Ultrahard diamonds and a method for preparation thereof

FIELD: carbon materials.

SUBSTANCE: monocrystalline diamond grown via chemical precipitation from gas phase induced by microwave plasma is subjected to annealing at pressures above 4.0 GPa and heating to temperature above 1500°C. Thus obtained diamonds exhibit hardness higher than 120 GPa and crack growth resistance 6-10 Mpa n1/2.

EFFECT: increased hardness of diamond product.

12 cl, 3 dwg, 5 ex

 

The present invention claims priority of the provisional application No. 60/486435, filed July 14, 2003, which is incorporated in this description by reference.

Confirmation of state law

The present invention is carried out with U.S. government support under grant number EAR-0135626 provided by the National Science Foundation. The U.S. government has certain rights to this invention.

Background of the invention

The technical field to which the invention relates.

The present invention relates to diamond and more particularly to a superhard diamond produced using chemical vapor deposition, microwave induced plasma (MPCVD) in the deposition chamber.

Description of the prior art,

Large-scale production of synthetic diamond has long been the aim of both scientific research and industrial production. Diamond, in addition to its properties of a gemstone, is the hardest known substance, has the highest known thermal conductivity and is transparent in a wide spectrum of electromagnetic radiation. Therefore, diamond is highly valued because of the wide range of applications in several industries along with its value as a precious stone.

For at least the last twenty the et was available way to obtain small amounts of diamond by chemical deposition from the gas phase (CVD). As reported .V.Spitsyn in "Vapor Growth of Diamond on Diamond and Other Surfaces", Journal of Crystal Growth, 1981, vol.52, pp.219-226, the method is CVD diamond on a substrate using a combination of methane or other simple hydrocarbon gas and hydrogen gas at low pressures and temperatures of 800-1200°C. Inclusion of hydrogen gas prevents the formation of graphite, while the formation of centers of crystallization and growth of diamond. In the case of use of this method have been reported growth rates of up to 1 μm/hour.

In subsequent work, for example work Kamo et al., reported in "Diamond Synthesis from Gas Phase in Microwave Plasma", Journal of Crystal Growth, 1983, vol.62, pp.642-644, shows the use of chemical vapor deposition, microwave induced plasma (MPCVD), to obtain a diamond at pressures 1-8 kPa within temperatures of 800-1000°With a microwave power of 300 to 700 watts at a frequency of 2.45 GHz. In the specified way Kamo et al. used the concentration of methane gas 1-3%. In the case of using MPCVD method reported maximum growth rates of 3 μm/hour.

Natural diamonds have a hardness in the range of 80-120 HPa. Most grown or artificial diamonds, regardless of the mode of production, have a hardness less than 110 GPA. There were no reports that other natural diamonds other than diamonds of type IIa, which was subjected to annealing had a hardness of greater than 120 GPA.

The invention

Thus, the present invention relates to a device and method for producing a diamond, which essentially eliminates one or more problems due to limitations and disadvantages of the prior art.

The aim of the present invention is a device and method for producing diamond in a system for chemical vapor deposition, microwave induced plasma, which has a high hardness.

Another objective of the present invention is to improve optical properties of single-crystal diamond.

Additional features and advantages of the invention will be set forth in the following description and will be partially understood from the description or can be learned in the practical implementation of the invention. These objectives and other advantages of this invention will be realized and attained by the system, in particular as specified in the description and in the claims, and accompanying drawings.

To achieve these and other advantages and in accordance with the present invention, which is implemented and described in detail, the single-crystal diamond grown using chemical vapor deposition, microwave induced plasma, carry out the annealing at pressures in excess of 4.0 GPA and heated to the temperatures above about 1500° With that it has a hardness of greater than 120 GPA.

In another embodiment, the single crystal diamond has a hardness of 160 to 180 GPA.

In accordance with another embodiment of the present invention is a method of obtaining a solid monocrystalline diamond includes growing a single crystal diamond and annealing of single-crystal diamond at pressures in excess of 4.0 GPA and a temperature of more than 1500°to achieve a hardness of more than 120 GPA.

It should be understood that as the foregoing General description and the subsequent detailed description are illustrative and explanatory and are intended for further explanation of the claimed invention.

