RU2470414C1 - METHOD OF PRODUCING p-TYPE THERMOELECTRIC MATERIAL BASED ON SOLID SOLUTIONS OF Bi2Te3-Sb2Te3 - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to thermoelectric materials. Proposed method comprises synthesis of solid solution by alloying initial components Bi, Sb, Te taken in stoichiometric ratio in sealed ampoules protected by pyrocarbon layer in atmosphere of argon and placed in three-zone tubular furnace swinging about horizontal axis at temperature some 150-200°C higher than fusion point of solid solution of bismuth and antimony chalcogenides. Then, the melt is cooled at the rate of 200-250°C/min. Synthesized material is minced. Powder is placed in tight mould to be placed into compaction unit. Produced powder is compacted by spark plasma fritting in vacuum or inert atmosphere at 400-450°C and 50-100 MPa for not over 5 min. Then, extrusion is performed at 400÷500°C and 5.0-6.0 t/cm² at the rate of thermoelectric rod extrusion of 2.0-3.0 mm/min. Thereafter extruded rod is annealed at 340-370°C.

EFFECT: high thermoelectric efficiency and mechanical strength.

5 cl, 1 dwg, 2 tbl

Description

The invention relates to the field of thermoelectric energy conversion, in particular to the manufacture of p-type thermoelectric material (TEM) used in thermoelectric cooling devices and thermogenerators. Thermoelectric converters are capable of producing "environmentally friendly" energy without emission of harmful substances into the environment. Such devices are successfully used in air conditioning, waste heat recovery, refrigeration, medicine, space, computer technology, micro and optoelectronics, etc.

The thermoelectric efficiency of the material Z is determined by the expression

Z = α ² σ / æ,

where α is the Seebeck coefficient, σ is the electrical conductivity, and æ is the thermal conductivity of the TEM. Z depends on the concentration of current carriers, and for each interval of operating temperatures of thermoelectric devices (TEU) there is an optimal concentration of current carriers at which the value of Z TEM reaches a maximum. The value of Z is in a limited region, since the electrical conductivity and the Seebeck coefficient have feedback between themselves, i.e. when the electrical conductivity increases, the Seebeck coefficient decreases and vice versa.

The low energy conversion coefficient (ZT≤1) is a significant limitation for the widespread use of bulk thermoelectric materials for coolers and thermogenerators.

Thermoelectric solid solutions based on bismuth and antimony chalcogenides, due to the layered crystallographic lattice, have strong anisotropy of electrophysical and thermal properties. Thus, the anisotropy of electrical conductivity is explained by a change in the mobility of current carriers depending on the crystallographic direction. As a result, the thermoelectric figure of merit Z largely depends on the ratio of the anisotropic coefficients of electrical and thermal conductivity (σ / æ), which reaches a value of ≥2.

A known method for producing nanostructured thermoelectric materials based on solid solutions containing p-type Bi-Sb-Te. The method includes grinding the initial ternary solid solution in a high-energy ball mill to nanosized particles and consolidating the obtained nanosized powders either by hot pressing or by hot sintering using direct current under load (International Application No. WO 2008/140596, IPC H01L 35/34, publ. November 20, 2008).

This method made it possible to obtain a p-type thermoelectric material based on bismuth and antimony chalcogenides, the thermoelectric figure of which amounted to ZT≥1.2 ÷ 1.4 (Example 1 in the patent) for a triple solid solution of uncertain composition in the temperature range of 50 ÷ 100 ° C, respectively (as follows from graph 9, at room temperature 25 ° C, the value of ZT = 1.18). In example 3 of the patent, for the composition Bi _0.3 Sb _1.7 Te ₃ the value ZT = 1.2 was obtained at 150 ° C (from graph 30 it follows that at 25 ° C the value ZT = 0.9), and for composition Bi _0.5 Sb _1.5 Te _{3 the} value of ZT = 1.2 at 75 ° C (while at 25 ° C the value of ZT = 1.12). Hot pressing modes: temperature - 450 ÷ 600 ° С; pressure - 40 ÷ 160 MPa and a duration of up to 60 min, including experiments using direct current on a P2C installation. Thus sintered material is an isotropic medium, the properties of which are the same regardless of the direction in it.

