of the single crystal diamond.

[0046] In this disclosure, "single crystal diamond" refers to NV ― The fact that a compound contains a center can be identified by confirming that an emission peak exists at a fluorescence wavelength of about 637 nm (e.g., a fluorescence wavelength of 637±2 nm) in a fluorescence spectrum obtained by irradiating the compound with excitation light having a wavelength shorter than about 637 nm, for example, excitation light having a wavelength of 514 nm.

[0047] <H2 Center> Single crystal diamond has H2 center (2NV － ) may be contained. This can further improve the wear resistance and chipping resistance of the single crystal diamond.

[0048] In the present disclosure, whether or not a "single crystal diamond contains an H center" can be identified by confirming that an emission peak exists near a fluorescence wavelength of 986 nm (e.g., a fluorescence wavelength of 986±2 nm) in a fluorescence spectrum obtained by irradiating the diamond with excitation light having a wavelength shorter than approximately 986 nm, for example, excitation light having a wavelength of 830 nm.

[0049] <H3 Center> The single crystal diamond may contain an H3 center (2NV), which can further improve the wear resistance and chipping resistance of the single crystal diamond.

[0050] In the present disclosure, whether or not a "single crystal diamond contains an H3 center" can be identified by confirming that an emission peak exists at a fluorescence wavelength of around 503 nm (e.g., a fluorescence wavelength of 503±2 nm) in a fluorescence spectrum obtained by irradiating the diamond with excitation light having a wavelength shorter than approximately 503 nm, for example, excitation light having a wavelength of 457 nm.

[0051] The single crystal diamond may contain an N3 center (3NV), which can further improve the wear resistance and chipping resistance of the single crystal diamond.

[0052] In the present disclosure, "single crystal diamond contains an N3 center" can be identified by confirming that, in a fluorescence spectrum obtained by irradiating the diamond with excitation light of a wavelength shorter than approximately 410 nm, for example, excitation light of a wavelength of 325 nm, there is an emission peak at either or both of a fluorescence wavelength of around 415 nm (for example, a fluorescence wavelength of 415±2 nm) and a fluorescence wavelength in the range of 420 nm or more and 470 nm or less.

[0053] <Configuration of Single Crystal Diamond> Fig. 2 is a schematic cross-sectional view of a single crystal diamond according to one aspect of the present disclosure. As shown in Fig. 2, an altered portion 27 may be present in the outer periphery of the single crystal diamond 21 of embodiment 1.

[0054] The shape of the single crystal diamond 21 is not particularly limited and can be appropriately selected depending on the application. The shape of the single crystal diamond 21 may be, for example, a flat plate, a prism, a pyramid, a truncated pyramid, or a polyhedron. The size of the single crystal diamond of the first embodiment is not particularly limited, but may be, for example, 0.1 mm ３ ~1000mm ３ may be.

[0055] The altered regions 27 may be present in the outer periphery of the single crystal diamond 21. The altered regions 27 may be present in at least a part of the outer periphery of the single crystal diamond 21. The altered regions 27 may be present so as to cover a part of the outer periphery of the single crystal diamond 21, or may be present so as to cover the entire outer periphery of the single crystal diamond 21. A plurality of altered regions 27 may be scattered around the outer periphery of the single crystal diamond 21.

[0056] <Altered portion> In the single crystal diamond of embodiment 1, in the altered portion, in the core electron excitation spectrum obtained by electron energy loss spectroscopy (hereinafter also referred to as "TEM-EELS") using a transmission electron microscope, the amount of energy loss is in the range of 285 eV±5 eV. ＊ Maximum intensity of the peak Iπ ＊ and σ in the range of energy loss 291±5 eV. ＊ Maximum intensity of the peak Iσ ＊ The ratio Iπ ＊ / Iσ ＊ is 0.15 or more, and in the altered portion, the percentage of the number N1 of primary carbon atoms to the sum N1+N2 of the number N1 of primary carbon atoms constituting amorphous carbon and the number N2 of secondary carbon atoms constituting graphite, {N1 / (N1+N2)}×100, may be 90% or more.

[0057] In the core electron excitation spectrum obtained by the TEM-EELS method in the altered area, the amount of energy loss is in the range of 285 eV ± 5 eV. ＊ The peak is derived from the π bond of carbon, and exists in the range of energy loss 291±5 eV. ＊ The peak is a peak derived from the σ bond of carbon. ＊ / Iσ ＊ is 0.15 or more indicates that the ratio of carbon π bonds to carbon σ bonds is a predetermined amount or more in the altered portion of the single crystal diamond of embodiment 1.