BRIEF DESCRIPTION of DRAWINGS

Accompanying drawings, which are included to provide further understanding of the invention and are included within this description and be part of it, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

Figure 1 is a schematic depiction of the indenter for testing the hardness of a diamond.

Figure 2 is an image of a hole made on the diamond.

Figure 3 is a graph showing the hardness and strength of annealed CVD-grown in a microwave induced plasma monocrystalline diamonds compared with the natural and the MAZ type IIa, annealed natural diamonds are type IIa, annealed natural diamonds are type Ia and annealed synthetic NRNT-diamonds are type Ib.

A DETAILED description of the PREFERRED OPTIONS

Further reference is made to the detailed description of preferred embodiments of the present invention, the results of which are illustrated in the accompanying drawings.

CVD-grown in a microwave induced plasma monocrystalline diamond relating to this application, was grown using the device described in the patent application U.S. No. 10/288499, filed November 6, 2002, entitled "Apparatus and Method for Diamond Production", which is incorporated in this description by reference. In the General case, a seed crystal of diamond is placed in the holder, which moves the seed diamond/growing diamond as the diamond is grown. The authors of this application are also the authors of the patent application U.S. No. 10/288499.

CVD-grown in a microwave induced plasma monocrystalline diamond with a thickness of more than 1 mm was deposited on the faces {100} of synthetic diamond type Ib. To increase the growth rate (50-150 μm/h) and activation of the smoothing process of growth faces {100} single-crystal diamonds grown in an atmosphere of N2/CH4=0.2 to 5.0% and CH4/N2=12-20% for total pressure 120-220 Torr and 900-1500°from ICRI is the wave-induced plasma in the CVD chamber. Raman spectra showed the presence of small amounts of hydrogenated amorphous carbon (a-C:H)4and nitrogen-containing a-C:N(N:a-C:H)4resulting brown diamond at <950°and >1400°C. photoluminescence Spectrum (SF) indicated that impurities associated with nitrogen vacancy (N-V). Monocrystalline diamonds up to 4.5 mm were obtained when the growth rates of which the largest were two orders of magnitude higher than in conventional methods polycrystalline CVD growth.

CVD-grown in a microwave induced plasma monocrystalline diamond is annealed at a pressure in excess of 4.0 GPA, such as 5-7 GPA, and was heated to a temperature above 1500°such as 1800-2900°With, for 1-60 minutes in a chemical reactor, using the device of the belt type or rod type. Chemical reactor can be a cell, such as described in U.S. patent No. 3745623 or 3913280, which are included in this description by reference. The same annealing treatment reduces or eliminates color CVD-grown in a microwave induced plasma monocrystalline diamonds and lightens the color of the synthetic seed NRNT crystals of type Ib. In addition, the hardness of annealed CVD-grown in a microwave induced plasma monocrystalline diamond, annealed CVD diamond (at least ˜140 HPa) p is Evesham hardness annealed or geotagging synthetic NRNT-diamond type Ib (˜ 90 HPa), annealed natural diamond type Ia (˜100 HPa), natural diamond type IIa (˜110 GPA), and annealed natural diamond type IIa (˜140 HPa) and sintered polycrystalline diamond (120-140 HPa).

EXAMPLE 1

Single-crystal CVD diamond was grown in the atmosphere with respect to N2/CH4equal to 5%at a temperature of about 1500°With yellow synthetic NRNT-diamond type Ib in a microwave CVD chamber. The size of the CVD-grown in a microwave induced plasma monocrystalline diamond was one centimeter square and a few exceed one millimeter in thickness. Color CVD-grown in a microwave induced plasma monocrystalline diamond was brown. Brown CVD-grown in a microwave induced plasma monocrystalline synthetic diamond seed NRNT diamond type Ib then placed as a sample in a chemical reactor.

Chemical reactor was placed in ordinary NMT device. First, the pressure was increased to a pressure of 5.0 GPA, and then the temperature was raised to 2200°C. the Sample was kept under these conditions, annealing for five minutes, and then the temperature was reduced for approximately one minute to room temperature before it was carried out by removing the pressure.

The sample was removed from the reaction chamber and examined under optical the microscope. Brown CVD-grown in a microwave induced plasma monocrystalline diamond became transparent with a light green color and the diamond remained strongly associated with yellow synthetic NRNT-diamond type Ib. Yellow synthetic NRNT-diamond type Ib became light yellow or more transparent-yellow. The hardness was about 160 GPA.