A known method of producing thermoelectric materials based on solid solutions containing Bi-Sb-Te. Solid solutions of Bi _0.5 Sb _1.5 Te ₃ with the addition of an excess of Te (2-5 wt.%) (P-type conductivity) were synthesized by direct fusion of the components in a sealed quartz ampoule with vibration for 2 hours. Then, the obtained material was cooled and ground into powder in a glove box under argon atmosphere until a powder with grain sizes of 60, 100, 150, and 210 μm was obtained, and powder was compacted into a tablet by cold pressing. The cold-pressed tablet was transferred to the apparatus (powder-extrusion-sintering) and a simultaneous sintering and extrusion process was carried out (sintering conditions: 300-400 ° C and a constant current of 250-350 A, and then a pressure of 100-200 MPa was applied and the extrusion process was carried out ) (Report by BG Min et al. (Korea); “Preparation and characterization of thermoelectric materials based on Bi ₂ Te ₃ -Sb ₂ Te ₃ solid solutions using the powder-extrusion-sintering technique”, at the 16th International Conference on Thermoelectrics, Germany (Dresden), 1997, pp. 76-80).

The disadvantage of this method is to obtain material with low indicators of electrophysical properties, since the maximum thermoelectric figure of merit is Z≤2.6 · 10 ^-3 K ^-1 .

A known method of producing ingots of thermoelectric materials based on solid solutions of Bi ₂ Te ₃ -Sb ₂ Te ₃ large sizes with thermoelectric (Zp≥2.9 · 10 ^-3 K ^-1 ) and mechanical (> 90 MPa) properties by hot extrusion. The method includes the operations of mechanochemical sintering of the starting components (Bi, Te and Sb) in an attritor (ball mill), cold pressing of the powder followed by annealing of the workpiece, hot extrusion and, finally, annealing of the extruded material (US patent No. 6596226, Nl. 419/32, IPC B22F3 / 20, published on July 22, 2003). The method adopted for the prototype.

The significant disadvantages of the prototype method include the following:

- the method of mechanochemical synthesis of components in the attritor does not allow to obtain powders of complex solid solutions of bismuth chalcogenides and antimony of stoichiometric composition due to kinetic limitations of solid-phase reactions (which proceed at very low rates);

- when compacting powders by cold pressing, despite a relatively high pressure (≥300 MPa), the density of the billet (especially large sizes) does not exceed 65–70%, which leads to increased porosity of the extruded material;

- upon subsequent annealing of the cold-pressed billet for its compaction, at the annealing temperature <300 ° С, the material practically does not condense, and at the annealing temperature> 300 ° С the thermoelectric material undergoes a recrystallization process, as a result of which the grain size increases and the thermoelectric figure of merit Z decreases ;

- the mode of annealing of the extruded material is indicated in a wide temperature range without taking into account the temperature of the extrusion process itself, however, annealing of the extruded rod of the thermoelectric material at a temperature higher than the temperature of the extrusion process leads to blurring of the texture. Therefore, in the end, the thermoelectric figure of merit and mechanical strength of the thermoelectric material obtained in a known manner do not exceed 2.9 · 10 ^-3 K ^-1 and 90 MPa, respectively.

The technical result of the invention is to achieve a reproducibly high level of thermoelectric figure of merit ZT≥1.3 and a mechanical strength of at least 150 MPa for p-type material at room temperature.

