Method for preparing nanodiamonds with methane pyrolysis in electric field
SUBSTANCE: invention may be used in medicine in producing preparations for a postoperative supporting therapy. What is involved is the high-temperature decomposition of methane on silicone or nickel substrate under pressure of 10-30 tor and a temperature of 1050-1150°C. The heating is conducted by passing the electric current through a carbon foil, cloth, felt or a structural graphite plate whereon the substrates are arranged. An analogous plate whereon a displacement potential from an external source is sent is placed above the specified plate. Nanodiamonds of 4 nm to 10 nm in size are deposited on the substrates.
EFFECT: higher effectiveness of the method.
1 dwg, 6 ex
The invention relates to the field of fabricating films of crystalline carbon containing clusters of nanodiamonds, on substrates and can be used for the production of drugs used in therapy after surgical operations. Now for the synthesis of nanodiamonds in the industry uses the method of detonation, which involves the use of highly explosive substances (a mixture of TNT with RDX).
The known method (Z.Y.Chen, J.P.Zhao, T.Yano, T.Ooie, M.Yoneda, J.Sakakibara. Growth of nanocrystalline diamond by pulsed laser deposition in oxygen atmosphere. Journal of Crystal Growth 226 (2001) p.62-66) obtain nanocrystalline diamond on sapphire substrates in an oxygen atmosphere using a pulse laser. The method allows to obtain crystals of nanodiamond size of 30 nm, but is purely laboratory character. The cycle time of deposition of the film is 4 hours when using the small area of the substrate, which is unacceptable for industrial production.
The known method (May P. Diamond Thin Films: A 21stCentury Material. Phil. Trans. R. Soc. Lond. A 358 (2000) p.473-495) growing a thin diamond-like films during the pyrolysis of methane in a high-frequency microwave plasma. This method has been successfully developing, but its implementation requires very sophisticated and expensive equipment, and the process takes many hours.
The known method (Patent RF №2230702, IPC C1B 31/06, publ. 20.06.2004,) receipt of nanodiamonds, based on the use of detonation, which involves the use of explosives (a mixture of TNT with RDX). The explosive charge is placed inside the ice bookings in a sealed explosion chamber and produce a bombing, then the resulting suspension of nanodiamonds in the water is poured into the receiving tank, separate nanodiamonds and purified. The disadvantages of the known method are the use of explosives, low reproducibility and difficulty in purification of the synthesized nanodiamonds from the decay products of explosive mixture.
The closest to the technical nature of the claimed and adopted for the prototype is a method (Patent RF №2429315, IPC C30B 30/02,SW 31/04) pyrolytic growing nanocrystalline layers of graphite, including heating plates made of carbon material in a sealed water-cooled chamber direct transmission of electric current and thermal decomposition of methane in the gap between the plates with the deposition of nanocrystalline layers of carbon on substrates of silicon, is placed in the gap, and the temperature of the substrate maintained within the range of 1200-1350°C and pressure of methane from 10 to 30 Torr.
Prototype method has the following disadvantages:
1. In the narrow gap between two parallel carbon plates occurs different the th electric potentials at the level of 5-7 In due to the voltage drop on graphite gaskets and screws connecting plate. The field strength is about 70 V/cm, which corresponds to the pressure of the carbon ions C4-at 1 HPa, insufficient to obtain perfect nanodiamonds small size.
2. In the prototype circuit heating it follows that the electric field strength between the carbon plates has a maximum value at the boundary areas and due to the polarity (both at constant and alternating current) passes through zero at the center, which leads to heterogeneity of the conditions of the deposition of layers on substrate surfaces.
In the result, resulting in the implementation of the prototype method nanodiamonds have too large size (from 30 to 50 nm) for use in medicine, and their exit by weight of the grown layer is quite low.
The main distinguishing feature of the claimed method of producing nanodiamonds is passing electric current only through the bottom carbon plate and feed on the upper plate is electrically isolated from the lower, high voltage from an external source. During thermal decomposition of methane in the gap between the belts occurs a layer of ionized gas, and through which current flows between the upper and lower plates, the gap between which is placed the substrate. The electric field thus p is constant along the length of the plates.