EXAMPLE 2

Fully meets the above discussed example 1, except that the sample under the conditions of annealing was kept for 1 hour. Brown CVD verseny in microwave induced plasma monocrystalline diamond has acquired a light green hue, which is more transparent than the light green color tone obtained in example 1, and the diamond remained strongly associated with synthetic NRNT-diamond type Ib. Yellow synthetic NRNT-diamond type Ib became light yellow or more transparent-yellow. The hardness was approximately 180 HPa.

EXAMPLE 3

Single-crystal CVD diamond was grown in the atmosphere with respect to N2/CH4equal to 5%at a temperature of about 1450°With yellow synthetic NRNT-diamond type Ib in a microwave CVD chamber. The size of the CVD-grown in a microwave induced plasma monocrystalline diamond was one centimeter square and a few exceed one millimeter in thickness. Color CVD-you is asenovo in microwave induced plasma monocrystalline diamond was light brown. In other words, yellow or light brown color was not as dark as the brown CVD-grown in a microwave induced plasma monocrystalline diamond in example 1. Yellow or light brown CVD-grown in a microwave induced plasma monocrystalline synthetic diamond seed NRNT diamond type Ib then placed as a sample in a chemical reactor. Hardness was more than 160 GPA.

Chemical reactor was placed in ordinary NMT device. The pressure was increased to a pressure of 5.0 GPA, and the temperature was then rapidly raised to about 2200°C. the Sample was kept under these conditions, annealing for five minutes, and then the temperature was reduced for approximately one minute to room temperature before it was carried out by removing the pressure.

The sample was removed from the reaction chamber and examined under an optical microscope. Light brown CVD-grown in a microwave induced plasma monocrystalline diamond became colorless and the diamond remained strongly associated with yellow synthetic NRNT-diamond type Ib. Yellow synthetic NRNT-diamond type Ib became light yellow or more translucent yellow.

EXAMPLE 4

Fully corresponds to example 1, except that colorless CVD-grown in a microwave induced plasma, monoki the metallic diamond in the atmosphere with respect to N 2/CH4equal to 5%at a temperature of 1200°was annealed. After annealing of CVD-grown in a microwave induced plasma crystal was blue. Specified blue CVD-grown in a microwave induced plasma monocrystalline diamond had a very high strength >20 MPa m1/2. The hardness was about ˜140 GPA.

EXAMPLE 5

Fully corresponds to example 1, except that colorless CVD-grown in a microwave induced plasma monocrystalline diamond in the atmosphere with respect to N2/CH4equal to 5%at a temperature of 1200°was annealed. CVD-grown in a microwave induced plasma monocrystalline diamond remained colorless. Specified colorless CVD-grown in a microwave induced plasma monocrystalline diamond had a hardness of ˜160 GPA and strength ˜10 MPa m1/2.

Figure 1 is a schematic depiction of the indenter for testing the hardness of a diamond. Determination of hardness by Vickers performed for annealed CVD-grown in a microwave induced plasma monocrystalline diamonds on the indenter 1, shown in figure 1. The indenter 1 figure 1 includes pressing material 2 placed on the holder 3. Pressing the substance 2 may be silicon carbide, diamond, or some other solid the substance. Pressing the substance has the face of a pyramidal shape corresponding to the indenter Vickers, in which the parties pyramidal shape corresponding to the indenter Vickers, form an angle of 136°.

The indenter applies a point load to test the diamond 2 until not formed recess or crack in the tested diamond 2. To prevent elastic deformation of the indenter, the goods range from 1 to 3 kg on the faces {100} in the direction <100> test diamonds. The dimensions of the cavities and cracks associated with deepening, measured by optical microscopy. Figure 2 is an image of a hole made on CVD-grown in a microwave induced plasma monocrystalline diamond.

Due to errors in determining the hardness of identical measurements were also performed on other diamonds. It was found that measurements were made on other diamonds correspond to published data for other diamonds. Determination of hardness by Vickers were made on the faces (100) different types of diamonds in the direction (100).

