Method for preparing of nanodiamond powders for producing of stable suspensions
FIELD: production of nanodiamond suspensions in various media for conducting of plating processes.
SUBSTANCE: method involves providing thermal processing of nanodiamond powder in air at temperature of 440-600 C until powder weight losses reach 5-85%. Thermally processed powder forms stable suspensions in water, ethyl alcohol and other solvents upon common mixing. Sediment stability of nanodiamond suspensions thermally processed in accordance with invention and produced using supersonic treatment is at least 1.5 times as high as similar parameter of nanodiamond suspensions produced by prior art processes.
EFFECT: simplified method allowing stability of nanodiamond suspension in various media to be improved.
The invention relates to the field of production almatadema materials, namely suspensions diamond in different environments.
In recent years, methods of dynamic synthesis obtained new diamond products, called nanodiamonds (in the literature there are also names: ultradispersed diamonds of detonation diamonds, ultrananocrystalline diamonds) [1,2]. Such products are diamond particles with a size of 4-6 nm (sometimes up to 15 nm) with high surface area. Dry particles of nanodiamond aggregate in units larger than 1 μm. Nanodiamonds are used in a number of areas, it is often used in the form of aqueous and non-aqueous suspensions, for example in electroplating processes . When used in the form of suspensions it is necessary to ensure their sustainability over time, however, a tendency inherent to the aggregation prevents this. Especially difficult is the preparation of suspensions of dry powder of nd in aqueous and nonaqueous media, not containing added surfactants.
The known method described in , which consists in drying of ultradispersed diamond in oxygen-containing atmosphere that allows you to simplify the process of obtaining suspensions of nanodiamonds. However, the suspension of nanodiamond obtained by a known method, do not have high sediment is sure stability.
The objective of the invention is to develop a method of preparing powders of nd to obtain stable suspensions allows to simplify the method of preparation of the suspensions and to improve their stability in different environments.
The objective of the invention is solved in the proposed method by oxidation of nanodiamond powders in oxygen-containing atmosphere to weight loss 5-85%. As oxygen-containing environment is preferable to use air as an available source of oxygen. The process of oxidation is expediently carried out at temperatures 440-600°C.
The invention consists in the following. The complexity of making the suspension of nanodiamond lies in the ability of particles to aggregation and formation of relatively large aggregates. The units are fairly stable. The oxidation of the nanodiamond powder is the interaction of the surface of the individual particles of nanodiamond with oxygen with the formation of gaseous oxides of carbon. Thus, with the surface of the particles gradually removed layers of carbon atoms. The oxidation process affects the contact area ("passages") between the particles, resulting in the formation of aggregates. Thereby a considerably weakened. When placing the treated nanodiamond powder in water or selected organic solvents unit easily raspugaet the I portions of which greatly simplifies the preparation of the suspension.
Oxidant in the described process is oxygen, which, of course, can be applied in mixture with other inert gases, for example nitrogen. More convenient and easier to carry out the process using air. The temperature oxidation, it is advisable to choose in the range of 440-600°C. At lower temperatures, the process may take a long time, and at temperatures above 600°on the contrary, to proceed too quickly, which complicates its control. However, the choice of temperature range depends on the processed powder of nd and used gas environment.
It should be emphasized that the proposed solution provides not just a surface treatment with oxygen, and the implementation of deep oxidation of nanodiamond particles with a large change in its mass. This is the main essence of the invention provides the solution of the invention and fundamentally distinguishes it from other methods.
The following examples describe the invention.
Example 1. The nanodiamond powder is placed in a quartz Cup. Cup with nanodiamond placed in a muffle furnace and heated in air (oxidized) at a temperature of 460°C for 1 hour. After that, the Cup is removed from the muffle furnace and cooled. The decrease in the mass of nanodiamond is 22%. According to the scientists the sample readily forms a stable suspension in water, even in mild stirring. Whereas the original powder nd very quickly falls to the bottom of the vessel.