[0058] The carbon atoms having a π bond present in the altered portion may include carbon atoms constituting amorphous carbon (also referred to as "primary carbon atoms" in the present disclosure) and carbon atoms constituting graphite (also referred to as "secondary carbon atoms" in the present disclosure).

[0059] In the altered portion of the single crystal diamond of embodiment 1, the percentage of the number of primary carbon atoms N1 relative to the sum N1+N2 of the number of primary carbon atoms N1 constituting amorphous carbon and the number of secondary carbon atoms N2 constituting graphite, {N1 / (N1+N2)}×100, may be 90% or more. This indicates that 90% or more of the carbon atoms having π bonds present in the altered portion exist as amorphous carbon. Amorphous carbon has a high absorption rate for lasers with wavelengths of 355 nm to 1064 nm, which are used in processing single crystal diamonds, compared to diamond and graphite.

[0060] In the core electron excitation spectrum obtained by the TEM-EELS method in the altered part of single crystal diamond, the ratio Iπ ＊ / Iσ ＊ When the ratio N1 / (N1+N2) is 0.15 or more and the percentage {N1 / (N1+N2)}×100 is 90% or more, the amorphous carbon with high laser absorption rate present on the surface of the single crystal diamond improves the workability of the single crystal diamond when laser processing it. Also, the wear resistance and chipping resistance of the single crystal diamond can be improved.

[0061] In the present disclosure, the presence of an altered portion in a single crystal diamond is indicated by the ratio Iπ ＊ / Iσ ＊ and the percentage {N1 / (N1+N2)}×100 in the affected area.

[0062] <Ratio Iπ in the core electron excitation spectrum obtained by TEM-EELS in the altered area ＊ / Iσ ＊ Measurement of the ratio Iπ in the core electron excitation spectrum obtained by the TEM-EELS method in the altered part of single crystal diamond ＊ / Iσ ＊ The specific measurement method is as follows:

[0063] Step A1: A single crystal diamond is sliced ​​using an argon ion slicer along a plane parallel to the normal direction of the surface to obtain a measurement sample with a thickness of 3 to 100 nm. The measurement sample is observed using a transmission electron microscope (TEM, JEOL Ltd., "JEM-2100F / Cs" (trademark)) at 50,000 to 500,000 magnifications to obtain a bright-field image of the single crystal diamond.

[0064] Step A2: Next, identify the region corresponding to the altered portion in the bright-field image. The region corresponding to the altered portion in the bright-field image can be identified, for example, by a difference in contrast. The following measurements are performed in a region corresponding to the altered portion in the bright-field image that is estimated to have a thickness of 3 nm or more.

[0065] Step A3: Starting from the surface of the region corresponding to the altered portion, a measurement point is set within a distance of 2 nm to 3 nm along the normal direction of the surface of the single crystal diamond, and an electron energy loss spectroscopy (EELS) method is applied to observe the energy loss (K edge) associated with the excitation of carbon K-shell electrons by scanning a 1 nm diameter observation spot 100 nm in a direction parallel to the surface of the single crystal diamond. In this way, a core electron excitation spectrum of around 300 eV associated with the excitation of carbon K-shell electrons at the measurement point is obtained.

[0066] Step A4. In the core electron excitation spectrum at the measurement point, the energy loss amount is within the range of 285 eV ± 5 eV. ＊ Maximum intensity of the peak Iπ ＊ and σ in the range of energy loss 291±5 eV. ＊ Maximum intensity of the peak Iσ ＊ and obtain Iπ ＊ Iσ ＊ By dividing by, the ratio Iπ ＊ / Iσ ＊ Ask for.

[0067] Step A5: The above measurement is performed at five measurement points that do not overlap each other. At all five measurement points, the ratio Iπ ＊ / Iσ ＊ When the ratio Iπ is 0.15 or more, the ratio Iπ in the core electron excitation spectrum obtained by the TEM-EELS method in the region corresponding to the altered portion＊ / Iσ ＊ is judged to be 0.15 or more.

[0068] <<Measurement of percentage {N1 / (N1+N2)}×100 in the affected area>> Step B1. Next, the ratio Iπ is calculated by the above steps A1 to A4. ＊ / Iσ ＊ At each of five measurement points set in the region corresponding to the altered portion where it is determined that π is 0.15 or more, ＊ The peaks are separated into peaks derived from amorphous carbon and peaks derived from graphite. The five measurement points are the same as the five measurement points set in step A5 above.