The surface coated with recesses for annealed CVD-grown in a microwave induced plasma monocrystalline diamond, as follows from the data of optical microscopy, obviously, differ from the data of optical microscopy for other (softer) ALM the call. Annealed CVD-grown in a microwave induced plasma monocrystalline diamond shows pictures of the cracks in the form of a planar profile along the <110> or <111>, with no cross line cracks along the <100> and deformation of the label type adopodobny prints, which were formed on the surface of the annealed CVD-grown in a microwave induced plasma monocrystalline diamond under the action of a pyramidal indenter Vickers. In contrast, the annealed natural diamond type IIa is characterized by figures of cracks along the <110> or <111> less regular planar profile and detects cross line cracks along the <100>typical softer diamonds. These results show that the annealed CVD-grown in a microwave induced plasma monocrystalline diamond is harder than the indenter, and the pressure due to the plastic deformation of the indenter causes slippage his softer faces {111}.

Indentor Vickers usually crack after ˜15 measurements neutogena CVD-grown in a microwave induced plasma monocrystalline diamonds and natural diamonds are type Ib. In addition, indentor Vickers usually crack after ˜5 measurements annealed natural diamonds are type IIa, isn't it the military natural diamonds are type Ib and annealed synthetic NRNT diamonds are type Ib. However, annealed CVD-grown in a microwave induced plasma single-crystal diamond indenter Vickers cracked after only one or two dimensions. These observations provide further confirmation that the annealed CVD-grown in a microwave induced plasma monocrystalline diamonds are more solid compared to the recorded measured values. In fact, many annealed CVD-grown in a microwave induced plasma monocrystalline diamonds just destroyed the softer the indenter. In such cases, the indenter did not leave any mark on the surface of the annealed CVD-grown in a microwave induced plasma monocrystalline diamonds.

Figure 3 is a chart describing the hardness and strength of annealed CVD-grown in a microwave induced plasma monocrystalline diamonds compared to natural diamonds are type IIa, annealed natural diamonds are type IIa, annealed natural diamonds are type Ia and annealed synthetic NRNT the diamonds are type Ib. As shown in figure 3, annealed CVD-grown in a microwave induced plasma monocrystalline diamonds have a much higher hardness than natural diamond type IIa, as shown at selected points PR is Mohelnice 10 figure 3. All annealed CVD-grown in a microwave induced plasma monocrystalline diamonds also have a much higher hardness than the above ranges of values of hardness polycrystalline CVD diamond, as shown at selected points on the rectangle 20 figure 3. CVD-grown in a microwave induced plasma monocrystalline diamonds are presented on figure 3, have the crack resistance of 6-10 MPa m1/2and hardness 140-180 HPa and signs that they may be more solid.

Since the present invention can be implemented in several forms without departing from the essence or essential features thereof, it should also be understood that the above options are not limited by any details of the above description, unless otherwise noted, and should be construed broadly within its essence and scope defined in the attached claims, and therefore assumes that all changes and modifications that come within the scope of the claims, or the equivalent of these amounts included in the accompanying claims.

1. Single-crystal diamond grown by chemical deposition from the gas phase, microwave induced plasma, subjected to annealing at pressures in excess of 4.0 GPA and temperatures up to over 1500°who, which has a hardness greater than 120 GPA.

2. Single-crystal diamond according to claim 1, the crack resistance which is 6-10 MPa m1/2.

3. Single-crystal diamond according to claim 1, the hardness of which is 160-180 HPa.

4. Single-crystal diamond according to claim 3, having a fracture toughness of 6-10 MPa m1/2.

5. Monocrystalline diamond with a hardness of 160 to 180 GPA.

6. Single-crystal diamond according to claim 5, having a fracture toughness of 6-10 MPa m1/2.

7. A method of obtaining a solid monocrystalline diamond, including:

growing single-crystal diamond by chemical vapor deposition, microwave induced plasma; and

annealing of single-crystal diamond at pressures in excess of 4.0 GPA and a temperature of more than 1500°to achieve a hardness of more than 120 GPA.

8. The method of claim 7, in which the growing single-crystal diamond is carried out in an atmosphere of N2/CH4=0.2 to 5.0% and CH4/N2=12-20% for total pressure 120-220 Torr.

9. The method of claim 7, in which the annealing is carried out for the production of single-crystal diamond, with a hardness of more than 160 to 180 GPA.

10. The method of claim 7, in which the growing single-crystal diamond is carried out in an atmosphere having a temperature of 900 to 1,500°C.

