US20100146865A1 - Polycrystalline diamond - Google Patents

Polycrystalline diamond Download PDF

Info

Publication number
US20100146865A1
US20100146865A1 US12/600,618 US60061809A US2010146865A1 US 20100146865 A1 US20100146865 A1 US 20100146865A1 US 60061809 A US60061809 A US 60061809A US 2010146865 A1 US2010146865 A1 US 2010146865A1
Authority
US
United States
Prior art keywords
diamond
grain diameter
average grain
polycrystalline diamond
orifice
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/600,618
Inventor
Takeshi Sato
Katsuko Yamamoto
Naohiro Toda
Hitoshi Sumiya
Yutaka Kobayashi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sumitomo Electric Hardmetal Corp
Sumitomo Electric Industries Ltd
Original Assignee
Sumitomo Electric Hardmetal Corp
Sumitomo Electric Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sumitomo Electric Hardmetal Corp, Sumitomo Electric Industries Ltd filed Critical Sumitomo Electric Hardmetal Corp
Assigned to SUMITOMO ELECTRIC INDUSTRIES, LTD, SUMITOMO ELECTRIC HARDMETAL CORP. reassignment SUMITOMO ELECTRIC INDUSTRIES, LTD ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KOBAYASHI, YUTAKA, SATO, TAKESHI, SUMIYA, HITOSHI, TODA, NAOHIRO, YAMAMOTO, KATSUKO
Publication of US20100146865A1 publication Critical patent/US20100146865A1/en
Priority to US14/738,116 priority Critical patent/US9630853B2/en
Abandoned legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/25—Diamond
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J3/00—Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; Apparatus therefor
    • B01J3/06—Processes using ultra-high pressure, e.g. for the formation of diamonds; Apparatus therefor, e.g. moulds or dies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
    • B26F—PERFORATING; PUNCHING; CUTTING-OUT; STAMPING-OUT; SEVERING BY MEANS OTHER THAN CUTTING
    • B26F3/00—Severing by means other than cutting; Apparatus therefor
    • B26F3/004—Severing by means other than cutting; Apparatus therefor by means of a fluid jet
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/25—Diamond
    • C01B32/26—Preparation
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B33/00—Severing cooled glass
    • C03B33/10—Glass-cutting tools, e.g. scoring tools
    • C03B33/105—Details of cutting or scoring means, e.g. tips
    • C03B33/107—Wheel design, e.g. materials, construction, shape
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/52—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite
    • C04B35/528—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite obtained from carbonaceous particles with or without other non-organic components
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/64—Burning or sintering processes
    • C04B35/645—Pressure sintering
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/42—Non metallic elements added as constituents or additives, e.g. sulfur, phosphor, selenium or tellurium
    • C04B2235/422—Carbon
    • C04B2235/425—Graphite
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54—Particle size related information
    • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
    • C04B2235/5427—Particle size related information expressed by the size of the particles or aggregates thereof millimeter or submillimeter sized, i.e. larger than 0,1 mm
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54—Particle size related information
    • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
    • C04B2235/5436—Particle size related information expressed by the size of the particles or aggregates thereof micrometer sized, i.e. from 1 to 100 micron
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54—Particle size related information
    • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
    • C04B2235/5445—Particle size related information expressed by the size of the particles or aggregates thereof submicron sized, i.e. from 0,1 to 1 micron
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54—Particle size related information
    • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
    • C04B2235/5454—Particle size related information expressed by the size of the particles or aggregates thereof nanometer sized, i.e. below 100 nm
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54—Particle size related information
    • C04B2235/5463—Particle size distributions
    • C04B2235/5481—Monomodal
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/72—Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/74—Physical characteristics
    • C04B2235/78—Grain sizes and shapes, product microstructures, e.g. acicular grains, equiaxed grains, platelet-structures
    • C04B2235/781—Nanograined materials, i.e. having grain sizes below 100 nm
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/74—Physical characteristics
    • C04B2235/78—Grain sizes and shapes, product microstructures, e.g. acicular grains, equiaxed grains, platelet-structures
    • C04B2235/785—Submicron sized grains, i.e. from 0,1 to 1 micron
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/21—Circular sheet or circular blank
    • Y10T428/218—Aperture containing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/26—Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
    • Y10T428/268—Monolayer with structurally defined element