[0069] Step B2. At each measurement point, the maximum intensity Iπ is calculated based on the state separation result. ＊ The percentage of the number N1 of primary carbon atoms to the sum N1+N2 of the number N1 of primary carbon atoms constituting amorphous carbon and the number N2 of secondary carbon atoms constituting graphite in the amount of energy loss indicated above is calculated as {N1 / (N1+N2)}×100.

[0070] If the percentage {N1 / (N1+N2)}×100 is 90% or more at all five measurement points, the percentage {N1 / (N1+N2)}×100 of the region corresponding to the measured altered part is determined to be 90% or more. In other words, the region corresponding to the altered part identified in step B1 is determined to be the region corresponding to the ratio Iπ in the core electron excitation spectrum obtained by the TEM-EELS method. ＊ / Iσ ＊ is 0.15 or more and the percentage {N1 / (N1+N2)}×100 is 90% or more, it is determined to be an altered part, and it is confirmed that an altered part exists on the outer periphery of the single crystal diamond being measured.

[0071] As long as measurements are taken on the same single crystal diamond, it has been confirmed that there is almost no variation in the measurement results even if multiple non-overlapping bright-field images are obtained and the measurement point in the region corresponding to the altered area in each bright-field image is changed.

[0072] In the altered portion of the single crystal diamond of embodiment 1, the ratio Iπ ＊ / Iσ＊ is 0.15 or more, and may be 0.17 or more, or may be 0.19 or more.

[0073] In the altered portion of the single crystal diamond of embodiment 1, the percentage {N1 / (N1+N2)}×100 may be 90% or more, 93% or more, 96% or more, or 99% or more.

[0074] <Composition> <Nitrogen Atom> In the single crystal diamond of this embodiment, the content of nitrogen atom based on atomic number is 1 ppm or more and 2000 ppm or less.If this content is less than 1 ppm, the aggregation of nitrogen atoms, the aggregation of nitrogen atoms and vacancies, or both are difficult to occur, so the wear resistance and chipping resistance of single crystal diamond tend to be insufficient.On the other hand, if this content is more than 2000 ppm, the lattice defects in single crystal diamond tend to increase, so the wear resistance and chipping resistance of single crystal diamond tend to be insufficient.The lower limit of this content can be 3 ppm or more, 10 ppm or more, 15 ppm or more, or 30 ppm or more.The upper limit of this content can be 1400 ppm or less, 879 ppm or less, 800 ppm or less, or 300 ppm or less. The content may be 3 ppm or more and 1400 ppm or less, 10 ppm or more and 879 ppm or less, 15 ppm or more and 800 ppm or less, or 30 ppm or more and 300 ppm or less.

[0075] In the single crystal diamond of this embodiment, the content of nitrogen atoms on an atomic number basis can be measured by secondary ion mass spectrometry (SIMS).

[0076] <Arithmetic mean height Sa and maximum height Sz> The surface of the single crystal diamond of embodiment 1 includes a first region, and the arithmetic mean height Sa of the first region as defined in JIS B 0681-2:2018 may be 3 nm or more, and the maximum height Sz of the first region as defined in JIS B 0681-2:2018 may be 60 nm or more. This can improve wear resistance and chipping resistance. Furthermore, because the surface of the single crystal diamond has moderate irregularities, when the single crystal diamond is fixed to a substrate via a bonding material, the adhesion between the single crystal diamond and the bonding material is improved.

[0077] The lower limit of the arithmetic mean height Sa of the first region may be 3 nm or more from the viewpoint of improving the adhesion between the single crystal diamond and the bonding material. The upper limit of the arithmetic mean height Sa of the first region may be 100 nm or less from the viewpoint of facilitating material installation. The arithmetic mean height Sa of the first region may be 5 nm or more and 80 nm or less, 5 nm or more and 60 nm or less, or 5 nm or more and 40 nm or less.

[0078] The lower limit of the maximum height Sz of the first region is 60 nm or more from the viewpoint of improving the adhesion between the single crystal diamond and the bonding material. The upper limit of the maximum height Sz of the first region may be 500 nm or less from the viewpoint of ease of material installation. The maximum height Sz of the first region may be 80 nm or more and 400 nm or less, or may be 100 nm or more and 300 nm or less.

[0079] The arithmetic mean height Sa and maximum height Sz defined in JIS B 0681-2:2018 (Geometrical product specifications (GPS) - Surface texture: Areal - Part 2: Terms, definitions and surface texture parameters) correspond to the arithmetic mean height Sa and maximum height Sz defined in ISO 25178-2:2012 (Geometrical product specifications (GPS) - Surface texture: Areal - Part 2: Terms, definitions and surface texture parameters (MOD)).