11. The method of claim 7, in which the annealing is carried out for 1-60 minutes

12. When persons claim 7, in which annealing is carried out for the production of single-crystal diamond, with a hardness of more than 140-180 HPa.



 

Same patents:

FIELD: microelectronics, namely processes for preparing even-atom surfaces of semiconductors.

SUBSTANCE: method comprises steps of chemical-dynamic polishing of substrate surface in polishing etching agent containing sulfuric acid, hydrogen peroxide and water for 8 - 10 min; removing layer of natural oxide in aqueous solution of hydrochloric acid until achieving hydrophobic properties of purified surface of substrate; washing it in deionized water and drying in centrifuge. Then substrate is treated in vapor of selenium in chamber of quasi-closed volume while forming gallium selenide layer at temperature of substrate Ts = (310 -350)°C, temperature of chamber walls Tc = (230 - 250)°C, temperature of selenium Tsel = (280 - 300)°C for 3 - 10 min. After such procedure substrate is again placed in aqueous solution of hydrochloric acid in order to etch layer of gallium selenide. Invention allows produce even-atom surface of gallium arsenide at non-uniformity degree such as 3Å.

EFFECT: possibility for using substrates for constructing nano-objects with the aid of self-organization effects.

4 dwg

FIELD: jewelry industry; optics.

SUBSTANCE: proposed method is used for coloring fianites (man-made diamonds) in green, blue and brownish-yellow colors; proposed method may be also used in optics for production of colored light filters withstanding temperatures above 1000°C. Proposed method includes preliminary application of cobalt on fianite surface to be colored and at least one metal whose oxide is liable to spinelle-forming with oxide of bivalent cobalt, iron and/or aluminum, for example. Then material is subjected to heat treatment in oxygen-containing atmosphere at temperature above 1000°C but not exceeding the fianite melting point. The procedure is continued for no less than 3 h. Coat is applied by thermal spraying of metals in vacuum. Said metals may be applied in turn and simultaneously. For obtaining bluish-green color of fianite, cobalt and aluminum are applied at atomic ratio of 1:1 to 1:2. For obtaining yellowish-green color, cobalt, aluminum and iron are applied at atomic ratio of 1:1 :0.1-0.2. For obtaining yellowish-brown color, cobalt and iron are applied at ratio of 1:1 to 1:2.

EFFECT: enhanced resistance to high temperature and chemical action.

7 cl, 11 ex

FIELD: processes and equipment for working natural and artificial origin diamonds, possibly in jewelry for refining diamonds and for imparting to them new consumer's properties.

SUBSTANCE: method comprises steps of acting upon crystal with electron beam whose integral flux is in range 5 x 1015 - 5 x 1018 electron/cm2; annealing crystal in temperature range 300 - 1900°C and acting with electron beam in condition of electric field having intensity more than 10 V/cm at least upon one local zone of crystal for imparting desired color tone to said zone. Local action of electron beams is realized through protection mask. As irradiation acts in condition of electric field local flaws such as bubbles or micro-inclusions are effectively broken.

EFFECT: possibility for producing diamonds with different local three-dimensional colored images such as letters or patterns of different tints and color ranges.

2 dwg

FIELD: electronic industry; methods of production of the crystals with the triclinic crystal system.

SUBSTANCE: the invention is pertaining to the method of production of the crystals with the triclinic crystal system. Substance of the invention: the monocrystals of lanthanum-gallium silicate grown in compliance with Czochralski method from the iridium crusible are subjected to the two-stage thermal treatment. The monocrystals are preliminary subjected to the vacuum annealing at the pressure of 1·10-2 -1·10-4Pa and the temperature of 600-1200°C within 0.5-10 hours, and then conduct their isothermal air aging at the temperature of 300-350°C within 0.5-48 hours. The invention allows reproducibly produce the discolored monocrystals of lanthanum-gallium silicate and also to speed up propagation of the surface-acoustic waves (SAW) by 1-1.5 m\s at the simultaneous decrease of dispersion of the waves propagation velocity by 20-30 ppm.

EFFECT: the invention ensures production of the discolored monocrystals of lanthanum-gallium silicate and allows to increase the speed of propagation of the surface-acoustic waves at simultaneous reduction of the waves propagation dispersion by 20-30 ppm.

FIELD: decolorizing diamonds and brilliants.