Definitions

  • the present invention relates to polycrystalline diamond obtained by converting and sintering non-diamond carbon without addition of a sintering aid or a catalyst.
  • a tool including monocrystalline diamond is, for example, a water jet orifice (Patent Document 1), a stylus for gravure printing (Patent Documents 2 and 3), a scriber (Patent Document 4), a diamond cutting tool (Patent Documents 5 and 6), or a scribing wheel (Patent Document 7).
  • Such monocrystalline diamond also has a property that abrasion losses vary (uneven wear) depending on crystal orientations of the diamond. For example, abrasion loss considerably varies between the (111) plane and the (100) plane. For this reason, monocrystalline diamond applied to such tools described above is worn away only in a specific plane in a short time as the tools are used, and predetermined effects are not provided, which has been a problem.
  • Monocrystalline diamond also has a property of cleaving along the (111) plane. For this reason, when monocrystalline diamond is applied to a tool subjected to a stress during use, the tool breaks or cracks, which also has been a problem.
  • sintered diamond may be used.
  • Such sintered diamond is obtained by sintering diamond grains with a metal binder such as cobalt and hence the metal binder is present among the diamond grains.
  • the metal binder region is softer than the diamond grains and hence is worn away in a short time. As the amount of the binder decreases, the diamond grains come off and the effects are not provided with stability for a long period of time.
  • adhesive wear occurs between the metal binder region and a metal material being worked and working for a long period of time cannot be performed.
  • a binderless sintered diamond may be produced by dissolving the metal binder with acid to thereby remove the metal binder.
  • removal of a metal binder reduces the binding power of diamond grains, which most likely increases abrasion loss.
  • a water jet orifice including monocrystalline diamond has a problem in that a target cutting width is no longer achieved after the lapse of usage time.
  • Patent Document 8 sintered diamond may be used (Patent Document 8).
  • this causes coming off of diamond grains with a decrease in the amount of a binder as described above and an orifice bore is expanded.
  • a cutting width is not provided with stability for a long period of time, which is a problem.
  • a water jet intended to provide enhanced cutting efficiency is configured to expel liquid containing water and rigid particles (alumina or the like) at a high pressure.
  • a metal binder region which is softer than diamond grains, wears away in a short time and a cutting width is not provided with stability for a long period of time, which is a problem.
  • a method may be used in which the interior surface of a metal orifice bore is coated with a diamond thin film free from a metal binder by CVD (chemical-vapor deposition) as described above (see Patent Document 9).
  • CVD chemical-vapor deposition
  • a diamond thin film has a short wear life, and has a small binding strength among grains and hence has a short wear life, which has been a problem.
  • FIG. 2 Another example is a stylus for gravure printing in which natural or artificial monocrystalline diamond is used as material for the stylus (see Patent Documents 2 and 3).
  • natural or artificial monocrystalline diamond is used as material for the stylus (see Patent Documents 2 and 3).
  • such diamond has a property of cleaving, such a tool breaks or cracks by a stress during use, which is a problem. Due to the property of uneven wear, such diamond is worn away only in a specific plane in a short time as the tool is used, and hence working for a long period of time cannot be performed, which has also been a problem.
  • Still another example is a scriber including monocrystalline diamond.
  • polyhedron-shaped monocrystalline diamond is used to scribe monocrystalline substrates, glass substrates, and the like with a vertex of the polyhedron, the vertex serving as a blade.
  • Such a scriber composed of monocrystalline diamond is produced by working monocrystalline diamond such that the (111) plane, which is the most resistant to abrasion against a workpiece that is to be scribed and is composed of a monocrystalline material such as sapphire, is particularly positioned to be aligned parallel to the work to be scribed.
  • Still another example is a diamond cutting tool in which natural or artificial monocrystalline diamond is used as material for the tool (see Patent Documents 5 and 6).
  • a tool composed of monocrystalline diamond has a problem in that the tool breaks or cracks due to a stress during use, is worn away only in a specific plane in a short time as the tool is used, and working for a long period of time cannot be performed.
  • Still another example is a scribing wheel in which monocrystalline diamond is used as material for the scribing wheel.
  • a scribing wheel in which monocrystalline diamond is used as material for the scribing wheel.
  • scribed lines are formed in a brittle material such as glass for liquid crystal panels with the V-shaped edge of the wheel, the edge serving as a cutting edge.
  • a scribing wheel composed of monocrystalline diamond has a V-shaped edge in which crystals have various crystal orientations in the circumferential direction.
  • the edge having the shape of a perfect circle at the initial stage of use is worn away in a plane susceptible to wear in a short time and the perfect circular shape is deformed into the shape of a polygon. As a result, the wheel becomes no longer able to roll, which has been a problem.
  • a sintered diamond compact may be used as material for such tools, the compact containing metal serving as a binder (Patent Documents 7 and 10).
  • a metal binder region containing cobalt or the like is softer than diamond grains and hence wears away in a short time, and adhesive wear occurs between the metal binder region and a metal material being worked such as copper and working for a long period of time cannot be performed.
  • Such a metal binder in the sintered diamond compact may be removed by dissolving the metal binder with acid. However, this reduces the binding power of diamond grains, which most likely increases abrasion loss.
  • Polycrystalline diamond that is produced by CVD and is free from a metal binder has a small binding strength among grains and hence probably has a problem in that such diamond has a short wear life.
  • Patent Document 1 Japanese Unexamined Patent Application Publication No. 2000-061897
  • Patent Document 2 Japanese Unexamined Patent Application Publication No. 2006-123137
  • Patent Document 3 Japanese Unexamined Patent Application Publication No. 2006-518699
  • Patent Document 4 Japanese Unexamined Patent Application Publication No. 2005-289703
  • Patent Document 5 Japanese Unexamined Patent Application Publication No. 2004-181591
  • Patent Document 6 Japanese Unexamined Patent Application Publication No. 2003-025118
  • Patent Document 7 Japanese Unexamined Patent Application Publication No. 2007-031200
  • Patent Document 8 Japanese Unexamined Patent Application Publication No. 10-270407
  • Patent Document 9 Japanese Unexamined Patent Application Publication No. 2006-159348
  • Patent Document 10 International Publication No. 2003/051784
  • an object of the present invention is to provide a 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 a polycrystalline diamond.
  • an object of the present invention is to provide a water jet orifice that provides a cutting width with stability for a long period of time, a stylus for gravure printing, a scriber, a diamond cutting tool, and a scribing wheel that enable stable working for a long period of time, compared with conventional tools including monocrystalline diamonds and sintered diamond compacts containing metal binders.
  • a polycrystalline diamond is advantageously applicable to diverse applications, the polycrystalline diamond not containing a metal binder such as cobalt, having an average grain diameter of more than 50 nm and less than 2500 nm and a purity of 99% or more, and the D90 grain diameter of the sinter being (average grain diameter+0.9 ⁇ average grain diameter) or less.
  • a metal binder such as cobalt
  • the present invention is directed to, as described below, a polycrystalline diamond; a water jet orifice, a stylus for gravure printing, a scriber, a diamond cutting tool, and a scribing wheel that include such a polycrystalline diamond and allow stable working for a long period of time.
  • Polycrystalline diamond according to the present invention does not wear unevenly and hence is applicable to diverse applications.
  • a water jet orifice according to the present invention can provide a cutting width with stability for a long period of time, compared with conventional orifices including monocrystalline diamonds and sintered diamond compacts containing metal binders.
  • a stylus for gravure printing, a scriber, a diamond cutting tool, and a scribing wheel according to the present invention allow stable working for a long period of time, compared with conventional tools including monocrystalline diamonds and sintered diamond compacts containing metal binders.
  • Polycrystalline diamond according to the present invention is substantially a single-phase diamond (purity of 99% or more) and does not contain a metal binder such as cobalt.
  • a metal binder such as cobalt.
  • Such polycrystalline diamond can be obtained by directly converting and simultaneously sintering non-diamond carbon serving as a material such as graphite, glassy carbon, or amorphous carbon into diamond under an ultrahigh pressure and at a high temperature (temperature: 1800° C. to 2600° C., pressure: 12 to 25 GPa) without a catalyst or a solvent.
  • the resultant polycrystalline diamond does not wear unevenly, which does occur in monocrystals.
  • Reference 1 discloses a polycrystalline diamond and the diamond grains constituting this polycrystalline diamond have an average grain diameter of 80 nm to 1 ⁇ m, which is in the range defined by the present invention.
  • Ref 1 states that the polycrystalline diamond was obtained by the method described in Ref 2.
  • Reference 2 states that polycrystalline diamond is produced by a method of sintering diamond powder with carbonate serving as a sintering aid and the carbonate remains in the resultant polycrystalline diamond after the sintering. Therefore, the structure of the polycrystalline diamond disclosed in Ref 1 is different from the structure of a polycrystalline diamond according to the present invention.
  • Ref 3 Another method of sintering diamond powder with a sintering aid is disclosed in Ref 3.
  • Ref 3 states that it has been ascertained with IR spectra that the sintering aid partially remains in a polycrystalline diamond obtained by this method. Therefore, the structure of this polycrystalline diamond is also different from the structure of a polycrystalline diamond according to the present invention.
  • Reference 4 states that the sinters of Refs. 2 and 3 are inferior in hardness to a sinter free from a sintering aid according to the present invention. Thus, Ref 4 shows that a sinter according to the present invention is excellent.
  • Reference 4 above also discloses a method for producing a polycrystalline diamond in which a sintering aid is not used.
  • This method uses diamond micro powder as a starting material and the grain diameter of the resultant sinter is 100 nm or less, which is in the range defined by the present invention.
  • non-diamond carbon is used as a starting material in the present invention.
  • a polycrystalline diamond can be provided having a special structure referred to as a lamellar structure, which is not present in the polycrystalline diamond of Ref 4.
  • Reference 5 described below states that extension of cracks is suppressed in a region having the lamellar structure. This demonstrates that a polycrystalline diamond according to the present invention is less prone to breaking than that described in Ref 4.
  • polycrystalline diamond according to the present invention is totally different in structure from diamond sinters that have been disclosed and, as a result, has mechanical characteristics that are far superior to those of the latter.
  • the above-described problem can be solved by use of a polycrystalline diamond in which sintered 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 sinter has a D90 grain diameter of (average grain diameter+0.9 ⁇ average grain diameter) or less. This is because abnormal wear is suppressed by making the D90 grain diameter of sintered grains of polycrystalline diamond be (average grain diameter+0.9 ⁇ average grain diameter) or less.
  • the average grain diameter in the present invention is number-average grain diameter determined with a transmission electron microscope (TEM).
  • TEM transmission electron microscope
  • the average grain diameter and the D90 grain diameter can be controlled by controlling the grain diameter of a starting material or sintering conditions.
  • Example 1 when the average grain diameter is 60 nm, the D90 grain diameter is 114 nm or less.
  • Example 2 when the average grain diameter is 100 nm, the D90 grain diameter is 190 nm or less.
  • Example 3 when the average grain diameter is 500 nm, the D90 grain diameter is 950 nm or less.
  • the D90 grain diameter is more preferably (average grain diameter+0.7 ⁇ average grain diameter) or less, and still more preferably (average grain diameter+0.5 ⁇ average grain diameter) or less.
  • the average grain diameter is 50 nm or less or 2500 nm or more, the hardness becomes less than 100 GPa and wearing away is caused in a short period of time and hence a cutting width is not obtained with stability for a long period of time.
  • an orifice according to the present invention Since the material of an orifice according to the present invention is the above-described polycrystalline diamond according to the present invention, a water jet orifice according to the present invention does not wear unevenly, which does occur in orifices composed of monocrystals.
  • the inventors of the present invention produced orifices with diamonds obtained by the methods described in Refs. 5 to 7 above and determined the cutting widths of these orifices. This determination revealed that, the diamonds obtained in accordance with these References contain coarse grains as described above and hence portions corresponding to such coarse grains wear extremely rapidly. In this case, the velocity of flow of a water jet solvent decreases in such portions and the direction of the flow changes. As a result, the cutting width decreases or increases with the passage of cutting time and the cutting width is not stabilized, and hence a desired cutting width is not provided, which has been a problem.
  • the inventors have found that, to obtain a desired cutting width with stability, such portions wearing extremely rapidly need to be eliminated, and this is achieved by controlling the distribution of the grain diameters of a sinter.
  • grains wearing extremely rapidly are eliminated in an orifice composed of a diamond having a controlled distribution of grain diameters, the diamond being polycrystalline diamond according to the present invention in which the polycrystalline diamond has an average grain diameter of more than 50 nm and less than 2500 nm and a purity of 99% or more, and the sinter has a D90 grain diameter of (average grain diameter+0.9 ⁇ average grain diameter) or less.
  • Polycrystalline diamond used for a water jet orifice according to the present invention preferably has an average grain diameter and a D90 grain diameter that respectively satisfy the above-described ranges.
  • the D90 grain diameter of a sinter is desirably selected in accordance with the average diameter of rigid particles contained in fluid used for water jetting.
  • the average diameter of rigid particles is substantially equal to or less than the average grain diameter of the structure of a sinter, a cutting width with stability is not provided for a long period of time. This is because rigid particles collide with not a plurality of but a single surface of a grain of a sinter upon collision with the structure of the sinter, and when the surface has a crystal orientation susceptible to wear, the grain wears extremely rapidly. For this reason, the D90 grain diameter of a sinter of an orifice is selected so as to be 1/10 or less of the diameter of rigid particles.
  • Example 4 when the diameter of rigid particles is 50 ⁇ m, the D90 is 5 ⁇ m or less.
  • Polycrystalline diamond constituting a water jet orifice preferably has a hardness of 100 GPa or more. When the polycrystalline diamond has a hardness of less than 100 GPa, the orifice has a shorter life.
  • the interior surface of an orifice bore through which water jet fluid passes preferably has a surface roughness Ra of 300 nm or less. When the surface roughness Ra is more than 300 nm, the orifice has a shorter life.
  • the ratio (L/D) of an orifice level (L) to an orifice bore diameter (D) is preferably 10 to 500.
  • the ratio (L/D) of an orifice level (L) to an orifice bore diameter (D) is preferably 0.2 to 10.
  • a stylus for gravure printing according to the present invention Since the material of a stylus for gravure printing according to the present invention is the above-described polycrystalline diamond according to the present invention, a stylus for gravure printing according to the present invention does not wear unevenly, which does occur in styluses composed of monocrystals.
  • the inventors of the present invention produced styluses with diamonds obtained by the methods described in Refs. 5 to 7 above and inspected the workability of these styluses. This inspection revealed that, the diamonds obtained by the methods described in these References contain coarse grains as described above and hence portions corresponding to such coarse grains wear extremely rapidly. In this case, such portions cause streaky scratches on metal being worked and hence a desired working is not possible, which has been a problem.
  • a stylus including polycrystalline diamond having a controlled distribution of grain diameters according to the present invention was produced. Grains wearing extremely rapidly are eliminated in this stylus and a desired stable working was achieved with the stylus for a long period of time.
  • Polycrystalline diamond according to the present invention includes sintered diamond grains having a D90 grain diameter of (average grain diameter+0.9 ⁇ average grain diameter) or less. As a result, abnormal wearing can be suppressed.
  • Polycrystalline diamond constituting a stylus for gravure printing preferably has a hardness of 100 GPa or more.
  • the stylus has a shorter life.
  • the average grain diameter is 50 nm or less or 2500 nm or more, the hardness becomes less than 100 GPa and wearing away is caused in a short period of time and hence stable working is not possible for a long period of time.
  • a stylus for gravure printing according to the present invention does not wear unevenly, which does occur in styluses composed of monocrystals.
  • Reference 1 above discloses a scriber composed of a polycrystalline diamond and the diamond grains constituting the polycrystalline diamond of this scriber have an average grain diameter of 80 nm to 1 ⁇ m, which is in the range defined by the present invention.
  • a polycrystalline diamond produced by the production method described in Ref 1 (Ref 2) contains carbonate remaining after sintering. Therefore, such a polycrystalline diamond is different in structure from a polycrystalline diamond according to the present invention.
  • the inventors of the present invention produced scribers from diamonds obtained by the methods described in Refs. 5 to 7 above and inspected the workability of these scribers. This inspection revealed that, the diamonds obtained by the methods described in these References contain coarse grains as described above and hence portions corresponding to such coarse grains wear extremely rapidly.
  • a scriber including a polycrystalline diamond having a controlled distribution of grain diameters according to the present invention was produced. Grains wearing extremely rapidly were eliminated in this scriber and a desired stable working was achieved with the scriber for a long period of time.
  • Polycrystalline diamond constituting a scriber preferably has a hardness of 100 GPa or more.
  • the hardness becomes less than 100 GPa.
  • wearing away is caused in a short period of time and hence stable working is not possible for a long period of time and the scriber has a shorter life.
  • polycrystalline diamond serving as the material of a diamond tool according to the present invention is the above-described polycrystalline diamond according to the present invention, the polycrystalline diamond substantially being a single-phase diamond (purity of 99% or more) and not containing a metal binder such as cobalt. For this reason, a diamond cutting tool according to the present invention does not wear unevenly, which does occur in diamond tools including monocrystals.
  • the inventors of the present invention produced diamond tools from diamonds obtained by the methods described in Refs. 5 to 7 above and inspected the workability of these tools. This inspection revealed that, the diamonds obtained by the methods described in these References contain coarse grains as described above and hence portions corresponding to such coarse grains wear extremely rapidly. In this case, such portions cause streaky scratches or the like in metal being worked and hence a desired working is not possible, which has been a problem.
  • a diamond tool including a polycrystalline diamond having a controlled distribution of grain diameters according to the present invention was produced. Grains wearing extremely rapidly were eliminated in this tool and a desired stable working was achieved with the tool for a long period of time.