[0080] In the present disclosure, whether the surface of a single crystal diamond includes a first region is confirmed by the following procedure.

[0081] The surface of the single crystal diamond is divided into rectangular unit areas of 10 μm × 10 μm, and the arithmetic mean height Sa and maximum height Sz are measured for each unit area. Depending on the shape of the surface of the single crystal diamond, it may not be possible to divide the surface into an integer number of unit areas, resulting in a remainder. In such cases, only the unit areas are measured, and the remainder areas are excluded from the measurement object.

[0082] When there is a unit region having an arithmetic mean height Sa of 3 nm or more and a maximum height Sz of 60 nm or more, it is confirmed that the surface of the single crystal diamond includes a first region. ２ That's all.

[0083] In the present disclosure, the arithmetic mean height Sa and maximum height Sz of the first region are measured by the following procedure. On the surface of the single crystal diamond, all unit regions A having an arithmetic mean height Sa of 3 nm or more and a maximum height Sz of 60 nm or more are identified. The arithmetic mean height Sa and maximum height Sz are measured based on all unit regions A. The unit regions A may or may not be in contact with each other. In the present disclosure, the arithmetic mean height Sa measured based on all unit regions A corresponds to the arithmetic mean height Sa of the first region. In the present disclosure, the maximum height Sz measured based on all unit regions A corresponds to the maximum height Sz of the first region.

[0084] In the present disclosure, the position and size of the first region on the surface of the single crystal diamond can be appropriately set depending on the application of the single crystal diamond. For example, when the single crystal diamond is fixed to a substrate via a bonding material, the first region can constitute at least a part of the region on the surface of the single crystal diamond that contacts the bonding material. Furthermore, the first region can constitute the entire surface of the single crystal diamond. The proportion of the first region to the entire surface of the single crystal diamond can be, for example, 25% or more, 50% or more, or even 100%.

[0085] <<Method for manufacturing single-crystal diamond>> The method for manufacturing a single-crystal diamond according to the present disclosure will be explained with reference to Figure 1. Figure 1 is a schematic cross-sectional view showing an example of a sample chamber configuration used in manufacturing a synthetic single-crystal diamond according to one embodiment of the present disclosure. The method for manufacturing a single-crystal diamond according to one embodiment of the present disclosure includes the steps of obtaining a diamond single crystal by a temperature difference method using a solvent metal (hereinafter also referred to as the "temperature difference method step"), irradiating the diamond single crystal with an electron beam (hereinafter also referred to as the "irradiation step"), annealing the diamond single crystal irradiated with the electron beam (hereinafter also referred to as the "annealing step"), and performing an acid treatment on the annealed diamond single crystal (hereinafter also referred to as the "acid treatment step").

[0086] <Temperature Difference Method Step> Diamond single crystals can be produced by the temperature difference method using a sample chamber having the configuration shown in FIG. 1, for example.

[0087] As shown in Figure 1, in a sample chamber 10 used for producing diamond single crystals, an insulator 2, a carbon source 3, a solvent metal 4, and a seed crystal 5 are arranged in a space surrounded by a graphite heater 7, and a pressure medium 6 is arranged outside the graphite heater 7. The temperature difference method is a method in which a vertical temperature gradient is provided inside the sample chamber 10, and a high temperature part (T ｈｉｇｈ ) carbon source 3, low temperature part (T ｌｏｗ In this synthesis method, a diamond seed crystal 5 is placed in a carbon source 3, a solvent metal 4 is placed between the carbon source 3 and the seed crystal 5, and a diamond single crystal is grown on the seed crystal 5 by maintaining the temperature at which the solvent metal 4 dissolves and at a pressure at which the diamond becomes thermally stable.

[0088] Diamond powder can be used as the carbon source 3. Graphite or pyrolytic carbon can also be used. The solvent metal 4 can be one or more metals selected from iron (Fe), cobalt (Co), nickel (Ni), manganese (Mn), etc., or an alloy containing these metals.

[0089] The carbon source 3 or the solvent metal 4 may contain, as a nitrogen source, iron nitride (Fe ２ N, Fe ３ N), aluminum nitride (AlN), phosphorus nitride (P３ N ４ ), silicon nitride (Si ３ N ４ Nitrides such as nitrates, melamine, and sodium azide can be added singly or as a mixture to the diamond. This allows nitrogen atoms to be present in the diamond single crystal. The nitrogen atoms in the diamond single crystal are primarily present as isolated substitutional nitrogen atoms.