The technical result obtained by the present method, is expressed in obtaining nanocrystals of diamond small size in a matrix of crystalline carbon and increase their output on the total weight of the layer of carbon.
Scheme of practical implementation of the proposed method is illustrated in Fig. 1.
In the gap between two parallel plates 1 and 2 of the carbon material are placed substrate 3 made of silicon or Nickel. The power current is passed through the tape 2 through the external electrodes 4 and 5. On the upper belt 1 through the external electrode 6 is supplied with alternating or constant high voltage. In the result, the difference voltage between the heating plate 2 and the upper plate 1 in a narrow gap between them creates a significant electric field, the intensity of which is up to 2000 In/see In insulated airtight chamber is methane at a pressure of 10-30 Torr, pirolizy according to the reaction CH4→-4+4H+. When this electrically charged atoms of carbon have significant kinetic energy sufficient to create the perfect nanodiamonds. The temperature of the substrate maintained within the range of 1050-1150°C. On the surface of the substrate 3 grown layer of nanocrystalline carbon 7, in the matrix which contains the nanodiamonds.
To achieve kazanovichyakov result in a known way, including heating plates made of carbon material in a sealed water-cooled chamber direct transmission of electric current and thermal decomposition of methane in the gap between the plates at a pressure of 10-30 Torr with a deposition of nanocrystalline layers of carbon on substrates placed in the gap, the current is passed only through the bottom plate and the top serves bias potential from the external voltage source, thermal decomposition of methane is carried out at a temperature of 1050-1150°C on a substrate of silicon or Nickel, as the material of the plates can be used carbon foil, structural graphite, carbon-graphite fabric or felt.
During thermal decomposition of methane occurred in the electric field carbon ions gain kinetic energy, allowing them to create contact with a growing layer of pressure up to 30 GPA, which is comparable, and according to other sources exceeds the pressure attained when the detonation of TNT. The temperature of the substrate maintained within the range of 1050-1150°C and pressure of methane from 10 to 30 Torr.
If the partial pressure of methane below 10 Torr, then its concentration in the atmosphere chamber is not sufficient to produce a dense layer of crystalline carbon.
If you raise the partial pressure of methane above 30 Torr, the surface of the substrate planted soot, which makes the growing content of asego nanodiamonds crystalline carbon layer is not possible.
If the temperature of the heated carbon plates is below 1050°C, the specified range of pressures of methane noticeable sediment carbon will not occur.
With increasing temperature above 1150°C substrate enter into chemical interaction with heated above this temperature the lower the carbon plate is plastic deformation and partial melting.
When using as a substrate of polished silicon wafers, which are synthesized film after cooling, can be easily separated from the substrate due to the large difference in CTE, but the reuse of expensive silicon substrates impossible due to impaired quality polishing their surfaces after ion bombardment by carbon.
When using cheaper substrates of Nickel adhesion of the synthesized films are great and their departments need to dissolve the Nickel substrate in a heated aqueous solution of sulfuric acid.
Between the two plate - lower 1 (made of 3 layers of flexible carbon foil and connected to the output bus of the power transformer) and 2 - top (made of solid carbon felt isolated from the plate 1 and is connected to an adjustable source of alternating voltage, a width of 120 mm and a length of 230 mm each - set of two substrates 3 of monokristally the definition of silicon with a diameter of 100 mm each. After sealing and evacuation of the reaction chamber it has filled with methane qualification microwave until a pressure of 20 Torr and turned on the heat by passing current through the plate 2. The temperature of the silicon substrate has reached a temperature of 1070±20°C. Then filed a voltage 05 In the external electrode 6 of the upper plate 2 and recorded by the ammeter in the circuit: top plate - phase pole of the external voltage source current of 1-2,5 A. in the gap between the plates 1 and 2 was observed blue glow. Operating cycle duration was 8 minutes. After removing the substrate 3 on their polished surfaces the detected film 7 with a metallic sheen thickness of 3-5 μm. After mechanical separation of the obtained films from substrates in their composition nanodiamonds found in sizes from 4 to 10 nm in an amount up to 80 wt.%.