  • Polycrystalline diamond constituting a diamond cutting tool preferably has a hardness of 100 GPa or more.
  • the polycrystalline diamond has a hardness of less than 100 GPa, wearing away is caused in a short period of time and hence stable working is not possible for a long period of time and such a diamond tool has a shorter life.
  • the sintered grains of polycrystalline diamond are made to have an average grain diameter of more than 50 nm and less than 2500 nm and a hardness of 100 GPa or more.
  • the average grain diameter is 50 nm or less or 2500 nm or more, the hardness becomes less than 100 GPa.
  • the grains of a sinter are made to have a D90 grain diameter of (average grain diameter+0.9 ⁇ average grain diameter) or less to suppress abnormal wearing.
  • polycrystalline diamond serving as the material of a scribing wheel according to the present invention is the above-described polycrystalline diamond according to the present invention, the polycrystalline diamond substantially being a single-phase diamond (purity of 99% or more) and not containing a metal binder such as cobalt. For this reason, a scribing wheel according to the present invention does not wear unevenly, which does occur in scribing wheels including monocrystals.
  • the inventors of the present invention produced scribing wheels from polycrystalline diamonds obtained by the methods described in Refs. 5 to 7 above and inspected the workability of these scribing wheels. This inspection revealed that, the diamonds obtained by the methods described in these References contain coarse grains as described above and hence portions corresponding to such coarse grains wear extremely rapidly.
  • a scribing wheel including a polycrystalline diamond having a controlled distribution of grain diameters according to the present invention was produced. Grains wearing extremely rapidly were eliminated in this scribing wheel and a desired stable working was achieved with the scribing wheel for a long period of time.
  • Polycrystalline diamond constituting a scribing wheel preferably has a hardness of 100 GPa or more.
  • the hardness becomes less than 100 GPa.
  • wearing away is caused in a short period of time and hence stable working is not achieved for a long period of time and the scribing wheel has a shorter life.
  • polycrystalline diamond according to the present invention is used as materials for water jet orifices, styluses for gravure printing, scribers, diamond cutting tools, and scribing wheels.
  • the D50 grain diameters (average grain diameters) and the D90 grain diameters of graphite grains in fired graphite material and sintered diamond grains in polycrystalline diamond in the present invention are obtained by conducting image analysis on the basis of photographic images with a transmission electron microscope under a magnification of 100,000 to 500,000.
  • the thus-obtained distribution of grain diameters is processed with a data analysis software (for example, Origin manufactured by OriginLab Corporation, Mathchad manufactured by Parametric Technology Corporation, or the like) to calculate the D50 grain diameter and the D90 grain diameter.
  • a data analysis software for example, Origin manufactured by OriginLab Corporation, Mathchad manufactured by Parametric Technology Corporation, or the like
  • a transmission electron microscope used in Examples and Comparative Examples described below was an H-9000 manufactured by Hitachi, Ltd.
  • the surface roughness of the interior surface of an orifice bore was adjusted by adjusting the particle diameters of a polishing agent for polishing the interior surface. Surface roughness was measured in accordance with JIS B0601 with a contact-type surface roughness tester. Since a measurement stylus cannot be inserted into an orifice bore, another orifice separately produced by the same processes was cut and measured.
  • Examples 1-1 to 1-3 are examples in which surface roughness was varied.
  • Examples 1-4 to 1-6 are examples in which orifice bore diameter was varied.
  • Examples 1-7 to 1-12 are examples in which average grain diameter and D90 grain diameter were varied.
  • Examples 1-13 and 1-14 are examples in which both average grain diameter and orifice bore diameter were increased.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 290 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 ⁇ m was determined and it was a long time of 160 hours. For comparison purposes, an orifice composed of a sintered diamond having an average crystal grain diameter of 5 ⁇ m (containing a cobalt binder) was also evaluated for the same cutting property and the time was about 50 hours, which were extremely short.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 50 nm in the surface of the orifice bore.
  • This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 ⁇ m was determined and it was a long time of 240 hours.
  • an orifice composed of a sintered diamond having an average crystal grain diameter of 5 ⁇ m (containing a cobalt binder) was also evaluated for the same cutting property and the time was about 70 hours, which were extremely short.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 5 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 ⁇ m was determined and it was a long time of 520 hours. For comparison purposes, an orifice composed of a sintered diamond having an average crystal grain diameter of 5 ⁇ m (containing a cobalt binder) was also evaluated for the same cutting property and the time was about 90 hours, which were extremely short.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 450 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 290 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 550 ⁇ m was determined and it was a long time of 165 hours. For comparison purposes, an orifice composed of a sintered diamond having an average crystal grain diameter of 5 ⁇ m (containing a cobalt binder) was also evaluated for the same cutting property and the time was about 55 hours, which were extremely short.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 50 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 290 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 100 ⁇ m was determined and it was a long time of 210 hours. For comparison purposes, an orifice composed of a sintered diamond having an average crystal grain diameter of 5 ⁇ m (containing a cobalt binder) was also evaluated for the same cutting property and the time was about 75 hours, which were extremely short.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 15 ⁇ m, an orifice level of 7 mm, and a surface roughness Ra of 290 nm in the surface of the orifice bore.
  • This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 30 ⁇ m was determined and it was a long time of 230 hours.
  • an orifice composed of a sintered diamond having an average crystal grain diameter of 5 ⁇ m (containing a cobalt binder) was also evaluated for the same cutting property and the time was about 80 hours, which were extremely short.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 280 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 ⁇ m was determined and it was a long time of 180 hours.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 280 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 ⁇ m was determined and it was a long time of 210 hours.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 250 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 200 ⁇ m was determined and it was a long time of 130 hours.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 240 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 ⁇ m was determined and it was a long time of 160 hours.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 250 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 ⁇ m was determined and it was a long time of 150 hours.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 270 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 ⁇ m was determined and it was a long time of 110 hours.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 1500 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 270 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 2000 ⁇ m was determined and it was a long time of 210 hours.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 3500 ⁇ m, an orifice level of 0.7 mm, and a surface roughness Ra of 270 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 4500 ⁇ m was determined and it was a long time of 160 hours.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 350 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 ⁇ m was determined and it was a short time of 95 hours.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 290 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 ⁇ m was determined and it was a short time of 90 hours.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 250 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 ⁇ m was determined and it was a short time of 80 hours.
  • An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 ⁇ m, an orifice level of 5 mm, and a surface roughness Ra of 240 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 ⁇ m was determined and it was a short time of 85 hours.
  • Table I shows values of the sintered grains of the polycrystalline diamonds in Examples and Comparative Examples above in terms of average grain diameter, D90 grain diameter, a coefficient (K), hardness, and wear life. Note that the coefficient (K) is defined by Equation (1) below.
  • Example 1-1 200 370 0.85 110 290 200 5 25 160 50
  • Example 1-2 200 370 0.85 110 50 200 5 25 240 70
  • Example 1-3 200 370 0.85 110 5 200 5 25 520 90
  • Example 1-4 200 370 0.85 110 290 450 5 11 165 55
  • Example 1-5 200 370 0.85 110 290 50 5 100 210 75
  • Example 1-6 200 370 0.85 110 290 15 7 467 230 80
  • Example 1-8 180 260 0.44 125 280 200 5 25 210 —
  • Example 1-9 55 80 0.45 105 250 200 5 25 130 —
  • Example 1-10 560 830 0.48 120 240 200 5 25 160 —
  • a stylus having an included angle of 120° was produced from polycrystalline diamond obtained.
  • a copper workpiece was worked with this stylus being driven at a frequency of 8 kHz and working time over which wear depth in an edge line portion on one side was increased to 10 ⁇ m was determined The wear resistance of the stylus was evaluated on the basis of this working time defined as the wear life of the stylus.
  • This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 55 nm and a D90 grain diameter of 80 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 105 GPa.
  • a stylus having an included angle of 120° was produced from the obtained polycrystalline diamond. This stylus produced from the polycrystalline diamond had a long wear life of 200 hours.
  • This material was directly converted and sintered into diamond over a longer time than in Example 4 under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 560 nm and a D90 grain diameter of 830 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 120 GPa.
  • a stylus produced from this polycrystalline diamond had a long wear life of 180 hours.
  • This material was directly converted and sintered into diamond over a longer time than in Example 5 under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 1100 nm and a D90 grain diameter of 1600 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 112 GPa.
  • a stylus produced from this polycrystalline diamond had a long wear life of 170 hours.
  • This material was directly converted and sintered into diamond over a longer time than in Example 6 under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 2400 nm and a D90 grain diameter of 3500 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 102 GPa.
  • a stylus produced from this polycrystalline diamond had a long wear life of 150 hours.
  • a stylus produced from monocrystalline diamond serving as a material was tested for wear resistance in the same manner as in Example 1 and this stylus had a wear life of 60 hours.
  • Table II shows values of the sintered grains of the polycrystalline diamonds in Examples and Comparative Examples above in terms of average grain diameter, D90 grain diameter, the coefficient (K), hardness, and wear life. Note that the coefficient (K) is defined by Eq. (1) above.
  • a 4-point scriber was produced from polycrystalline material obtained and it was subjected to a wear test where a sapphire substrate was scribed with the scriber under a load of 50 g, at a scribing speed of 1 cm/min, and for a scribing distance of 1 m. The wear resistance of the scriber was evaluated on the basis of abrasion loss in the test.
  • This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 230 nm and a D90 grain diameter of 380 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 115 GPa.
  • An abrasion loss of a scriber produced from this polycrystalline diamond was extremely small and it was about 1/80 of that of a scriber composed of monocrystalline diamond.
  • This material was directly converted and sintered into diamond over a longer time than in Example 4 under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 560 nm and a D90 grain diameter of 830 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 120 GPa.
  • An abrasion loss of a scriber produced from this polycrystalline diamond was extremely small and it was about 1/50 of that of a scriber composed of monocrystalline diamond.
  • This material was directly converted and sintered into diamond over a longer time than in Example 5 under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 1100 nm and a D90 grain diameter of 1600 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 112 GPa.
  • An abrasion loss of a scriber produced from this polycrystalline diamond was extremely small and it was about 1/50 of that of a scriber composed of monocrystalline diamond.
  • This material was directly converted and sintered into diamond over a longer time than in Example 6 under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 2400 nm and a D90 grain diameter of 3500 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 102 GPa.
  • An abrasion loss of a scriber produced from this polycrystalline diamond was extremely small and it was about 1/40 of that of a scriber composed of monocrystalline diamond.
  • Table III shows values of the sintered grains of the polycrystalline diamonds in Examples and Comparative Examples above in terms of average grain diameter, D90 grain diameter, the coefficient (K), hardness, and abrasion loss. Note that the coefficient (K) is defined by Eq. (1) above.
  • Example 3-1 200 370 0.85 110 68.0
  • Example 3-2 230 380 0.65 115 79.3
  • Example 3-3 180 260 0.44 125 90.7
  • Example 3-4 55
  • Example 3-5 560 830 0.48 120 51.0
  • Example 3-6 1100 1600 0.45 112 48.2
  • Example 3-7 2400 3500 0.46 102 42.5
  • Comparative 200 400 1.00 112 3.6
  • Example 3-1 Comparative 45 80 0.78 95 3.4
  • Example 3-3 200 370 0.85 110 68.0
  • Example 3-2 230 380 0.65 115 79.3
  • Example 3-3 180
  • Example 3-5 560 830 0.48
  • Example 3-6 1100 1600 0.45 112 48.2
  • Example 3-7 2400 3500 0.46 102 42.5
  • Comparative 200 400 1.00 112 3.6
  • Example 3-1 Comparative 45
  • Cutting tools having an edge included angle of 90° and an edge R of 100 nm were produced from polycrystalline diamonds obtained in Examples and Comparative Examples and these cutting tools were used to form grooves having a depth of 5 ⁇ m and a pitch of 5 ⁇ m in a metal plate that was a copper plate on which nickel was plated.
  • the wear resistance of the cutting tools was evaluated on the basis of time (tool life) over which the edges of the cutting tools wore down to about 1 ⁇ m.
  • This material was directly converted and sintered into diamond over a longer time than in Example 4 under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 560 nm and a D90 grain diameter of 830 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 120 GPa.
  • a cutting tool produced from this polycrystalline diamond had an extremely long tool life of 11 hours.
  • This material was directly converted and sintered into diamond over a longer time than in Example 5 under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 1100 nm and a D90 grain diameter of 1600 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 112 GPa.
  • a cutting tool produced from this polycrystalline diamond had an extremely long tool life of 10 hours.
  • This material was directly converted and sintered into diamond over a longer time than in Example 6 under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 2400 nm and a D90 grain diameter of 3500 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 102 GPa.
  • a cutting tool produced from this polycrystalline diamond had an extremely long tool life of 9 hours.
  • a tool produced from monocrystalline diamond serving as a material was tested for wear resistance in the same manner as in Example 1 and this tool had a tool life of 3 hours.
  • Table IV shows the values of the sintered grains of the polycrystalline diamonds in Examples and Comparative Examples above in terms of average grain diameter, D90 grain diameter, the coefficient (K), hardness, and tool life. Note that the coefficient (K) is defined by Eq. (1) above.
  • Example 4-1 200 370 0.85 110 15 Example 4-2 230 380 0.65 115 18 Example 4-3 180 260 0.44 125 20 Example 4-4 55 80 0.45 105 13 Example 4-5 560 830 0.48 120 11 Example 4-6 1100 1600 0.45 112 10 Example 4-7 2400 3500 0.46 102 9 Comparative 200 400 1.00 112 6 Example 4-1 Comparative 45 80 0.78 95 5 Example 4-2 Comparative 2700 3900 0.44 91 4 Example 4-3 Comparative — — — — 3 Example 4-4
  • Scribing wheels having a diameter of 3 mm, a thickness of 0.8 mm, and an edge included angle of 120° were produced from polycrystalline diamonds obtained in Examples and Comparative Examples. These scribing wheels were used to scribe glass substrates and the scribing property of the scribing wheels was evaluated by determining scribed distances.
  • This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 370 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 110 GPa.
  • the resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a long distance of about 300 km was achieved with this polycrystalline diamond.
  • This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 230 nm and a D90 grain diameter of 380 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 115 GPa.
  • the resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a long distance of about 350 km was achieved with this polycrystalline diamond.
  • This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 55 nm and a D90 grain diameter of 80 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 105 GPa.
  • the resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a long distance of about 250 km was achieved with this polycrystalline diamond.
  • This material was directly converted and sintered into diamond over a longer time than in Example 4 under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 560 nm and a D90 grain diameter of 830 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 120 GPa.
  • the resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a long distance of about 230 km was achieved with this polycrystalline diamond.
  • This material was directly converted and sintered into diamond over a longer time than in Example 5 under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 1100 nm and a D90 grain diameter of 1600 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 112 GPa.
  • the resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a long distance of about 210 km was achieved with this polycrystalline diamond.
  • This material was directly converted and sintered into diamond over a longer time than in Example 6 under a pressure condition under which diamond is thermodynamically stable.
  • a polycrystalline diamond having an average grain diameter of 2400 nm and a D90 grain diameter of 3500 nm was obtained.
  • the thus-obtained polycrystalline diamond had an extremely high hardness of 102 GPa.
  • the resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a long distance of about 190 km was achieved with this polycrystalline diamond.
  • a scribing wheel was produced from monocrystalline diamond and evaluated in terms of scribing. As a result, scribing for a short distance of 100 km was barely conducted with this monocrystalline diamond.
  • a scribing wheel was produced from a sintered diamond compact bound with metal and evaluated in terms of scribing. As a result, scribing for a short distance of 6 km was barely conducted with this sintered diamond compact.
  • Table V shows values of the sintered grains of the polycrystalline diamonds in Examples and Comparative Examples above in terms of average grain diameter, D90 grain diameter, the coefficient, hardness, and tool life. Note that the coefficient (K) is defined by Eq. (1) above.
  • Example 5-1 200 370 0.85 110 300
  • Example 5-2 230 380 0.65 115 350
  • Example 5-3 180 260 0.44 125 400
  • Example 5-4 55
  • Example 5-5 560 830 0.48 120
  • Example 5-6 1100 1600 0.45 112 210
  • Example 5-7 2400 3500 0.46 102
  • Comparative 200 400 1.00 112 120
  • Example 5-1 Comparative 45 80 0.78 95 110
  • Example 5-3 Comparative — — — — 100
  • Example 5-4 Comparative — — — — 6
  • Example 5-5 Comparative — — — 100
  • Polycrystalline diamond used in the present invention is less prone to wear unevenly and allows stable working for a long period of time compared with conventional monocrystalline diamonds and sintered diamond compacts containing metal binders. Therefore, such polycrystalline diamond can be suitably applied to water jet orifices, styluses for gravure printing, scribers, cutting tools, and scribing wheels.
  • a water jet orifice according to the present invention can provide a cutting width with stability for a long period of time compared with conventional orifices and hence can be suitably used as an orifice for a water jet configured to expel fluid containing rigid particles (alumina or the like) at a high pressure to thereby cut or work workpieces.