[0090] The content of the nitrogen source in the carbon source 3 or the solvent metal 4 can be, for example, 1 ppm to 5000 ppm of nitrogen atoms derived from the nitrogen source in the carbon source based on the number of atoms. ３ In the case of N, the content of the nitrogen source can be set to 0.01% by mass or more and 10% by mass or less.

[0091] The solvent metal 4 may further contain one or more elements selected from the group consisting of titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), copper (Cu), zirconium (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), hafnium (Hf), tantalum (Ta), tungsten (W), osmium (Os), iridium (Ir), and platinum (Pt).

[0092] <Irradiation step> Next, the obtained diamond single crystal is processed to a thickness of 0.1 mm to 10 mm in the case of a 10 mm square size, for example. The processed diamond single crystal is then irradiated with an electron beam to introduce lattice defects into the diamond single crystal and form vacancies.

[0093] The electron beam irradiation conditions were: electron beam energy of 1.0 MeV to 10 MeV, and a dose of 1.0×10 １９ e / m ２ Above 1.0 x 10 ２３ e / m ２The range of irradiation with the electron beam is larger than the surface (region) of the diamond single crystal that is irradiated with the electron beam. If the energy or dose of the electron beam is less than the above lower limit, there is a risk that the introduction of lattice defects will be insufficient. Conversely, if it exceeds the above upper limit, there is a risk that excessive vacancies will be generated, resulting in a significant decrease in crystallinity.

[0094] <Annealing step> Next, the electron beam irradiated diamond single crystal is annealed in a vacuum or in an inert gas for 10 minutes. －３ The annealing is performed at a pressure of 1 Pa or more and 0.2 MPa or less and a temperature of 1600 ° C or more and 1800 ° C or less. The heating rate until the maximum temperature is reached is 1 ° C / min or more and 3 ° C / min or less. Then, the temperature is lowered at a rate of 0.5 ° C / min or more and 5 ° C / min or less. As a result, isolated substitutional nitrogen atoms in the diamond single crystal move through the vacancies, causing agglomerated nitrogen defects. The annealing time can be 10 minutes or more and 1000 minutes or less.

[0095] If the temperature during annealing is less than 1600 ℃, the speed of nitrogen migration will be slow, and annealing will be insufficient, so it is not preferred.On the other hand, if the temperature during annealing is more than 1800 ℃, the speed of nitrogen migration will be fast, but under normal pressure, diamond single crystal will be graphitized.Therefore, when annealing at the temperature above 1800 ℃, it is necessary to carry out under the super-high pressure condition that diamond is thermodynamically stable, but this is not preferred from the viewpoint of cost increase and productivity decrease.

[0096] The irradiation step and the annealing step are each performed once, and can be repeated two or more times. This can promote the movement of isolated substitutional nitrogen atoms in the diamond single crystal. By performing the irradiation step and the annealing step sufficiently, a moderately sufficient amount of agglomerated nitrogen defects are generated from the isolated substitutional nitrogen atoms in the diamond single crystal.

[0097] <Acid Treatment Step> Next, the annealed diamond single crystal is immersed in acid to perform acid treatment. The acid used in the acid treatment step is a mixed solution of concentrated sulfuric acid and concentrated nitric acid. The acid treatment step lasts for 5 minutes or more. This time may be 300 minutes or less. The temperature of the acid may be from room temperature to 300°C.

[0098] <Features of the method for producing single crystal diamond according to this embodiment> In this embodiment, the method for producing single crystal diamond is as follows: "In the irradiation step, the electron beam irradiation conditions are: electron beam energy of 1.0 MeV or more and 10 MeV or less, dose amount of 1.0×10 １９ e / m ２ Above 1.0 x 10 ２３ e / m ２ "In the annealing step, 10 －３ "The annealing step is performed at a pressure of 1600° C. or more and 1800° C. or less in the annealing step," "the temperature increase rate is 1° C. / min. or more and 10° C. / min. or less and the temperature decrease rate is 0.5° C. / min. or more and 5° C. / min. or less in the annealing step" (in other words, the temperature is increased and decreased slowly), and "the acid treatment step is performed under the condition of immersion in a mixed solution of concentrated sulfuric acid and concentrated nitric acid for 5 minutes or more." By these, even when the content of nitrogen atoms is low (in other words, when the content of nitrogen atoms based on the atomic number is 1 ppm or more and 2000 ppm or less), "the atomic number N of nitrogen atoms of the C center can be increased or decreased. Ｃ The total number of nitrogen atoms, N ＡＬＬ and the number of nitrogen atoms in the C center, N Ｃ Difference with N ＡＬＬ -N Ｃ The proportion of (N ＡＬＬ -N Ｃ ) / N Ｃ is 1 or more and 10 ５ The reason for this is presumably as follows.

