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WO1986006057A1 - Preparation de cristaux d'agregats solides de nitrure de bore - Google Patents

Preparation de cristaux d'agregats solides de nitrure de bore Download PDF

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Publication number
WO1986006057A1
WO1986006057A1 PCT/US1985/002277 US8502277W WO8606057A1 WO 1986006057 A1 WO1986006057 A1 WO 1986006057A1 US 8502277 W US8502277 W US 8502277W WO 8606057 A1 WO8606057 A1 WO 8606057A1
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Prior art keywords
container
density
boron nitride
surrounding
powder
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Ceased
Application number
PCT/US1985/002277
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English (en)
Inventor
Carl F. Cline
Allan Hare
Mark L. Wilkins
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Individual
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Publication of WO1986006057A1 publication Critical patent/WO1986006057A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • C04B35/58—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 borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
    • C04B35/583—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 borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on boron nitride
    • C04B35/5831—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 borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on boron nitride based on cubic boron nitrides or Wurtzitic boron nitrides, including crystal structure transformation of powder
    • 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
    • B01J3/08—Application of shock waves for chemical reactions or for modifying the crystal structure of substances

Definitions

  • This invention relates to the production of the solid aggregate crystals of boron nitride by a shock wave process.
  • Boron nitride is similar to carbon in that both materials have a soft hexagonal form which can be converted under high pressure conditions to two very hard forms: (1) the cubic form with a zincblende crystalline structure, and (2) the hexagonal form with a wurtzite crystalline structure.
  • the soft form and the two hard forms have specific gravity of about 2.28 and 3.49, respectively.
  • the soft form will be referred to as low density boron nitride, and the hard forms as high density boron nitride.
  • the high density cubic form will be designated here as cubic boron nitride, CBN, and the high density hexagonal form will be designated wurtzite boron nitride, wBN.
  • boron nitride To produce high density boron nitride, one may begin with low density boron nitride and apply static or dynamic high pressures to produce small aggregates, usually no more than 100 microns in diameter. However, many commercial applications of high density boron nitride require much larger aggregates.
  • the subject invention provides method and apparatus to start with small particle sizes of cubic or wurtzite boron nitride or mixtures of both and convert them into polycrystalline aggregates of sizes of one centimeter and greater. In U.S. Patent No.
  • Cowan and Holtz an disclose a method for producing a shock wave of sufficient intensity to convert carbon to diamond initially, and using a contiguous cooling medium to keep the temperature of the shocked material below 2000°C, and preferably below 1800°C, where the cooling medium also has sufficient thermal conductivity that excessive graphitization after release of the shock wave pressure does not occur.
  • Cowan et al remark that the straightforward shock synthesis technique is incapable of producing satisfactory yields of diamond due to excessive graphitization of the diamond, which is initially hotter than the carbon from which it is converted, upon release of the shock wave pressures.
  • Cowan et al begin with carbon (preferably graphite) compacted to a density of about 75 percent of the theoretical density for diamond, and apparently allow the chosen cooling medium to surround and fill the interstitial regions of the compacted carbon.
  • the admixture is subjected to a shock wave of at least 750- kilobars, and preferably
  • Cowan et al invention begins with graphite and requires very high shock wave pressures to convert the carbon to diamond form.
  • Cowan discloses an end closure or plug for a cylindrical container of material that is to be subjected to a shock wave.
  • the plug comprises a first, substantially cylindrically shaped section in contact with the sample at one end along the cylinder longitudinal axis, and having a shock impedance (the product of shock wave velocity in, and initial density of, the material) equal to the shock impedance of the sample; and a second section, in contact with the first section along the cylinder longitudinal axis at the second end of the first section, having a shock impedance substantially equal to the shock impedance of the first section's material, and arranged to carry off most of the longitudinally-propagating shock wave by spallation of one end of the second section.
  • a shock impedance the product of shock wave velocity in, and initial density of, the material
  • the first section has a gradually decreasing porosity as one moves away from the sample toward the second end, and the second section has a gradually increasing porosity as one continues in the same direction.
  • the Cowan invention contemplates that the shock wave will move primarily along the longitudinal axis of the cylinder.
  • Balchan and Cowan in U.S. Patent No. 3,667,911, disclose a method of shock wave treatment of a solid material such as diamond, boron nitride or silicon carbide powder by propagating the shock wave axially along the sample at substantially uniform velocity, where the sample's physical extension in the axial direction is much greater than its physical extension in any direction transverse to the axial direction.
  • the shock wave itself is generated (1) by impacting the sample at one end by an explosively-driven impact plate, or (2) by detonating a high explosive in contact at one end with the sample.