Example 2. Carried out analogously to example 1. The oxidation is carried out at a temperature of 520°C for 6 hours. Reducing the mass of sample nd - 82%. The resulting nanodiamond easily forms a stable suspension in ethanol under mild stirring. Source material does not form stable suspensions in similar conditions.
Example 3. To implement the example was selected powder nd ADCS (made by "Center of the diamond technology" gsneric). The powder is divided into 2 parts. The first part of the powder was dried in air at 120°as specified in the prototype (sample 1). The second part of the powder was processed similarly to example 1. The oxidation was carried out at a temperature 480°C for 3 hours (sample 2). Reducing the mass of sample nd - 77%. From powders of sample 1 and sample 2 were prepared suspension: 1 mg nd in 10 ml of water. The suspension was subjected to ultrasonic treatment at a frequency of 22 kHz for 30 seconds After it was determined the change in optical density of the suspension through a 100 hours on the instrument FEC-56 (at a wavelength of 440 nm). For suspension based on a sample of 1 optical density was 20% of the initial optical density (measured immediately after preparation of the suspension). The optical density when spencie based on the sample 2, measured after 100 hours, amounted to 55% of the initial optical density. Thus shows a large sedimentation stability of the suspension, obtained using the proposed method.
Thus, the proposed solution allows the preparation of nano-diamond powders to obtain stable suspensions. The implementation of the method greatly simplifies the process of obtaining suspensions, and the method is relatively simple.
The sources used in the preparation of the description
1. Dolmatov VY Ultradispersed diamonds of detonation synthesis. Production, properties, application. St. Petersburg: Izd. SPb GPU, 2003. 344 S.
2. V.V. Danilenko Synthesis and sintering of the diamond explosion. Moscow: Energoatomizdat, 2003, 272 S.
3. Dolmatov VY Ultradispersed diamonds of detonation synthesis: properties and application. USP, 2001, t, No. 7, s-708.
The method of preparing powders of nd to obtain stable suspensions, including heat treatment in air at elevated temperatures, characterized in that the heat treatment is carried out at a temperature of 440-600°With the loss of the mass of powder on 5-85%.
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: electrochemical extraction of metals from complex compounds; purification of diamond synthesis products.
SUBSTANCE: proposed method includes electrochemical treatment of synthesis product in acid electrolyte for obtaining graphite-diamond product containing 0.5-2.0% of metallic admixtures and deposition of metallic nickel and manganese on cathode. During purification of diamond synthesis products at extraction of nickel and manganese in form of metallic product, electrochemical treatment is carried out in membrane-type electrolyzer at circulation of catholyte through second electrolyzer. Process is conducted in area of temperatures of 25-30°C at cathode current density in the first electrolyzer of 2-15 A/dm2 and 15-30 A/dm2 in the second electrolyzer; catholyte pH in the presence of 100-150 g/l of (NH4)2SO4 in it is maintained at outlet from the first electrolyzer of 5-7.5 and 2.5-5 at return.
EFFECT: possibility of performing nickel and manganese extraction and purification of diamond synthesis products in one cycle.
1 tbl, 6 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: mineral dressing.
SUBSTANCE: method comprises charging, chemically enriching concentrate, cleaning, and discharging desired product. Chemical enrichment is carried out by way of single or multiple processing in acid or in acids and then in alkali or alkali mixture, while heating material to 900-1000°C and holding it at this temperature in inert gas medium at stirring.
EFFECT: enhanced diamond cleaning efficiency.
6 cl, 1 tbl
FIELD: production of diamonds of jewelry property; high-quality cleaning of diamonds.