[0099] (i) In the method for producing a single crystal diamond according to this embodiment, "in the irradiation step, the electron beam irradiation conditions are: electron beam energy of 1.0 MeV or more and 10 MeV or less, and a dose of 1.0×10 １９ e / m ２ Above 1.0 x 10 ２３ e / m ２ "In the annealing step, 10 －３ By "annealing at a pressure of 1600°C or more and 0.2 MPa or less" and "annealing at a temperature of 1600°C or more and 1800°C or less in the annealing step," it is possible to promote aggregation between nitrogen atoms, aggregation between nitrogen atoms and vacancies, or both. For example, in Patent Document 2, the temperature in the annealing step is less than 1600°C, making it difficult to sufficiently promote aggregation between nitrogen atoms, aggregation between nitrogen atoms and vacancies, or both.

[0100] (ii) However, "in the irradiation step, the electron beam irradiation conditions are: electron beam energy of 1.0 MeV or more and 10 MeV or less, and a dose of 1.0 × 10 １９ e / m ２ Above 1.0 x 10 ２３ e / m ２ "In the annealing step, 10 －３ "Annealing at a pressure of 1600°C or more and 0.2MPa or less" and "Annealing at a temperature of 1600°C or more and 1800°C or less in the annealing step" can promote the aggregation of nitrogen, but the high temperature in the annealing step tends to make it easier for reverse phase transformation from diamond to graphite to occur. Therefore, in order to produce the single crystal diamond of this embodiment, it is necessary to suppress the occurrence of this reverse phase transformation.

[0101] (iii) In the method for producing a single crystal diamond according to this embodiment, by "setting the temperature rise rate to 1°C / min or more and 3°C / min or less, and the temperature fall rate to 0.5°C / min or more and 5°C / min or less in the annealing step" (in other words, by slowly raising and lowering the temperature), it is possible to make it difficult for "reverse phase transformation from diamond to graphite" to occur, which is caused by the high temperature in the annealing step. Therefore, it is possible to keep the amount of graphite that occurs on the surface of the single crystal diamond to a minimum.

[0102] (iv) In the method for manufacturing a single crystal diamond according to this embodiment, the graphite that forms on the surface of the single crystal diamond (in other words, the graphite that is kept to a minimum in (iii) above) can be removed by "carrying out the acid treatment step under the condition of immersing the diamond in a mixed solution of concentrated sulfuric acid and concentrated nitric acid for 5 minutes or more."

[0103] The fact that the single crystal diamond of the present disclosure can be realized by the above manufacturing method is a new discovery made by the present inventors as a result of extensive research.

[0104] [Embodiment 2: Tool] A tool according to this embodiment will be described. This embodiment is a tool comprising the single crystal diamond described in embodiment 1.

[0105] According to the present disclosure, a tool including a single crystal diamond having excellent wear resistance can be provided.

[0106] <Tools> Examples of tools according to this embodiment include wear-resistant tools such as dressers, wire-drawing dies, surgical knives, injection molding nozzles, wire guides, scribing tools, and water jet orifices, cutting tools such as precision cutting tools and woodworking cutters, and grinding tools such as grinding wheels. This makes it possible to provide wear-resistant tools, cutting tools, and grinding tools as tools equipped with single-crystal diamond having excellent wear resistance.

[0107] <Tool Manufacturing Method> The tool manufacturing method according to this embodiment can be carried out by a conventionally known method, except that the single crystal diamond according to embodiment 1 is used as the material of the tool.

[0108] The present embodiment will be described in more detail with reference to examples, although the present embodiment is not limited to these examples.

[0109] <<Preparation of Single Crystal Diamond>> Single crystal diamonds according to Samples 1 to 14 were prepared as follows.

[0110] <Temperature Difference Method Step> First, a diamond single crystal was synthesized by the temperature difference method using a solvent metal, using a sample chamber having the configuration shown in FIG.

[0111] An alloy consisting of iron-cobalt-nickel was prepared as a solvent metal, and iron nitride (Fe ３ Iron nitride (Fe) powder was added to the solvent metal. ３ The concentration of iron nitride in the solvent metal is shown in Table 1 under "Iron nitride concentration [mass %]".