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.

Description

    TECHNICAL FIELD
  • The present invention relates to polycrystalline diamond obtained by converting and sintering non-diamond carbon without addition of a sintering aid or a catalyst.
    • BACKGROUND ART
  • Natural and artificial monocrystalline diamonds have been used for various applications because of their excellent properties. A tool including monocrystalline diamond is, for example, a water jet orifice (Patent Document 1), a stylus for gravure printing (Patent Documents 2 and 3), a scriber (Patent Document 4), a diamond cutting tool (Patent Documents 5 and 6), or a scribing wheel (Patent Document 7).
  • However, such monocrystalline diamond also has a property that abrasion losses vary (uneven wear) depending on crystal orientations of the diamond. For example, abrasion loss considerably varies between the (111) plane and the (100) plane. For this reason, monocrystalline diamond applied to such tools described above is worn away only in a specific plane in a short time as the tools are used, and predetermined effects are not provided, which has been a problem.
  • Monocrystalline diamond also has a property of cleaving along the (111) plane. For this reason, when monocrystalline diamond is applied to a tool subjected to a stress during use, the tool breaks or cracks, which also has been a problem.
  • To deal with the property of uneven wear and the cleaving property of monocrystalline diamond, sintered diamond may be used. Such sintered diamond is obtained by sintering diamond grains with a metal binder such as cobalt and hence the metal binder is present among the diamond grains. The metal binder region is softer than the diamond grains and hence is worn away in a short time. As the amount of the binder decreases, the diamond grains come off and the effects are not provided with stability for a long period of time. There is also a problem in that adhesive wear occurs between the metal binder region and a metal material being worked and working for a long period of time cannot be performed.
  • To solve such a problem caused by a metal binder, a binderless sintered diamond may be produced by dissolving the metal binder with acid to thereby remove the metal binder. However, removal of a metal binder reduces the binding power of diamond grains, which most likely increases abrasion loss.
  • For polycrystalline diamond free from a metal binder, there is a polycrystalline diamond obtained by chemical-vapor deposition (CVD). However, this polycrystalline diamond has a small binding strength among grains and hence suffers from large abrasion loss, which has been a problem.
  • Hereinafter, the above-described tools are specifically described.
  • A water jet orifice including monocrystalline diamond has a problem in that a target cutting width is no longer achieved after the lapse of usage time.
  • This is caused by the following mechanism. In such an orifice composed of monocrystalline diamond, diamond crystals in the interior surface of an orifice bore have various crystal orientations toward surroundings. The orifice having the shape of a cylinder at the initial stage of use suffers from abrasion in a plane susceptible to abrasion in a short time. As a result, the cylindrical shape of the orifice is lost and the interior surface is expanded into the shape of a polygon such as hexagon.
  • To deal with such deformation into a polygonal shape caused by uneven wear, sintered diamond may be used (Patent Document 8). However, this causes coming off of diamond grains with a decrease in the amount of a binder as described above and an orifice bore is expanded. Thus, a cutting width is not provided with stability for a long period of time, which is a problem. In particular, a water jet intended to provide enhanced cutting efficiency is configured to expel liquid containing water and rigid particles (alumina or the like) at a high pressure. As a result, a metal binder region, which is softer than diamond grains, wears away in a short time and a cutting width is not provided with stability for a long period of time, which is a problem.
  • To cover the interior surface of an orifice with polycrystalline diamond free from a metal binder, a method may be used in which the interior surface of a metal orifice bore is coated with a diamond thin film free from a metal binder by CVD (chemical-vapor deposition) as described above (see Patent Document 9). However, such a diamond thin film has a short wear life, and has a small binding strength among grains and hence has a short wear life, which has been a problem.
  • Another example is a stylus for gravure printing in which natural or artificial monocrystalline diamond is used as material for the stylus (see Patent Documents 2 and 3). However, possibly because such diamond has a property of cleaving, such a tool breaks or cracks by a stress during use, which is a problem. Due to the property of uneven wear, such diamond is worn away only in a specific plane in a short time as the tool is used, and hence working for a long period of time cannot be performed, which has also been a problem.
  • Still another example is a scriber including monocrystalline diamond. For example, as shown in Patent Document 4, polyhedron-shaped monocrystalline diamond is used to scribe monocrystalline substrates, glass substrates, and the like with a vertex of the polyhedron, the vertex serving as a blade. Such a scriber composed of monocrystalline diamond is produced by working monocrystalline diamond such that the (111) plane, which is the most resistant to abrasion against a workpiece that is to be scribed and is composed of a monocrystalline material such as sapphire, is particularly positioned to be aligned parallel to the work to be scribed.
  • However, possibly because monocrystalline diamond has a property of cleaving along the (111) plane as described above, scribers composed of monocrystalline diamond crack or wear unevenly when a plane used for scribing only slightly deviates from the (111) plane, which has been a problem.
  • Still another example is a diamond cutting tool in which natural or artificial monocrystalline diamond is used as material for the tool (see Patent Documents 5 and 6). However, because of the problems of the cleaving property and the property of uneven wear of monocrystalline diamond as described above, such a tool composed of monocrystalline diamond has a problem in that the tool breaks or cracks due to a stress during use, is worn away only in a specific plane in a short time as the tool is used, and working for a long period of time cannot be performed.
  • Still another example is a scribing wheel in which monocrystalline diamond is used as material for the scribing wheel. For example, as shown in Patent Document 7, scribed lines are formed in a brittle material such as glass for liquid crystal panels with the V-shaped edge of the wheel, the edge serving as a cutting edge.
  • However, as with other tools, such a scribing wheel breaks or cracks due to a stress during use because of the problem of the cleaving property of monocrystalline diamond, which has been a problem.
  • Due to the property of uneven wear, such a tool is worn away only in a specific plane in a short time as the tool is used, and use of the tool for a long period of time is not possible, which has been a problem. A scribing wheel composed of monocrystalline diamond has a V-shaped edge in which crystals have various crystal orientations in the circumferential direction. Thus, the edge having the shape of a perfect circle at the initial stage of use is worn away in a plane susceptible to wear in a short time and the perfect circular shape is deformed into the shape of a polygon. As a result, the wheel becomes no longer able to roll, which has been a problem.
  • To deal with the cleaving property and the property of uneven wear in the above-described various tools, a sintered diamond compact may be used as material for such tools, the compact containing metal serving as a binder (Patent Documents 7 and 10).
  • However, even though sintered diamond is used, the following problems are likely to occur: a metal binder region containing cobalt or the like is softer than diamond grains and hence wears away in a short time, and adhesive wear occurs between the metal binder region and a metal material being worked such as copper and working for a long period of time cannot be performed. Such a metal binder in the sintered diamond compact may be removed by dissolving the metal binder with acid. However, this reduces the binding power of diamond grains, which most likely increases abrasion loss.
  • Polycrystalline diamond that is produced by CVD and is free from a metal binder has a small binding strength among grains and hence probably has a problem in that such diamond has a short wear life.
  • [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2000-061897
  • [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2006-123137
  • [Patent Document 3] Japanese Unexamined Patent Application Publication No. 2006-518699
  • [Patent Document 4] Japanese Unexamined Patent Application Publication No. 2005-289703
  • [Patent Document 5] Japanese Unexamined Patent Application Publication No. 2004-181591
  • [Patent Document 6] Japanese Unexamined Patent Application Publication No. 2003-025118
  • [Patent Document 7] Japanese Unexamined Patent Application Publication No. 2007-031200
  • [Patent Document 8] Japanese Unexamined Patent Application Publication No. 10-270407
  • [Patent Document 9] Japanese Unexamined Patent Application Publication No. 2006-159348
  • [Patent Document 10] International Publication No. 2003/051784
    • DISCLOSURE OF INVENTION Problems To Be Solved By the Invention
  • In view of the problems described above, an object of the present invention is to provide a 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 a polycrystalline diamond.
  • In particular, an object of the present invention is to provide a water jet orifice that provides a cutting width with stability for a long period of time, a stylus for gravure printing, a scriber, a diamond cutting tool, and a scribing wheel that enable stable working for a long period of time, compared with conventional tools including monocrystalline diamonds and sintered diamond compacts containing metal binders.
    • Means For Solving the Problems
  • To solve the above-described problems, the inventors of the present invention have performed thorough studies. As a result, they have found that a polycrystalline diamond is advantageously applicable to diverse applications, the polycrystalline diamond not containing a metal binder such as cobalt, having an average grain diameter of more than 50 nm and less than 2500 nm and a purity of 99% or more, and the D90 grain diameter of the sinter being (average grain diameter+0.9×average grain diameter) or less. Thus, they have accomplished the present invention.
  • Specifically, the present invention is directed to, as described below, a polycrystalline diamond; a water jet orifice, a stylus for gravure printing, a scriber, a diamond cutting tool, and a scribing wheel that include such a polycrystalline diamond and allow stable working for a long period of time.
    • <Polycrystalline Diamond>
    • (1) 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.
    • (2) The polycrystalline diamond according to (1) above, wherein the sintered diamond grains have a D90 grain diameter of (average grain diameter+average grain diameter×0.7) or less.
    • (3) The polycrystalline diamond according to (1) above, wherein the sintered diamond grains have a D90 grain diameter of (average grain diameter+average grain diameter×0.5) or less.
    • (4) The polycrystalline diamond according to any one of (1) to (3) above, wherein the polycrystalline diamond has a hardness of 100 GPa or more.
    • (5) The polycrystalline diamond according to any one of (1) to (4) above, wherein the non-diamond carbon is a carbon material having a graphite-type layer structure.
    <Water Jet Orifice>
    • (6) A water jet orifice including the polycrystalline diamond according to any one of (1) to (5) above.
    • (7) The water jet orifice according to (6) above, wherein an interior surface of an orifice bore through which water jet fluid passes, the bore being formed in the polycrystalline diamond, has a surface roughness Ra of 300 nm or less.
    • (8) The water jet orifice according to (6) or (7) above, wherein the orifice bore formed in the polycrystalline diamond has a diameter of 10 μm or more and 500 μm or less.
    • (9) The water jet orifice according to any one of (6) to (8) above, wherein a ratio (L/D) of an orifice level (L) to an orifice bore diameter (D) is 10 to 500, the orifice bore being formed in the polycrystalline diamond.
    • (10) The water jet orifice according to (6) or (7) above, wherein the orifice bore formed in the polycrystalline diamond has a diameter of more than 500 μm and 5000 μm or less.
    • (11) The water jet orifice according to any one of (6), (7), and (10) above, wherein a ratio (L/D) of an orifice level (L) to an orifice bore diameter (D) is 0.2 to 10, the orifice bore being formed in the polycrystalline diamond.
    <Stylus for Gravure Printing>
    • (12) A stylus for gravure printing including the polycrystalline diamond according to any one of (1) to (5) above.
    <Scriber>
    • (13) A scriber including the polycrystalline diamond according to any one of (1) to (5) above.
    • (14) The scriber according to (13) above, wherein a cutting face at a tip of the scriber has a shape of a polygon including three or more edges and the edges, in part or entirety, of the polygon are used as a blade.
    <Diamond Cutting Tool>
    • (15) A diamond cutting tool including the polycrystalline diamond according to any one of (1) to (5) above.
    <Scribing Wheel>
    • (16) A scribing wheel including the polycrystalline diamond according to any one of (1) to (5) above.
    Advantages
  • Polycrystalline diamond according to the present invention does not wear unevenly and hence is applicable to diverse applications.
  • A water jet orifice according to the present invention can provide a cutting width with stability for a long period of time, compared with conventional orifices including monocrystalline diamonds and sintered diamond compacts containing metal binders.
  • A stylus for gravure printing, a scriber, a diamond cutting tool, and a scribing wheel according to the present invention allow stable working for a long period of time, compared with conventional tools including monocrystalline diamonds and sintered diamond compacts containing metal binders.
    • BEST MODES FOR CARRYING OUT THE INVENTION
  • Hereinafter, polycrystalline diamond according to the present invention is described in detail.
  • Polycrystalline diamond according to the present invention is substantially a single-phase diamond (purity of 99% or more) and does not contain a metal binder such as cobalt. Such polycrystalline diamond can be obtained by directly converting and simultaneously sintering non-diamond carbon serving as a material such as graphite, glassy carbon, or amorphous carbon into diamond under an ultrahigh pressure and at a high temperature (temperature: 1800° C. to 2600° C., pressure: 12 to 25 GPa) without a catalyst or a solvent. The resultant polycrystalline diamond does not wear unevenly, which does occur in monocrystals.
  • Note that a method is known by which polycrystalline diamond is produced from diamond powder or graphite serving as a material. Specifically, methods by which polycrystalline diamonds are produced from diamond powder serving as a material and polycrystalline diamonds obtained by these methods are disclosed in References 1 to 4 below.
  • [Reference 1] Japanese Unexamined Patent Application Publication No. 2006-007677
  • [Reference 2] Japanese Unexamined Patent Application Publication No. 2002-187775
  • [Reference 3] Japanese Patent No. 3855029
  • [Reference 4] Japanese Unexamined Patent Application Publication No. 2004-168554
  • Reference 1 discloses a polycrystalline diamond and the diamond grains constituting this polycrystalline diamond have an average grain diameter of 80 nm to 1 μm, which is in the range defined by the present invention. However, Ref 1 states that the polycrystalline diamond was obtained by the method described in Ref 2. Reference 2 states that polycrystalline diamond is produced by a method of sintering diamond powder with carbonate serving as a sintering aid and the carbonate remains in the resultant polycrystalline diamond after the sintering. Therefore, the structure of the polycrystalline diamond disclosed in Ref 1 is different from the structure of a polycrystalline diamond according to the present invention.
  • Another method of sintering diamond powder with a sintering aid is disclosed in Ref 3. However, Ref 3 states that it has been ascertained with IR spectra that the sintering aid partially remains in a polycrystalline diamond obtained by this method. Therefore, the structure of this polycrystalline diamond is also different from the structure of a polycrystalline diamond according to the present invention. Reference 4 states that the sinters of Refs. 2 and 3 are inferior in hardness to a sinter free from a sintering aid according to the present invention. Thus, Ref 4 shows that a sinter according to the present invention is excellent.
  • Reference 4 above also discloses a method for producing a polycrystalline diamond in which a sintering aid is not used. This method uses diamond micro powder as a starting material and the grain diameter of the resultant sinter is 100 nm or less, which is in the range defined by the present invention. However, non-diamond carbon is used as a starting material in the present invention. In particular, when a carbon material having a graphite-type layer structure is used as a starting material, a polycrystalline diamond can be provided having a special structure referred to as a lamellar structure, which is not present in the polycrystalline diamond of Ref 4. Reference 5 described below states that extension of cracks is suppressed in a region having the lamellar structure. This demonstrates that a polycrystalline diamond according to the present invention is less prone to breaking than that described in Ref 4.
  • In summary, polycrystalline diamond according to the present invention is totally different in structure from diamond sinters that have been disclosed and, as a result, has mechanical characteristics that are far superior to those of the latter.
  • The following are examples of references describing methods of obtaining polycrystalline diamonds in which a non-diamond carbon material serving as a starting material is converted and sintered without addition of a sintering aid or a catalyst at an ultrahigh pressure of 12 GPa or more and at a high temperature of 2200° C. or more, as in the present invention.
  • [Reference 5] SEI Technical Review, 165 (2004) 68 (Sumiya et al.)
  • [Reference 6] Japanese Unexamined Patent Application Publication No. 2007-22888
  • [Reference 7] Japanese Unexamined Patent Application Publication No. 2003-292397
  • Various tools were produced from diamonds obtained by the methods described in Refs. 5 to 7 above and the performance of the resultant tools was evaluated. Probably because the diamond described in Ref 5 contains abnormally grown grains having a diameter of about 10 times the average grain diameter and the diamond described in Ref 6 contains coarse diamond grains that are converted from an added coarse material, the evaluation revealed that portions having such coarse grains wear extremely rapidly.
  • Then, thorough studies on how to eliminate such portions wearing extremely rapidly were performed and it has been revealed that the diameter distribution of sintered grains constituting polycrystalline diamond needs to be controlled. Accordingly, various tools produced with grain diameter distributions being controlled had no grains wearing extremely rapidly and exhibited stable performance for a long period of time. The diamond described in Ref 7 has abnormal grain growth probably because its production method is similar to that in Ref 5. The diamond described in Ref 7 also has a problem similar to that in Ref 5.
  • The above-described problem can be solved by use of a polycrystalline diamond in which sintered 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 sinter has a D90 grain diameter of (average grain diameter+0.9×average grain diameter) or less. This is because abnormal wear is suppressed by making the D90 grain diameter of sintered grains of polycrystalline diamond be (average grain diameter+0.9×average grain diameter) or less.
  • The average grain diameter in the present invention is number-average grain diameter determined with a transmission electron microscope (TEM). The average grain diameter and the D90 grain diameter can be controlled by controlling the grain diameter of a starting material or sintering conditions.
  • The following are specific values for the average grain diameter and the D90 grain diameter that satisfy the above-described relationship in polycrystalline diamond.
  • Example 1: when the average grain diameter is 60 nm, the D90 grain diameter is 114 nm or less.
  • Example 2: when the average grain diameter is 100 nm, the D90 grain diameter is 190 nm or less.
  • Example 3: when the average grain diameter is 500 nm, the D90 grain diameter is 950 nm or less.
  • The D90 grain diameter is more preferably (average grain diameter+0.7×average grain diameter) or less, and still more preferably (average grain diameter+0.5×average grain diameter) or less.
  • When the average grain diameter is 50 nm or less or 2500 nm or more, the hardness becomes less than 100 GPa and wearing away is caused in a short period of time and hence a cutting width is not obtained with stability for a long period of time.
  • Hereinafter, a water jet orifice according to the present invention will be described in detail.
  • Since the material of an orifice according to the present invention is the above-described polycrystalline diamond according to the present invention, a water jet orifice according to the present invention does not wear unevenly, which does occur in orifices composed of monocrystals.
  • The inventors of the present invention produced orifices with diamonds obtained by the methods described in Refs. 5 to 7 above and determined the cutting widths of these orifices. This determination revealed that, the diamonds obtained in accordance with these References contain coarse grains as described above and hence portions corresponding to such coarse grains wear extremely rapidly. In this case, the velocity of flow of a water jet solvent decreases in such portions and the direction of the flow changes. As a result, the cutting width decreases or increases with the passage of cutting time and the cutting width is not stabilized, and hence a desired cutting width is not provided, which has been a problem.
  • The inventors have found that, to obtain a desired cutting width with stability, such portions wearing extremely rapidly need to be eliminated, and this is achieved by controlling the distribution of the grain diameters of a sinter. Specifically, grains wearing extremely rapidly are eliminated in an orifice composed of a diamond having a controlled distribution of grain diameters, the diamond being polycrystalline diamond according to the present invention in which the polycrystalline diamond has an average grain diameter of more than 50 nm and less than 2500 nm and a purity of 99% or more, and the sinter has a D90 grain diameter of (average grain diameter+0.9×average grain diameter) or less. Thus, the above-described problem has been solved with such an orifice and use of such an orifice can provide a desired cutting width with stability for a long period of time.