Same as in example 1, but the pressure of methane in the reaction chamber was maintained at a level of 7 Torr, and the length of the operating cycle is 17 minutes. After removing the silicon substrates detected amorphous yellow tape, easy to remove organic solvents.
Same as in example 2, but the pressure of methane in the reaction chamber was maintained at a level of 45 Torr. The surface of a silicon substrate covered with a thick layer of soot. After removal of soot traces crystal layer is not about naruhina.
Same as in example 2, but the temperature of the silicon substrates was 950°C. On the surface of the substrate precipitation of crystalline carbon is not detected.
Same as in example 2, but the temperature of the silicon substrates was 1200°C. the Plates are strongly deformed, cracked and partially melted. Layer pyrographite on their surface is observed, but their further use is not possible.
Same as in example 2, but as substrates used plates of Nickel foil with a thickness of 30 μm, and the length of the operating cycle was 5 minutes. After removal of the substrate detected film with a metallic luster thickness of 2-3 μm. After etching in 30% sulfuric acid solution with the addition of 5% chromic anhydride at 60°C for 2 hours, the Nickel was removed and the composition of the residual carbon films nanodiamonds found in sizes from 4 to 8 nm in an amount up to 80 wt.%.
The method of producing nanodiamonds in the pyrolysis of methane in an electric field, comprising heating plates made of carbon material in a sealed water-cooled chamber direct transmission of electric current and thermal decomposition of methane in the gap between the plates at a pressure of 10-30 Torr with a deposition of nanocrystalline layers of carbon on substrates placed in the gap is, characterized in that the current is passed only through the bottom plate and the top serves bias potential from the external voltage source, thermal decomposition of methane is carried out at a temperature of 1050-1150°C on a substrate of silicon or Nickel, as the material of the plates can be used carbon foil, structural graphite, carbon-graphite fabric or felt.
SUBSTANCE: invention relates to technology of obtaining pure substances, which are applied in field of high technologies: semi-conductor, solar energy, fiber-optic communication. Method of obtaining polycrystalline silicon is realised by plasmochemical pyrolysis of initial quartz raw material particles in flow reactor in flow of plasma of inert gas - argon and hydrogen, and as initial quartz raw material applied is natural quartz concentrate with size of particles not larger than 20 mcm, pyrolysis is realised at temperature 6500-13000 K with decomposition of reacting mixture into silicon and oxygen atoms, after which gas phase atomic mixture is cooled in the interval from 6500 to 2000 K at rate 105-106 K/s to form silicon vapour due to binding of free oxygen with hydrogen without silicon re-oxidation, after which obtained silicon vapour is condensed by further cooling of mixture to 1000 K with formation of polycrystalline silicon in form of spherical particles.
EFFECT: method is highly effective and ecologically clean and makes it possible to obtain polysilicon with low prime cost directly from concentrates of natural quartz without application of additional reducers.
7 dwg, 2 tbl
SUBSTANCE: brass target coated by carbon nanotubes is processed in air by continuous radiation of ytterbium fiber laser in the presence of electrostatic filed of 250-750 V/m intensity ordering zinc and oxygen ion motion and accelerating it toward reaction area. Changing electric field parameters in said range allows producing blocks of zinc oxide 50-400 nm-dia whiskers including vertically ordered crystals.
EFFECT: production of crystals without catalysts or crystallisation chambers.
SUBSTANCE: methane undergoes thermal decomposition on polarised silicon plates at pressure 50-100 torr and temperature 1050-1150°C. Heating is carried out by passing electric current through two parallel plates of structural graphite, flexible carbon foil or coal-graphite fabric, in the gap between which silicon plates are placed. Considerable electric potential difference is formed between the plates.
EFFECT: use of the disclosed method enables to obtain nanodiamonds with size of 4-10 nm.
SUBSTANCE: methane is thermally decomposed on polished plate of silicon at pressure 10-30 torr and temperature 1200-1350°C. Heating is performed by transmitting electric current through two parallel tapes of carbon foil. The silicon plate is positioned in a gap between these tapes.
EFFECT: production of nano crystal layers of graphite of high quality.