SUBSTANCE: proposed method includes stage-by-stage treatment of diamond by mixture of acids under action of microwave radiation; at first stage, use is made of nitric acid and hydrogen peroxide at volume ratio of components of 10:1, respectively; at second stage, volume ratio of mixture of concentrated nitric acid, hydrochloric acid and hydrofluoric acid is 6:2:1, respectively; diamond is treated at temperature not higher than 210°C, pressure of 35 atm as set by loading ratio of autoclave equal to 1:10 at power of oven of microwave radiation of 1200 W; duration of each phase does not exceed 40 min. Proposed method ensures perfect cleaning of diamonds from contamination of mineral and organic nature including bitumen compounds on surface and in cracks of diamond.
EFFECT: enhanced efficiency; reduction of time required for process.
FIELD: jewelry industry, in particular, production of precious stone, more particular diamond which may be personified or identified with certain individual or animal.
SUBSTANCE: personified grown jewelry diamond comprises heavy metals Sr, Cd, Sn, Ba, Pb, Bi separated from hairs of certain individual or animal, with ratio of concentrations of said metals corresponding to that of said elements in hairs of the given individual or animal. Method involves processing hairs of certain individual or animal by mineralization of hairs at temperature below 550 C until complete decomposition of organic component; forming source for growing of diamond from spectrally pure graphite and hair processing product containing heavy metals Sr, Cd, Sn, Ba, Pb, Bi; growing diamond from melt by seed crystal recrystallization process; determining ratio of concentrations of these elements in grown diamond and comparing with their content in processing product. Jewelry diamond produced has microelements characteristic of certain individual or animal.
EFFECT: simplified method and improved quality of grown jewelry diamond.
3 cl, 2 tbl
FIELD: carbon materials.
SUBSTANCE: invention concerns manufacture of diamond films that can find use in biology, medicine, and electronics. Initial powder containing superdispersed diamonds with level of incombustible residue 3.4 wt %, e.g. diamond blend, is placed into quartz reactor and subjected to heat treatment at 600-900оС in inert of reductive gas medium for 30 min. When carbon-containing reductive gas medium is used, heat treatment is conducted until mass of powder rises not higher than by 30%. After heat treatment, acid treatment and elevated temperatures is applied. Heat treatment and acid treatment can be repeated several times in alternate mode. Treated powder is washed and dried. Level of incombustible impurities is thus reduced to 0.55-0.81 wt %.
EFFECT: reduced level of incombustible impurities.
4 cl, 3 ex
FIELD: carbon materials.
SUBSTANCE: weighed quantity of diamonds with average particle size 4 nm are placed into press mold and compacted into tablet. Tablet is then placed into vacuum chamber as target. The latter is evacuated and after introduction of cushion gas, target is cooled to -100оС and kept until its mass increases by a factor of 2-4. Direct voltage is then applied to electrodes of vacuum chamber and target is exposed to pulse laser emission with power providing heating of particles not higher than 900оС. Atomized target material form microfibers between electrodes. In order to reduce fragility of microfibers, vapors of nonionic-type polymer, e.g. polyvinyl alcohol, polyvinylbutyral or polyacrylamide, are added into chamber to pressure 10-2 to 10-4 gauge atm immediately after laser irradiation. Resulting microfibers have diamond structure and content of non-diamond phase therein does not exceed 6.22%.
EFFECT: increased proportion of diamond structure in product and increased its storage stability.
FIELD: chemical industry and electronics; production of diamonds.
SUBSTANCE: the invention is intended for chemical industry and electronics. The chemical product is prepared out of the following organic compounds (in weight %): acetamide - 6.7; carbamide - 0.8; ethylene glycol - 2.0; glycolic acid - 11.7; lactamide - 8.8; glycerine - 2.3; hexamethylenetetramine - 11; indene - 7.6; 1,2-dimethylnaftaline - 2.6; 1,4 -diisopropenylbenzol - 3.3; cyclohexylphenylketon - 8.1; 4'-cyclohexylacetophenone - 7.2; 4-(1-adamantyl)phenol - 2.1; 4,4'-methylenebis (2,6-dimethyl phenol) - 2.3; α,α'- bis (4-hydroxyfenyl)-1.4-diisopropylbenzol - 0.2; phenanthrene - 11.0; lauric acid - 6.2; sebacic acid-6.3; eicosanic acid - 9.7. The indicated components are mixed with water in the ratio of 1:(1-2). The mixture is heated up to 150-200°С in vacuum of 10-1-10-6Pa. A reaction sample formed this way is refrigerated in conditions of vacuum and dried for removal of water and the volatile organic substances. The dried reaction sample is heated in vacuum up to 200-400°С for 80 hours. The invention allows to use the raw material being in lower power state as compared with the known methods and to produce the high-clean diamonds.
