Method used for the synthesis of the needle-shaped lengthened diamonds
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
The invention relates to the field of inorganic chemistry, namely the method of production of synthetic diamonds elongated and under high static pressures and temperatures with the use of carbon-graphite material and solvent-catalyst, and may find application as components nodes to be audio - or video playback, for making probes, micromechanical devices, as heatsinks for the manufacture of tools, in which diamond grains are oriented in a special way, for example, in drilling crowns and ruling pencils.
The known method of synthesis of diamonds in the shape of a needle with conductive properties (see U.S. patent No. 3310501, CL 252-502, 1957), in which the acicular diamond shape obtained by the addition of boron in the reaction cell with a special design.
In French patent No. 2243906, CL SW 31/06, 1976 elongated diamonds with ribbed hem synthesized in the reaction cell special designs, however, the synthesis process has a random character. A necessary condition for the process of synthesis occurs in graphite weak zones, which penetrates the metal-solvent, is unconditional and is not regulated. In the synthesis process get single crystals.
The method according to U.S. patent No. 4036937, CL 423-407, 1977 improves the method of synthesis according to French patent No. 2243906. In this paragraph the tent getting elongated diamond particles is also achieved by the special design of the reaction cell. This carbonaceous material is used in the form of a hollow cylinder, inside of which is placed a metal solvent. The ratio of the thickness of the walls of the cylinder to its internal diameter must be within 1:20 to 1:5. Elongated diamonds are obtained through the same effect penetration of the metal solvent through cracks in the graphite cylinder, as in French patent No. 2243906. This method has the same disadvantages as the method according to the French patent.
Waiten and Amentiferous - "Synthetic diamonds", 1973, No. 4, p.3-7 and Butuzov, Vlaev and Stunin - DAN SSSR, 1975, 20, R-720, has developed a method of growing acicular and tabular crystals by careful selection of the synthesis temperature and temperature gradient at the location of the growing crystal. Single crystals were grown on the seed in metastable conditions. A.ËCID ËMiyamoto etc. - Sat. Superhard materials: synthesis, properties, application. Sciences. Dumka. Kiev, 1983, p.45 - informed about how to obtain the acicular diamond in the reaction cell complex construction: - tube of metal foil is placed spectroscopic graphite, which is inserted into a rod of boron nitride. Prior to Assembly cells on the inner surface of the metal tube besieged by vacuum evaporation of a gold layer with a thickness of several thousand angstr the m The maximum length of an acicular crystals is 0.8 mm, the ratio of the crystal length to its width is from 2 to 20. The output of such diamonds accounted for about 10% of the total mass of crystals per cycle of synthesis. The authors argue that the addition of Au is always necessary for the formation of elongated diamonds, and the influence of the temperature gradient cannot be found. The disadvantage of this method is the complexity of technology and consumption of the precious metal Au.
The closest in technical essence and the achieved result is a method for the synthesis of needle-like and elongated diamonds, including the use of the mixture of the alloy Mn-Ni-Fe, in a weight ratio of 60±5:30±5:10±5, and graphite powder, mixing them, and processing the mixture at a pressure of >40 kbar and T>950°C, and the heating rate is adjusted so that it was <100°C/min (see paponi No. 48-42355, CL SW 31/06, 1973).
The disadvantages of this method include the difficulty of manufacturing technology and high cost due to the necessity of using a special design of the reaction cell and precious metals.
An object of the invention is to simplify the technology of synthesis of needle-like and elongated diamonds and increase their output in one cycle of the synthesis process.
The specified technical task is solved in that the synthesis of needle-like and elongated diamond is the use of the mixture of the alloy Mn-Ni-Fe, in a weight ratio of 60±5:30±5:10±5, and powder or disks carbon-containing substance, by mixing them or interlayering (in the case of disks) and processing the mixture at a pressure of >40 kbar and a temperature T>950°in the reaction cell.
Thus the heating rate of the reaction cell using the programmable controller is set such that it was less than 100°C/min
According to the invention, the carbonaceous material used needle coke or graphite-based coke with one-component anisotropic structure, with coke or graphite have graphitization degree is not less than 0.55 and relative units.