[0112] Diamond powder was used as the carbon source, and a diamond single crystal with the mass listed in Table 1 was used as the seed crystal. The temperature in the sample chamber was adjusted with a heater so that there was a temperature difference of several tens of degrees between the high-temperature section where the carbon source was placed and the low-temperature section where the seed crystal was placed. Using an ultra-high pressure generator, this was held for 100 hours under conditions of a pressure of 5.5 GPa and a "low-temperature section temperature" of 1370°C ± 10°C (1360°C to 1380°C), and a diamond single crystal was synthesized on the seed crystal.

[0113] <Irradiation step> Next, in cases where the "Whether electron beam irradiation was performed" column in Table 1 states "Yes," the obtained diamond single crystal was irradiated with an electron beam (electron beam energy: as shown in Table 1; electron beam dose: as shown in Table 1).

[0114] <Annealing step> Next, in cases where the "Heat treatment performed" column in Table 2 states "Yes", the diamond single crystal after the irradiation step was subjected to an annealing step in a vacuum under normal pressure under the conditions listed in Table 2.

[0115] Next, the annealed diamond single crystal was subjected to an acid treatment for 30 minutes in a mixed solution of concentrated sulfuric acid and concentrated nitric acid, to obtain a single crystal diamond. In the mixed solution, the ratio of concentrated sulfuric acid (concentration 95% by mass) to concentrated nitric acid (concentration 60% by mass) was 3:1 by volume.

[0116] By the above procedure, single crystal diamonds according to Samples 1 to 14 were produced.

[0117] <<Characteristics evaluation of single crystal diamond>> <Nitrogen atom content based on atomic number> For the single crystal diamond of each sample, the nitrogen atom content based on atomic number was obtained by the method described in embodiment 1. The obtained results are shown in the column of "nitrogen atom content [ppm]" in Table 3.

[0118] <(N ＡＬＬ -N Ｃ ) / N Ｃ For each sample of single crystal diamond, the number of nitrogen atoms in the C center, N Ｃ The total number of nitrogen atoms, N ＡＬＬ and the number of nitrogen atoms in the C center, N Ｃ Difference with N ＡＬＬ -N Ｃ The proportion of (N ＡＬＬ -N Ｃ ) / N Ｃ was determined by the method described in embodiment 1. The results are shown in Table 3 under "(N ＡＬＬ -N Ｃ ) / N Ｃ " column.

[0119] <Presence or Absence of A Center> The presence or absence of the A center was determined for each sample of single crystal diamond by the method described in embodiment 1. The results obtained are shown in the "Presence or Absence of A Center" column of Table 3.

[0120] <Presence or Absence of B Center> The presence or absence of B center was determined for each sample of single crystal diamond by the method described in embodiment 1. The results obtained are shown in the "Presence or Absence of B Center" column of Table 3.

[0121] <NV ０ Presence or absence of center > For each sample of single crystal diamond, NV０ The presence or absence of a center was determined by the method described in embodiment 1. The results obtained are shown in Table 3 as "NV ０ Please indicate in the "Whether or Not a Center" column.

[0122] <NV ― Presence or absence of center > For each sample of single crystal diamond, NV ― The presence or absence of a center was determined by the method described in embodiment 1. The results obtained are shown in Table 3 as "NV ― Please indicate in the "Whether or Not a Center" column.

[0123] <Presence or Absence of H2 Center> The presence or absence of H2 center for the single crystal diamond of each sample was determined by the method described in embodiment 1. The results obtained are shown in the "Presence or Absence of H2 Center" column of Table 3.

[0124] <Presence or Absence of H3 Center> The presence or absence of the H3 center for the single crystal diamond of each sample was determined by the method described in embodiment 1. The results obtained are shown in the column of "Presence or Absence of H3 Center" in Table 3.

[0125] <Presence or Absence of N3 Center> The presence or absence of the N3 center for the single crystal diamond of each sample was determined by the method described in embodiment 1. The results obtained are shown in the column of "Presence or Absence of N3 Center" in Table 3.

[0126] <Wear Resistance Evaluation Test> A cutting tool (holder: CSRP R3225-N12, tip: SPGN120308, tool equipped with the single crystal diamond at the cutting edge of the tip) was produced using each of the single crystal diamond samples, and the outer diameter of the workpiece was turned using the cutting tool under the following cutting conditions, and the cutting distance [km] until the average flank wear width of the cutting tool reached 200 μm was measured. The results are shown in the "Cutting Distance [km]" column in the "Wear Resistance Test" column of Table 4. A longer cutting distance [km] indicates better wear resistance. (Cutting Conditions) Workpiece: Ti-6Al-4V (φ120mm x 280mm) Cutting speed: 250m / min Feed rate: 0.1mm / rev Depth of cut: 0.4mm Coolant: wet