  • the sample may be contained in a container.
  • the shock wave is planar, with the defining plane being perpendicular to the axial direction of propagation, and with sufficient shock wave energy that the associated wave pressure is substantially constant throughout the perpendicular plane.
  • the sample's axial length should substantially exceed the length or distance required to achieve shock wave steady state conditions (the "start-up length") which is approximately five times the transverse diameter of the sample; or a solid material, having the same density, shock impedance and transverse diameter as the sample, and having an axial length at least equal to the start-up length, should be provided at an axial position between and in contact with both the sample and the axial position for application of the pressure pulse that produces the shock wave.
  • a method of aggregating small, hard particles, such as diamond, into larger aggregates by passage of shock waves therethrough is disclosed by Balchan and Cowan in U.S. Patent No. 3,851,027.
  • the sample particles are dispersed interstitially in a carrier matrix having smaller porosity and greater post-shock deformability than the interstitial particles, usually formed as a flat disc or slab, and one broad face of the carrier matrix is impacted by an explosively-driven projectile or driver plate to produce a shock wave that travels through the matrix/interstitial particles combination and bonds many of the hard particles together.
  • the hard particles are intended to coalesce into a multiplicity of larger size aggregates as the use of the carrier matrix appears to prevent aggregation of all the hard particles into a single mass.
  • the hard particles that are bondable by this technique allegedly include diamond, boron nitride, silicon carbide and silicon nitride, and shock wave pressures of 100 kilobars and up are used for this purpose. Again, the direction of shock wave propagation is axial.
  • Axial propagation of a shock through brittle inorganic aggregates ( ⁇ 4500 ⁇ diameter) powders such as -alumina, barium ferrite, barium titanate, silicon carbide, boron carbide, magnesium oxide, titanium carbide and bismuth telluride, is disclosed in U.S. Patent No. 3,367,766, issued to Barrington and Bergmann.
  • the shock wave is produced by detonation of an explosive contiguous with one end of a container that confines the powder to be aggregated.
  • the technique is apparently orientation-dependent, as the inventor emphasizes that the shock wave must be directed along the C-axis of the soft form of boron nitride.
  • the shock wave pressure range used by Corrigan is 100-500 kilobars. The pressure as noted is applied to the low density form of boron nitride (recrystaliized pyrolytic boron nitride) rather than the high density forms of boron nitride.
  • the Corrigan patent describes a process for producing the wurtzite high density form of boron nitride having an average particle size of 100 microns.
  • One object of the invention is to provide method and apparatus to convert small particle sizes of cubic or wurtzite boron nitride or mixture of both into polycrystalline aggregates of sizes one centimeter or greater.
  • Another object is to provide a shock wave synthesis method for producing solid aggregate crystals of boron nitride, using high density boron nitride as a starting material.
  • Another object is to provide method and apparatus for producing solid aggregate crystals of boron nitride that do not depend upon orientation of the starting materials.
  • Another object is* to provide method and apparatus for producing solid aggregate crystals of boron nitride of diameters large enough for use in grinding, drilling and machining. Another object is to provide method and apparatus for producing solid aggregate crystals of boron nitride or Mohs hardness substantially- 9.5 or more, and Knoop microhardness of substantially 30 gigaNewtons/ or more.
  • Another object is to provide method and apparatus for producing large solid aggregates of high density boron nitride with Knoop hardness substantially greater than can be achieved by static consolidation of high density boron nitride.
  • the method comprises the steps of: Providing high density boron nitride in the form of powder (2-100 microns diameter) inside a first cylindrical container; surrounding the first container on all sides with a predetermined fluid-like material, such as a metal powder of moderate relative density; surrounding the fluid-like material with a hollow, substantially cylindrical, rigid container that is closed at both ends, is in contact with the fluid-like materials it surrounds, and has its interior purged of substantially all air; surrounding the rigid container on the side wall and one end wall with the predetermined amount of high explosive having a detonation velocity D that is greater than the shock wave velocity S of the fluid-like materials, and detonating the high explosive at the end wall of the rigid container.
  • a predetermined fluid-like material such as a metal powder of moderate relative density
  • surrounding the fluid-like material with a hollow, substantially cylindrical, rigid container that is closed at both ends, is in contact with the fluid-like materials it surrounds, and has its interior purged of substantially all air
  • Figure 1 illustrates one configuration for the tubes containing boron nitride used in the invention.
  • Figure 2 is a schematic cross-sectional longitudinal view of a first embodiment of the invention.
  • Figure 3 is a schematic cross-sectional longitudinal view of a second embodiment of the invention.
  • Figure 4 is a schematic view of the movement of initial and reflected shock waves produced in the apparatus of the invention.
  • Figure 5 is a graph of development of local pressure with time at a representative point in the fluid-like medium in the first embodiment.
  • Figure 6 is a graph of development of local pressure with time at a representative point in the fluid-like medium in the second embodiment.