1 dwg, 7 ex
SUBSTANCE: procedure is performed in reactor and consists in hydrogen reduction of mixture of chlorine-silane with thermal decomposition of silane, in sedimentation to required thickness of layer of poly-crystal silicon on core base heated to 1100-1200°C. Also, poly-crystal silicon is settled first on the silicon core for obtaining a layer of thickness about 2 mm. Further, surface of this layer is polarised by application of positive potential 8-10 V to it relative to the base and a loose layer of polycrystalline silicon of 1.5-2.0 mm thickness is settled, where upon polarisation potential is switched off and sedimentation of polycrystalline silicon is proceeded for obtaining a layer of required thickness.
EFFECT: simplified process of removal of layer of polycrystalline silicon settled on core base.
SUBSTANCE: invention can be used in production semiconductor materials, solar cells and in microelectronics. Silicon is deposited on substrates made from pure silicon, which are pre-heated with high frequency current.
EFFECT: obtaining highly pure silicon.
2 cl, 2 dwg
FIELD: metallurgy, crystals.
SUBSTANCE: invention relates to field of receiving of films of photonic crystals. Formation of films of photonic crystals is implemented by means of sedimentation of monodisperse of microspheres of colloidal particles from suspension on located vertically in it conducting substrate, herewith in the capacity of monodisperse microspheres there are used colloidal particles from polystyrene, polymethyl methacrylate or silicon oxide, and sedimentation is implemented at temperature of suspension (60±3)°C at simultaneous feeding to substrates of potential difference 1 V. In the capacity of conducting substrates can be used glasses with conductive coating from indium-tin oxide (ITO), glass with evaporated film of gold etc.
EFFECT: invention provides specifically to receive uniform and high-ordered structures of photonic crystals at big areas with high rate of grow.
2 cl, 1 ex, 6 dwg
SUBSTANCE: invention relates to the technology of growing monocrystals using Chokhralsky method. Growth of doped crystals of lithium niobate with composition close to stoichiometric is done on an inoculating crystal from molten mixture of lithium niobate of identical composition with ratio Li/Nb equal to 0.938-0.946 and containing 9-13 mol % K2O and 0.5-2.5 mol % MgO or ZnO, in conditions of applied electric field with current density of 0.2-40 A/m2. A device is provided for realising the method, comprising a housing with a growth station and a cooling chamber, crucible 1, placed in the growth station, induction heater, top metallic heating shield 4, fitted above the crucible 1, mechanism for moving the crystal with a coupling rod, a rod with a holder 3 for the inoculating crystal 2. The device is also provided with a regulated direct current source 10 with electrodes; under the inoculating crystal 2 there is an additional load from electrically conducting material, separated from the wall of the holder by electrically insulating material. One of the electrodes is connected to the crucible 1, and the second - to the load.
EFFECT: invention allows for growing large optically homogenous crystals of lithium niobate with composition close to stoichiometric Li/Nb>0,994, additionally doped with MgO or ZnO, composition of which in the top and bottom parts of the crystal is virtually the same, without destroying the inoculating crystal.
5 cl, 2 ex, 2 dwg
SUBSTANCE: invention concerns technology of obtaining multicomponent semiconductor materials and can be applied in electronic industry for obtaining semiconductor material, solid (SiC)1-x(AlN)x solution, in manufacturing of solid power or optic electronic devices based on it, in obtaining cushion (SiC)1-x(AlN)x layers for aluminum nitride (AlN) or gallium nitride (GaN) crystal cultivation on silicon carbide (SiC) substrate. Epitaxial films of solid solution of silicon carbide and aluminum nitride (SiC)1-x(AlN)XJ where 0<x<1, are obtained by sedimentation of solid solution to monocrystallic SiC-6H substrate at 1000°C via ion plasma magnetron sputtering of solid polycrystallic (SiC)1-x(AlN)x solution target, where 0<x<1, the sputtering performed under effect of alternate current with frequency of 13.56 MHz.
EFFECT: obtaining high-quality monocrystallic films in the whole range of chemical composition transformation and improved efficiency of high-resistance target sputtering.
1 ex, 3 dwg
FIELD: machine building.