SUBSTANCE: method is realized due to physically acting in closed reaction space upon samples of diamonds and brilliants by means of high pressure and temperature for time period sufficient for enhancing their quality. Pressure acting upon samples is in range 6 - 9 GPa in region of thermodynamic stability. Temperature during physical action upon samples is in range 1700 - 2300°C. Samples are subjected to physical action in medium of graphite powder filling reaction space. Heating till high temperature is realized due to applying AC to samples of diamond or brilliant through graphite powder at specific electric current power from 0.18 kWt/cm3 and more. Then electric power is gradually increased from zero till working value and further it is decreased and increased at least two times for some time interval at each change of electric power. Process of annealing samples is completed by smoothly lowering electric current power till zero. At physical action upon sample electric current intensity is lowered by 11 - 13 % and it is increased by 15 - 17 % for time interval from 8 min and more at each change of electric power. Sample is AC heated and it is cooled at rate no more than 0.05kWt/min per cubic centimeter of reaction volume of chamber.

EFFECT: shortened time period of treating for whole decolorizing, lowered voltage values, keeping of desired parameters existing before treatment in diamonds and brilliants.

3 cl, 3 ex

FIELD: crystal growing.

SUBSTANCE: method comprises growing germanium monocrystals from melt onto seed followed by heat treatment, the latter being effected without removing monocrystals from growing apparatus at temperature within 1140 and 1200 K during 60-100 h, temperature field being radially directed with temperature gradient 3.0 to 12.0 K/cm. Once heat treatment comes to end, monocrystals are cooled to 730-750°C at a rate of at most 60-80 K/h. Monocrystals are characterized by emission scattering at wavelength 10.6 μm not larger than 2.0-3.0% and extinction not higher than 0.02-0.03 cm-1, which is appropriate for use of monocrystals in IR optics.

EFFECT: allowed growth of germanium monocrystals with high optical characteristics.

3 ex

FIELD: jewelry technology; manufacture of jewelry colored inserts.

SUBSTANCE: synthetic corundum contains alumina, color-forming additives and binder-paraffin. Required color is obtained as follows: for obtaining black color molybdenum oxide is added to alumina in the amount of 0.03%; for obtaining gray color, tungsten oxide is added to alumina in the amount of 0.01%; for obtaining blue color, neodymium oxide is added in the amount of 0.01%; for obtaining pink color, erbium oxide is added to alumina in the amount of 0.01%; for obtaining red color, chromium oxide is added in the amount of 0.05%. Proposed method of manufacture of jewelry articles includes molding in casting machines at a pressure of 4 atm and roasting; first roasting cycle is performed in continuous furnaces for burning-out the binder and is continued for 90 h at temperature of 1150 C; second roasting cycle is performed in batch furnaces at temperature of 1750 C and is continued for 170 h for forming and sintering of microcrystals making translucent crock at density of 4 g/cu cm and hardness of 9 according to Mohs hardness scale; then polishing is performed with the aid of diamond materials. Articles thus made have high-quality miniature texture at hardness which is disadvantage in relation to diamond only.

EFFECT: high quality of articles; enhanced hardness of articles.

7 cl

The invention relates to a technology for obtaining compounds of zinc and cadmium, suitable for the manufacture of optical components, transparent in a wide spectral range
The invention relates to the field of processing (refining) of the diamond to give them a different color colouring and may find application in the jewelry industry

FIELD: crystal growth.

SUBSTANCE: method comprises separating the inoculation from the source of carbon by a metal-dissolver made of an alloy of ferrous, aluminum, and carbon when a 20-30°C temperature gradient is produced between the carbon source and inoculation. The growth zone is heated up to a temperature higher than the melting temperature of the alloy by 10-20°C, and the melt is allowed to stand at this temperature for 20 hours. The temperature then suddenly increases above the initial temperature by 10-25°C and decreases down to the initial value with a rate of 0.2-3 degree per minute.

EFFECT: improved quality of crystal.

1 tbl, 2 ex

FIELD: inorganic chemistry; mining industry; electronics; other industries; methods of the synthesis of the needle-shaped and lengthened diamonds.