  • Polycrystalline diamond used for a water jet orifice according to the present invention preferably has an average grain diameter and a D90 grain diameter that respectively satisfy the above-described ranges.
  • The D90 grain diameter of a sinter is desirably selected in accordance with the average diameter of rigid particles contained in fluid used for water jetting. When the average diameter of rigid particles is substantially equal to or less than the average grain diameter of the structure of a sinter, a cutting width with stability is not provided for a long period of time. This is because rigid particles collide with not a plurality of but a single surface of a grain of a sinter upon collision with the structure of the sinter, and when the surface has a crystal orientation susceptible to wear, the grain wears extremely rapidly. For this reason, the D90 grain diameter of a sinter of an orifice is selected so as to be 1/10 or less of the diameter of rigid particles.
  • This is shown by the following example with specific values.
  • Example 4: when the diameter of rigid particles is 50 μm, the D90 is 5 μm or less.
  • Polycrystalline diamond constituting a water jet orifice preferably has a hardness of 100 GPa or more. When the polycrystalline diamond has a hardness of less than 100 GPa, the orifice has a shorter life.
  • The interior surface of an orifice bore through which water jet fluid passes preferably has a surface roughness Ra of 300 nm or less. When the surface roughness Ra is more than 300 nm, the orifice has a shorter life.
  • When an orifice bore formed in polycrystalline diamond has a diameter of 10 μm or more and 500 μm or less, the ratio (L/D) of an orifice level (L) to an orifice bore diameter (D) is preferably 10 to 500.
  • When an orifice bore formed in polycrystalline diamond has a diameter of more than 500 μm and 5000 μm or less, the ratio (L/D) of an orifice level (L) to an orifice bore diameter (D) is preferably 0.2 to 10.
  • Hereinafter, a stylus for gravure printing according to the present invention will be described in detail.
  • Since the material of a stylus for gravure printing according to the present invention is the above-described polycrystalline diamond according to the present invention, a stylus for gravure printing according to the present invention does not wear unevenly, which does occur in styluses composed of monocrystals.
  • The inventors of the present invention produced styluses with diamonds obtained by the methods described in Refs. 5 to 7 above and inspected the workability of these styluses. This inspection revealed that, the diamonds obtained by the methods described in these References contain coarse grains as described above and hence portions corresponding to such coarse grains wear extremely rapidly. In this case, such portions cause streaky scratches on metal being worked and hence a desired working is not possible, which has been a problem.
  • The inventors have found that, to allow a desired stable working, such portions wearing extremely rapidly needs to be eliminated, and this is achieved by controlling the distribution of the grain diameters of a sinter. Accordingly, a stylus including polycrystalline diamond having a controlled distribution of grain diameters according to the present invention was produced. Grains wearing extremely rapidly are eliminated in this stylus and a desired stable working was achieved with the stylus for a long period of time.
  • Polycrystalline diamond according to the present invention includes sintered diamond grains having a D90 grain diameter of (average grain diameter+0.9×average grain diameter) or less. As a result, abnormal wearing can be suppressed.
  • Polycrystalline diamond constituting a stylus for gravure printing preferably has a hardness of 100 GPa or more. When the polycrystalline diamond has a hardness of less than 100 GPa, the stylus has a shorter life. When the average grain diameter is 50 nm or less or 2500 nm or more, the hardness becomes less than 100 GPa and wearing away is caused in a short period of time and hence stable working is not possible for a long period of time.
  • Hereinafter, a scriber according to the present invention will be described in detail.
  • Since the material of a scriber according to the present invention is the above-described polycrystalline diamond according to the present invention, a stylus for gravure printing according to the present invention does not wear unevenly, which does occur in styluses composed of monocrystals.
  • Reference 1 above discloses a scriber composed of a polycrystalline diamond and the diamond grains constituting the polycrystalline diamond of this scriber have an average grain diameter of 80 nm to 1 μm, which is in the range defined by the present invention. However, as described above, a polycrystalline diamond produced by the production method described in Ref 1 (Ref 2) contains carbonate remaining after sintering. Therefore, such a polycrystalline diamond is different in structure from a polycrystalline diamond according to the present invention.
  • The inventors of the present invention produced scribers from diamonds obtained by the methods described in Refs. 5 to 7 above and inspected the workability of these scribers. This inspection revealed that, the diamonds obtained by the methods described in these References contain coarse grains as described above and hence portions corresponding to such coarse grains wear extremely rapidly.
  • The inventors have found that, to allow a desired stable working, such portions wearing extremely rapidly needs to be eliminated, and this is achieved by controlling the distribution of the grain diameters of a sinter. Accordingly, a scriber including a polycrystalline diamond having a controlled distribution of grain diameters according to the present invention was produced. Grains wearing extremely rapidly were eliminated in this scriber and a desired stable working was achieved with the scriber for a long period of time.
  • Polycrystalline diamond constituting a scriber preferably has a hardness of 100 GPa or more. When the average grain diameter is 50 nm or less or 2500 nm or more, the hardness becomes less than 100 GPa. When the hardness is less than 100 GPa, wearing away is caused in a short period of time and hence stable working is not possible for a long period of time and the scriber has a shorter life.
  • Hereinafter, a diamond cutting tool according to the present invention will be described in detail.
  • Since polycrystalline diamond serving as the material of a diamond tool according to the present invention is the above-described polycrystalline diamond according to the present invention, the polycrystalline diamond substantially being a single-phase diamond (purity of 99% or more) and not containing a metal binder such as cobalt. For this reason, a diamond cutting tool according to the present invention does not wear unevenly, which does occur in diamond tools including monocrystals.
  • The inventors of the present invention produced diamond tools from diamonds obtained by the methods described in Refs. 5 to 7 above and inspected the workability of these tools. This inspection revealed that, the diamonds obtained by the methods described in these References contain coarse grains as described above and hence portions corresponding to such coarse grains wear extremely rapidly. In this case, such portions cause streaky scratches or the like in metal being worked and hence a desired working is not possible, which has been a problem.
  • The inventors have found that, to allow a desired stable working, such portions wearing extremely rapidly needs to be eliminated, and this is achieved by controlling the distribution of the grain diameters of a sinter. Accordingly, a diamond tool including a polycrystalline diamond having a controlled distribution of grain diameters according to the present invention was produced. Grains wearing extremely rapidly were eliminated in this tool and a desired stable working was achieved with the tool for a long period of time.
  • Polycrystalline diamond constituting a diamond cutting tool preferably has a hardness of 100 GPa or more. When the polycrystalline diamond has a hardness of less than 100 GPa, wearing away is caused in a short period of time and hence stable working is not possible for a long period of time and such a diamond tool has a shorter life.
  • For this reason, the sintered grains of polycrystalline diamond are made to have an average grain diameter of more than 50 nm and less than 2500 nm and a hardness of 100 GPa or more. When the average grain diameter is 50 nm or less or 2500 nm or more, the hardness becomes less than 100 GPa.
  • The grains of a sinter are made to have a D90 grain diameter of (average grain diameter+0.9×average grain diameter) or less to suppress abnormal wearing.
  • Hereinafter, a scribing wheel according to the present invention will be described in detail.
  • Since polycrystalline diamond serving as the material of a scribing wheel according to the present invention is the above-described polycrystalline diamond according to the present invention, the polycrystalline diamond substantially being a single-phase diamond (purity of 99% or more) and not containing a metal binder such as cobalt. For this reason, a scribing wheel according to the present invention does not wear unevenly, which does occur in scribing wheels including monocrystals.
  • The inventors of the present invention produced scribing wheels from polycrystalline diamonds obtained by the methods described in Refs. 5 to 7 above and inspected the workability of these scribing wheels. This inspection revealed that, the diamonds obtained by the methods described in these References contain coarse grains as described above and hence portions corresponding to such coarse grains wear extremely rapidly.
  • The inventors have found that, to allow a desired stable working, such portions wearing extremely rapidly needs to be eliminated, and this is achieved by controlling the distribution of the grain diameters of a sinter. Accordingly, a scribing wheel including a polycrystalline diamond having a controlled distribution of grain diameters according to the present invention was produced. Grains wearing extremely rapidly were eliminated in this scribing wheel and a desired stable working was achieved with the scribing wheel for a long period of time.
  • Polycrystalline diamond constituting a scribing wheel preferably has a hardness of 100 GPa or more. When the average grain diameter is 50 nm or less or 2500 nm or more, the hardness becomes less than 100 GPa. When the hardness is less than 100 GPa, wearing away is caused in a short period of time and hence stable working is not achieved for a long period of time and the scribing wheel has a shorter life.
    • Examples
  • Hereinafter, the present invention is described with reference to examples in which polycrystalline diamond according to the present invention is used as materials for water jet orifices, styluses for gravure printing, scribers, diamond cutting tools, and scribing wheels.
  • Measurement methods and evaluation methods used in Examples and Comparative Examples will be described.
    • <Average Grain Diameter and D90 Grain Diameter>
  • The D50 grain diameters (average grain diameters) and the D90 grain diameters of graphite grains in fired graphite material and sintered diamond grains in polycrystalline diamond in the present invention are obtained by conducting image analysis on the basis of photographic images with a transmission electron microscope under a magnification of 100,000 to 500,000.
  • Hereinafter, this method is described in detail.
  • First, the distribution of the diameters of crystal grains constituting a sinter is determined on the basis of an image taken with a transmission electron microscope. Specifically, each grain is sampled, a sampled grain is subjected to binarization, and the area (S) of each grain is calculated with an image analysis software (for example, Scion Image manufactured by Scion Corporation). The diameter (D) of each grain is calculated as the diameter (D=2√(S/π)) of a circle having the same area as the grain.
  • Second, the thus-obtained distribution of grain diameters is processed with a data analysis software (for example, Origin manufactured by OriginLab Corporation, Mathchad manufactured by Parametric Technology Corporation, or the like) to calculate the D50 grain diameter and the D90 grain diameter.
  • A transmission electron microscope used in Examples and Comparative Examples described below was an H-9000 manufactured by Hitachi, Ltd.
    • <Hardness>
  • Hardness was measured in Examples and Comparative Examples with a Knoop indenter with a measurement load of 4.9 N.
    • <Surface Roughness>
  • The surface roughness of the interior surface of an orifice bore was adjusted by adjusting the particle diameters of a polishing agent for polishing the interior surface. Surface roughness was measured in accordance with JIS B0601 with a contact-type surface roughness tester. Since a measurement stylus cannot be inserted into an orifice bore, another orifice separately produced by the same processes was cut and measured.
    • Example 1 Water Jet Orifice
  • Examples of orifices according to embodiments of the present invention are described below.
  • Examples 1-1 to 1-3 are examples in which surface roughness was varied. Examples 1-4 to 1-6 are examples in which orifice bore diameter was varied. Examples 1-7 to 1-12 are examples in which average grain diameter and D90 grain diameter were varied. Examples 1-13 and 1-14 are examples in which both average grain diameter and orifice bore diameter were increased.
    • Example 1-1
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 370 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 110 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 μm, an orifice level of 5 mm, and a surface roughness Ra of 290 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 μm was determined and it was a long time of 160 hours. For comparison purposes, an orifice composed of a sintered diamond having an average crystal grain diameter of 5 μm (containing a cobalt binder) was also evaluated for the same cutting property and the time was about 50 hours, which were extremely short.
    • Example 1-2
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 370 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 110 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 μm, an orifice level of 5 mm, and a surface roughness Ra of 50 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 μm was determined and it was a long time of 240 hours. For comparison purposes, an orifice composed of a sintered diamond having an average crystal grain diameter of 5 μm (containing a cobalt binder) was also evaluated for the same cutting property and the time was about 70 hours, which were extremely short.
    • Example 1-3
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 370 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 110 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 μm, an orifice level of 5 mm, and a surface roughness Ra of 5 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 μm was determined and it was a long time of 520 hours. For comparison purposes, an orifice composed of a sintered diamond having an average crystal grain diameter of 5 μm (containing a cobalt binder) was also evaluated for the same cutting property and the time was about 90 hours, which were extremely short.
    • Example 1-4
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter), was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 370 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 110 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 450 μm, an orifice level of 5 mm, and a surface roughness Ra of 290 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 550 μm was determined and it was a long time of 165 hours. For comparison purposes, an orifice composed of a sintered diamond having an average crystal grain diameter of 5 μm (containing a cobalt binder) was also evaluated for the same cutting property and the time was about 55 hours, which were extremely short.
    • Example 1-5
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 370 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 110 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 50 μm, an orifice level of 5 mm, and a surface roughness Ra of 290 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 100 μm was determined and it was a long time of 210 hours. For comparison purposes, an orifice composed of a sintered diamond having an average crystal grain diameter of 5 μm (containing a cobalt binder) was also evaluated for the same cutting property and the time was about 75 hours, which were extremely short.
    • Example 1-6
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 370 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 110 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 15 μm, an orifice level of 7 mm, and a surface roughness Ra of 290 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 30 μm was determined and it was a long time of 230 hours. For comparison purposes, an orifice composed of a sintered diamond having an average crystal grain diameter of 5 μm (containing a cobalt binder) was also evaluated for the same cutting property and the time was about 80 hours, which were extremely short.
    • Example 1-7
  • Graphite having an average grain diameter of 110 nm and a D90 grain diameter of 175 nm, which is (average grain diameter+0.7×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 230 nm and a D90 grain diameter of 380 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 115 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 μm, an orifice level of 5 mm, and a surface roughness Ra of 280 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 μm was determined and it was a long time of 180 hours.
    • Example 1-8
  • Graphite having an average grain diameter of 95 nm and a D90 grain diameter of 135 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 180 nm and a D90 grain diameter of 260 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 125 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 μm, an orifice level of 5 mm, and a surface roughness Ra of 280 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 μm was determined and it was a long time of 210 hours.
    • Example 1-9
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 55 nm and a D90 grain diameter of 80 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 105 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 μm, an orifice level of 5 mm, and a surface roughness Ra of 250 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 200 μm was determined and it was a long time of 130 hours.
    • Example 1-10
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 9 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 560 nm and a D90 grain diameter of 830 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 120 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 μm, an orifice level of 5 mm, and a surface roughness Ra of 240 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 μm was determined and it was a long time of 160 hours.
    • Example 1-11
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 9 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 1100 nm and a D90 grain diameter of 1600 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 112 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 μm, an orifice level of 5 mm, and a surface roughness Ra of 250 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 μm was determined and it was a long time of 150 hours.
    • Example 1-12
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 9 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 2400 nm and a D90 grain diameter of 3500 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 102 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 μm, an orifice level of 5 mm, and a surface roughness Ra of 270 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 μm was determined and it was a long time of 110 hours.
    • Example 1-13
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 9 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 2400 nm and a D90 grain diameter of 3500 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 102 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 1500 μm, an orifice level of 5 mm, and a surface roughness Ra of 270 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 2000 μm was determined and it was a long time of 210 hours.
    • Example 1-14
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 9 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 2400 nm and a D90 grain diameter of 3500 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 102 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 3500 μm, an orifice level of 0.7 mm, and a surface roughness Ra of 270 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 4500 μm was determined and it was a long time of 160 hours.
    • Comparative Example 1-1
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 370 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 110 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 μm, an orifice level of 5 mm, and a surface roughness Ra of 350 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 μm was determined and it was a short time of 95 hours.
    • Comparative Example 1-2
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 210 nm, which is about (average grain diameter+1.1×average grain diameter), was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 400 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 112 GPa. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 μm, an orifice level of 5 mm, and a surface roughness Ra of 290 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 μm was determined and it was a short time of 90 hours.
    • Comparative Example 1-3
  • Graphite having an average grain diameter of 20 nm and a D90 grain diameter of 37 nm, which is about (average grain diameter+0.9×average grain diameter), was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 45 nm and a D90 grain diameter of 80 nm was obtained. The thus-obtained polycrystalline diamond had a hardness of 95 GPa and was slightly soft. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 μm, an orifice level of 5 mm, and a surface roughness Ra of 250 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 μm was determined and it was a short time of 80 hours.
    • Comparative Example 1-4
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is about (average grain diameter+0.9×average grain diameter), was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable over a long period of time. As a result, a polycrystalline diamond having an average grain diameter of 2700 nm and a D90 grain diameter of 3900 nm was obtained. The thus-obtained polycrystalline diamond had a hardness of 91 GPa and was slightly soft. An orifice was produced from this polycrystalline material, the orifice having an orifice bore diameter of 200 μm, an orifice level of 5 mm, and a surface roughness Ra of 240 nm in the surface of the orifice bore. This orifice was evaluated for a water jet cutting property. The cutting time over which the orifice diameter was expanded to 300 μm was determined and it was a short time of 85 hours.
  • Table I shows values of the sintered grains of the polycrystalline diamonds in Examples and Comparative Examples above in terms of average grain diameter, D90 grain diameter, a coefficient (K), hardness, and wear life. Note that the coefficient (K) is defined by Equation (1) below.