SUBSTANCE: proposed unit comprises frame to support vacuum chamber communicated with vacuum pump, part fixture, gas flame torch for high-rate gas-dynamic sputtering arranged at 45 degrees to part surface, feeder of powder with shape memory effect to gas-flame torch, pyrometer to measure part temperature, module for ion-beam cleaning, appliance for surface straining to produce nanostructured layer, step-down transformer for additional heating of part surface, device to cool part surface to temperature of martensitic transformation at surface straining, and control device. Proposed unit comprises extra two magnetrons and metal ion implantation source secured on in vacuum chamber to be directed towards processed part. Surface straining appliance is composed of the press with moving top crossbar and fixed bottom crossbar arranged inside vacuum chamber. Note here that part fixture and surface cooler are mounted at said bottom crossbar. Gas-flame torch is rigidly secured inside vacuum chamber.
EFFECT: higher strength and wear resistance, expanded processing performances.
1 dwg, 2 ex
SUBSTANCE: method involves arrangement of powder charge from titanium diboride between two layers of aluminium foil and electric explosion of foil with formation of pulse multiphase plasma jet, melting of aluminium surface using it at the value of specific energy flow of 3.8…4.1 GW/m2 and sputtering onto the molten layer of components of plasma jet, with further self-hardening and formation of a composite coating containing titanium diboride and aluminium.
EFFECT: increasing wear resistance and microhardness of a coating; improving its adhesion to base.
4 dwg, 3 ex
FIELD: process engineering.
SUBSTANCE: invention relates to reconditioning and repairing assembly units and parts and may be used at repair enterprises in reconditioning steering boosters. In compliance with first version, during replacement of seal in rod-cover joint, hydraulic cylinder rear cover worn-out bore is reamed to repair size while coating layer is applied on rod surface and shaft journal via intermediate layer. In compliance with second version, medium- or high-carbon steel coating is applied on slide valve surface by electric arc deposition while worn-out bore in cylinder body id reamed by diamond expansion reamers to apply the coating on slide valve worn-out fillets. In compliance with third and fourth versions, meta; coating is applied by electric arc machining while copper-bearing alloy later is applied on worn-out seats of worm shaft and worn-out surfaces of bores for pin in rack and rod. In compliance with fifth version, seals in piston-cylinder joint is replaced to hone cylinder worn-out bore to remove wear traces while rod working surface and thrust face surface are hardened by molybdenum electrode.
EFFECT: one-hundred-percent recovery.
5 cl, 1 tbl, 1 dwg
FIELD: machine building.
SUBSTANCE: plant includes a frame with a vacuum chamber arranged on it, a mechanism for fastening of a part with a socket and a back poppet, a part rotation mechanism, and a plasmatron with mechanism of its longitudinal movement, a powder material supply mechanism with shape memory effect, the first pyrometer for temperature measurement of the part before the front of plasma arc, a control device, a device for surface-plastic deformation (SPD) of the part for formation of a nanostructured layer, the second pyrometer, a step-down transformer, a gas-flame burner for gas-flame spraying, a process module for ionic cleaning of the processed part with a power supply and a part surface cooling device. Gas-flame burner and device for SPD are arranged on longitudinal plasmatron movement mechanism; at that, burner is installed at an angle of 45° or 90° to the part surface. Positive side of the power supply of the process module of ionic cleaning is connected to housing of vacuum chamber, and its negative side is connected to back poppet of the part fastening mechanism. The second pyrometer is installed in SPD zone and connected to the control device related to powder material supply mechanism and longitudinal plasmatron movement mechanism and the first pyrometer. Step-down transformer is connected to SPD device to provide an additional heating of the part surface. Cooling device is connected to longitudinal plasmatron movement device that is installed on the longitudinal movement mechanism at an angle of 46-50° to the part surface.
EFFECT: improving functional properties and reliability of the part coatings.
2 cl, 1 dwg, 2 ex
SUBSTANCE: proposed composition comprises molybdenum disulphide, colloidal graphite and diamond nanoparticles powder with grain size of 4-6 nm as filler, and binder consisting of the mix of magnesium oxide with water solution of nitric and phosphoric acid.
EFFECT: higher wear resistance at higher temperatures.