Graphite is made by the standard technology of reactor grade graphite HSV, THE 48-20-86-76 using oil pyrolysis coke (for example CNPS). Material type HSV is characterized by the following parameters: C=6,719 Åand=2,4636 Å, where C is the lattice parameter along the axis C; a - lattice parameter axis in angstroms.
The coherent scattering (crystallite size) of such graphite is characterized by the values La=455÷550 Å and Lc=180÷200 Å and the degree of graphitization is set to g=0.75÷0.80 Rel. units. Coke has a high content of striated component in the texture of the material. Use graphite coke one is the component of the anisotropic structure allows to reach the value of graphitization in the range g=0,55÷ 0,80 relative units at temperatures 2500-2800°respectively, while graphite, balanced striated and spherical components, characterized by the value of graphitization in the range g=0,36÷0,44 oted at the same temperature. Since the birth of the diamond crystal is in the solid phase due to the restructuring of the lattice microcrystallites of graphite or reconstructive martensitic mechanism at high pressures and temperatures, needle coke are the matrix-the seed for further growth of the crystal due to the diffusion of carbon substances to the crystal.
A half-century practice of diamond synthesis from graphite with a balanced structure of striated and spherical components having a degree of graphitisation in the range g=0,36÷0,44 oted at the same temperature, shows that under similar synthesis conditions are obtained by single-crystal diamond isometric forms (octahedra, cubooctahedrons, Cuba), grains of irregular shape.
The invention is illustrated in the drawing, in which figure 1 shows that the shape of the obtained crystals of diamond depends on how focused the crystallites of needle coke in the sample relative to the isotherm temperature field in the reaction cell. If the coke crystallite in the sample is directed strictly to the radius of the cell (perpendicular to Yateley to the isotherm, it crosses), it turns out crystal diamond right needle shape (figure 1, item 1). If the crystallite coke is positioned so that its long axis is a tangent to the isotherm angle other than 90°we get diamonds elongated, asymmetrical forms (figure 1, item 2). The degree of asymmetry depends on the orientation angle between the long axis of the crystallite and the tangent to the isotherm. In graphite, there is no strict orientation of the crystallites coke, so for one synthesis cycle is a whole gamut of elongated diamond crystals of varying degrees of symmetry. As graphite is used as a binder and even coal tar, from which also comes the synthesis of diamond, Speke after synthesis are present and normal isometric crystals 3. Figure 2 shows the needle diamond in an enlarged scale.
From a monolithic piece of artificial graphite type HSV brand with filler of needle coke was drilled cylindrical rod with a diameter of 10 mm Of rod cut disks with a thickness of 2.4 mm Disks were loaded into the reaction cell, alternating with the catalyst - solvent (Ni, Mn). The cell was placed between two block matrices with grooves, generated pressure in the cell to 4.5 GPA, was heated to a temperature of 1250±50°speed 80÷90°C / min and held at this same time is the temperature value 10 minutes After synthesis, spectra were purified from unreacted graphite by the standard technology of chemical treatment. The result is a 5% diamond right needle shape and about 30% of the crystals are elongated. The rest of the diamonds represented the grains of irregular shape, the twins type dovetail, with rough edges. The maximum size of the crystals along the long axis of 1.0 mm, ratio of length to width is from 3:1 to 6:1.
Same as in app.1, only the diameter of the disks of graphite with needle coke was 8 mm, the Pressure in the reaction cell was brought to 7.0 GPA, temperatures of up to 1300°50÷75°C/min, the result is about 7.5% of the crystals right needle shape and about 40% of the crystals are elongated, various degrees of skewness. The size of the crystals along the long axis lie in the range 0.5-0.8 mm, a width in the range of 0.15-0.20 mm
Technical and economic effect is to replace short supply and expensive natural diamonds XV group "a", VII group G and XXII group "a" in the manufacture of diamond needles on synthetic diamonds needle shape. This eliminates the need for the grinding operation when cut natural diamond crystal octahedral form.
Technical documentation for the synthesis of diamonds according to the technology described in the application, is available in full
The method of synthesis needle and elongated diamond, comprising mixing the mixture of the alloy Mn-Ni-Fe in a weight ratio of 60±5:30±5:10±5 and powder of carbonaceous substances and processing the mixture at a pressure of >40 kbar and T>950°C at a heating rate of less than 100°C/min, wherein the carbonaceous substance use needle coke or graphite-based coke with one-component anisotropic structure with the degree graphitization is not less than 0.55 relative units.
