Superfine-grained diamond sintered article of the high purity and the high hardness

FIELD: chemical industry; other industries; production of the superfine-grained diamond sintered articles of the high purity and high hardness.

SUBSTANCE: the invention is pertaining to the production of the superfine-grained diamond sintered articles of the high purity and high hardness, which is intended for usage in the capacity of the wear-resistant material capable to let the light go through it, and may be used in production of jewels. The article has the size of the grain equal to 100 nanometers or less. For its manufacture the superfine-grained natural diamond powder having the granulometric spread of values from null up to 0.1 microns is subjected to desiliconization, to sublimation drying in the solution, inclusion into the tantalum or molybdenum capsule without the sintering additive, heating and application of the excessive pressure to the capsule using the device for the synthesis at the super-high pressure at the temperature of 1700°С or more and under pressure of 8.5 GPa or more, which meet the conditions of the thermodynamic stability of the diamond. The technical result of the invention is realization of the synthesis of the diamond sintered article at the more low pressure, than in the standard method and without usage of any sintering additive. The article has hardness according to Vickers - 80 GPa and more and is excellent concerning resistance to the tear and wear and the thermal resistance.

EFFECT: the invention ensures realization of the synthesis of the diamond sintered article at the more low pressure, than in the standard method, and without usage of any sintering additive, ensures its hardness of 80 GPa and more according to Vickers and the excellent properties concerning resistance to the tear and wear and the thermal resistance.

4 cl, 5 ex, 3 dwg

 

The technical FIELD TO WHICH the PRESENT INVENTION

The present invention relates to sortingiterator diamond sintered product of high purity and high hardness and method of its production.

Prerequisites FOR the CREATION of the PRESENT INVENTION

Hitherto known method of obtaining a diamond sintered products or fine-grained diamond sintered product in the presence of metal sintering additives, such as cobalt (Co), using the standard apparatus for synthesis at high pressure (see the following patent publications 1 and 2). Also there is a method of synthesizing diamond sintered products of high hardness with excellent heat resistance, which provides for the performance of technological operations sintering under conditions of higher pressure/temperature than the terms provided for in the standard processing, the use of carbonate of alkaline earth metal as a sintering additive, instead of metal sintering additives (see the following non-patent publication 1). However, these sintered products have a relatively large grain size of approximately 5 microns.

The inventors have described a method of obtaining fine-grained diamond sintered products, which provides for the introduction of the DIAC is dratha oxalic acid, serving as phase fluid CO2-N2Oh, the carbonate to obtain a mixed powder, and application of natural diamond powder having a particle size variation (the range of the diameter distribution of the particles) from zero to 1 micron, the mixed powder for the formation of the layered structure (see the following patent publication 3 and non-patent publications 2 and 3). However, this method of obtaining essentially requires a high temperature component of the 2000°s or greater.

The inventors have also described a method similar to the above described method, which involves the sintering of fine-grained diamond powder having, for example, the particle size range from zero to 0.1 ám (see the following non-patent publication 4). In this case, any diamond sintered product of high hardness cannot be obtained due to the presence of abnormal grain growth in the diamond.

Was recently published article, which describes a method of synthesizing diamond sintered product under pressure 12-25 HPa and at a temperature of 2000-2500°without sintering additives by reaction of direct conversion of graphite into diamond. In this article it is reported that the resulting diamond sintered product has the ability to transmit light (see the following non-patent publication 5).

Patent publication 1: Panska patent publication No. 52-012126.

Patent publication 2: Japanese patent publication No. 04-050270.

Patent publication 3: Publication No. 2002-187775 Japanese patent application laid.

Non-patent publication 1: Diamond and related materials. Vol.5, R-37, Elsevier Science S.A., 1996.

Non-patent publication 2: Journal of the 41stHigh Pressure Symposium, p.108, the Japan Society of High Pressure Science and Technology, 2000.

Non-patent publication 3: Proceedings of the 8thNIRIM International Symposium on Advanced Materials, pp.33-34, the National Institute for Research in Inorganic Materials, 2001.