  • D90 grain diameter=average grain diameter+average grain diameter×K   (1)
  • TABLE I
    Orifice
    Average bore Orifice Life of
    grain Surface diameter level Life Co-containing
    diameter D90 Hardness roughness (D) (L) hour diamond hour
    (nm) (nm) Coefficient (GPa) (nm) (μm) (mm) L/D*1) (H) (H)
    Example 1-1 200 370 0.85 110 290 200 5 25 160 50
    Example 1-2 200 370 0.85 110 50 200 5 25 240 70
    Example 1-3 200 370 0.85 110 5 200 5 25 520 90
    Example 1-4 200 370 0.85 110 290 450 5 11 165 55
    Example 1-5 200 370 0.85 110 290 50 5 100 210 75
    Example 1-6 200 370 0.85 110 290 15 7 467 230 80
    Example 1-7 230 380 0.65 115 280 200 5 25 180 —
    Example 1-8 180 260 0.44 125 280 200 5 25 210 —
    Example 1-9 55 80 0.45 105 250 200 5 25 130 —
    Example 1-10 560 830 0.48 120 240 200 5 25 160 —
    Example 1-11 1100 1600 0.45 112 250 200 5 25 150 —
    Example 1-12 2400 3500 0.46 102 270 200 5 25 110 —
    Example 1-13 2400 3500 0.46 102 270 1500 5 3 210 —
    Example 1-14 2400 3500 0.46 102 270 3500 0.7 0.2 160 —
    Comparative 200 370 0.85 110 350 200 5 25 95 —
    Example 1-1
    Comparative 200 400 1.00 112 290 200 5 25 90 —
    Example 1-2
    Comparative 45 80 0.78 95 250 200 5 25 80 —
    Example 1-3
    Comparative 2700 3900 0.44 91 240 200 5 25 85 —
    Example 1-4
    *1)L/D = orifice bore diameter (D)/orifice level (L)
    • Example 2 Stylus for Gravure Printing
  • Examples of styluses for gravure printing according to the present invention and Comparative Examples are described below.
  • An evaluation method for styluses in terms of wear resistance will be described.
    • <Evaluation of Wear Resistance>
  • A stylus having an included angle of 120° was produced from polycrystalline diamond obtained. A copper workpiece was worked with this stylus being driven at a frequency of 8 kHz and working time over which wear depth in an edge line portion on one side was increased to 10 μm was determined The wear resistance of the stylus was evaluated on the basis of this working time defined as the wear life of the stylus.
    • Example 2-1
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 370 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 110 GPa. A stylus produced from this polycrystalline diamond had a long wear life of 240 hours. For comparison purposes, a stylus composed of monocrystalline diamond was evaluated for the same working property and the time was about 60 hours, which were extremely short.
    • Example 2-2
  • Graphite having an average grain diameter of 110 nm and a D90 grain diameter of 175 nm, which is (average grain diameter+0.7×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 230 nm and a D90 grain diameter of 380 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 115 GPa. A stylus produced from this polycrystalline diamond had a long wear life of 280 hours.
    • Example 2-3
  • Graphite having an average grain diameter of 95 nm and a D90 grain diameter of 135 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 180 nm and a D90 grain diameter of 260 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 125 GPa. A stylus produced from this polycrystalline diamond had a long wear life of 320 hours.
    • Example 2-4
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 55 nm and a D90 grain diameter of 80 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 105 GPa. A stylus having an included angle of 120° was produced from the obtained polycrystalline diamond. This stylus produced from the polycrystalline diamond had a long wear life of 200 hours.
    • Example 2-5
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 4 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 560 nm and a D90 grain diameter of 830 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 120 GPa. A stylus produced from this polycrystalline diamond had a long wear life of 180 hours.
    • Example 2-6
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 5 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 1100 nm and a D90 grain diameter of 1600 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 112 GPa. A stylus produced from this polycrystalline diamond had a long wear life of 170 hours.
    • Example 2-7
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 6 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 2400 nm and a D90 grain diameter of 3500 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 102 GPa. A stylus produced from this polycrystalline diamond had a long wear life of 150 hours.
    • Comparative Example 2-1
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 210 nm, which is (average grain diameter+1.1×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 400 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 112 GPa. A stylus produced from this polycrystalline diamond had a short wear life of 90 hours.
    • Comparative Example 2-2
  • Graphite having an average grain diameter of 20 nm and a D90 grain diameter of 37 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 45 nm and a D90 grain diameter of 80 nm was obtained. The thus-obtained polycrystalline diamond had a hardness of 95 GPa and was slightly soft. A stylus produced from this polycrystalline diamond had a short wear life of 85 hours.
    • Comparative Example 2-3
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 2700 nm and a D90 grain diameter of 3900 nm was obtained. The thus-obtained polycrystalline diamond had a hardness of 91 GPa and was slightly soft. A stylus produced from this polycrystalline diamond had a short wear life of 70 hours.
    • Comparative Example 2-4
  • A stylus produced from monocrystalline diamond serving as a material was tested for wear resistance in the same manner as in Example 1 and this stylus had a wear life of 60 hours.
  • Table II shows values of the sintered grains of the polycrystalline diamonds in Examples and Comparative Examples above in terms of average grain diameter, D90 grain diameter, the coefficient (K), hardness, and wear life. Note that the coefficient (K) is defined by Eq. (1) above.
  • TABLE II
    Average
    grain
    diameter Coefficient Hardness Wear life
    nm D90 nm (K) GPa hour (H)
    Example 2-1 200 370 0.85 110 240
    Example 2-2 230 380 0.65 115 280
    Example 2-3 180 260 0.44 125 320
    Example 2-4 55 80 0.45 105 200
    Example 2-5 560 830 0.48 120 180
    Example 2-6 1100 1600 0.45 112 170
    Example 2-7 2400 3500 0.46 102 150
    Comparative 200 400 1.00 112 90
    Example 2-1
    Comparative 45 80 0.78 95 85
    Example 2-2
    Comparative 2700 3900 0.44 91 70
    Example 2-3
    Comparative — — — — 60
    Example 2-4
    • Example 3 Scriber
  • Examples of scribers according to the present invention and Comparative Examples are described below.
  • An evaluation method for scribers in terms of wear resistance will be described.
    • <Evaluation of Wear Resistance>
  • A 4-point scriber was produced from polycrystalline material obtained and it was subjected to a wear test where a sapphire substrate was scribed with the scriber under a load of 50 g, at a scribing speed of 1 cm/min, and for a scribing distance of 1 m. The wear resistance of the scriber was evaluated on the basis of abrasion loss in the test.
    • Example 3-1
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 370 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 110 GPa. An abrasion loss of a scriber produced from this polycrystalline diamond was extremely small and it was about 1/70 of that of a scriber composed of monocrystalline diamond.
    • Example 3-2
  • Graphite having an average grain diameter of 110 nm and a D90 grain diameter of 175 nm, which is (average grain diameter+0.7×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 230 nm and a D90 grain diameter of 380 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 115 GPa. An abrasion loss of a scriber produced from this polycrystalline diamond was extremely small and it was about 1/80 of that of a scriber composed of monocrystalline diamond.
    • Example 3-3
  • Graphite having an average grain diameter of 95 nm and a D90 grain diameter of 135 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 180 nm and a D90 grain diameter of 260 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 125 GPa. An abrasion loss of a scriber produced from this polycrystalline diamond was extremely small and it was about 1/90 of that of a scriber composed of monocrystalline diamond.
    • Example 3-4
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 55 nm and a D90 grain diameter of 80 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 105 GPa. An abrasion loss of a scriber produced from this polycrystalline diamond was extremely small and it was about 1/60 of that of a scriber composed of monocrystalline diamond.
    • Example 3-5
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 4 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 560 nm and a D90 grain diameter of 830 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 120 GPa. An abrasion loss of a scriber produced from this polycrystalline diamond was extremely small and it was about 1/50 of that of a scriber composed of monocrystalline diamond.
    • Example 3-6
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 5 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 1100 nm and a D90 grain diameter of 1600 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 112 GPa. An abrasion loss of a scriber produced from this polycrystalline diamond was extremely small and it was about 1/50 of that of a scriber composed of monocrystalline diamond.
    • Example 3-7
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 6 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 2400 nm and a D90 grain diameter of 3500 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 102 GPa. An abrasion loss of a scriber produced from this polycrystalline diamond was extremely small and it was about 1/40 of that of a scriber composed of monocrystalline diamond.
    • Comparative Example 3-1
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 210 nm, which is (average grain diameter+1.1×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 400 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 112 GPa. An abrasion loss of a scriber produced from this polycrystalline diamond was about ¼ of that of a scriber composed of monocrystalline diamond.
    • Comparative Example 3-2
  • Graphite having an average grain diameter of 20 nm and a D90 grain diameter of 37 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 45 nm and a D90 grain diameter of 80 nm was obtained. The thus-obtained polycrystalline diamond had a hardness of 95 GPa and was slightly soft. An abrasion loss of a scriber produced from this polycrystalline diamond was about ⅓ of that of a scriber composed of monocrystalline diamond.
    • Comparative Example 3-3
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 2700 nm and a D90 grain diameter of 3900 nm was obtained. The thus-obtained polycrystalline diamond had a hardness of 91 GPa and was slightly soft. An abrasion loss of a scriber produced from this polycrystalline diamond was about ½ of that of a scriber composed of monocrystalline diamond.
  • Table III shows values of the sintered grains of the polycrystalline diamonds in Examples and Comparative Examples above in terms of average grain diameter, D90 grain diameter, the coefficient (K), hardness, and abrasion loss. Note that the coefficient (K) is defined by Eq. (1) above.
  • TABLE III
    Average Abrasion loss
    grain Co- Ratio relative
    diameter D90 efficient Hardness to monocrystal
    [nm] [nm] (K) [Gpa] (reciprocal)
    Example 3-1 200 370 0.85 110 68.0
    Example 3-2 230 380 0.65 115 79.3
    Example 3-3 180 260 0.44 125 90.7
    Example 3-4 55 80 0.45 105 56.7
    Example 3-5 560 830 0.48 120 51.0
    Example 3-6 1100 1600 0.45 112 48.2
    Example 3-7 2400 3500 0.46 102 42.5
    Comparative 200 400 1.00 112 3.6
    Example 3-1
    Comparative 45 80 0.78 95 3.4
    Example 3-2
    Comparative 2700 3900 0.44 91 2.8
    Example 3-3
    • Example 4 Diamond Cutting Tool
  • Examples of diamond cutting tools according to embodiments of the present invention are described below.
  • An evaluation method for diamond cutting tools in terms of wear resistance will be described.
    • <Wear Resistance (Tool Life)>
  • Cutting tools having an edge included angle of 90° and an edge R of 100 nm were produced from polycrystalline diamonds obtained in Examples and Comparative Examples and these cutting tools were used to form grooves having a depth of 5 μm and a pitch of 5 μm in a metal plate that was a copper plate on which nickel was plated. The wear resistance of the cutting tools was evaluated on the basis of time (tool life) over which the edges of the cutting tools wore down to about 1 μm.
    • Example 4-1
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 370 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 110 GPa. A cutting tool produced from this polycrystalline diamond had an extremely long tool life of 15 hours.
    • Example 4-2
  • Graphite having an average grain diameter of 110 nm and a D90 grain diameter of 175 nm, which is (average grain diameter+0.7×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 230 nm and a D90 grain diameter of 380 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 115 GPa. A cutting tool produced from this polycrystalline diamond had an extremely long tool life of 18 hours.
    • Example 4-3
  • Graphite having an average grain diameter of 95 nm and a D90 grain diameter of 135 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 180 nm and a D90 grain diameter of 260 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 125 GPa. A cutting tool produced from this polycrystalline diamond had an extremely long tool life of 20 hours.
    • Example 4-4
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 55 nm and a D90 grain diameter of 80 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 105 GPa. A cutting tool produced from this polycrystalline diamond had an extremely long tool life of 13 hours.
    • Example 4-5
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 4 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 560 nm and a D90 grain diameter of 830 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 120 GPa. A cutting tool produced from this polycrystalline diamond had an extremely long tool life of 11 hours.
    • Example 4-6
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 5 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 1100 nm and a D90 grain diameter of 1600 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 112 GPa. A cutting tool produced from this polycrystalline diamond had an extremely long tool life of 10 hours.
    • Example 4-7
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 6 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 2400 nm and a D90 grain diameter of 3500 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 102 GPa. A cutting tool produced from this polycrystalline diamond had an extremely long tool life of 9 hours.
    • Comparative Example 4-1
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 210 nm, which is (average grain diameter+1.1×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 400 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 112 GPa. A cutting tool produced from this polycrystalline diamond had a tool life of 6 hours.
    • Comparative Example 4-2
  • Graphite having an average grain diameter of 20 nm and a D90 grain diameter of 37 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 45 nm and a D90 grain diameter of 80 nm was obtained. The thus-obtained polycrystalline diamond had a hardness of 95 GPa and was slightly soft. A cutting tool produced from this polycrystalline diamond had a tool life of 5 hours.
    • Comparative Example 4-3
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as non-diamond carbon serving as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 2700 nm and a D90 grain diameter of 3900 nm was obtained. The thus-obtained polycrystalline diamond had a hardness of 91 GPa and was slightly soft. A cutting tool produced from this polycrystalline diamond had a tool life of 4 hours.
    • Comparative Example 4-4
  • A tool produced from monocrystalline diamond serving as a material was tested for wear resistance in the same manner as in Example 1 and this tool had a tool life of 3 hours.
  • Table IV shows the values of the sintered grains of the polycrystalline diamonds in Examples and Comparative Examples above in terms of average grain diameter, D90 grain diameter, the coefficient (K), hardness, and tool life. Note that the coefficient (K) is defined by Eq. (1) above.
  • TABLE IV
    Average
    grain D90 grain Co-
    diameter diameter efficient Hardness Tool life
    [nm] [nm] (K) [Gpa] [Hr]
    Example 4-1 200 370 0.85 110 15
    Example 4-2 230 380 0.65 115 18
    Example 4-3 180 260 0.44 125 20
    Example 4-4 55 80 0.45 105 13
    Example 4-5 560 830 0.48 120 11
    Example 4-6 1100 1600 0.45 112 10
    Example 4-7 2400 3500 0.46 102 9
    Comparative 200 400 1.00 112 6
    Example 4-1
    Comparative 45 80 0.78 95 5
    Example 4-2
    Comparative 2700 3900 0.44 91 4
    Example 4-3
    Comparative — — — — 3
    Example 4-4
    • Example 5 Scribing Wheel
  • Examples of scribing wheels according to embodiments of the present invention are described below.
  • An evaluation method for scribing wheels in terms of a scribing property will be described.
    • <Evaluation of Scribing Property>
  • Scribing wheels having a diameter of 3 mm, a thickness of 0.8 mm, and an edge included angle of 120° were produced from polycrystalline diamonds obtained in Examples and Comparative Examples. These scribing wheels were used to scribe glass substrates and the scribing property of the scribing wheels was evaluated by determining scribed distances.
    • Example 5-1
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 370 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 110 GPa. The resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a long distance of about 300 km was achieved with this polycrystalline diamond.
    • Example 5-2
  • Graphite having an average grain diameter of 110 nm and a D90 grain diameter of 175 nm, which is (average grain diameter+0.7×average grain diameter) or less, was prepared as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 230 nm and a D90 grain diameter of 380 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 115 GPa. The resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a long distance of about 350 km was achieved with this polycrystalline diamond.
    • Example 5-3
  • Graphite having an average grain diameter of 95 nm and a D90 grain diameter of 135 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 180 nm and a D90 grain diameter of 260 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 125 GPa. The resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a long distance of about 400 km was achieved with this polycrystalline diamond.
    • Example 5-4
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 55 nm and a D90 grain diameter of 80 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 105 GPa. The resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a long distance of about 250 km was achieved with this polycrystalline diamond.
    • Example 5-5
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 4 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 560 nm and a D90 grain diameter of 830 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 120 GPa. The resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a long distance of about 230 km was achieved with this polycrystalline diamond.
    • Example 5-6
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 5 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 1100 nm and a D90 grain diameter of 1600 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 112 GPa. The resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a long distance of about 210 km was achieved with this polycrystalline diamond.
    • Example 5-7
  • Graphite having an average grain diameter of 30 nm and a D90 grain diameter of 40 nm, which is (average grain diameter+0.5×average grain diameter) or less, was prepared as the material of diamond. This material was directly converted and sintered into diamond over a longer time than in Example 6 under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 2400 nm and a D90 grain diameter of 3500 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 102 GPa. The resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a long distance of about 190 km was achieved with this polycrystalline diamond.
    • Comparative Example 5-1
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 210 nm, which is (average grain diameter+1.1×average grain diameter) or less, was prepared as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 200 nm and a D90 grain diameter of 400 nm was obtained. The thus-obtained polycrystalline diamond had an extremely high hardness of 112 GPa. The resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a short distance of about 120 km was barely conducted with this polycrystalline diamond.
    • Comparative Example 5-2
  • Graphite having an average grain diameter of 20 nm and a D90 grain diameter of 37 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 45 nm and a D90 grain diameter of 80 nm was obtained. The thus-obtained polycrystalline diamond had a hardness of 95 GPa and was slightly soft. The resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a short distance of about 110 km was barely conducted with this polycrystalline diamond.
    • Comparative Example 5-3
  • Graphite having an average grain diameter of 100 nm and a D90 grain diameter of 180 nm, which is (average grain diameter+0.9×average grain diameter) or less, was prepared as the material of diamond. This material was directly converted and sintered into diamond under a pressure condition under which diamond is thermodynamically stable. As a result, a polycrystalline diamond having an average grain diameter of 2700 nm and a D90 grain diameter of 3900 nm was obtained. The resultant polycrystalline material was evaluated in terms of scribing. As a result, scribing for a short distance of about 90 km was barely conducted with this polycrystalline diamond.
    • Comparative Example 5-4
  • A scribing wheel was produced from monocrystalline diamond and evaluated in terms of scribing. As a result, scribing for a short distance of 100 km was barely conducted with this monocrystalline diamond.
    • Comparative Example 5-5
  • A scribing wheel was produced from a sintered diamond compact bound with metal and evaluated in terms of scribing. As a result, scribing for a short distance of 6 km was barely conducted with this sintered diamond compact.
  • Table V shows values of the sintered grains of the polycrystalline diamonds in Examples and Comparative Examples above in terms of average grain diameter, D90 grain diameter, the coefficient, hardness, and tool life. Note that the coefficient (K) is defined by Eq. (1) above.
  • TABLE V
    Average
    grain Scribed
    diameter D90 Coefficient Hardness distance
    [nm] [nm] (K) [Gpa] [km]
    Example 5-1 200 370 0.85 110 300
    Example 5-2 230 380 0.65 115 350
    Example 5-3 180 260 0.44 125 400
    Example 5-4 55 80 0.45 105 250
    Example 5-5 560 830 0.48 120 230
    Example 5-6 1100 1600 0.45 112 210
    Example 5-7 2400 3500 0.46 102 190
    Comparative 200 400 1.00 112 120
    Example 5-1
    Comparative 45 80 0.78 95 110
    Example 5-2
    Comparative 2700 3900 0.44 91 90
    Example 5-3
    Comparative — — — — 100
    Example 5-4
    Comparative — — — — 6
    Example 5-5
    • INDUSTRIAL APPLICABILITY
  • Polycrystalline diamond used in the present invention is less prone to wear unevenly and allows stable working for a long period of time compared with conventional monocrystalline diamonds and sintered diamond compacts containing metal binders. Therefore, such polycrystalline diamond can be suitably applied to water jet orifices, styluses for gravure printing, scribers, cutting tools, and scribing wheels.
  • A water jet orifice according to the present invention can provide a cutting width with stability for a long period of time compared with conventional orifices and hence can be suitably used as an orifice for a water jet configured to expel fluid containing rigid particles (alumina or the like) at a high pressure to thereby cut or work workpieces.