[0127] <Chipping Resistance Evaluation Test> Using each single crystal diamond of each sample, a turning insert specified by catalog number "NF-DNMA150408" (Sumitomo Electric Industries, Ltd.) was produced. Next, the turning insert was used to cut a workpiece under the following cutting conditions. When the size of the chipping at the cutting edge of the turning insert exceeded 0.1 mm, cutting was stopped and the time [minutes] from the start of the test to that point was measured. The results obtained are recorded in the "Time [minutes]" column of the "Chipping Resistance Test" column in Table 4. The longer the time [minutes], the better the chipping resistance. (Cutting Conditions) Workpiece: cemented carbide (VM-40 (dimensions: diameter φ60 mm x length 100 mm), hardness: HRA88) Processing machine: lathe Cutting speed Vc: 10 m / min Feed rate f: 0.05 mm / rev Depth of cut ap: 0.05 mm / rev Cutting oil (coolant): None

[0128]

[0129]

[0130]

[0131]

[0132] The single crystal diamonds of Samples 7 to 14 correspond to Examples. The single crystal diamonds of Samples 1 to 6 correspond to Comparative Examples. The results in Table 1 show that the single crystal diamonds of Samples 7 to 14 have both superior wear resistance and superior chipping resistance compared to the single crystal diamonds of Samples 1 to 6.

[0133] From the above, it was found that the single crystal diamonds according to Samples 7 to 14 had both excellent wear resistance and excellent chipping resistance.

[0134] Although the embodiments and examples of the present disclosure have been described above, it is originally intended that the configurations of the above-described embodiments and examples may be appropriately combined or modified in various ways.

[0135] The embodiments and examples disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims, not by the embodiments and examples described above, and is intended to include meanings equivalent to the claims and all modifications within the scope of the claims.

[0136] 1 Single crystal diamond, 2 Insulator, 3 Carbon source, 4 Solvent metal, 5 Seed crystal, 6 Pressure medium, 7 Graphite heater, 21 Single crystal diamond, 27 Altered portion.

Claims

1. The content of nitrogen atoms based on the atomic number is 1 ppm or more and 2000 ppm or less, and the atomic number N of nitrogen atoms in the C center is Ｃ The total number of nitrogen atoms, N ＡＬＬ and the number N of nitrogen atoms in the C center Ｃ Difference with N ＡＬＬ -N Ｃ The proportion of (N ＡＬＬ -N Ｃ ) / N Ｃ is 1 or more and 10 ５ Below is a single crystal diamond.

2. The single crystal diamond according to claim 1, wherein the single crystal diamond contains an A center.

3. A single crystal diamond according to claim 1 or claim 2, wherein the single crystal diamond contains a B center.

4. The single crystal diamond is NV ０ 4. A single crystal diamond according to any one of claims 1 to 3, comprising a center.

5. The single crystal diamond is NV ― 5. A single crystal diamond according to any one of claims 1 to 4, comprising a center.

6. A single crystal diamond according to any one of claims 1 to 5, wherein the single crystal diamond contains an H2 center.

7. A single crystal diamond according to any one of claims 1 to 6, wherein the single crystal diamond contains an H3 center.

8. A single crystal diamond according to any one of claims 1 to 7, wherein the single crystal diamond contains an N3 center.

9. A single crystal diamond according to any one of claims 1 to 8, wherein the surface of said single crystal diamond includes a first region, said first region having an arithmetic mean height Sa as defined in JIS B 0681-2:2018 of 3 nm or more, and said first region having a maximum height Sz as defined in JIS B 0681-2:2018 of 60 nm or more.

10. The single crystal diamond has an altered portion on its outer periphery, and in the core electron excitation spectrum of the altered portion obtained by electron energy loss spectroscopy using a transmission electron microscope, the amount of energy loss is in the range of 285 eV ± 5 eV. ＊ Maximum intensity of the peak Iπ ＊ and σ in the range of energy loss 291±5 eV. ＊ Maximum intensity of the peak Iσ ＊ The ratio Iπ ＊ / Iσ ＊ is 0.15 or more, and in the altered portion, the percentage {N1 / (N1+N2)}×100 of the number N1 of primary carbon atoms to the sum N1+N2 of the number N1 of primary carbon atoms constituting amorphous carbon and the number N2 of secondary carbon atoms constituting graphite is 90% or more.

11. A tool comprising a single crystal diamond according to any one of claims 1 to 10.

12. The tool of claim 11, wherein the tool is a cutting tool, a wear-resistant tool, or a grinding tool.

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