Non-patent publication 4: Journal of the 42ndHigh Pressure Symposium, p.89, the Japan Society of High Pressure Science and Technology, 2001.

Non-patent publication 5: Terebun and other "characterization of polycrystalline diamond synthesized by direct conversion of graphite using multisupport apparatus, 6thHigh Pressure Mineral Physics Seminar, 28 August, 2002, Verbania, Italy.

A SUMMARY of the PRESENT INVENTION

Diamond sintered article containing a sintering additive, has difficulty in obtaining the ability to transmit light from the solid sintering additives. In addition, compared to the ideal diamond sintered product containing no sintering additive containing sintering additive diamond sintered product has a lower hardness, because the presence of the occupying amount of sintering additives leads to reduction of the area of connection between alaznispireli.

The synthesis of the diamond sintered product of high purity, based on the reaction method of sintering, which uses the reaction of conversion of graphite into diamond, you want to run at extremely high pressure of 12-25 HPa. Thus, amenable to the synthesis of the sample usually has a fairly small size, approximately 1-2 mm, and the range of its application is limited to only a specific area.

All standard diamond sintered products contain a similar type of sintering additives on the basis of metal or non-metal (carbonate), and in accordance with this, the area of connection of the diamond grains inevitably decreases proportionally to volume ratio of sintering additives in the sintered product. Thus, it can obviously be assumed that the hardness Vickers standard diamond sintered products is less than the hardness of the diamond sintered products, not containing sintering additives. In addition, standard diamond sintered product of high purity requires a synthesis of very high pressure.

If such ultra-high pressure is applied to the diamond powder, diamond powder is partially graffitilouis due to the combined effects of high temperature, causing difficulties in the formation of connections between the diamond grains. To avoid vozniknove is of this problem used a sintering additive. Sintering additive selected from catalysts for the synthesis of diamond. Sintering additive induces partial melting in each of the diamond grains to highlight the diamond on each surface of the diamond grains to form a bond between the diamond grains.

The inventors have previously developed a method of preparing a diamond powder for preventing the formation of secondary grains. This final stage involves the exposure of natural diamond powder desilication, the conclusion in the container containing the working solution for dispersion therein of diamond powder, the freezing of the working solution containing diamond powder in the container and sequentially drying by sublimation of the diamond powder to obtain diamond powder.

In addition, the inventors proposed a method of obtaining fine-grained diamond sintered products of high hardness, which involves sintering the above-mentioned diamond powder at a temperature of 1700°s or greater, in the presence of sintering additives carbonate, mixed with the dihydrate of oxalic acid (organic acid sintering additive containing carbonate - C-O-H), due to the use of the apparatus for synthesis at high pressures, and filed a patent application [Japanese patent application No. 2002-030863 (publication No. 2003-22657 Japanese patent application laid)]. However, on the basis of the conditions described in this invention, for example, at a pressure of 7.7 GPA and a temperature of 1700-2300°With diamond sintered product of high hardness cannot be synthesized without the use of sintering additives.

The object of the present invention is the provision of a method of synthesizing diamond sintered products having the original hardness of diamond and not containing sintering additives, at a lower pressure than is used in standard ways.

The inventors have found that by using a method comprising desilication sverkhdolgosrochnogo natural diamond powder having a particle size range from zero to 0.1 μm, drying subjected disilicate powder sublimation and sintering the dried sublimation powder at the temperature of 1700°s or greater, and under the pressure of 8.5 GPA or more without any use of sintering additives, can be synthesized diamond sintered product having a very high hardness compared to a standard diamond sintered product with the use of sintering additives and having a high purity without the content of the component obtained as a result of sintering additives.

In particular, in accordance with the first aspect of the present invention provides sverkhdolgosrochnogo and the maznyj sintered product of high purity and high hardness, having a grain size of 100 nm or less, which is obtained by disilicate sverkhdolgosrochnogo natural diamond powder having a particle size range from zero to 0.1 μm, subjected to freeze-drying of disilicate powder in solution and sintering the dried by freeze-drying powder without sintering additives.

Sortonasinnic diamond sintered product of high purity and high hardness, obtained as described in the first aspect of the present invention, may have the ability to transmit light.

In accordance with the second aspect of the present invention provides a method of obtaining sverkhdolgosrochnogo diamond sintered product of high purity and high hardness, which provides disilicate sverkhdolgosrochnogo natural diamond powder having a particle size range from zero to 0.1 μm, freeze-drying the drained subjected disilicate powder in the solution, the conclusion drained sublimation powder tantalum (TA) or molybdenum (Mo) capsule, heating and sealing the capsule with the help of the apparatus for synthesis at high pressure at the temperature of 1700°s or greater, and under the pressure of 8.5 GPA or more that meet the conditions of thermodynamic stability diamond for specan what I drained sublimation powder.

In the method described in the second aspect of the present invention, heat sealing is carried out at a temperature of 2150°s or greater, and under the pressure of 8.5 GPA or more, making the sintered product has the ability to transmit light.

Unlike conventional diamond sintered products, synthesized from natural diamond powder with the use of sintering additives, sortonasinnic diamond sintered product of high purity and high hardness, synthesized in a way consistent with the present invention has excellent characteristics of high hardness and light transmittance. Thus, it is expected the use of such a diamond sintered product as not only the material high hardness, but also as a material having high hardness and ability to transmit light. In accordance with the method corresponding to the present invention, the diamond sintered product of high purity, having such excellent characteristics can be reliably obtained at a lower pressure than when using standard methods.

Sortonasinnic diamond sintered product of high purity and high hardness corresponding to the present invention has a nanometer size grains and has not the conventional excellent properties. Thus, it is expected the use of such a diamond sintered products in a wide range of applications, such as tools for ultra-precision machining on the machine and working tools for materials that are difficult to be machined on the machine.

BRIEF DESCRIPTION of DRAWINGS

Figure 1 - cross section illustrating one example of a capsule for the synthesis of sintered products intended for sintering the diamond powder in the manufacturing method corresponding to the present invention.

Figure 2(A) and figure 2(C) electron micrograph, which is illustrated by the fracture surface of the diamond sintered products obtained in accordance with patentable example 1.

Figure 3 electron micrograph, which illustrates the ability of the diamond sintered products obtained in accordance with patentable example 2, to transmit light.

DETAILED DESCRIPTION of PREFERRED embodiments of the PRESENT INVENTION

Put desilication hyperfine natural diamond powder for use in obtaining a diamond sintered product corresponding to the present invention were prepared in the following special way. This method is similar to the method for preparing a diamond powder and prevents at the same the Amoy time education secondary grains, which is described in Japanese patent application No. 2002-030863 (publication No. 2003-226578 Japanese patent application laid).

Manufactured on an industrial basis of natural diamond powder having a particle size range from zero to 0.1 μm, is placed in the molten sodium hydroxide in a zirconium crucible for the transformation of the silicate contained in the diamond as impurities in the water-soluble sodium silicate.

In the absence of a standard grain size based on the standardised measurement method for fine powder of diamond, natural diamond powders arrive on the market in accordance with the particle size standard, limited classification particle size of the dispersion (in microns) from zero to 1/4, from zero to 1/2, from zero to 1, from zero to 2, 1 to 3, from 2 to 4 and from 4 to 8 (average grain size is an intermediate value of each particle size range). Granulometric dispersion of natural diamond powder, this description is based on such a classification.

After that diamond powder collected from the molten sodium hydroxide in aqueous alkali solution and subjected to neutralization with hydrochloric acid. Diamond powder is washed several times in distilled water to remove sodium chloride.

Then form a slurry containing diamond then the shock, dispersed therein, and to this solution add Royal vodka in order to expose the diamond powder processing in hot Aqua Regia to remove zirconium, which can be entered from zirconium crucible in the diamond powder. After treatment in hot Aqua Regia diamond powder was washed with distilled water three times or more, and then collected in a solution of a weak acid. The working solution containing diamond powder dispersed therein, has a low acidity with a pH of 3-5.

An aqueous solution of a weak acid containing subjected disilicate diamond powder dispersed therein, is placed in a container made, for example, from a polymeric material, and subjected to mixing by agitation using a shaker, for a sufficient time, for example within about 20-30 minutes. Then the container is moved in liquid nitrogen for rapid freezing subjected desilication diamond powder. The period of time prior to immersion of the container in liquid nitrogen after removal from the shaker should be minimized and preferably to be 30 seconds. This makes it possible to prevent deposition of diamond powder on the bottom of plastic containers and the formation of secondary grains. Liquid nitrogen is an acceptable material for freezing, because it is inexpensive is the material and can easily freeze the solution.

Then perform the following way process of freeze drying. After loosening the cap of the container containing the frozen diamond powder, the container is placed in a vacuum atmosphere. During curing of the frozen solution in a vacuum to sublimate slightly frozen water or ice. Sublimation takes heat from the container containing the frozen diamond powder, allowing the diamond powder to remain in a frozen state. Evaporated water is captured by a cooling unit with cooling capacity -100°s or less, which is located in-line pumping the vacuum pump. For example, freeze-drying 100 ml of a solution containing 15 g of diamond powder, requires approximately four days.

In the above method is subjected disilicate fine diamond powder enclosed in a container that is in a state in which it is dispersed in water, or the surface of each diamond grain is covered with frozen water, successively dried by sublimation to prevent the formation of secondary grains. Diamond powder, passed through a process of freeze-drying, is in a powdered state or formed as discrete grains. That is significantly different from the diamond powder, the resulting group is the standard rotary process filtration/heating/drying the above method can provide dry or loose diamond powder having a high fluidity. The powder prepared by using the above-described process of freeze drying, consists of the primary grains having an average grain size of about 80 nm, as follows from the observations, obtained using an electron microscope. Although in the above description, shows specific numerical terms, they can be changed accordingly to until dry or loose diamond powder can be obtained without formation of secondary grains.

In the method of obtaining a diamond sintered product corresponding to the present invention, ultrafine natural diamond powder prepared as described above freeze-drying, is used as the source material. Figure 1 is a cross section illustrating one example of a capsule for the synthesis of sintered products intended for sintering diamond powder with a manufacturing method corresponding to the present invention. As shown in figure 1, tantalum or molybdenum capsule 2 has a cylindrical shape has a first graphite disk 1A, attached to its bottom to prevent deformation of the capsule. The first layer 3A of the diamond powder was formed on the graphite disea through tantalum or molybdenum foil 5A at a given pressure, and then the second layer 3B is similar to the diamond powder is formed on the first layer 3A of the diamond powder through tantalum or molybdenum foil 5V at the same pressure. Then, tantalum or molybdenum foil 5C is placed on the second layer 3B of the diamond powder and the second graphite disk 1B is placed on the tantalum or molybdenum foil 5S for preventing the deformation of the capsule. Each tantalum or molybdenum foil 5A and 5C is used to separate layers of diamond powder from each other for synthesis of diamond sintered product having the desired thickness, separating the graphite disks from the layer of diamond powder and preventing the pressure medium to penetrate into the capsule. Sintering additive is not used.

This capsule is placed in a compressive environment and is compressed up to the pressure which is of 8.5 GPA or more, at room temperature, due to the use of the device to create ultra high pressure based on static compression process, such as the default tape device for synthesis at high pressures. Then, under such pressure, the capsule is heated to effect the sintering up to this temperature, component 1700°s or greater. If the pressure is less than 8.5 HPa, the sintered product of the desired high hardness cannot be obtained even if the temperature is avna or higher than the temperature of 1700° C. in Addition, if the temperature is less than 1700°C, the sintered product of the desired high hardness cannot be obtained even if the pressure is equal to or greater than 8.5 HPa. It is desirable to limit the temperature and pressure to an absolute minimum, taking into account the possibility of the device, since the excessive temperature or pressure just lead to deterioration in the efficiency of energy use.

The sintered product can transmit light can be obtained by performing sintering at a temperature of 2150°s or greater. The reason is that the temperature component 2150°C, is the temperature that enables the conversion of graphite directly into diamond, and at a temperature of 2150°or more accelerates the formation of links between the diamond grains.

If the tape device for synthesis at high pressures is used as a device to create a very high pressure, it is difficult graphite heater to serve as the heat source device to stably achieve a high temperature component of the 1700°s or greater. As the material of the heater is capable of reaching high temperatures, component 2000°or more can be preferably used developed by the authors of this proposal sintered is the first product based on compounds of titanium carbide-diamond (patent pending Japanese patent application No. 2002-244629). This sintered product based on compounds of titanium carbide-diamond obtained using as starting material a mixture of diamond powder and a powder of titanium carbide.

In particular, as a powder of titanium carbide choose powder non-stoichiometric titanium carbide relevant C/Ti in the range from 0.7 to less than 1 and the grain size of 4 microns, and mixed with diamond powder for the preparation of mixed powders containing these powders. The mixed powder is pressed and processed to remove the binder. Then the mixed powder is sintered in a non-oxidizing atmosphere to induce diffusion connection of diamond and non-stoichiometric titanium carbide. This way can be obtained sintered product based on the connection diamond-titanium carbide having a specified strength and workability, and the method provides the ability to adjust the thickness to the desired value by the subsequent grinding.

In accordance with the present invention, the sintering is carried out with the use of natural diamond powder prepared by using the above-mentioned process of freeze drying. This makes it possible to easily achieve the synthesis of the diamond sintered products of high hardness, the Vickers hardness is 80 GPA or more is her of ultra fine natural diamond powder having a particle size range from zero to 0.1 μm, which could not be achieved using standard methods.

EXAMPLE

A method of obtaining a diamond sintered product corresponding to the present invention will be specifically described in connection with the following examples.

(Patentable example 1)

Manufactured on an industrial basis of natural diamond powder having a particle size range from zero to 0.1 microns, was used as starting material and the above-mentioned process of freeze-drying was used for the preparation of diamond powder. In accordance with the observation using an electron microscope, it was found that this diamond powder had an average grain size of 80 nm. Was prepared in a cylindrical tantalum capsule, having a wall thickness of 0.2 mm and an outer diameter of 6 mm, and the first graphite disc, having a thickness of 0.5 mm, was attached to the bottom of the capsule to prevent deformation of the capsule. 60 mg of the diamond powder was placed on the ground graphite disk through the first tantalum foil and extruded under a compressive pressure of 100 MPa for the formation of the lower layer of diamond powder. In addition, 60 mg of the diamond powder was placed on the bottom layer of diamond powder through the second tantalum foil and press the and in a similar compressive pressure for the formation of the upper layer of diamond powder. Then the third tantalum foil was placed on the top layer of diamond powder, and the second graphite disc, having a thickness of 0.5 mm, was placed on third tantalum foil to prevent deformation of the capsule.

Then the capsule was placed in a compressive environment cesium chloride and subjected to sintering under pressure of 9.4 HPa at a temperature of 2000°C for 30 minutes in a tape device for synthesis at high pressures using the heater sintered product based on compounds of titanium carbide and diamond. After completion of the sintering capsule was removed from the device for synthesis.

Then the product, such as tantalum carbide (TAC)formed on the surface of the sintered products were removed using a solution of hydrofluoric acid and nitric acid, and the upper and lower surface of the sintered product was ground using a grinding wheel with diamond grit. After grinding the sintered product had a very high hardness Vickers, 100 HPa. As shown in figure 2(A) and figure 2(b)are microphotographs corresponding to figure 1, in accordance with the observation using an electron microscope of the surface of the destruction of the sintered products was proved that the sintered product has a homogeneous structure consisting of fine grains with an average grain size of 80 nm.

(Comparative ol the measures 1)

Except that of natural diamond powder having a particle size range from zero to 1 micron, was used as starting material, the sintered product was obtained in a similar way as patentable in example 1. The obtained sintered product had a hardness Vickers 69 GPA. This hardness is significantly lower compared to the hardness obtained patentable in example 1, using the powder having the particle size range from zero to 0.1 microns. This takes place as a result of excessively large grain size in natural diamond powder used as the starting material.

(Patentable example 2)

Except that the sintering was carried out at a temperature of 2150°C for 20 minutes, the sintered product was obtained in a similar way as patentable in example 1. The obtained sintered product had a hardness Vickers 115 GPA and a thickness, component of 0.7 mm As follows from figure 3, it is sintered product has the ability to transmit light and dividing the scale of the measuring range can be clearly visible through the sintered product. That is, the diamond sintered product, which is able to transmit light, can be synthesized under a pressure of less than 10 GPA.

(Comparative example 2)

Except that the sintering was carried out under a pressure of 7 GPA at a temperature of 2300° C for 10 minutes, the sintered product was obtained in a similar way as patentable in example 1. During the grinding of the obtained sintered product had no resistance to grinding. This is due to the fact that the pressure sintering was installed less than 8.5 GPA. In accordance with the measurement of electrical resistance has been proven that the sintered product has electrical conductivity. This conductivity is obtained through graphitization in the surface of each diamond grain.

(Patentable example 3)

Except that the sintering was carried out under the pressure of 9.4 HPa at a temperature of 1800°C for 30 minutes, the sintered product was obtained in a similar way as patentable in example 1. During the grinding of the obtained sintered product had a high resistance to polishing. In accordance with the measurement of the Vickers hardness was proved that the obtained sintered product has a very high hardness 100 HPa, even when the sintering carried out at a temperature of 1800°C.

INDUSTRIAL APPLICABILITY

Diamond sintered product corresponding to the present invention has a grain size of 100 nm or less, as shown when observed under an electron microscope, and has a high hardness Vickers, component 80 GPA or more, and comp is it from a homogeneous fine grain without abnormal grain growth. Thus, the diamond sintered product excellent in resistance to wear/abrasion and heat resistance and is operable in a configuration with a sharp cutting edge. For example, if you use this diamond sintered product when finishing machining for material, difficult mechanical machining, such as alloy Al-Si with a high silicon content, or high-precision machining of metal or alloy, it can have excellent cutting efficiency.

In addition, although the diamond sintered product, which is used sintering additive, has transparency, diamond sintered product corresponding to the present invention, has no diffraction lines, in addition to the diffraction line of diamond powder x-ray diffractometry, and can transmit light, providing clear visibility through letters or similar characters. Thus, the diamond sintered product corresponding to the present invention, suitable for use as a wear-resistant material that can transmit light (e.g., material for Windows, designed for use in missiles, or hydrothermal reaction vessels, or pressure elements for generating high pressure), and jewelry, such as jewelry is.

1. Sortonasinnic diamond sintered product of high purity and high hardness with grain size of 100 nm or less, which is obtained by exposure sverkhdolgosrochnogo natural diamond powder having a particle size range from zero to 0.1 μm, desilication, freeze-drying powder, subjected disilicate, in solution and sintering the dried sublimation powder without sintering additives.

2. Sortonasinnic diamond sintered product of high purity and high toughness according to claim 1, which is able to transmit light.

3. The method of obtaining sverkhdolgosrochnogo diamond sintered product of high purity and high hardness, which desilication sverkhdolgosrochnogo natural diamond powder having a particle size range from zero to 0.1 μm; freeze-drying subjected disilicate powder in solution; conclusion drained sublimation powder tantalum or molybdenum capsule; and heating and the application of excessive pressure to the capsule using the device for synthesis at high pressure at a temperature of 1700°s or greater and a pressure of 8.5 GPA or more that meet the conditions of thermodynamic stability of diamond, for sintering the dried sublimation powder.

4. The method according to claim 3, wherein said load is in and the application of excess pressure is carried out at a temperature of 2150° With or more and under a pressure of 8.5 GPA, making the sintered product is able to transmit light.



 

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1 tbl, 7 ex

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.

3 ex

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.

2 dwg

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.

8 dwg

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.

2 cl

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