US3652220A - Method of manufacturing synthetic diamonds - Google Patents

Method of manufacturing synthetic diamonds Download PDF

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Publication number
US3652220A
US3652220A US37425A US3652220DA US3652220A US 3652220 A US3652220 A US 3652220A US 37425 A US37425 A US 37425A US 3652220D A US3652220D A US 3652220DA US 3652220 A US3652220 A US 3652220A
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United States
Prior art keywords
carbonaceous material
solvent
diamond
reaction mixture
current
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.)
Expired - Lifetime
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US37425A
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English (en)
Inventor
Cedric E Lindstrom
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Scandimant AB
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Scandimant AB
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Filing date
Publication date
Priority claimed from SE1754/66A external-priority patent/SE324355B/xx
Priority claimed from SE08611/66A external-priority patent/SE339459B/xx
Application filed by Scandimant AB filed Critical Scandimant AB
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Publication of US3652220A publication Critical patent/US3652220A/en
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Expired - Lifetime legal-status Critical Current

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    • 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
    • B01J3/062—Processes using ultra-high pressure, e.g. for the formation of diamonds; Apparatus therefor, e.g. moulds or dies characterised by the composition of the materials to be processed
    • 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
    • B01J2203/00—Processes utilising sub- or super atmospheric pressure
    • B01J2203/06—High pressure synthesis
    • B01J2203/0605—Composition of the material to be processed
    • B01J2203/061—Graphite
    • 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
    • B01J2203/00—Processes utilising sub- or super atmospheric pressure
    • B01J2203/06—High pressure synthesis
    • B01J2203/0605—Composition of the material to be processed
    • B01J2203/0625—Carbon
    • 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
    • B01J2203/00—Processes utilising sub- or super atmospheric pressure
    • B01J2203/06—High pressure synthesis
    • B01J2203/065—Composition of the material produced
    • B01J2203/0655—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
    • B01J2203/00—Processes utilising sub- or super atmospheric pressure
    • B01J2203/06—High pressure synthesis
    • B01J2203/0675—Structural or physico-chemical features of the materials processed
    • B01J2203/068—Crystal growth