  • Figure 7 is a schematic cross-sectional end view of the apparatus used in the first or second embodiment of the invention.
  • the invention provides a method of using explosively-generated shock waves in certain fluid-like materials to produce large solid aggregate crystals of boron nitride, starting from fine powders of high density boron nitride, with reference to Figure 1, the interior of a hollow, rigid, substantially cylindrical container 11 (which may be comprised of copper or some other suitable metal) is filled with high density boron nitride powder 13 and evacuated to a pressure less than
  • the boron nitride powder 13 will initially have a density of about 50 percent of the solid, high density boron nitrides.
  • the tubes 11 are then placed in a suitable fluid-like, pressure-transmitting material 15 (which may be a low strength material such as copper or a powder of such material of about 50 percent normal density), which is in turn placed in a second hollow, rigid, substantially cylindrical container 17 ( Figure 2) that is filled with the tubes and fluid-like material.
  • the second container 17 may have a side wall 17s of 0.3-0.7 cm thick steel or other hard metal, and have outer diameter of 6.35cm.
  • the container 17 should, in its preferred embodiment, have two end walls 17e, each comprising a steel outer wall 3-5 cm thick, 17eo and an inner wall 17ei of softer metal such as Al or Mg that is 1.5-3 cm thick.
  • the container is surrounded on the side wall 17s and one end wall 17e with a high explosive 18 that may be 7-12 cm thick.
  • the combination of rigid tubes 11 and fluid-l ke material 15 extends to the center line CC of the container 17.
  • a central core of the interior of the second container 17 is filled by a solid, substantially cylindrical, metal mandrel 19.
  • the metal mandrel is required when a powder material is used for the fluid-like material.
  • the high explosive is detonated at or adjacent to one end wall 17e, and the detonation wave sweeps longitudinally along the container perimeter as shown in Figure 4, imploding the container walls toward the container center line CC and producing a radially converging shock wave in the combination of fluid-like material 15 and tubes 11.
  • the high explosive detonation velocity D is chosen to be greater than the shock wave velocity
  • a fluid-like material 15 in the form of a powdered metal such as copper, or preferably a powder of a higher density material such as tungsten metal or tungsten carbide, allows much larger shock wave pressures to be transmitted to the tubes compared to a solid material.
  • the radially converging shock wave S. drills or otherwise produces a central channel in the assembly when it reflects from the center line CC.
  • the reflected shock wave S has a greater amplitude than the incident shock wave S. and moves radially outward, producing for radial positions away from the center line CC a pressure profile such as shown in Figure 5.
  • the first pressure wave S- pre-compresses the boron nitride powder, and the second pressure wave S compresses the powder further to its final density.
  • the boron nitride powder is transformed (permanently) into large aggregate crystals of boron nitride of diameter as large as 1 cm and greater.
  • one or more release waves R pass through the material and decrease the local pressure to approximately ambient conditions, when a tube 11 is placed on the center line, only a single pressure peak occurs, of extraordinary amplitude, that is of little value for the production of large solid aggregate crystals of boron nitride.
  • the embodiment of Figure 3 using a substantially centrally positioned, solid, metal mandrel 19
  • the radial shock wave again produces a two-fold rise in pressure as shown in Figure 6.
  • the use of two pressure waves in succession rather than a single higher amplitude wave causes less local thermal heating of the boron nitride aggregate, and the resulting aggregate has a higher density [ — 3.49 gm/cm ) and other superior properties.
  • the mandrel is required to reduce the material axial velocity when a powder is used for the fluid-like material.
  • the high axial velocity material flow is disruptive to the nearby tubes containing the boron nitride powder.
  • the separation in time of the two pressure pulses is a measure of the radial distance of the pressure measurement point from either the center line of the container 17 (first embodiment) or the mandrel perimeter (second embodiment).
  • the two pressure rises sho.wn in Figures 5 and 6 should be separated as much as possible in time so that the pressure is applied to the boron nitride aggregate for as long a time period as possible, we have found that the best radial position for the tubes 11 is approximately midway between the center line (first embodiment) or mandrel perimeter (second embodiment) and the initial inner diameter of the container 17, as illustrated in Figure 7.
  • the pressure-transmitting material 15 in Figures 2 and 3 may be a metal such as copper, iron, tantalum, tungsten or uranium in powder or other fluid-like form; the use of a powdered form increases the shock wave pressure transmitted through the medium 15. At the same time, a material initially in powdered form undergoes a large relative volume change in response to applied pressure. This results in a control! bly lower shock wave velocity in a powder than in a solid of the same material.
  • the material 15 is preferably powdered copper or other suitable powdered metal at approximately half normal density, with this choice of materials, the initial pressure wave amplitude is usually ⁇ 550 kilobars. with these pressure wave amplitudes, the boron nitride aggregate can be consolidated to 99 percent of its theoretical maximum density.
  • cubic boron nitride varies from 29 to 43 gigaNewtons/M , depending upon stress plane and direction. Generally, the diamond hardness is 1.4-2.5 times that of the corresponding cubic boron nitride.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Organic Chemistry (AREA)
  • Ceramic Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Carbon And Carbon Compounds (AREA)