The technical result is achieved by the fact that in the method for producing a p-type thermoelectric material based on Bi ₂ Te ₃ -Sb ₂ Te ₃ solid solutions, which includes synthesis of a solid solution, making powder from it, compacting the obtained powder into a briquette, extruding the material from the briquette obtained in the previous operation, and annealing the extruded material, according to the invention, the synthesis of the solid solution is carried out by fusion of the initial components Bi, Sb, Te taken in a stoichiometric ratio in an argon atmosphere, in sealed ampoules protected by a layer of pyrocarbon and placed in a three-zone tube furnace that sways near a horizontal position at a temperature exceeding 150–200 ° C the melting point of a solid solution of bismuth and antimony chalcogenides, followed by cooling of the melt at a rate of 200–250 ° C / min, grinding the synthesized material obtained, loading the powder into an airtight mold and placing it in a compacting unit, and compacting the obtained powder by spark plasma sintering (SPS spec s) in vacuum or in an inert atmosphere at a temperature of 400 ÷ 450 ° C, a pressure of 50 ÷ 100 MPa for not more than 5 minutes; the extrusion of briquetted material is carried out at a temperature of 400 ÷ 500 ° C and a specific load of 5.0 ÷ 6.0 t / cm ² to ensure the extrusion rate of the extruded rod of thermoelectric material 2.0 ÷ 3.0 mm / min, and annealing of the extruded rod is carried out at a temperature of 340 ÷ 370 ° C for a duration of 1 to 5 days; wherein the swing of the three-zone tube furnace is carried out at a speed of 5 ÷ 7 rolling / min; grinding the synthesized solid solution, loading the powder into the mold and placing it in the spark plasma sintering apparatus is carried out in a box with an argon atmosphere with a 3% hydrogen content, and before extrusion, the inner surface of the container and the briquetted material are treated with a suspension of colloidal graphite in the Aquadag ammonia solution "At a temperature of 50 ÷ 100 ° C.

The general technological scheme of the process is shown in Fig. 1.

The invention consists in the following.

The synthesis of the Bi ₂ Te ₃ -Sb ₂ Te ₃ solid solution is carried out by direct fusion of the initial components Bi, Sb, and Te taken in a stoichiometric ratio in an argon atmosphere at a temperature exceeding 150 ÷ 200 ° C the melting point of a solid solution of bismuth and antimony chalcogenides ( 610 ÷ 615 ° C), in sealed ampoules with a protective layer of pyrocarbon, placed in order to achieve better homogenization of the melt in a three-zone tube furnace with a speed of 5-7 cpm per horizontal position, then the melt crystallizes at a cooling rate Denia 200 ÷ 250 ° C / min in order to avoid the formation of solid solution in the synthesized form of phase separation in the intracrystalline and intercrystalline inhomogeneity. The claimed conditions for the synthesis of a solid solution, in comparison with the method of the prototype provide a material of stoichiometric composition.

The following conditions for grinding the synthesized material and its compacting, namely, using micron, submicron and nanoscale powder or mixtures thereof for compacting in a sealed mold filled with argon + 3.0% H ₂ , the powder is compacted by spark plasma sintering (SPS ), passing a pulsed electric current and at the same time mechanical loading according to a given program (temperature 400 ÷ 450 ° C, pressure 50 ÷ 100 MPa), provide a uniformly structured press blank, hydrostatic optical density which is not less than 98% and mechanical strength reaches at least 150 MPa (as measured by ASTM E9-89a strength standard).

Compared to traditional methods of hot pressing, SPS-sintering of samples occurs due to spark discharges that occur in a pulsed mode between sintered powder particles under pressure, without binding additives, at a sufficiently low sintering temperature and a short period of time. This makes it possible to significantly limit the grain growth in the powder material, which is of fundamental importance for creating a high-density throughout the volume, practically no micropores, and mechanically high-strength uniformly sintered volumetric press-piece of thermoelectric material suitable for carrying out a high-quality hot extrusion process.

In order to achieve the maximum level of thermoelectric figure of merit on extruded ingots of thermoelectric material during hot extrusion, in addition to giving the sample a given shape and size, it is necessary to create a directional texture with a favorable crystallographic orientation in which the cleavage planes (001) are parallel to the axis of the ingot. To do this, the workpiece material, the walls of the container and the die are treated, for example, with a suspension of colloidal graphite in the Akvadag ammonia solution to reduce the friction of the workpiece against the walls of the container and the die, then the container with the workpiece is uniformly heated and the plastic strain is applied with a specific load on the press blank 5 , 0 ÷ 6.0 t / cm ² and its uniform distribution over the area of the workpiece.

