Procedure for production of silicon of nano or micro-wave structure
SUBSTANCE: electrolysis is performed in melt containing (wt %): to 65CsCl, 15-50 KCl, 5-50 KF, 10-60 K2SiF6 at temperature 550-750 °C. As anode there is used material containing silicon. Also electrolysis is carried out with variation of cathode density of current from 0.005 to 1.5 A/cm2 and with successive separation of silicon deposit off surface of a cathode-substrate and electrolyte.
EFFECT: high output of finished product at relatively simple hardware implementation of process.
3 cl, 4 ex
The invention relates to the field of metallurgy of non-metals, namely the electrolytic production of silicon in the form of nanofibers and microfibers, suitable for use in lithium chemical power sources, load cells, thermoelectric converters, temperature sensors, field emission electronics, composite materials, etc.
Known methods for producing fibrous nano - (micro-size particles) silicon structures from the vapor phase on Agrocomplex mechanism ("vapor - liquid - solid"), when the surface of the substrate are formed nanocable alloy of silicon with the originating metals (Au, Ag, Cu, Pt, Pd, Ni). When saturation of the alloy on the silicon on the surface of the substrate begins to form nanovolume (microfiber) and silicon of the same diameter as the drop of the alloy. Nano - (micro-size particles) drop alloy of silicon with the originating metal remains on top of the silicon nanofibers (microfiber) and consumes silicon from the gas phase.
Known chloride process, i.e. the interaction SiCl4+H2going in the temperature range of 900-1050°C [Givargizov H. / filamentous Growth, and lamellar crystals from the vapor. / Nauka, M., 1977, 304; Wagner, R.S. / sat "single-crystal fiber and reinforced their materials", M., Mir, 1973, p.42].
A known method of transferring silicon vials using yo is a (bromine), when the source is heated to 1100-1200°C, and the substrate to 850-1000°C [Sandalova AV, Epiphany, AS Dronyk M.I. / Reports of USSR Academy of Sciences 153, 82 (1963)].
Developed a method of obtaining nanofibers silicon deposition in a vacuum running in the temperature range 500-1000°C [K.Ishiwatari, T.Oka, K.Akiyama / Japan J Phys Apple 6, 1170 (1967)].
Reported obtaining nanofibers silicon by decomposition of SiH4in the temperature range 550-900°C [G.A.Bootsma, H.G.Gassen / J. Crystal growth 10, 223 (1971); Majumdar A et al / U.S. Patent No. 7569941 from 04.08.2009].
The above methods of obtaining nanofibers or microfibers silicon have complex instrumentation, and, consequently, for their organization requires a large capital investment for the purchase of equipment and large operating costs for its operation.
Relatively high operating temperatures (1000°C) of the above technologies in combination with processes in chemically aggressive halogenated carrier gas of silicon, and the need to create in some cases deep vacuum imposes high requirements (quality and cost) to construction materials that can be used in installations for the operation of the above technologies. This ultimately leads to an increase in the cost of silicon nanofibers.
In addition, all of the above technologies in the teaching of Si nanofibers are toxic silicon-containing gases, are harmful to the environment. Therefore, it is necessary to provide measures (and thus increase energy consumption) to prevent the ingress of toxic substances in the environment.
Finally, the use of noble metals-activators, including: gold, platinum, palladium, and others, leads to an inevitable loss of these metals during long-term operation.
In General, the currently existing technologies for silicon nanofibers have great energy used to produce one kg of elemental silicon, which increases the cost of its production.
Upon receipt of refractory metals and materials a significant gain in energy per unit mass while maintaining the desired purity and quality compared to other metallurgical technology gives the electrolysis of molten salts, and especially the process of electrolytic refining of the above mentioned refractory materials in molten salt. However, the electrolytic method of producing nanofibers or microfibers silicon is not known.
An object of the invention is to develop the electrolytic production of silicon nanocolonies and microfiber structure with a lower cost of electricity and thermal energy.
The problem is solved by the fact that in the inventive production method of silicon nano - or micropaleontol patterns by electrolytic refining material containing silicon, the electrolysis is carried out in the melt, containing (wt.%): up to 65 CsCl, 15-50 KCl, 5-50 KF, 10-60 K2SiF6at a temperature of 550-750°C using as the anode material containing silicon, the variation of cathode current density of 0.005 to 1.5 A/cm2with subsequent sludge separation of silicon from the surface of the cathode substrate and the electrolyte.
As a cathode material used graphite, glass carbon, Nickel, silver or other inert with respect to silicon under the conditions of electrolysis materials. Released at the cathode of the silicon periodically removed from the bath together with replaceable electrode, mechanically cleaned from the cathode and separated from the electrolyte by use of heated hydrochloric acid, a solution of ammonium fluoride and distilled water.
As the anode material, which is subjected to electrolytic refining, you can use relatively cheap technical silicon. Technical silicon receive on an industrial scale by a carbothermic recovery quartz carbon. The purity of its primary substance from 98.0 to 99.0%, the structure is fibrous.
The above lower and upper limits of the parameters of the proposed method were obtained experimentally based on itnyj research and analysis of the experimental results with the achievement of the task and technological results in the production of high-purity silicon powder with nanocolonies and microfiber structure.
The inventive method can be characterized as a method of electrolytic refining of technical silicon to obtain nanovoloknistykh and microfiber precipitation of silicon with high yield, in which the electrolyte is sodium chloride and fluoride salt melt.
Silicon chloride-fluoride melt on the basis of salts of alkali metals, especially potassium and cesium, has a number of advantages.
First, the chloride-fluoride melts due to the formation of solid fluoride-chloride complexes of silicon with large cations of alkali metals (potassium or cesium) allows to reduce the vapor pressure over the melt and to prevent loss of silicon via the gas phase in the process of electrolysis. Secondly, the chloride salt is much easier to clean from undesirable impurities, particularly oxygen-containing impurities, which have a significant impact on the structure of the cathode Deposit.
In addition, the low temperature regime (550-750°C) allows the use of relatively cheap, but stable at this temperature structural materials in cells, though this temperature range is suitable for electrolytic selection of crystalline nanovoloknistykh or microfiber electrolytic precipitation of elemental Si.
The technical result is ablanovo method is the possibility to realize the production of silicon nanocolonies or microfiber structure with a high yield of high quality with relatively simple equipment the registration process.
Example 1. The electrorefining technical grade silicon KR-1, which served as the anode, is carried out in the melt, consisting of 39.3 wt.% potassium chloride, 33.8 wt.% fluoride and potassium 26.9 wt.% potassium fluorosilicate preparation, graphite and glassy carbon cathodes. Cathode current density range 0.005 to 0.1 A/cm2. The temperature of the process support 650°C. the Precipitate is mechanically separated from the cathode surface of the substrate and washed from the electrolyte. Released at the cathode residue on 80% consists of curved fibers of silicon with a diameter of 50 to 500 nm and a length of 100 μm, depending on the terms of refinement.
Example 2. The electrorefining technical grade silicon KR-1 is carried out in the melt, consisting of 42,0 wt.% potassium chloride, 5.0 wt.% fluoride and potassium 53.0 wt.% potassium fluorosilicate preparation, with a graphite cathode, a cathode current density of 0.05 A/cm2and 700°C. the Precipitate is mechanically separated from the cathode surface of the substrate and washed from the electrolyte is Released at the cathode residue on 10% consists of fibers of silicon, having a form of rectilinear cylindrical fibers with a diameter of 50 to 500 nm and a length of 100 ám.
Example 3. The electrorefining technical grade silicon KR-1 is carried out in the melt, consisting of 62.1 wt.% cesium chloride, 14.9 wt.% potassium chloride, 14.1 wt.% fluoride of potassium and 8.9 wt.% Huck is afterselect potassium, Nickel cathode, in the range of cathode current densities from 0.01 to 0.15 A/cm2and at the process temperature of 580°C. the Precipitate is mechanically separated from the cathode surface of the substrate and washed from the electrolyte. Released at the cathode, the sediment consists of 70% of the fibers of silicon, having a form of a curved cylinder with a diameter of from 70 to 1500 nm and a length of 100 μm, depending on the conditions of electrolysis.
Example 4. The electrorefining technical grade silicon KR-1 is carried out in the melt, consisting of 33.6 wt.% potassium chloride, 21.4 wt.% fluoride of potassium and 45 wt.% potassium fluorosilicate preparation, with a silver cathode, a cathode current density of 0.02 A/cm2and the process temperature of 700°C. the Precipitate is mechanically separated from the cathode surface of the substrate and washed from the electrolyte. Released at the cathode, the sediment consists of 50% of the fibers of silicon, having a form of a curved cylinder with a diameter of from 200 to 400 nm and a length of 10 μm, depending on the conditions of electrolysis.
Thus, the above data confirm that the combination of stated characteristics of the method allows to obtain pure electrolytic nanofibers or microfibers of silicon, which are characterized by the content of the main component (silicon) > 99.99 wt.%.
1. A method of producing silicon nano - or microfiber structure by electrolytic refining material, terasawa silicon, characterized in that the electrolysis is carried out in the melt, containing (wt.%) up to 65 CsCl, 15-50 KCl, 5-50 KF, 10-60 K2SiF6at a temperature of 550-750°C using as the anode material containing silicon, the variation of cathode current density of 0.005 to 1.5 A/cm2with subsequent sludge separation of silicon from the surface of the cathode substrate and the electrolyte.
2. The method according to claim 1, characterized in that the material of the cathode-substrate use graphite, glass carbon, Nickel and silver.
3. The method according to claim 1, characterized in that as the material containing silicon, use technical silicon.
SUBSTANCE: method includes treatment of chloride melt, containing ions of platinum metals, by chlorination for removing of oxygen-containing admixtures. Treatment is implemented at presence of porous carbon-graphitic material at correlation of its area to the volume of melt 0.01-0.6 cm-1. Process is implemented at temperature 450-680°C during 1-4 hours.
EFFECT: improvement of quality of received coatings from platinum metals ensured by rising of cleanliness of electrolyte.
FIELD: electrolytic apparatuses used in processes for extracting oxides.
SUBSTANCE: apparatus includes common cathode 12 and two types of anodes having different shapes and arrangement and placed in electrolytic bath 10. First anode 14 is arranged under cathode. Second anode 16 is arranged in parallel to cathode. First unit 18 for controlling electrolysis process is connected between cathode and first anode; second unit 20 for controlling electrolysis is connected between cathode and second anode. Combination of cathode and one anode is used for main electrolysis; combination of cathode and other anode is used for additional electrolysis for realizing electrolysis of material 22 in electrolytic bath.
EFFECT: prevention of non-uniformity of deposition, increased rate of processing, increased useful time period of crucible operation, processing of nuclear fuel elements in industrial processes with use of water-free processes.
3 cl, 7 dwg, 2 tbl
FIELD: non-ferrous metallurgy; refining lead from admixtures.
SUBSTANCE: proposed method of refining lead from admixtures includes electrolysis of melt of potassium chlorides and lead by anode polarization; anode polarization of black lead is carried out at current density of 0.41-1.2 A/cm2 at temperature interval of 480-700°C. Concentration of KCl ranges from 30 to 50 mole/%.
EFFECT: high degree of refining lead from admixtures; reduced duration of process without expensive reagents.
2 cl, 1 tbl
FIELD: non-iron metallurgy, electrochemistry, in particular metal production from salt melts.
SUBSTANCE: claimed process is carried out in melt of sodium, potassium, and cesium chlorides in concentration ratio (molar %) of gold ions and impurity metals of 0.02-18.0, using anode made of refining gold containing not more 1 mass % of impurity. Method of present invention is useful in recovery and affinage of noble metals.
EFFECT: gold refining from impurities of foreign metals.
2 cl, 3 ex
FIELD: chemical and microelectronic industry.
SUBSTANCE: invention relates to method for production of powder platinum-group metals and alloys thereof by electrochemical deposition of metal powders from melt salts. Process in the first stage is carried out under galvanostatic conditions in chloride eutectic melt of formula NaCl-KCl-CsCl in ratio of platinum metal ion concentration (mass %) to predetermined current density (A/cm2) from 3.0 to 20 for such period of time as to obtain maximum potential, then electrolysis is carried out under controlled potential conditions.
EFFECT: method for production of powders of different structure type and in necessary amount.
SUBSTANCE: invention can be used to prepare dispersions of titanium dioxide nanoparticles suitable for photocatalytic coatings on surfaces, for photocatalytic disinfection of gases and liquids and for preparing cosmetic compositions with high degree of skin protection from the sun. The method of preparing dispersions of anatase nanoparticles involves the following steps: i) reaction of titanium alkoxide with a complexing solvent selected from a group consisting of ethylene glycol, diethylene glycol or polyethylene glycol; ii) distillation of the solution obtained at step i) to a small volume; iii) addition of water of to the solution obtained at step ii) together with the above mentioned complexing solvent and one or more polycondensation inhibitors, and then heating the reaction mixture with a reflux condenser. The polycondendation inhibitor consists of a mixture which contains at least one inorganic acid and one organic acid. The amount of inorganic acid ranges from 0.1 to 10% of the total volume of the reaction mixture and the amount of organic acid ranges from 1 to 20 vol %.
EFFECT: invention increases stability of dispersions of anatase nanoparticles.
3 dwg, 2 tbl, 12 ex
SUBSTANCE: invention can be used in chemical and electronic industries. Photonic-crystalline films based on monodispersed spherical silica particles are reinforced by immersing ready films into an alcohol nanosol of silica for a short period of time and then drying. The nanosol is prepared by mixing tetraethoxysilane with an aqueous solution of HCl at pH 1.5 and ethanol in ratio of 3.5:1:2.5. The mixture is held at 65-75°C for 1-2 hours. Cetyltrimethylammonium chloride is then added in amount of 200 mg per 3 ml of the sol. Before immersing the substrate with the photonic-crystalline film, the sol is diluted with ethanol in ratio of 1:10.
EFFECT: invention enables to obtain a photonic-crystalline film with Moh's hardness of 3,5-4 and mechanical strength comparable with strength of glass-like silica gel.
2 cl, 1 ex
SUBSTANCE: invention relates to nanotechnologies, in particular to production of water-resistant and heat-resistant structured chemosensor films on the basis of photon-crystalline opalescent matrix, which may find application in express analysis of hazardous admixtures in gaseous and liquid wastes. Method includes thermal treatment of single-crystal photon-crystalline film with particle size of 185-250 nm at the temperature of 350-500°C in air medium for 120-30 minutes accordingly, then impregnation with diluted ethanol nanosol of silica with particle size of up to 8 nm, stabilised with cetyltrimethylammonium chloride and modified with luminescent organic dye, and further drying of produced composite optical chemosensor film.
EFFECT: invention makes it possible to produce water-resistant, mechanically strong and heat-resistant films.
2 cl, 2 dwg
SUBSTANCE: invention relates to nanotechnologies, in particular to production of optical structured chemosensor films on the basis of photon-crystalline opalescent matrix, which may find application in express analysis of hazardous admixtures. Finished film-matrix with size of monodisperse spherical silica particles (MSSP) from 190 to 250 nm applied onto substrate, spherical silica particles with size of up to 8 nm are once submerged vertically in water-ethanol nanosol, modified with luminescent dye. After impregnation with sol the film is dried at the temperature of 20-25°C for 15-20 min. Invention provides for production of chemosensor, in which sensor is represented by nanofilms of mesoporous silica with luminescent dye on surface. Open nature of pores assists in quick penetration of analysed medium inside film.
EFFECT: produced material has high strength.
3 cl, 2 dwg
SUBSTANCE: pressure sensor with thin-film tensoresistor nano- and micro-electromechanical system has a housing in which there is a nano- and micro-electromechanical system (NMEMS) consisting of a membrane with a rigid centre embedded on the contour in the support base, a heterogeneous structure formed on the membrane from thin films of materials in which contact pads, first radial tensoresistors and second radial tensoresistors are formed, connected by thin-film jumpers connected in the measuring bridge. Ends of the first radial tensoresistors lie between the rigid centre and a circle whose radius r is defined by a corresponding relationship. Ends of the second radial tensoresistors lie between the support base and a circle whose radius r is also defined by a corresponding relationship.
EFFECT: higher accuracy, higher reliability and higher technological effectiveness of the pressure sensor.
SUBSTANCE: invention can be used in the paint industry for painting different surfaces (wood, concrete, brick etc), particularly in water paint for interior decoration of facilities with high humidity (vegetable stores, pools, toilet facilities etc) and places where there are a lot of people (hospitals, child care centres, metro etc). The water paint biocidal additive contains a schungite-silver nanocomposite in weight ratio schungite: silver equal to 2:1. The additive has high bactericidal activity and is environmentally safe during production and use. The bactericidal effect is more stable in time than in existing additives using nanosilver.
EFFECT: obtaining a schungite-silver nanocomposite with high bactericidal and fungicidal activity and prolonged bactericidal effect.
SUBSTANCE: composition contains a composite which is a product of reacting 10-15 pts. wt of a polymer and 1-5 pts. wt of nanoparticles of a metal oxide in an aqueous solution, water and a nanoparticle stabiliser. The metal oxide is selected from a group comprising zinc oxide, zirconium oxide, cerium oxide and titanium oxide. The nanoparticle stabiliser is selected from a group comprising alkoxyalkyl-substituted silane, alkylenediamine, cationic surfactant and a neutral surfactant.
EFFECT: invention enables increasing biocidal activity of the composition.
9 ex, 2 tbl
SUBSTANCE: invention relates to composition of material containing concentrated dispersion of nanomaterial and composition of dissolvent, to product prepared with application of such composition and methods for preparation of such composition. Substance of invention consists in the fact that composition of material is produced, which contains concentrated dispersion of nanomaterial and composition of dissolvent, in which volume density of concentrated dispersion is at least three times higher than volume density of nanomaterial in dry form, concentrate requires less volume for storage and transportation compared to volume required for dry nanomaterial, and filling of nanomaterial in concentrated dispersion makes at least 40 wt %. At the same time composition of dissolvent is selected so that coefficient of interphase compliance of Hansen between nanomaterial and composition of dissolvent makes at least 20.
EFFECT: invention provides for cheaper storage and transportation of nanomaterials composition compared to dry nanomaterial.
16 cl, 1 tbl, 1 dwg
SUBSTANCE: invention refers to production of cellulose materials exhibiting fungicidal and bactericidal properties. The material contains a cellulose matrix coated with copper particles. 0.7-2.2 wt % of copper coating the surface and integrated in the thickness of the cellulose matrix represent copper nanoparticles of 20-100 nm and copper microparticles of 125-3000 nm. A woven or nonwoven material chosen from the group, including linen, cotton, rayon materials or their mixtures is used as a cellulose-containing material. The material can be used as sanitary tissue.
EFFECT: material exhibits resistance to natural association of germ cultures in multiple use and reduced strength loss.
2 cl, 7 ex
SUBSTANCE: nanoconverter has a constant optical signal source, an optical nanofibre Y-junction divider, two optical nanofibre N-output dividers lying in mutually perpendicular planes, two telescopic nanotubes, an input optical nanofibre, an optical N-input nanofibre coupler and a group of N optical nanofibres. The telescopic nanofibres are arranged such that in the extreme left position the inner nanotube breaks optical connection between outputs of the first N-output optical nanofibre divider and inputs of the N-input optical nanofibre divider, as well as optical connection between outputs of the second N-output optical nanofibre divider and inputs of the group of N optical nanofibres whose outputs are outputs of the device.
EFFECT: provision for digital conversion to a weighted binary code of optical analogue signals, with fast operation which is potentially achieved for purely optical information processing nanodevices.
FIELD: magnetic materials whose axial symmetry is used for imparting magnetic properties to materials.
SUBSTANCE: memory element has nanomagnetic materials whose axial symmetry is chosen to obtain high residual magnetic induction and respective coercive force. This enlarges body of information stored on information media.
EFFECT: enhanced speed of nonvolatile memory integrated circuits for computers of low power requirement.
4 cl, 8 dwg