Definitions

  • the invention relates to the manufacture of synthetic diamonds.
  • synthetic diamonds can be manufactured by subjecting a mixture of particles of a non-diamond carbonaceous material and particles of a solvent for carbon, for example iron or nickel or an alloy containing one of these metals, to temperatures and pressures in the diamond stable region, in which the temperature is sufficiently high for the solvent to occur in molten form in the presence of the carbonaceous material. It is also known instead of particles of solvent to use bodies of the solvent which have a substantial extension in relation to the reaction vessel, for example in the form of rods, cylinders, plates, etc.
  • a solvent for carbon for example iron or nickel or an alloy containing one of these metals
  • the present invention relates to a method of manufacturing synthetic diamonds by subjecting a reaction mixture comprising a non-diamond carbonaceous material and a solvent for carbon having the capacity to convert the carbonaceous material to diamond in a reaction vessel, to temperatures and pressures in the diamond stable region, whereby the reaction mixture is heated by an electric current led through the reaction mixture to a temperature sufficiently high to melt the solvent and the solvent is shaped as at least one body having a substantial extension in relation to the reaction vessel and arranged substantially perpendicular to the current direction, characterized in that the solvent body is shaped with several narrowing or projecting parts, for example in the form of peaks, points or ridges, facing the carbonaceous material and that a negative temperature gradient is effected in the direction from the carbonaceous material to the solvent body when heating the reaction mixture.
  • the diamond stable region is the region above the equilibrium line for graphite-diamond in the phase diagram for carbon published by Herman and Simon in Zeitschrift fiir Elektrochemie 59 (1955), page 333. ,m.
  • the temperature is at least so high that the solvent is melted in the presence of the carbonaceous material.
  • a temperature of 50-250 C. above the eutectic melting point for a mixture of carbon and the solvent should not be exceeded.
  • Temperatures above 2,200 C. should be avoided so that problems with the apparatus do not unnecessarily become more complicated.
  • the required minimum pressure is obtained in each case with a knowledge of the temperature used, from said phase diagram for carbon. To avoid unnecessarily complicating the method it is normally suitable to use a pressure not exceeding 120,000 atm.
  • the carbonaceous material may consist of amorphous carbon, charcoal, anthracite or other naturally occurring carbon types, or of carbonaceous substances such as anthracene and naphthalene which disintegrate under the prevailing reaction conditions to liberate carbon.
  • the solvent may consist of iron, nickel, cobalt, platinum metals and other metals having the capacity to dissolve carbon and convert carbonaceous material to diamond, or of alloys containing such metals, such as alloys consisting of nickel and iron, of nickel, chromium and iron, of
  • nickel and chromium of nickel, cobalt, chromium and iron, for example stainless steel, and of nickel and copper.
  • Compounds of said metals may also be used, such as carbides, for example iron carbide. All these metals, alloys and metal compounds having the capacity to dissolve carbon and convert carbonaceous material to diamond are known per se and form no part of the present invention.
  • the carbonaceous material and solvent are subjected to pressures and temperatures within the diamond stableregion for preferably 1 15 mins. However, it is also possible for them to be thus subjected for a longer time of the magnitude of l or several hours.
  • a possible explanation of the good result obtained according to the invention may be that the narrowing or projecting parts of the solvent body in contact with the hotter carbon melt before the other parts of the solvent body, a rather limited number of diamond crystals then being formed which then act as seeds for further crystal growth. This would then take place during continued melting of the solvent body and continued dissolving of thecarbon.
  • the narrowing or projecting parts can be produced mechanically, for example, by milling, stamping or drawing, the last mentioned if the solvent body consists of a thread-like body, for example a spiral.
  • the solvent body consists of a thread-like body, for example a spiral.
  • one long projecting part may be used, for example a continuous spiral ridge.
  • the solvent body may, inter alia, be in the form of a disc having projecting parts in the form of, for example concentric ridges or in the form of a continuous, for example spiral, ridge. It may also be in the form of a layer of balls arranged close to each other or as a flat spiral, which may be wound with its adjacent turns close to each other.
  • the solvent body has several parts arranged with gaps between them which are filled with the non-diamond carbonaceous material and this is also arranged around the solvent body as such.
  • the parts of the solvent body may then form a continuous unit and the narrowing or projecting parts a long narrowing or projecting part on the solvent body, facing the carbonaceous material. the gaps between the parts.
  • these parts may have narrowing or projecting parts facing the carbonaceous material arranged around the solvent body as such and narrowing or projecting parts facing the carbonaceous material arranged in the gaps between the parts.
  • the solvent body When the solvent body is arranged with gaps between the parts it is particularly advantageous to shape the solvent body as a loosely wound spiral, as several concentric rings or as a layer of balls arranged at a distance from each other.
  • FIG. 1 shows the solvent body consists of a disc
  • FIG. 2 shows a tightly wound spiral
  • FIG. 3 shows a layer of balls arranged close to each other
  • FIG. 4 shows a loosely wound spiral and FIG. 5 shows several concentric rings.
  • FIG. 10, FIG. 2a, FIG. 4a and FIG. 5a show parts of the solvent body on a larger scale.
  • the reaction chamber 10 shown in FIGS. 1 5 is cylindrical. It is limited sideways by an insulating tube 1 1 of, for example talcum and at the top by two circular metal plates 12 and 13.
  • the reaction chamber is heated electrically by leading an electrical current through it in vertical direction.
  • the pressure can be generated, for example, with a vertically movable punch the insulating tube 11 being surrounded by a pressureabsorbing casing and a bearer being arranged at the end surface of the reaction chamber which is not influenced by the movable punch.
  • the solvent body consists of a plate 14 of a chromium-nickel alloy containing 20 percent by weight chromium and 80 percent by weight nickel.
  • the plate is arranged between two pre-compressed graphite cylinders 15 and 16.
  • the plate is provided on each side with projecting parts in the form of a continuous spiral ridge 17 (FIG. la) with a height h of about l min. and a width b at the base of about 1.5 mm., or in the form of several concentric ridges having, for example, the height and width mentioned.
  • the projecting parts may also consist of several separate peaks arranged at a distance from each other.
  • the reaction mixture is heated by an electric current as previously mentioned to a temperature of about l,480 C. and subjected to a pressure of about 65,000 atm. for 2 minutes.