At the same time, during plastic deformation during the extrusion process, there is not only a change in shape, but also the accumulation of point structural defects in the volume of the extruded material, which have a significant effect on the thermoelectric properties of the material. To reduce the concentration of intrinsic point structural defects, the extruded material is subjected to heat treatment. In this case, the annealing temperature, in order to avoid texture blurring, should be lower than the temperature of the extrusion (i.e., Totz <Text), which guarantees the preservation of the necessary preferential crystallographic orientation, and, therefore, obtaining the maximum thermoelectric properties of the extruded material.

Justification of the declared parameters of the process of obtaining thermoelectric material.

The synthesis of a solid solution of Bi ₂ Te ₃ -Sb ₂ Te _{3 is} carried out at a temperature exceeding by 150 ÷ 200 ° C the melting temperature of the ternary solid solution.

The synthesis process at a temperature higher than the melting point of the solid solution by less than 150 ° C. The melt viscosity remains still quite high, which reduces the mixing efficiency when the ampoule is rocked, which leads to heterogeneity of the synthesized material and, therefore, reduces the thermoelectric properties of the material.

Conducting the synthesis process at a temperature exceeding the melting temperature of the solid solution by more than 200 ° C, the melt viscosity decreases and the mixing efficiency increases, but at the same time, the degree of dissociation of molecules in the melt increases, which violates the stoichiometry of the material and, therefore, reduces the thermoelectric properties of the material.

Crystallization of the synthesized material is carried out with a melt cooling rate of 200 ÷ 250 ° C / min.

When the melt of the synthesized material is cooled at a rate of less than 200 ° C / min in a ternary solid solution, segregation zones form in the form of intracrystalline, intercrystalline, and other inhomogeneities.

When the melt of the synthesized material is cooled at a rate of more than 250 ° C / min, the synthesized material, in addition to increasing uniformity, becomes more brittle, which greatly facilitates its grinding in the future to micron, submicron and nanosized particles. However, to further increase the cooling rate of the molten material, another technique is required, for example, spinning of the melt, which is not always economically justified.

The powder compaction of Bi ₂ Te ₃ -Sb ₂ Te ₃ solid solution is carried out by the method of spark plasma sintering (SPS) at a temperature of 400-450 ° С, a pressure of 50 ÷ 100 MPa for no more than 5 minutes.

When compacting at a temperature below 400 ° C and a pressure below 50 MPa, the density of the briquette becomes less than 98% and to increase it requires an increase in the sintering time to 30 or more minutes, which leads to an increase in particle size due to recrystallization and, consequently, to a deterioration in thermoelectric efficiency by ~ 15%.

When compacted at temperatures above 450 ° C and pressures above 100 MPa, microcracks appear in the sintered sample.

The extrusion of briquetted material is carried out at a temperature of 400 ÷ 500 ° C and a specific load of 5.0 ÷ 6.0 t / cm ² .

Changing the extrusion regimes both in the direction of decreasing, and in the direction of their increase, does not provide the formation of a directional texture with the necessary crystallographic orientation.

Isothermal annealing of the extruded rods is carried out at a temperature of 340 ÷ 370 ° C for a duration of 1 to 5 days.

Annealing the extruded rods at a temperature below 340 ° C and a duration of less than 1 day, it is not possible to completely get rid of the nonequilibrium intrinsic point structural defects that have a negative effect on the thermoelectric properties of the material.

Annealing of extruded rods at temperatures above 370 ° C and a duration of more than 5 days is accompanied by an increase in particle size due to recrystallization, which affects the thermoelectric properties of the material.

An example implementation of the method.