1 tbl, 1 ex
FIELD: process engineering.
SUBSTANCE: invention relates to machine building, particularly, to rotary pump stage reconditioning. Proposed method comprises turning worn-out surfaces of impeller and diffuser, thermal spraying of antiwear powder to recover initial sizes of impeller and diffuser with due allowance for machining allowance. Antiwear layer is applied on heating impeller and diffuser to 100°C - 200°C. Note here that tungsten carbide is sued as said powder.
EFFECT: higher efficiency of repair.
3 cl, 2 dwg
FIELD: machine building.
SUBSTANCE: method includes application of a sublayer from a heat-resistant alloy and formation of a reinforced ceramic layer on the sublayer. The reinforced ceramic layer is formed in stages. At first the discrete ceramic layer is applied in the form of isle sections on the sublayer surface, leaving open from 4% to 98% of the total sublayer surface. Then at least one discrete metal layer is applied onto the discrete ceramic layer and open sections of the sublayer in the form of strips or a grid with the area from 4% to 98% from the total surface of the formed coating and thickness from 0.8 mcm to 5 mcm. Afterwards the outer solid ceramic layer is applied.
EFFECT: higher operational properties of coatings, reduced labour intensiveness of the method, increased endurance and cyclic strength of parts with the coating.
24 cl, 3 tbl
FIELD: process engineering.
SUBSTANCE: invention relates to production of seamless steel tube, namely, to reusable piercing and rolling mandrel, to method of its reconditioning and process line to this end. Mandrel incorporates film consisting of oxides and Fe made on mandrel main metal surface. Proposed method comprises shot-blasting the mandrel surface for film removal and electric arc evaporation of film consisting of oxides and Fe. Evaporation is performed with Fe-based wire.
EFFECT: higher efficiency.
11 cl, 18 dwg, 5 tbl
FIELD: machine building.
SUBSTANCE: invention relates to method of producing heat-resisting coat on gas turbine vanes from nickel or cobalt alloys. Proposed method comprises ion-plasma preparation and ion-implanting vane surface treatment, and vacuum-plasma application of heat-resisting layer. Ion-implanting treatment of vane surface is performed by ions of one or several elements selected from N, C, B, Pd, Ag, and combination thereof with ions Nb, Pt, Yb, Y, La, Hf, Cr, Si. Note here that, in atmosphere of nitrogen and/or carbon in vacuum not lower than 10-3 mm Hg, applied is at least one of the following heat-resisting layers with composition that follows in wt %: Co - 12-20, Cr - 18-30, Al - 5-13, Y - 0.2- 0.65, Ni making the rest; Cr - 18-30, Al - 5-13, Y - 0.2-0.65, Ni making the rest; Si - 4.0-12.0, Y - 1.0 -2.0, Al making the rest. Then, coating is thermally treated.
EFFECT: higher heat resistance, longer life and higher cyclic strength.
22 cl, 3 tbl
FIELD: machine building.
SUBSTANCE: part has wear resistant structure (6) consisting of ceramic particles (9) implanted into metal matrix (8) and having rough surface formed by ledges of ceramic particles (9) and recesses (11) there between. Antiscuff coat (7) consisting of antiscuff material is applied on wear resistant structure (6) to level said surface irregularities, said antiscuff material being different from that of wear resistant structure and metallurgically jointed therewith by alloying or diffusion in supplying heat along wear resistant structure (6). Note here that antiscuff material wear resistance does not exceed that of sliding surface located opposite the machine part.
EFFECT: higher conformability.
32 cl, 5 dwg
FIELD: process engineering.
SUBSTANCE: invention relates to blast processes of the synthesis of materials, in particular, diamonds. Proposed device comprises flow vessel 1 with tight cover 3, mix of explosive arranged inside said vessel that features a high specific energy and graphite or carbon-bearing explosive with negative oxygen balance, initiator 5, indestructible cylindrical barrier 6 composed by pipe arranged aligned with vessel 1 there inside. Note here that said mix of graphite and explosive and initiator 5 are placed at barrier 6 centre.
EFFECT: protection of device wall against maximum loads, increased bulk of explosive without increase in device volume and weight.