  • EXAMPLE 2 A tightly wound spiral 18 of iron thread, in which adjacent turns, for example 19 and 20 (FIG. 2a) are in contact with each other, is arranged in accordance with FIG. 2 between two pre-compressed cylinders 21 and 22 of graphite.
  • the iron thread is flat along the contact surface between adjacent turns and has rounded edges 23 forming the narrowing or projecting parts.
  • the reaction mixture is heated by an electric current as previously indicated to a temperature of about l,5l C. and subjected to a pressure of about 75,000 atm. for 4 minutes.
  • the solvent body consists of a layer of tightly packed balls 24 of iron. Adjacent balls are thus in contact with each other.
  • the balls may have a diameter of about 0.5 mm.
  • On either side of the layer of iron balls are arranged two pre-compressed graphite cylinders 25 and 26. Due to their geometrical form, the balls are provided with narrowing parts in a radial direction, perpendicular to a plane chosen arbitrarily through the center of the ball.
  • the reaction mixture is heated by an electric current as mentioned previously to a temperature of about 1,450" C. and-subjected to a pressure of about 60,000 atm. for 9 minutes, whereby large diamonds with well defined crystals are formed.
  • 28c and 29b, 290, respectively, are arranged in accordance with FIG. 4 in graphite pre-compressed at approximately 3,000 kp./cm
  • the solvent bodies consist of the two spirals 28 and 29 which are arranged perpendicular to the pressure direction and current direction.
  • Each solvent body, for example 28 has parts consisting of its turns, two of which have been designated 28b and 28c, and between which parts there is thus a gap filled by graphite.
  • the spirals may be of nickel thread or cobalt thread with a diameter of about 1 mm. and the gaps'28a and 29a, respectively may be about 1 mm. wide.
  • the metalthread from an arbitrary axial plane in the thread, due to its own geometrical form, is provided with narrowing parts in a radial direction perpendicular to said plane. That part of the graphite surrounding the solvent bodies as such is designated 30 and that part of the graphite arranged in the gaps between the turns is designated 30a.
  • the reaction mixture is heated in the manner previously indicated by an electric current to a temperature of about 1,550 C. and subjected to a pressure of about 65,000 atm. for 3 4 minutes, whereby large, well crystallized diamonds are formed.
  • the solvent body consists of several concentric rings 32, 33, 34 and 35 arranged with gaps 36.
  • the solvent body thus has parts consisting of said rings 32, 33, 34 and 35.
  • the rings may be, for example of a chromiumnickel alloy containing 20 percent by weight chromium and percent by weight nickel.
  • Each ring has a square cross section with a side length of 1.5 mm. for the square. The distance between adjacent parts of two rings may be 2 mm. Due to its geometrical form each ring is provided with narrowing parts ending in axially directed edges 37 and 38 and in radially directed edges 39 and 40.
  • the reaction mixture is heated in the manner previously indicated by an electric current to a temperature of about l,480 C. and subjected to a pressure of about 65,000 atm. for 2 minutes.
  • rings having quadratic cross section may for example also be shaped so that they have inner and outer envelope surfaces parallel to the symmetry axis of the ring and end surfaces perpendicular to the symmetry axis.
  • rings having, for example, circular cross section may be used instead of rings having quadratic crosssection.
  • the solvent body may among other things consist of a layer of balls in which adjacent balls are separated from each other by graphite.
  • Method of manufacturing synthetic diamonds by subjecting a reaction mixture comprising a non-diamond carbonaceous material and a metallic solvent for carbon having the capacity to convert the carbonaceous material to diamond, in a reaction vessel, to temperatures and pressures in the diamond stable region, in which the reaction mixture is heated by an electric current led through the reaction mixture to a temperature sufficiently high to melt the solvent is shaped to extend over the greater part of the cross section of the reaction vessel transverse to the direction of the current and arranged substantiallyperpendicular to the current direction and embedded on all sides in the carbonaceous material, in which the solvent is constituted by a plurality of spaced apart substantially coplanar sections the spaces between which extend in the direction of the current completely through the solvent body and are filled by the carbonaceous material, said sections having portions tapering in the direction of the current embedded in the carbonaceous material and the sections being connected together in a unit, so that a negative temperature gradient is effected in the direction from the carbonaceous material to the solvent body.
  • Method of manufacturing synthetic diamonds by subjecting a reaction mixture comprising a non-diamond carbonaceous material and a metallic solvent for carbon having the capacity to convert the carbonaceous material to diamond, in a reaction vessel, to temperatures and pressures in the diamond stable region, in which the reaction mixture is heated by an electric current led through the reaction mixture to a temperature sufficiently high to melt the solvent, and the solvent is shaped to extend over the greater part of the cross section of the reaction vessel transverse to the direction of the current and arranged substantially perpendicular to the current direction and embedded on all sides in the carbonaceous material, in which the solvent is constituted by a spirally wound solid member, the coils of which are substantially coplanar and have portions tapering in the direction of the current embedded in the carbonaceous material, so that a negative temperature gradient is effected in the direction from the carbonaceous material to the solvent body.
  • Method of manufacturing synthetic diamonds by subjecting a reaction mixture comprising a non-diamond carbonaceous material and a metallic solvent for carbon having the capacity to convert the carbonaceous material to diamond, in a reaction vessel, to temperatures and pressures in the diamond stable region, in which the reaction mixture is heated by an electric current led through the reaction mixture to a temperature sufficiently high to melt the solvent, and the solvent is shaped as a spirally wound solid member, the coils of which are substantially coplanar and spaced apart, and extending over the greater part of the cross section of the reaction vessel transverse to the direction of the current and arranged substantially perpendicular to the current direction and embedded on all sides in the carbonaceous material, the spaces between the coils being filled by the carbonaceous material, the coils beingshaped so as to have portions tapering in the direction of the current embedded in the carbonaceous material, so that a negative temperature gradient is effected in the direction from the carbonaceous material to the solvent body.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Carbon And Carbon Compounds (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
US37425A 1966-02-11 1970-05-13 Method of manufacturing synthetic diamonds Expired - Lifetime US3652220A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE1754/66A SE324355B (ja) 1966-02-11 1966-02-11
SE08611/66A SE339459B (ja) 1966-06-23 1966-06-23