Claims (16)

1. 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.
2. The polycrystalline diamond according to claim 1, wherein the sintered diamond grains have a D90 grain diameter of (average grain diameter+average grain diameter×0.7) or less.
3. The polycrystalline diamond according to claim 1, wherein the sintered diamond grains have a D90 grain diameter of (average grain diameter+average grain diameter×0.5) or less.
4. The polycrystalline diamond according to claim 1, wherein the polycrystalline diamond has a hardness of 100 GPa or more.
5. The polycrystalline diamond according to claim 1, wherein the non-diamond carbon is a carbon material having a graphite-type layer structure.
6. A water jet orifice comprising the polycrystalline diamond according to claim 1.
7. The water jet orifice according to claim 6, wherein an interior surface of an orifice bore through which water jet fluid passes, the bore being formed in the polycrystalline diamond, has a surface roughness Ra of 300 nm or less.
8. The water jet orifice according to claim 6, wherein the orifice bore formed in the polycrystalline diamond has a diameter of 10 μm or more and 500 μm or less.
9. The water jet orifice according to claim 6, wherein a ratio (L/D) of an orifice level (L) to an orifice bore diameter (D) is 10 to 500, the orifice bore being formed in the polycrystalline diamond.
10. The water jet orifice according to claim 6, wherein the orifice bore formed in the polycrystalline diamond has a diameter of more than 500 μm and 5000 μm or less.
11. The water jet orifice according to claim 6, wherein a ratio (L/D) of an orifice level (L) to an orifice bore diameter (D) is 0.2 to 10, the orifice bore being formed in the polycrystalline diamond.
12. A stylus for gravure printing comprising the polycrystalline diamond according to claim 1.
13. A scriber comprising the polycrystalline diamond according to claim 1.
14. The scriber according to claim 13, wherein a cutting face at a tip of the scriber has a shape of a polygon including three or more edges and the edges, in part or entirety, of the polygon are used as a blade.
15. A diamond cutting tool comprising the polycrystalline diamond according to claim 1.
16. A scribing wheel comprising the polycrystalline diamond according to claim 1.
US12/600,618 2008-02-06 2009-02-05 Polycrystalline diamond Abandoned US20100146865A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US14/738,116 US9630853B2 (en) 2008-02-06 2015-06-12 Method of preparing polycrystalline diamond

Applications Claiming Priority (13)

Application Number Priority Date Filing Date Title
JP2008-026505 2008-02-06
JP2008026505 2008-02-06
JP2008-118376 2008-04-30
JP2008118375 2008-04-30
JP2008118377 2008-04-30
JP2008118378 2008-04-30
JP2008118376 2008-04-30
JP2008-118377 2008-04-30
JP2008-118375 2008-04-30
JP2008-118378 2008-04-30
JP2008244329 2008-09-24
JP2008-244329 2008-09-24
PCT/JP2009/051940 WO2009099130A1 (en) 2008-02-06 2009-02-05 Polycrystalline diamond

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2009/051940 A-371-Of-International WO2009099130A1 (en) 2008-02-06 2009-02-05 Polycrystalline diamond

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US14/738,116 Continuation US9630853B2 (en) 2008-02-06 2015-06-12 Method of preparing polycrystalline diamond

Publications (1)

Publication Number Publication Date
US20100146865A1 true US20100146865A1 (en) 2010-06-17

Family

ID=40952203

Family Applications (2)

Application Number Title Priority Date Filing Date
US12/600,618 Abandoned US20100146865A1 (en) 2008-02-06 2009-02-05 Polycrystalline diamond
US14/738,116 Active US9630853B2 (en) 2008-02-06 2015-06-12 Method of preparing polycrystalline diamond

Family Applications After (1)

Application Number Title Priority Date Filing Date
US14/738,116 Active US9630853B2 (en) 2008-02-06 2015-06-12 Method of preparing polycrystalline diamond

Country Status (10)

Country Link
US (2) US20100146865A1 (en)
EP (1) EP2239228B1 (en)
JP (1) JP5466506B2 (en)
KR (1) KR101604730B1 (en)
CN (2) CN101679041B (en)
ES (1) ES2816179T3 (en)
PL (1) PL2239228T3 (en)
RU (2) RU2522028C2 (en)
TW (1) TWI455881B (en)
WO (1) WO2009099130A1 (en)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100064538A1 (en) * 2007-01-18 2010-03-18 Geoffrey Alan Scarsbrook Polycrystalline diamond elements having convex surfaces
US20100243337A1 (en) * 2009-03-31 2010-09-30 Baker Hughes Incorporated Methods for bonding preformed cutting tables to cutting element substrates and cutting elements formed by such processes
WO2014011855A1 (en) * 2012-07-11 2014-01-16 Smith International Inc. Thermally stable pcd with pcbn transition layer
WO2014065965A1 (en) * 2012-10-22 2014-05-01 Smith International Inc. Ultra-hard material cutting elements, methods of forming the same, and bits incorporating the same
US9193038B2 (en) 2011-12-09 2015-11-24 Smith International Inc. Method for forming a cutting element and downhole tools incorporating the same
US9254554B1 (en) 2012-02-16 2016-02-09 Us Synthetic Corporation Polycrystalline diamond compact including substantially single-phase polycrystalline diamond body, methods of making same, and applications therefor
US9808909B2 (en) 2014-01-20 2017-11-07 Kmt Waterjet Systems Inc. Orifice for a waterjet cutter
US9850135B2 (en) 2011-07-28 2017-12-26 Sumitomo Electric Industries, Ltd. Polycrystalline diamond and manufacturing method thereof
US9950960B2 (en) 2014-04-30 2018-04-24 Sumitomo Electric Industries, Ltd. Composite sintered body
US10118861B2 (en) 2015-10-30 2018-11-06 Sumitomo Electric Industries, Ltd. Composite polycrystal
US10399149B2 (en) 2015-10-30 2019-09-03 Sumitomo Electric Industries, Ltd. Composite polycrystal
US10442007B2 (en) 2015-10-30 2019-10-15 Sumitomo Electric Industries, Ltd. Composite polycrystal
US10457606B2 (en) 2014-04-30 2019-10-29 Sumitomo Electric Industries, Ltd. Composite sintered body
US10703636B2 (en) 2015-10-30 2020-07-07 Sumitomo Electric Industries, Ltd. Composite polycrystal and method for manufacturing the same
GB2609893A (en) * 2021-07-07 2023-02-22 Element Six Uk Ltd Polycrystalline diamond scriber cutting wheel and its method of construction