SUBSTANCE: the invention is pertaining to the field of the inorganic chemistry, in particular, to the method of production of the needle shape synthetic diamonds and may be used in the industrial production of the special-purpose diamonds, for example, for manufacture of the boring crown bits and the dressers, and also in the capacity of the blocks details of the audio-video playback equipment, for manufacture of the feeler probes, in the micro-mechanical devices etc. The method provides for commixing of the fusion charge composed of the alloy of Mn-Ni-Fe in the mass ratio of 60±5÷30±5÷10±5 and the powder of the carbon-containing substance and treatment of the mixture at the pressure exceeding 40 kbar and the temperature over 950°С at heating rate less than 100°C/minutes. In the capacity of the carbon-containing substance use the needle-shaped coke or graphite on the coke basis with the single-component anisotropic structure with the degree of graphitization of no less than 0.55 relative units. The invention allows to simplify the production process of the synthesis of the needle-shaped and lengthened diamonds and to increase the percentage of their output within one cycle of the production process.

EFFECT: the invention ensures simplification of the production process of the synthesis of the needle-shaped and lengthened diamonds, the increased percentage of their output within one cycle of the production process.

2 ex, 2 dwg

FIELD: carbon materials.

SUBSTANCE: invention relates to preparation of boron-alloyed monocrystalline diamond layers via gas phase chemical precipitation, which can be used in electronics and as jewelry stone. The subject matter is uniformity of summary boron concentration in above-mentioned layer. The latter is formed in one growth sector and characterized by thickness above 100 μm and/or volume exceeding 1 mm3. Boron-alloyed monocrystalline diamond preparation involves diamond substrate provision step, said substrate having surface containing substantially no crystal lattice defects, initial boron source-containing gas preparation step, initial gas decomposition step, and the step comprising homoepitaxial growth of diamond on indicated surface containing substantially no crystal lattice defects.

EFFECT: enabled preparation of thick high-purity monocrystalline diamond layers exhibiting uniform and useful electronic properties.

44 cl, 5 tbl, 7 ex

FIELD: producing artificial diamonds.

SUBSTANCE: method comprises preparing diamond substrate virtually having no defects, preparing the initial gas, decomposing initial gas to produce the atmosphere for synthesis that nitrogen concentration of which ranges from 0.5 to 500 particles per million, and homogeneous epitaxy growth of diamond on the surface.

EFFECT: increased thickness of diamond.

40 cl, 9 dwg, 5 ex

FIELD: carbon particles.

SUBSTANCE: invention relates to technology of preparing particles having monocrystalline diamond structure via growing from vapor phase under plasma conditions. Method comprises step ensuring functioning of plasma chamber containing chemically active gas and at least one carbon compound and formation of reactive plasma, which initiate appearance of seed particles in the plasma chamber. These particles ensure multidirectional growing of diamond-structured carbon thereon so that particles containing growing diamond are formed. Functioning of plasma chamber proceeds under imponderability conditions but can also proceed under gravitation conditions. In latter case, seed particles and/or diamond-containing particles in reactive plasma are supported under effect of external gravitation-compensating forces, in particular by thermophoretic and/or optic forces. Temperature of electrons in the plasma are lowered by effecting control within the range from 0.09 to 3 ev. Chamber incorporates plasma generator to generate plasma with reduced electron temperature and device for controlling forces to compensate gravitation and to allow particles to levitate in the plasma with reduced electron temperature. This device comprises at least one levitation electrode for thermophoretic levitation of particles in plasma with reduced electron temperature or an optical forceps device.

EFFECT: enabled efficient growing of high-purity duly shaped particles with monocrystalline diamond structure having sizes from 50 μm to cm range (for instance, 3 cm).

19 cl, 5 dwg

FIELD: production of synthetic diamonds, which may be used as windows in high power lasers or as anvils in high pressure devices.

SUBSTANCE: device for forming a diamond in precipitation chamber contains heat-draining holder for holding a diamond and ensuring thermal contact with side surface of diamond, adjacent to the side of growth surface of diamond, non-contact temperature measurement device, positioned with possible measurement of diamond temperature from edge to edge of growth surface of diamond, and main device for controlling technological process for producing temperature measurement from non-contact device for measuring temperature and controlling temperature of growth surface in such a way, that all temperature gradients from edge to edge of growth surface are less than 20°C. A structure of sample holder for forming a diamond is also included. Method for forming a diamond includes placing a diamond in the holder in such a way, that thermal contact is realized with side surface of diamond, adjacent to growth surface side of diamond, measurement of temperature of growth surface of diamond, with the goal of realization of temperature measurements, control of growth surface temperature on basis of temperature measurements and growth of monocrystalline diamond by means of microwave plasma chemical precipitation from steam phase on growth surface, under which the speed of diamond growth exceeds 1 micrometer per hour.

EFFECT: possible production of sufficiently large high quality monocrystalline diamond with high growth speed.

7 cl, 1 tbl, 7 dwg

FIELD: chemical industry; cutting tool industry; mechanical engineering; methods of the production of the artificial highly rigid materials.

SUBSTANCE: the invention is pertaining to production of the artificial highly rigid materials, in particular, diamonds, and may be used in chemical industry; cutting tool industry; mechanical engineering, boring engineering. The method provides for compaction of the powdery carbon-containing materials in the field of the quasi-equilibrium state of the graphite-diamond system and the slow refrigeration in the zone of the thermodynamic stability of the diamond or other synthesized material. The heated capsule made out of tungsten with the pure carbon raw fill in with the liquid silicon at the temperature of 1750°K, hermetically plug up, then reduce the temperature to 1700°K during 30-40 minutes and cool to the room temperature within 5-6 hours in the process of the synthesis of the high-strength materials. The monocrystals of the boron carbide of the 400-450 microns fraction and the diamonds of the 40 microns fraction have been produced. The technical result of the invention consists in improvement of the quality, the increased sizes of the monocrystals, and also in the decreased labor input of the production process.

EFFECT: the invention ensures the improved quality and the increased sizes of the produced monocrystals, the decreased labor input of the production process.

2 cl, 2 ex

FIELD: treatment of diamonds.

SUBSTANCE: proposed method of change of diamond color includes the following stages: (i) forming reaction mass at presence of diamond in pressure-transmitting medium fully surrounds the diamond; (ii) subjecting the reaction mass to action of high temperature and pressure during required period of time; proposed diamond is brown diamond, type IIa; its color is changed from brown to colorless by subjecting the reaction mass to action of temperature of from 2200°C to 2600°C at pressure of 7.6 Gpa to 9 Gpa.

EFFECT: possibility of keeping diamond intact during treatment.

46 cl, 4 dwg, 1 ex

FIELD: treatment of diamonds.

SUBSTANCE: proposed method includes the following stages: (i) forming of reaction mass at presence of diamond in pressure-transmitting medium fully surrounding the diamond and (ii) action of reaction mass by high temperature and pressure during required period of time; diamond is of IIb type and its color is changed from gray to blue or dark blue or is enriched by action on reaction mass of temperature from 1800°C to 2600°C at pressure of from 6.7 GPa to 9 GPa (first version). Diamond of type II may be also proposed which contains boron and its color is changed to blue or dark blue by action on reaction mass by the same temperature and pressure (second version).

EFFECT: improved color of diamond by changing it from gray (brown-gray) to blue or dark blue.

31 cl, 4 dwg, 2 ex

FIELD: treatment of natural diamond for change of its color.

SUBSTANCE: proposed method includes the following stages: (i)forming of reaction mass at presence of diamond pressure-transmitting medium which fully surrounds it; (ii) action on reaction mass by high temperature and pressure during required period of time; proposed diamond is brown diamond, type IIa; its color is changed from brown to rose by action on reaction mass by temperature from 1900°C to 2300°C at pressure from 6.9 GPa to 8.5 GPa.

EFFECT: enhanced efficiency of enriching diamond color keeping its crystals intact.

30 cl, 4 dwg, 1 ex

FIELD: carbon materials.

SUBSTANCE: invention relates to preparation of boron-alloyed monocrystalline diamond layers via gas phase chemical precipitation, which can be used in electronics and as jewelry stone. The subject matter is uniformity of summary boron concentration in above-mentioned layer. The latter is formed in one growth sector and characterized by thickness above 100 μm and/or volume exceeding 1 mm3. Boron-alloyed monocrystalline diamond preparation involves diamond substrate provision step, said substrate having surface containing substantially no crystal lattice defects, initial boron source-containing gas preparation step, initial gas decomposition step, and the step comprising homoepitaxial growth of diamond on indicated surface containing substantially no crystal lattice defects.

EFFECT: enabled preparation of thick high-purity monocrystalline diamond layers exhibiting uniform and useful electronic properties.

44 cl, 5 tbl, 7 ex

Up!