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US3652220A true US3652220A (en) 1972-03-28

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BE (1) BE693619A (ja)
DE (1) DE1667362A1 (ja)
GB (1) GB1174940A (ja)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1982000458A1 (en) * 1980-07-31 1982-02-18 Apollonov V Method of obtaining diamond and/or diamond-like modifications of boron nitride
US4339304A (en) * 1980-12-30 1982-07-13 Grigoriev Anatoly P Method of treating diamond
US4563341A (en) * 1978-05-19 1986-01-07 Flynn Hugh G Method and means for converting graphite to diamond
US20090014314A1 (en) * 2006-06-20 2009-01-15 Snaper Alvin A Synthesis of diamond by extraction of a pulse derived from the abrupt collapse of a magnetic field
WO2012104722A1 (en) 2011-02-04 2012-08-09 Alexander Cherkasky Novel cherkasky's synthetic diamonds and diamond-like materials and methods and devices for production thereof
US20120298092A1 (en) * 2010-10-28 2012-11-29 Klishin Aleksandr V Method for producing gemstones from silicon carbide

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2947609A (en) * 1958-01-06 1960-08-02 Gen Electric Diamond synthesis
US2992900A (en) * 1958-12-29 1961-07-18 Gen Electric Method for producing improved diamond crystals
US3031269A (en) * 1959-11-27 1962-04-24 Gen Electric Method of diamond growth and apparatus therefor
US3124422A (en) * 1960-07-20 1964-03-10 Synthesis of diamonds
US3407445A (en) * 1966-03-02 1968-10-29 Gen Electric High pressure reaction vessel for the preparation of diamond

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2947609A (en) * 1958-01-06 1960-08-02 Gen Electric Diamond synthesis
US2992900A (en) * 1958-12-29 1961-07-18 Gen Electric Method for producing improved diamond crystals
US3031269A (en) * 1959-11-27 1962-04-24 Gen Electric Method of diamond growth and apparatus therefor
US3124422A (en) * 1960-07-20 1964-03-10 Synthesis of diamonds
US3407445A (en) * 1966-03-02 1968-10-29 Gen Electric High pressure reaction vessel for the preparation of diamond

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4563341A (en) * 1978-05-19 1986-01-07 Flynn Hugh G Method and means for converting graphite to diamond
WO1982000458A1 (en) * 1980-07-31 1982-02-18 Apollonov V Method of obtaining diamond and/or diamond-like modifications of boron nitride
AT386592B (de) * 1980-07-31 1988-09-12 Inst Khim Fiz An Sssr Verfahren zur herstellung von diamant und/oder kristallinisch diamantaehnlichen modifikationen von bornitrid
US4339304A (en) * 1980-12-30 1982-07-13 Grigoriev Anatoly P Method of treating diamond
US20090014314A1 (en) * 2006-06-20 2009-01-15 Snaper Alvin A Synthesis of diamond by extraction of a pulse derived from the abrupt collapse of a magnetic field
US7854823B2 (en) * 2006-06-20 2010-12-21 Snaper Alvin A Synthesis of diamond by extraction of a pulse derived from the abrupt collapse of a magnetic field
US20120298092A1 (en) * 2010-10-28 2012-11-29 Klishin Aleksandr V Method for producing gemstones from silicon carbide
WO2012104722A1 (en) 2011-02-04 2012-08-09 Alexander Cherkasky Novel cherkasky's synthetic diamonds and diamond-like materials and methods and devices for production thereof
DE102011010422A1 (de) 2011-02-04 2012-08-09 Alexander Cherkasky Neuartige synthetische Diamanten und diamantartige Materialien und Verfahren und Vorrichtung zu ihrer kontinuierlichen Herstellung
DE102011010422B4 (de) 2011-02-04 2023-01-19 Alexander Cherkasky Verfahren zur Herstellung von synthetischen Diamanten

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DE1667362A1 (de) 1972-04-20
BE693619A (ja) 1967-07-17
GB1174940A (en) 1969-12-17

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