EFFECT: the invention ensures production of the high-clean diamonds from the raw material of the lower power state.
16 cl, 1 tbl, 1 ex, 4 dwg
FIELD: production of color diamonds.
SUBSTANCE: the invention is pertaining to the field of production of fantasy neon yellow-green diamonds of precious quality produced from the pale (discolored) or so-called "brown" diamonds of the lowest quality. The method provides for placement of a pale natural diamond in the medium capable to transfer the pressure, which then is mold into a "tablet". Then the tablet is placed in the high-pressure press (HP/HT) and exposed to machining at an increased pressure and temperature being within the range of graphite stability or a diamond being on the phase diagram of carbon for the period of time necessary for improvement of a color of the mentioned diamond. In the end the diamond is removed from press. The indicated method ensures production of diamonds of an attractive yellowish-green or yellow-green and neon yellow-green colors.
EFFECT: the invention ensures production of diamonds of attractive yellow-green colors.
22 cl, 4 ex, 2 dwg
FIELD: chemical industry.
SUBSTANCE: the invention is intended for chemical industry. To 1 g of a powder of nanodiamonds of an explosive synthesis add 100 ml deionized water. The mixture is treated with the ultrasonic dispersant for 5 minutes. The produced suspension is added with an electrolyte - NaCl solution in the quantity exceeding sorptive capacity of nanoparticles by ions of sodium, for example, 20 ml of 0.9 M solution. Then separate the disperse medium and the settling. The disperse medium is removed. The settling is added with 100 ml of deionized water and is intensively agitated. The supernatant - hydrosol of nanodiamonds is separated and dried. At multiple add-on of water to the produced powder a stable nanodiamond hydrosol is formed. The share of the surface impurities in the produced nanodiamond is reduced. Simultaneously the share of sodium ions is increased.
EFFECT: the invention allows to reduce the share of the surface impurities in the produced nanodiamond and simultaneously to increase the share of sodium ions.
1 dwg, 1 tbl
FIELD: carbon materials.
SUBSTANCE: invention is designed for use in manufacture of hydrosols, organosols, and suspensions in oils. Nano-size diamond powder is charged into ultrasonic disperser and water and modifier, in particular organic ligand such as EDTA or ethylenebis(oxyethylenenitrilo)tetraacetic acid are then added. Resulting suspension is separated on centrifuge into dispersion medium and precipitate. The latter is treated with water to form suspension, which is centrifuged to give precipitate and hydrosol, which are concentrated separately by heating in vacuum into powderlike form. When concentrating hydrosol, depending on desire, following finished products may be obtained: concentrated hydrosol, cake, or dry black powder. When concentrating precipitate, clear nano-size diamond powder is obtained. Thus obtained products are appropriate to prepare sedimentation-resistant hydrosols and organosols with no ultrasound utilized, which products have no tendency to aggregate upon freezing and thawing, boiling and autoclaving, and which can be repetitively dried and reconstituted. Surface pollution of nanoparticles is reduced.
EFFECT: enabled preparation of hydrosols with precise concentration of nano-size diamonds.