FIELD: chemical technology.
SUBSTANCE: method for synthesis of threadlike aluminum nitride involves passing gaseous reagents as aluminum (III) halides and nitrogen through heated aluminum and the following condensation of the end product. Aluminum (III) halide is fed at the level rate 0.1-6 cm3/min per 1 cm2 of the condensation surface. Condensation is carried out on backing made of pure graphite. Invention provides synthesis of aluminum nitride as crystal fibers showing the ratio value of length to diameter above 200-300. Invention can be used for synthesis of threadlike aluminum nitride crystals useful in making sensor probes in cantilevers of atomic-power microscopes.
EFFECT: improved method of synthesis.
3 dwg, 2 ex
FIELD: engineering of microscopes.
SUBSTANCE: probes for probe microscopy are made of silicic whiskers, grown in accordance to steam-liquid-crystal mechanism on cantilevers with crystallographic orientation 111. Such cantilevers are made of silicon-on-insulator structures, which are formed by melting together silicon plates, while one of plates has orientation 111. Whiskers grown in accordance to aforementioned method, may have stepped shape, ideal for probes.
EFFECT: high resolution capacity with high anti-vibration stability.
4 cl, 4 ex, 17 dwg
FIELD: chemical industry; methods of production of mullite out of the quartz-topaz raw materials.
SUBSTANCE: the invention is pertaining to the field of a chemical industry, chemical technology and materials technology. The method of production of mullite includes: comminution of the source quartz-topaz raw materials; separation of impurities by lixiviation using treatment of the raw materials with a hydrochloric acid with concentration of 10-38 % within 0.5-2 hours; a water flushing; separation of redundant silicon oxide in the form of ammonium hexafluorosilicate by means of ammonium bifluoride; calcination of the gained product at the temperature of 1200°-1300°C. The technical result of the invention is production of the microfibrous mullite (microfibers of the mullite crystal may reach 200 microns in length with a fiber depth - about 1 micron) of high quality and in the commercial scale.
EFFECT: the invention ensures production of the microfibrous mullite (microfibers of the mullite crystal may reach 200 microns in length with a fiber depth - about 1 micron) of high quality and in the commercial scale.
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: 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.
FIELD: advanced techniques for creating diamonds, possibly micro- and nano-electronics for creating new super-strength construction materials widely used in different branches of industry, for producing semiconductor diamond base light emitting diodes, jewelry articles.
SUBSTANCE: diamond synthesis method comprises steps of irradiating carbon-containing materials with fluxes of magnetic mono-fields generated from plasma for time period determined by motion speed of magnetic mono-fields through irradiated material. Such process does not need high-pressure chambers, special heating members and it is possible to realize it at atmospheric pressure and room temperature or in vacuum.
EFFECT: possibility for producing high-purity diamonds of predetermined size and shapes.
FIELD: chemical industry; methods of processing of the diamond-containing concentrates.
SUBSTANCE: the invention is pertaining to separation of the diamonds from the diamonds-containing rock and the marks of technological processes concentration and may be used in the production shops of the final treatment of the diamond- -containing concentrates in the mining-and-processing integrated works of the diamond-mining firms. For creation of the self-contained ecologically safe cycle of production of pure diamonds the processing of the diamond-containing concentrates is conducted in the autoclave at the temperatures of 200-400° С using the saturated solution of the sodium carbonate with addition of 3-5 % of the weight % of sodium hydroxide in the field of the ultrasonic radiation, then the autoclave is cooled and in the reaction mass, which contains the non-reacted water solution of the sodium carbonate, they route oppositely to the gravitational force the stream of the concentrated hydrochloric and nitrogen acids for formation of the conditions of the flotation-gravitational division and separation of the diamonds from the products of the production process. At that for creation of the closed cycle of the production process at flotation-gravitational separation of the diamonds from the products of the production process use the concentrated acids, which have remained after the final cleaning of the diamonds. The invention ensures the high quality of the cleaning of the diamonds at the minimal usage of the toxic mediums, which allows the considerable reduction of the cost of the production process.
EFFECT: the invention ensures the high quality of the diamonds cleaning, the minimal usage of the toxic mediums in the production process, the considerable reduction of its cost.
2 cl, 2 ex