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101679041B (en) 2008-02-06 2014-01-29 住友电气工业株式会社 Polycrystalline diamond
JP5416507B2 (en) * 2009-08-07 2014-02-12 住友電気工業株式会社 Rotary cutting tool
JP5397403B2 (en) * 2011-03-31 2014-01-22 三星ダイヤモンド工業株式会社 Scribing wheel and scribing device
JP2012250352A (en) * 2011-05-31 2012-12-20 Mitsuboshi Diamond Industrial Co Ltd Scribing wheel and scribing apparatus
JP5891634B2 (en) * 2011-07-28 2016-03-23 住友電気工業株式会社 Polycrystalline diamond and method for producing the same
JP5891635B2 (en) * 2011-07-28 2016-03-23 住友電気工業株式会社 Polycrystalline diamond and method for producing the same
JP5891636B2 (en) * 2011-07-28 2016-03-23 住友電気工業株式会社 Polycrystalline diamond and method for producing the same
JP5468100B2 (en) * 2012-03-26 2014-04-09 オグラ宝石精機工業株式会社 stylus
EP3040116A4 (en) * 2014-10-11 2017-06-14 Henan Famous Diamond Industrial Co., Ltd. Rough-surface diamond synthesis method
CN105500120B (en) * 2015-11-25 2018-05-22 厦门市三安光电科技有限公司 A kind of control method of grinding wafer
CN105561882A (en) * 2015-12-28 2016-05-11 河南广度超硬材料有限公司 Polycrystalline diamond manufacturing method
CN106761429A (en) * 2016-12-07 2017-05-31 四川大学 A kind of diamond drill machine tooth
CN106625896A (en) * 2017-01-11 2017-05-10 四川大学 Novel superhard cutter
GB201802112D0 (en) * 2018-02-09 2018-03-28 Element Six Uk Ltd Tool cutting element
JP6521206B1 (en) * 2018-10-01 2019-05-29 住友電気工業株式会社 Diamond polycrystal, tool provided with diamond polycrystal and method for producing diamond polycrystal
CN111635231B (en) * 2020-06-05 2021-12-17 四川大学 Preparation method of polycrystalline diamond transparent ceramic
CN115228373A (en) * 2022-05-09 2022-10-25 蒋孟瑶 Polycrystalline diamond and preparation method thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5363556A (en) * 1992-03-27 1994-11-15 General Electric Company Water jet mixing tubes used in water jet cutting devices and method of preparation thereof
JP2003292397A (en) * 2002-04-01 2003-10-15 Techno Network Shikoku Co Ltd Diamond polycrystal and production method therefor
WO2007011019A1 (en) * 2005-07-21 2007-01-25 Sumitomo Electric Industries, Ltd. High-hardness polycrystalline diamond and process for producing the same

Family Cites Families (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU368937A1 (en) * 1971-02-05 1973-02-08 Всесоюзный научно исследовательский , проектный инстд тугоплавких металлов , твердых сплавов YANAYA'TSh
CN1036061C (en) * 1993-08-23 1997-10-08 复旦大学 Preparation of diamond from graphite or carbonaceous solid matter
JP3832923B2 (en) 1997-03-28 2006-10-11 株式会社ディスコ Cleaning device
JPH10310838A (en) * 1997-05-12 1998-11-24 Sumitomo Electric Ind Ltd Superhard composite member and its production
JP2890193B1 (en) 1998-04-13 1999-05-10 株式会社 ディアックス Diamond stylus
JP2000061897A (en) 1998-08-20 2000-02-29 Osaka Diamond Ind Co Ltd Water jetting nozzle
JP3550587B2 (en) 2000-12-18 2004-08-04 独立行政法人 科学技術振興機構 Method for manufacturing fine diamond sintered body
JP2003025118A (en) 2001-07-13 2003-01-29 Allied Material Corp Diamond tool for cutting
JP3958040B2 (en) * 2001-12-17 2007-08-15 京セラ株式会社 Manufacturing method of ceramic nozzle
DE60227841D1 (en) 2001-12-18 2008-09-04 Mitsuboshi Diamond Ind Co Ltd TOP HOLDER AND MANUFACTURING METHOD THEREFOR AS WELL AS SHARPENER AND HANDCUTTER WITH THE TOP HOLDER
JP2003192435A (en) * 2001-12-25 2003-07-09 Kyocera Corp Ceramic nozzle
JP4203900B2 (en) * 2002-10-11 2009-01-07 住友電気工業株式会社 Polycrystalline diamond and method for producing the same
JP3855029B2 (en) 2002-11-15 2006-12-06 独立行政法人科学技術振興機構 Manufacturing method of translucent ultrafine diamond sintered body
JP3992595B2 (en) 2002-11-15 2007-10-17 独立行政法人科学技術振興機構 Manufacturing method of high purity, high hardness ultrafine diamond sintered body
JP2004181591A (en) 2002-12-04 2004-07-02 Sanko Seiki Kk Single crystal diamond cutting tool
GB0303860D0 (en) 2003-02-19 2003-03-26 Element Six Ltd CVD diamond in wear applications
JP4252394B2 (en) 2003-07-30 2009-04-08 並木精密宝石株式会社 Diamond scriber
EP1704913B1 (en) * 2003-12-11 2016-05-18 Sumitomo Electric Industries, Ltd. High-hardness conductive diamond polycrystalline body and method for producing same
JP4365251B2 (en) 2004-03-31 2009-11-18 旭ダイヤモンド工業株式会社 Diamond scriber and method of manufacturing diamond scriber
JP2006007677A (en) 2004-06-29 2006-01-12 National Institute For Materials Science Diamond polycrystalline substance scriber
JP2006123137A (en) 2004-11-01 2006-05-18 Sadao Takeuchi Single crystal diamond tool
JP5048922B2 (en) 2004-12-07 2012-10-17 株式会社Ｒｏｓｅｃｃ Manufacturing method of nozzle for ultra-high pressure water
JP5076300B2 (en) * 2005-10-04 2012-11-21 住友電気工業株式会社 High hardness diamond polycrystal
JP5013156B2 (en) * 2005-07-21 2012-08-29 住友電気工業株式会社 High hardness diamond polycrystal and method for producing the same
JP2007031200A (en) 2005-07-27 2007-02-08 Allied Material Corp Cutter wheel
CN101062472A (en) * 2006-04-27 2007-10-31 彭国强 Production technique for high-grade fine-particle diamond with high grade of transparency
CN101679041B (en) 2008-02-06 2014-01-29 住友电气工业株式会社 Polycrystalline diamond

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5363556A (en) * 1992-03-27 1994-11-15 General Electric Company Water jet mixing tubes used in water jet cutting devices and method of preparation thereof
JP2003292397A (en) * 2002-04-01 2003-10-15 Techno Network Shikoku Co Ltd Diamond polycrystal and production method therefor
WO2007011019A1 (en) * 2005-07-21 2007-01-25 Sumitomo Electric Industries, Ltd. High-hardness polycrystalline diamond and process for producing the same
US20090305039A1 (en) * 2005-07-21 2009-12-10 Hitoshi Sumiya High-hardness polycrystalline diamond and method of preparing the same

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8468707B2 (en) * 2007-01-18 2013-06-25 Element Six Limited Polycrystalline diamond elements having convex surfaces
US20100064538A1 (en) * 2007-01-18 2010-03-18 Geoffrey Alan Scarsbrook Polycrystalline diamond elements having convex surfaces
US20100243337A1 (en) * 2009-03-31 2010-09-30 Baker Hughes Incorporated Methods for bonding preformed cutting tables to cutting element substrates and cutting elements formed by such processes
US8573333B2 (en) * 2009-03-31 2013-11-05 Baker Hughes Incorporated Methods for bonding preformed cutting tables to cutting element substrates and cutting elements formed by such processes
US8851208B2 (en) 2009-03-31 2014-10-07 Baker Hughes Incorporated Cutting elements including adhesion materials, earth-boring tools including such cutting elements, and related methods
US9839989B2 (en) 2009-03-31 2017-12-12 Baker Hughes Incorporated Methods of fabricating cutting elements including adhesion materials for earth-boring tools
US9878914B2 (en) 2011-07-28 2018-01-30 Sumitomo Electric Industries, Ltd. Polycrystalline diamond and manufacturing method thereof
US9850135B2 (en) 2011-07-28 2017-12-26 Sumitomo Electric Industries, Ltd. Polycrystalline diamond and manufacturing method thereof
US9193038B2 (en) 2011-12-09 2015-11-24 Smith International Inc. Method for forming a cutting element and downhole tools incorporating the same
US10119334B1 (en) 2012-02-16 2018-11-06 Us Synthetic Corporation Polycrystalline diamond compact including substantially single-phase polycrystalline diamond body and applications therefor
US9254554B1 (en) 2012-02-16 2016-02-09 Us Synthetic Corporation Polycrystalline diamond compact including substantially single-phase polycrystalline diamond body, methods of making same, and applications therefor
WO2014011855A1 (en) * 2012-07-11 2014-01-16 Smith International Inc. Thermally stable pcd with pcbn transition layer
CN104395547A (en) * 2012-07-11 2015-03-04 史密斯国际有限公司 Thermally stable PCD with PCBN transition layer
EP2909418A4 (en) * 2012-10-22 2016-07-20 Smith International Ultra-hard material cutting elements, methods of forming the same, and bits incorporating the same
CN104812988A (en) * 2012-10-22 2015-07-29 史密斯国际有限公司 Ultra-hard material cutting elements, methods of forming the same, and bits incorporating the same
WO2014065965A1 (en) * 2012-10-22 2014-05-01 Smith International Inc. Ultra-hard material cutting elements, methods of forming the same, and bits incorporating the same
US9808909B2 (en) 2014-01-20 2017-11-07 Kmt Waterjet Systems Inc. Orifice for a waterjet cutter
US9950960B2 (en) 2014-04-30 2018-04-24 Sumitomo Electric Industries, Ltd. Composite sintered body
US10457606B2 (en) 2014-04-30 2019-10-29 Sumitomo Electric Industries, Ltd. Composite sintered body
US10118861B2 (en) 2015-10-30 2018-11-06 Sumitomo Electric Industries, Ltd. Composite polycrystal
US10399149B2 (en) 2015-10-30 2019-09-03 Sumitomo Electric Industries, Ltd. Composite polycrystal
US10442007B2 (en) 2015-10-30 2019-10-15 Sumitomo Electric Industries, Ltd. Composite polycrystal
US10703636B2 (en) 2015-10-30 2020-07-07 Sumitomo Electric Industries, Ltd. Composite polycrystal and method for manufacturing the same
GB2609893A (en) * 2021-07-07 2023-02-22 Element Six Uk Ltd Polycrystalline diamond scriber cutting wheel and its method of construction

Also Published As

Publication number Publication date
TW200951069A (en) 2009-12-16
CN101679041B (en) 2014-01-29
ES2816179T3 (en) 2021-03-31
KR101604730B1 (en) 2016-03-18
TWI455881B (en) 2014-10-11
EP2239228A1 (en) 2010-10-13
JP5466506B2 (en) 2014-04-09
KR20100110721A (en) 2010-10-13
US9630853B2 (en) 2017-04-25
RU2581397C2 (en) 2016-04-20
CN101679041A (en) 2010-03-24
RU2014116561A (en) 2015-10-27
EP2239228A4 (en) 2015-09-30
PL2239228T3 (en) 2020-11-30
CN103752220A (en) 2014-04-30
RU2009142848A (en) 2012-03-20
JPWO2009099130A1 (en) 2011-05-26
EP2239228B1 (en) 2020-06-24
RU2522028C2 (en) 2014-07-10
US20150274535A1 (en) 2015-10-01
WO2009099130A1 (en) 2009-08-13

Similar Documents

Publication Publication Date Title
US9630853B2 (en) Method of preparing polycrystalline diamond
US9403215B2 (en) Cutting tool and method for producing same
KR101773267B1 (en) Green sheet cutting blade
RU2481187C2 (en) Powder of abrasive grains
WO2018174139A1 (en) Diamond coated cemented carbide cutting tool
KR20160021904A (en) Dicing device and dicing method
JP4711691B2 (en) Surface covering member and cutting tool
KR102126104B1 (en) Surface-coated cutting tool
EP3369717B1 (en) Composite polycrystal and method for manufacturing same
TW202012309A (en) Diamond polycrystal and tool including same
Harano et al. Cutting performance of nano-polycrystalline diamond
JP6421905B1 (en) Diamond polycrystalline body and tool provided with the same
CN102626853A (en) Cutting tool covered with diamond
CN102211331B (en) Diamond marking tool and method of manufacturing the same
CN201172156Y (en) Coarse crystal-face man-made diamond single-crystal
JP2020011887A (en) Diamond polycrystal body and industrial tool equipped with the same
JP2011036938A (en) Rotary cutting tool
Bhattacharya Ductile regime nano-machining of silicon carbide
JP2013176959A (en) Scribing wheel, scribing device, and scribing method
JP2020011886A (en) Diamond polycrystal body and industrial tool equipped with the same

Legal Events

Date Code Title Description
AS Assignment

Owner name: SUMITOMO ELECTRIC INDUSTRIES, LTD,JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SATO, TAKESHI;YAMAMOTO, KATSUKO;TODA, NAOHIRO;AND OTHERS;REEL/FRAME:023531/0329

Effective date: 20091013

Owner name: SUMITOMO ELECTRIC HARDMETAL CORP.,JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SATO, TAKESHI;YAMAMOTO, KATSUKO;TODA, NAOHIRO;AND OTHERS;REEL/FRAME:023531/0329

Effective date: 20091013

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION