Method for obtaining titanium-containing alloy for steel alloying |
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IPC classes for russian patent Method for obtaining titanium-containing alloy for steel alloying (RU 2497970):
Method to produce aluminium-copper alloys / 2486271
Aluminium alloy is prepared, reheated over alloy liquidus curve temperature. Copper is added into the aluminium melt in the form of a wire, at the same time electric current is sent between the wire and the melt. Wire melting is carried out without formation of an arc at the ratio of current density to speed of wire feed equal to 0.3-1.0·1010 A·s/m.
 Alloy of out-of-furnace production of steel and iron and blend to this end / 2483134
Proposed composition contains the following substances, in wt %: titanium - 30- 50, zirconium - 1-25, silicon - 15-30, aluminium - 0.1-3, iron making the rest. For production of proposed alloy the blend is used that contains ilmenite concentrate, rutile, coal, quartz sand, quartzite, and zirconium concentrate.
Alloy for alloying of steel with titanium / 2482210
Alloy contains the following components, wt %: titanium 45-75, silicon 5-45, aluminium 5-15, carbon not more than 0.2, iron - balance, at the same time the mass ratio of titanium to aluminium is within the limits from 3:1 to 15:1.
Method for production of aluminium-zirconium ligature (versions) / 2482209
For production of aluminium-zirconium ligature, aluminothermal recovery of zirconium is carried out from its compounds in the environment of melted metal halogenides. Zirconium is recovered from its fluoride or oxide, and also from fluozirconate or oxifluozirconate of alkaline or alkaline-earth metal in presence of potassium chloride, sodium fluoride and aluminium fluoride, introduced into the melt or formed in the process of aluminothermy. The temperature of the process amounts to 850-1150°C. Recovery is carried out under the layer of chloride cover flux, containing potassium and sodium chlorides at the following ratio of components, in the mixture, wt %: potassium chloride 42-45, sodium chloride - balance. The melt is soaked for 15-30 minutes, and bars are poured. The invention makes it possible to produce bars of ligature with homogeneous structure with dimensions of intermetallides of up to 15-30 mcm, at the same time non-return losses of zirconium are reduced down to 7-9%, environmental characteristics of the process are improved.
Alloy combination for production of castings from high-strength cast-iron (versions) / 2480530
As per Version 1, alloy combination contains the following, wt %: silicon 22.0-30.0, magnesium 9.0-12.0, cerium 0.4-0.6, copper is the rest; as per Version 2, alloy combination contains the following, wt %: silicon 22.0-30.0; magnesium 9.0-12.0, misch metal 0.8-1.2, and copper is the rest.
Method for obtaining nitrogen-containing alloy for alloying of steel and cast iron, and nitrogen-containing alloy for steel and cast iron alloying / 2479659
Bearing titanium-chrome ferroalloy is crushed to powder with particle size of less than 0.2 mm. Titanium-chrome ferroalloy contains the following, wt %: chrome - 5.0-35.0, titanium - 15.0-30.0, aluminium - 5.0-10.0, silicon - 5.0-8.0, and iron is the rest. Total amount of Ti, Cr, Si, Al is 30.0-82.0 wt %. Powder is loaded to the container that is moved to a SHS reactor; an exothermic burning reaction is initiated in a layer-by-layer mode at nitrogen pressure of 1.0-15.0 MPa.
 Method for obtaining aluminium-titanium alloy combination (versions) / 2477759
Invention refers to non-ferrous metallurgy and can be used for obtaining alloys based on aluminium. In order to obtain aluminium-titanium alloy combination, alumino-thermal reduction of titanium from its compounds is performed in the environment of molten halogenides of metals. Titanium is reduced from its fluoride or oxide, as well as from fluorotitanate or oxyfluorotitanate of alkali or alkali-earth metal in presence of potassium chloride, sodium fluoride and aluminium fluoride, which are introduced to molten metal or formed during aluminothermic process. The temperature of the process is 850-1150°C. Reduction is performed under the layer of covering flux chloride, which contains potassium and sodium chlorides at the following ratio of components in the mixture, wt %: potassium chloride 42-45, sodium chloride is the rest. Molten metal is exposed during 15-30 minutes and poured into billets. The invention allows obtaining billets of the alloy combination with homogeneous structure with intermetallides with the size of up to 15-30 mcm, reducing non-collectable titanium scrap to 7-9% and improving environmental characteristics of the process.
Foundry alloy for casting heat-resistant titanium alloy and method of its making / 2470084
Invention relates to metallurgy of nonferrous metals, particularly, to production of foundry alloy for alloying refractory titanium-base alloys. Proposed composition contains the following substances, in wt %: tungsten 48.0-52.0, titanium 10.0-20.0, hafnium 0.08-0.1, aluminium making the rest. Charge is smelted in vacuum arc furnace with nonconsumable tungsten electrode. Note here that at first step, titanium placed on bottom of copper water-cooled casting mould and tungsten of higher density is placed there above. Titanium and tungsten are dissolved and melted in proportion corresponding to their content in foundry alloy to make integral ingot at arc current between charge and electrode of 750-1100 A and melting time of 3-10 min. To average ingot chemical composition, ingot is removed from casing mould to subject it to remelting at temperature higher than liquidus temperature of the alloy of titanium and tungsten. Then, required amount of aluminium and hafnium is added to remelted ingot to be placed under aforesaid ingot to proceed with melting at 1750-1900°C.
 New generation nanomodifier (ngnm) / 2468110
Complex modifier contains the following components, wt %: fullerenes 0.1-27, nanosized composite particles of metal carbides selected from the following group: cobalt, iron, nickel 1-43, nanosized composite particles of cobalt 0.2-20, nanosized particles of lanthanum 0.1-29, nanosized composite particles of tungsten 0.5-42, nanosized composite particles of cerium 0.7-33, nanosized composite particles of iron 1-41, nanosized composite particles of nickel 0.6-36, nitrides or silicides or borides or oxides or carbonitrides of metals - balance.
Method of producing aluminium alloys with transition metals / 2467086
Invention relates to nonferrous metallurgy and may be used in production of foundry alloys based on aluminium with transition metals. It comprises making aluminium melt overheated to above alloy liquidus temperature and adding alloying components into melt by fusing the wire. Note here that electric current flows between wire and aluminium melt. Layer of fused flux is produced on aluminium melt surface while said wire is fused by heat released in flux layer at electric current existing therein. Note also that said flux contains cryolite - 40-45 wt %, aluminium oxide - 10-20 wt %, and magnesium fluoride - 35-40 wt %.
 Material for steel refining / 2245390
Claimed material contains (mass %): viterite concentrate 40-42; aluminum 38-40; lime 5-12; magnesium 6-8; titanium 1-2. Invention allows increasing the refining ability of material due to modification low valence sulfur and phosphorus compounds in metal melt.
Batch for refractory metal-based addition alloys / 2246551
Claimed batch contains refractory metal high oxides, aluminum powder, calcium oxide and fluoride-based fluxing agents, refractory metal low oxides and ballast additives if form of addition alloy and/or titanium powder or sponge waste returns. Vanadium trioxide and/or molybdenum dioxide are used as refractory metal low oxides. According to this invention, it is made possible to increase recovery degree of valuable components by 1.5-2.0 % and decrease refractory metal oxide content in dross. Utilization of addition alloy crumb returns makes it possible to increase the ingot-to-product yield by 2-4 %.
 Modifying agent / 2247170
Claimed modifying agent contains (mass %) ferrosilicon barium 0.5-5.0 and gypsum 25-5 %.
Addition alloy / 2247790
Claimed addition alloy contains (mass %): titanium 10-50; niobium 25-65; magnesium 2-35.
 Low-carbon high-purity ferrotitanium / 2247791
Invention relates to low-carbon high-purity ferrotitanium, containing (mass %): titanium 20.0-75.0; aluminum 0.05-0.30; silicon 0.10-0.30; manganese 0.10-0.30; carbon 0.005-0.07; molybdenum 0.02-0.10; chromium 0.02-0.10; vanadium 0.02-0.10; copper 0.02-0.10; nickel 0.02-0.10; zirconium 0.02-0.10; nitrogen 0.005-0.04; calcium 0.005-0.05; oxygen 0.01-0.15; and balance: iron and impurities, such as lead <=0.001; antimony <=0.002; bismuth <=0.002; tin <=0.002; arsenic <=0.001; zinc <=0.002; sulfur <=0.015, and phosphorus <=0.015, wherein total content of lead, tin, antimony, arsenic, bismuth, and zinc is not more than 0.008 mass %. Alloy of present invention is useful in manufacturing of welding and fluxing materials to obtain weld seam of refractory steel and alloy with high long-term strength at >6000C.
Composite material for deoxidation and/or desulfuration of steel and/or recrements / 2249058
Claimed composite material comprises aluminum-containing fusible matrix component and iron-based alloy as refractory reinforcing component in mass ratio of matrix and reinforcing components from 20/80 to 50/50. Fusible matrix component represents aluminum and magnesium alloy containing (mass %): magnesium 10-80 and aluminum 20-90. Method of present invention makes it possible to increase aluminum and magnesium recovery in liquid steel by 30-50 %.
 Method of high-titanium-bearing foundry alloy production / 2250271
The invention is dealt with the field of metallurgy, in particular, with production of the foundry alloy containing mainly titanium and also a small amount of other useful metals reduced from oxides of a charge together with the basic components of a foundry alloy. The method includes the following stages: after melting-down of the first portion of the charge representing an ilmenite concentrate formed on the rotating melt of the high-titanium-bearing foundry alloy and reduction by titanium and silicon of a part of oxides from the melted portion of ilmenite they use aluminum to reduce all oxides in a cinder melt. The obtained slag is added with the first portion of calcium oxide in the amount ensuring fluidity of the cinder. The second portion of the charge is introduced in the melt in the amount corresponding to the possibility of to reduce oxides by titanium. The produced titanium oxide is merged with the earlier produced cinder. A determined part of the produced melt in conditions of its rotation is poured out through a side tap hole. Using aluminum reduce titanium oxide from the merged cinder and the reduced titanium merge with the rest metal melt. In the formed final cinder enter the second portion of calcium oxide. A part of the produced foundry alloy is poured out through a side tap hole. Then a final cinder is also poured out and they feed a new portion of ilmenite onto the residue of the foundry alloy. The invention allows to reduce at least twice the power input used for reprocessing of the ilmenite concentrate, as in the process of reduction of the metals from oxides there are no endothermic reactions but exothermic reactions; to use ilmenite concentrates with a share of titanium oxide up to 45% and a strong metal reductant - aluminum, and also to realize a progressive technology of the liquid-phase reduction of metals from oxides in conditions of rotation of the melt by an electromagnetic field.
Alloy for deoxidation and alloying liquid blank in smelting low- and medium-carbon high-alloy steel / 2267548
Invention relates to alloy for deoxidation and alloying comprising the following components, wt.-%: carbon, 0.15-0.35; silicon, 2-3; manganese, 0.25-0.40; chrome, 41-46; nickel, 1.0-3.2; vanadium, 0.5-0.8; niobium, 0.5-0.7; molybdenum, 0.25-1.0, and iron, the balance. Alloy comprises additionally tungsten in the concentration 2.5-3.5 wt.-%. Invention provides the development of alloy balanced by its chemical composition wherein in its smelting waste of high-alloy steels is used and this alloy comprises deoxidizing and alloying components taken in the amounts excluding their losses in alloy smelting. Also, invention provides the minimal duration in treatment of liquid semi-finished product in aggregate of the steel complex treatment, electric energy and neutral gas consumption, and high resistance of fettling in pouring ladles. Invention can be used in smelting low- and medium-carbon high-alloy steel.
Method of preparation of master alloys and deoxidizers / 2269586
Proposed method includes mixing solid filler with melt of active metallic binder. First, porous blank of preset geometric shape is molded from material of filler selected from group including iron, nickel, titanium, silicon, boron, manganese; then, blank is heated to temperature corresponding to liquidus temperature of active binder; heating is performed in inert gas medium; after mixing the filler with binder, blank is impregnated with melt of this binder by forced infiltration of melt into pores of blank under pressure, mainly by molten-metal pressing method. Proposed method cuts costs of metallurgy products due to effective content of active components and complete assimilation.
Addition alloy for inoculation and doping of alloys / 2270266
The invention is pertaining to the field of metallurgy, in particular, to treatment of melts of metals and alloys with doping and inoculating additives. The addition alloy contains 14-17 % of magnesium, 0.4-0.6 % of cerium, the rest includes nickel and impurities and it is made in the form of an alloy fragmented particles. The particles sizes make from 0.5 up to 4 mm. In impurities carbon content is concluded within the limits of from 0.001 up to 0.1 %. The invention allows to produce cast irons containing globular graphite, and also expands possibilities of production of ingots from alloys with the improved structure in nonferrous metallurgy.
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FIELD: metallurgy. SUBSTANCE: reaction powder mixture containing 45-88 wt % of titanium-containing component and 12-55 wt % of silicon-containing component is prepared. Powders with particle size of less than 5 mm are used. After that, an exothermic reaction of combustion in inert atmosphere is initiated in the mixture. EFFECT: invention allows obtaining complex alloys with high content of titanium and low content of impurities, which include high-activity elements in relation to oxygen, at minimum electric power consumption. 13 cl, 1 tbl
The invention relates to metallurgy, in particular to the production of alloying alloys to steels and cast irons, and specifically relates to a method of obtaining titanium containing alloy to alloy steel. Currently, titanium is widely used for alloying steels of different grades. The greatest amount of production of such brands accounted for the low-alloy steel, intended for the manufacture of pipes, construction, automobile bodies, fasteners and other positive actions titanium on steel properties are increased toughness, strength, corrosion resistance, heat resistance, wear resistance and cold resistance. Traditionally for alloying steels titanium alloy is used ferrotitanium with high (~70% Ti) and low (~40% Ti) titanium content. High-grade ferrotitanium usually obtained by a method of melting titanium containing waste in induction furnaces. Ferrotitanium with ~40% titanium generally produce secondary recovery of ilmenite concentrate in a special melting aggregates. As the charge materials used ilmenite concentrate, iron ore, aluminum powder, ferrosilicon and lime. In both cases, ferrotitanium contains a considerable amount of impurities non-ferrous metals and gases (copper, zinc, vanadium, azo is, oxygen, hydrogen, and others). In addition, the positive effect of the use of such an alloy is only possible with careful preliminary deoxidation of the steel melt [Alloying alloys and steel to titanium. I.E. Lyakishev, UL Pliner, S. Lappo. - M.: Metallurgiya, 1985]. A method of obtaining iron-titanium alloys, including portions of the pressing electrode of the charge and remelting the vacuum-arc melting in a cooled mold (U.S. Pat. Of the Russian Federation No. 2117067, publ. 10.08.1998). This method allows you to obtain a dense ingots ferrotitanium low (0.1%) carbon content. However, this method cannot provide a complete and alloys, including strong eskikaya elements such as silicon, aluminum, calcium. A method of obtaining ferrotitanium, including the alloying of titanium and steel shavings in the slag bath in the water-cooled mold by supplying an electrical current in the slag through prashadhey graphite electrode (U.S. Pat. Of the Russian Federation No. 2346994, publ. 20.02.2009, BI No. 5). This way you can get ferrotitanium, corresponding to GOST 4761-91, with high uniformity of distribution of titanium in the height of the melted ingot. However, this method is very high electricity costs, in addition, it is not possible to obtain complex alloys type iron-titanium-silicon, iron-titanium-is remni-calcium and other Know of any other way of getting ferrotitanium by remelting of titanium scrap, including the loading of titanium scrap iron or steel pipe, clogging pipes, loading pipes in induction furnace to melt ferrotitanium, covered with the melt of the corresponding non-reactive salts, maintaining the temperature below the melting temperature of ferrotitanium and the finished product from the furnace. (U.S. Pat. U.S. No. 3410679, publ. 26.07.1965). The invention increases the economic efficiency of the process of obtaining ferrotitanium and allows you to adjust the carbon content in a wide range from 0.05 to 8.0% by choosing the composition of titanium scrap and use of solid graphite. However, this method inevitably leads to high levels of undesirable impurities (oxygen, hydrogen, nitrogen, base metals in the alloy in connection with the use as raw material scrap titanium alloys. Known another way of obtaining ferrotitanium, including the loading of titanium sponge in a container, pouring the molten iron or steel, the supply of inert gas to prevent oxidation and mixing of the melt to reduce the porosity of the finished alloy. This method allows to obtain relatively pure from impurities dense ingot ferrotitanium with titanium content up to 65% of titanium sponge. However, this way is impossible for ucati alloy containing titanium more than 65%, and an alloy composed of aluminum, silicon, calcium, and other highly radioactive elements. Closest to the claimed invention is a method for ferrosilicochromium ligatures (U.S. Pat. Of the Russian Federation No. 2177049, publ. 20.12.2001), including fusion of the ore-thermal furnace at a temperature 1750-1850°C mixture consisting of silicon-titanium and titanium-magnetite concentrates and carbonaceous reducing agent in a ratio of components 1:(0,05-0,15):(0,25-0,55). Prototype method allows to simultaneously receive two products: ferrosilicochromium the ligature for alloying of steel and titanium slag, suitable for the production of titanium metal. However, this method does not allow the ligature with high (>35%) titanium content. In addition, using a carbon reductant, silicon-titanium and titanium-magnetite concentrates inevitably leads to increased content of non-metallic impurities in the alloy, in particular of carbon. Thus, in the present invention the task of creating a new method of obtaining titanium containing alloy to alloy steel, with a minimum expenditure of power would make it possible to obtain complex alloys with high (>35%) titanium content, low content of impurities and optionally including highly active in respect to the of oxygen elements (silicon, aluminum, calcium). The problem is solved in that in the known method of obtaining such ligatures comprising preparing a base mixture consisting of a titanium containing and silicon-containing components, and its subsequent high-temperature processing, as the source of charge use exothermic mixture of powders of titanium containing and silicon-containing metals and/or alloys, with a particle size of not more than 5.0 mm in the following ratio, wt.%:
and high-temperature treatment is carried out in an inert atmosphere. Conducting high-temperature processing by initiating in the original mixture exothermic reaction allows, first, to significantly reduce the cost of electricity in the process, and secondly, to achieve a temperature at which the formation of the most stable refractory compounds. In addition, at these temperatures there is a selection present in the original mixture of impurities (oxygen, hydrogen, nitrogen, sulfur, phosphorus). To achieve such a high temperature furnace technology alloy is placed would need to spend a large amount of energy. To ensure high ekzotermicheskie mixture in the present invention uses a mixture of powders of titanium containing and silicon-containing components. Thermodynamic calculations showed that the heat released during the formation of silicides of titanium, will be enough for making the whole process in a self-sustaining mode in a very wide range of ratios of the components of the original mixture. It is known that with an increase in the dispersion of the powders increases the reaction surface, resulting in intensified interaction between them. Numerous experiments have shown that the particle size of powders of titanium containing and silicon-containing components should not exceed 5.0 mm, as in this case is greatly diminished contact between the particles and carrying out the reaction in a self-sustaining mode becomes impossible. At the same time, to obtain a more uniform distribution of elements on the volume of product it is preferable to use powders of titanium containing and silicon-containing components with a particle size less than 0,63 mm For a range of initial exothermic reaction mixtures, including the composition of the components in the form of alloys, to improve their reactionary activity there is a need to use powders with a particle size less than 0.25 mm, the alloys with low concentrations of titanium containing component, it is advisable to use a very fine powder dispersion less 0,074 mm The inventive method allows to obtain the alloy to alloy steel in a wide range of changes in its composition by selecting the concentration of the original ingredients, the best is the following ratio of initial components, wt.%:
When the concentration of the titanium containing component below 45%, and silicon - above 55% esotericist charge is reduced, and appear unreacted region with a high content of free silicon, and the use of the finished product is impractical because of the low titanium content. When the concentration of such component is higher than 88%, and silicon - below 12% of the mixture remains free titanium, and the target product has a low density. The best is the concentration of such component 48-72%, and silicon - 28-52%. In order to increase the purity of the final product, a high-temperature treatment is carried out in an inert atmosphere at a pressure of from 10-7up to 15 MPa. The inert atmosphere may serve as an inert gas or vacuum. In the optimal ways of execution of the invention the process of sin is ESA complex alloys must be conducted in vacuum at a pressure of from 0.0001 to 0.01 MPa. In this case, the maximum purification of the product from the gaseous impurities. It is known that the effectiveness of alloying alloys depends on the temperature of their melting. To increase the effectiveness of alloying titanium containing alloy in accordance with the claimed invention serves as a source of components to use powders ferrotitanium and/or ferrosilicon. Iron is included in the alloy in the form of silicides of iron, will form a low temperature eutectic (~1200°C), which will increase the solubility of ligatures and increase the efficiency of its use. In the best embodiments of the proposed technical solutions of the initial mixture further comprises a powder of aluminum in the amount of 1-14%. Aluminum, being highly active with respect to oxygen element, will better protect titanium from oxidation, thereby increasing the absorption of titanium. In addition, the joint deoxidizing of aluminum and silicon promotes the formation of low-melting oxide compositions. The optimum content of aluminum in the amount of 8-12%. The combustion temperature of the mixture at the end of such alloys in accordance with the proposed invention can achieve 2150°C, but it is most expedient to carry out high-temperature treatments the ku in the temperature range from 1250 to 1950°C. This ensures maximum safety of the process and the finished product has a composite structure with the best combination of physical-chemical properties (density, phase composition, micro - and macrostructure). Great influence on the characteristics of the process has a relative density of the original charge. The experiments showed that the optimal relative density of the original charge is 40-80%. At a relative density less than 40% deteriorates the contact between the particles, the combustion process proceeds nestacionarnog appear unreacted region. At a relative density of more than 80% dramatically increases the conductivity of the original charge, which contributes to the deterioration of the response due to the large heat loss from the combustion zone. In this case, the combustion becomes unstable, and the resulting product has a non-uniform properties of the volume. At the example of a titanium containing alloy to alloy steel titanium-silicon-iron will consider in detail the technology of its production. The source materials are titanium containing component, the titanium powder brand CCI-7 on THE 1791-449-05795388-99 containing 98.4% of titanium and silicon-containing component powder ferrosilicon brand VS GOST 1415-93 containing 78,7% silicon and 19.7% of iron. Source powders dispersion 0,315 and 0.100 mm according to the public are mixed in a mass ratio of 70:30 to obtain the initial exothermic reaction mixture with a relative density of 65% (porosity charge 35%). Local heating is initiated exothermic reaction the formation of silicides of titanium in vacuum at a pressure of 0.01 MPa. The maximum temperature developed in the combustion zone, is 1800°C for a duration of 13 minutes. The product after cooling is a dense sintered, which after crushing, you can either directly be used for doping or applied for the manufacture of flux-cored wire for subsequent microalloying of steel. The composition thus obtained titanium containing alloy alloy following, wt%: titanium - 69,3, silicon - 22,3, Fe - 7,4, the rest is inevitable impurities. In table 1 are given the results of the implementation of the claimed invention with different process conditions, and to compare the results obtained by the method prototype. As can be seen from the table, the duration of the process according to the method prototype is 72-84 minutes, which is 4-6 times longer than in the claimed invention (12-18 minutes). Using the prototype method does not allow to obtain alloys with high (>35%) content of titanium and complex alloys containing high activity towards oxygen components - aluminum, calcium, etc. in Addition, the process in ore-thermal furnaces expensive electricity (~35 kW·h/kg), and the use of Creditinfo is about and titaniferous magnetite concentrate will inevitably lead to high levels of undesirable impurities in the alloy. Thus, in the present invention solved the problem of creating a highly effective method of obtaining titanium containing alloy to alloy steel, with a minimum expenditure of power allows you to get a comprehensive alloys with high (>35%) titanium content and low content of impurities, which are highly active with respect to oxygen elements (silicon, aluminum, calcium).
1. The method of obtaining such ligatures, including the preparation of the initial charge consisting of titanium containing and silicon-containing components, and its subsequent high-temperature processing, characterized in that as the initial mixture is prepared exothermic mixture of powders of titanium containing and silicon-containing metals and/or alloys, with a particle size of not more than 5.0 mm in the following ratio, wt.%:
and high-temperature treatment is carried out in an inert atmosphere. 2. The method according to claim 1, characterized in that the quality of such component use the titanium powder and/or ferrotitanium. 3 the Method according to claim 1, characterized in that as the silicon-containing component using a powder of silicon, ferrosilicon and/or silicocalcium. 4. The method according to claim 1, characterized in that use exothermic mixture of powders in the following ratio, wt.%:
5. The method according to claim 1, characterized in that the starting mixture further comprises a powder of aluminum in the amount of 1-14%. 6. The method according to claim 1, characterized in that the heat treatment of the mixture of powders is carried out in a combustion mode by the local initiation in her exothermic reaction. 7. The method according to claim 1, characterized in that the heat treatment is carried out in an inert gas environment at a pressure of from 0.1 to 15 MPa. 8. The method according to claim 1, characterized in that the heat treatment is carried out in vacuum at a pressure of from 10-7up to 10-1MPa. 9. The method according to claim 1, characterized in that the heat treatment is carried out in the temperature range from 1250 to 1950°C. 10. The method according to claim 1, wherein preparing a mixture of powders with a particle size of not more than 0,63 mm 11. The method according to claim 1, characterized in that ovat mixture of powders with a particle size of not greater than 0.25 mm 12. The method according to claim 1, wherein preparing a mixture of powders with a particle size of not more than 0,074 mm 13. The method according to claim 1, characterized in that the starting mixture has a relative density of from 40 to 80%.
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