Abstract

Un agrégat de cristaux de nitrure de bore à haute densité est préparé en compactant de la poudre de nitrure de bore à haute densité au moyen d'un appareil comprenant un premier récipient (11) creux, sensiblement cylindrique contenant la poudre de nitrure de bore (13), un matériau analogue à un fluide (15), un second récipient (17) creux rigide, sensiblement cylindrique et un matériau hautement explosif (18) qui produit des ondes de choc.
PCT/US1985/002277 1985-04-08 1985-11-18 Preparation de cristaux d'agregats solides de nitrure de bore Ceased WO1986006057A1 (fr)

Applications Claiming Priority (2)

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US72102085A 1985-04-08 1985-04-08
US721,020 1985-04-08

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WO1986006057A1 true WO1986006057A1 (fr) 1986-10-23

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5053365A (en) * 1990-02-28 1991-10-01 The Ohio State University Research Foundation Method for the low temperature preparation of amorphous boron nitride using alkali metal and haloborazines
RU2128101C1 (ru) * 1997-11-26 1999-03-27 Городской центр технического творчества Способ взрывного прессования изделий из порошковых материалов
US9573324B2 (en) 2014-06-11 2017-02-21 Txl Group, Inc. Pressurized anneal of consolidated powders
CN116026195A (zh) * 2023-03-02 2023-04-28 中国工程物理研究院激光聚变研究中心 一种MXene复合薄膜飞片及其制备方法

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3022544A (en) * 1958-02-06 1962-02-27 Du Pont Explosive compaction of powders
US3084398A (en) * 1961-01-18 1963-04-09 Du Pont Compaction process
US3112166A (en) * 1960-03-10 1963-11-26 Ici Ltd Formation of hollow bodies from powdered materials
US3220103A (en) * 1962-09-27 1965-11-30 Battelle Development Corp Method of explosively compacting powders to form a dense body
US3344209A (en) * 1967-09-26 Fabrication of materials by high energy-rate impaction
US3367766A (en) * 1965-06-16 1968-02-06 Du Pont Preparation of brittle inorganic polycrystalline powders by shock-wave techniques
US3568248A (en) * 1969-03-04 1971-03-09 Du Pont Plug closure in a container for subjecting sample to shock wave
US3667911A (en) * 1968-06-28 1972-06-06 Du Pont Method of treating solids with high dynamic pressure
US4201757A (en) * 1973-09-06 1980-05-06 General Electric Company Large boron nitride abrasive particles
US4443420A (en) * 1981-10-26 1984-04-17 National Institute For Researches In Inorganic Materials Process for producing cubic system boron nitride

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3344209A (en) * 1967-09-26 Fabrication of materials by high energy-rate impaction
US3022544A (en) * 1958-02-06 1962-02-27 Du Pont Explosive compaction of powders
US3112166A (en) * 1960-03-10 1963-11-26 Ici Ltd Formation of hollow bodies from powdered materials
US3084398A (en) * 1961-01-18 1963-04-09 Du Pont Compaction process
US3220103A (en) * 1962-09-27 1965-11-30 Battelle Development Corp Method of explosively compacting powders to form a dense body
US3367766A (en) * 1965-06-16 1968-02-06 Du Pont Preparation of brittle inorganic polycrystalline powders by shock-wave techniques
US3667911A (en) * 1968-06-28 1972-06-06 Du Pont Method of treating solids with high dynamic pressure
US3568248A (en) * 1969-03-04 1971-03-09 Du Pont Plug closure in a container for subjecting sample to shock wave
US4201757A (en) * 1973-09-06 1980-05-06 General Electric Company Large boron nitride abrasive particles
US4443420A (en) * 1981-10-26 1984-04-17 National Institute For Researches In Inorganic Materials Process for producing cubic system boron nitride

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5053365A (en) * 1990-02-28 1991-10-01 The Ohio State University Research Foundation Method for the low temperature preparation of amorphous boron nitride using alkali metal and haloborazines
RU2128101C1 (ru) * 1997-11-26 1999-03-27 Городской центр технического творчества Способ взрывного прессования изделий из порошковых материалов
US9573324B2 (en) 2014-06-11 2017-02-21 Txl Group, Inc. Pressurized anneal of consolidated powders
CN116026195A (zh) * 2023-03-02 2023-04-28 中国工程物理研究院激光聚变研究中心 一种MXene复合薄膜飞片及其制备方法
CN116026195B (zh) * 2023-03-02 2023-11-21 中国工程物理研究院激光聚变研究中心 一种MXene复合薄膜飞片及其制备方法

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