3 cl, 1 tbl, 5 ex
SUBSTANCE: method comprises filling tank (11) with coolant (12) and igniting heating mixture (3) say silicon boride. At the moment of maximum heating of the graphite (5) to be processed, explosive (1), say trinitrotoluene, is initiated. The propagating explosion wave set heated mixture (3) and agent (5) to be processed into motion, and agent (5) enters closed passage between the cooled separated substrate (8) and rod (9). The passage can be diverging to provide additional compression of agent (5) and pressing substrate (8) into conical mandrel (1) under the action of shock wave. Deflecting diaphragm (7) is an insulator, and insulating layer (2) prevents agent (5) to be ignited up to the moment of its maximum heating.
EFFECT: enhanced efficiency and reduced power consumption.
1 cl, 2 dwg
FIELD: power industry, mechanical engineering and environmental control.
SUBSTANCE: the invention is pertaining to the field of high power industry, mechanical engineering and environmental control. In a explosion-proof chamber 1 with double-walls simultaneously feed a gaseous explosive mixture using pipeline 4 through channels 5 and inject hydrocarbons with the nucleuses of carbon crystallization using a pipeline 6 through an injector 7 with formation of a cone-shaped shell 8 with an inert cavity in the central zone. The shell 8 and the explosive mixture 9 form a cumulative charge. Conduct initiation of undermining of an explosive mixture 9, as a result of which the cumulative charge forms a cumulative spray 10 moving at a high speed along the axis of the cumulation. The gaseous products withdraw through pipeline 17. At collision of the cumulative spray 10 with a barrier having channels 11 of the cooling unit 2 the pressure and temperature there sharply increase ensuring growth of the formed crystals of diamond. Simultaneously conduct cooling with the help of pipelines 12 located in metal filings and granules 13. The atomized and cooled cumulative spray gets into the auxiliary chamber 3, where the diamonds 14 are separated, feed through the pipeline 15 to a power accumulator 16, in which they are settling. Separated hot hydrogen is removed for storing or utilization. The invention allows to magnify the sizes of dimensions crystals of diamond up to 800 microns and more, to decrease atmospheric injections, to reduce the net cost of the diamonds, to increase effectiveness of the device.
EFFECT: the invention ensures growth of sizes of diamonds crystals up to 800 microns and more, decrease of atmospheric injections, reduction of the net cost of the diamonds, increased effectiveness of the device.
2 cl, 2 dwg
FIELD: methods and devices used for production of diamonds.
SUBSTANCE: the invention is pertaining to methods and devices for production of diamonds and may be used in materials technology. Assemble a mold. Ignite a thermit grain and heat up the powdered graphite. After that they initiate explosion of a charge. The explosion energy sets in motion a striker, which is directly caulking the powder graphite in the capsule. After that disassemble the mold, extract the produced diamond. The invention allows to miniaturize the sizes of the charge and the mold, to simplify the production process and to use such a mold multiply.
EFFECT: the invention allows to miniaturize the charge and the mold sizes, to simplify the process of diamonds production and to use such a mold multiply.
FIELD: production of the jewelry quality diamonds from the natural low-grade undecoratively colored diamonds.
SUBSTANCE: the invention is pertaining to production of the diamonds of the jewelry quality from the natural low grade undecoratively colored so-called "brown" diamonds, especially from the diamonds of IIa type and IaA/B type, in which nitrogen forms predominantly B-center for improvement of heir color. The invention provides for realization of the rough faceting and molding of the undecoratively colored natural diamond for giving it the streamline form to avoid its breakup in the press of the high-pressure and heating (HP/HT press). The indicated undecoratively colored natural diamond is put in the pressure transferring medium, which then is compacted into the tablet. Then the tablet is put in the HP/HT squeezer under the high pressure and temperature kept in the field of stability of the blacklead or the field of stability of the diamond of the phase diagram of carbon for the time duration sufficient for improvement of the color of the diamond. After the operation is terminated extract the diamond from the squeezer. The method ensures production of the colorless and decoratively colored diamonds.
EFFECT: the invention ensures production of the colorless and decoratively colored diamonds.
25 cl, 6 ex, 2 dwg