To obtain a p-type thermoelectric material with a stoichiometric composition of Bi _0.4 Sb _1.6 Te _{3, the} loading of components is calculated by the formulas depending on the total mass of the ternary solid solution Gzag: the amount of bismuth g (Bi) = 0.1264 · Gzag, g; the amount of antimony g (Sb) = 0.2946 · Gzagr, g; and the amount of tellurium g (Te) = 0.5790 · Gzagr, g. The initial main components are loaded into a prepared quartz ampoule, protected from the inside with a layer of pyrolytic carbon. After loading all the necessary components, the ampoule is vacuumized to 1.33 · 10 ^-1 Pa, then an inert gas (dried argon or nitrogen) is injected into it to a residual pressure of about 0.8 atmosphere (0.8 · 10 ⁵ Pa), followed by sealing .

The prepared quartz ampoule with a charge is placed in a horizontal resistance furnace having a temperature plateau at the level of 760 ÷ 815 ° С (which is ~ 150 ÷ 200 ° С higher than the melting temperature of the ternary solid solution: 610 ÷ 615 ° С), and the ternary solid solution is synthesized in for 2 hours in continuous swing conditions (5 ÷ 7 kpm / min) near a horizontal position. After this, the ampoule with the melt is removed from the furnace, placed horizontally in ice water and the melt is crystallized at a cooling rate of 200 ÷ 250 ° C / min to avoid the formation of segregation in the synthesized solid solution in the form of intracrystalline or intercrystalline heterogeneity.

The synthesized thermoelectric material obtained is subjected to crushing (to particle sizes of ~ 1 ÷ 2 mm). The crushed material is loaded into a high-speed (28,000 rpm) knife-type mill inside a glove box filled with an inert gas (for example, pure dry argon with 3% hydrogen content, while humidity is continuously monitored inside the box) and it is turned on. The mill was carried out in a cyclic mode lasting 5 minutes each. For each sample, 3 cycles were selected. In the intervals between cycles, the mill cooled for 10-15 minutes. The average particle size distribution of the grains in the powder after grinding is: particles with sizes of 50 ÷ 80 microns - ~ 72%; particles of submicron sizes 0.9 ÷ 0.3 μm - ~ 18% and particles with nanosized 12 ÷ 25 nm - ~ 10%. The powder is also unloaded from the mill in a glove box, where the mill is opened and the powder is discharged into the prepared mold.

The powder mold is transferred from the glove box through the lock and is installed in the working chamber of the spark plasma sintering plant. The chamber is evacuated to a residual pressure (1 ÷ 0.5) Pa, the powder is pre-pressed, and then, according to the specified program (temperature 400 ÷ 450 ° C, pressure 50 ÷ 100 MPa and a duration of 5 min), the process of spark plasma sintering (current - 600 ÷ 700 A, frequency - 300 Hz).

The sintered billet press (briquette) with a diameter of 45 mm has a uniform structure, its hydrostatic density is at least 98%, and the mechanical strength (compressive strength) reaches a value of at least 150 MPa.

Next, the sintered billet is subjected to hot extrusion. A 200-ton press was used to conduct the hot extrusion process. To implement this process, a tool is assembled with a die (diameter 20 mm at the outlet) of hardened tool steel, which is preheated to a temperature of ~ 50 ÷ 100 ° C. Then turn off the heater and disassemble the snap. Using a brush, a suspension of colloidal graphite in the Aquadag ammonia solution is applied to the inner surface of the container and die, and then to the outer surface of the sintered preform and press washer. As soon as the “Akvadag” dries up, the workpiece is loaded with special forceps into the internal cavity of the container, a press washer and punch are placed on top of the workpiece, a heater is installed on the outside of the container, an XA thermocouple is inserted into the container and its connection with the pid temperature controller is checked. After that, the movement of the lower plate is turned on and the punch is pushed close to the upper plate of the press. A small pressure is applied to the punch (~ 5 t) so that the press washer comes into close contact with the workpiece, which is fixed by the dial indicator, which is set to the initial zero position. Then, a protective screen is installed, power is supplied to the heater and the desired temperature is set in the container (in the range 400–500 ° C), and exposure is given for 30 minutes to equalize the heating temperature of the equipment. Next, the movement of the bottom plate is turned on and the specific load on the workpiece is gradually increased to a speed of 10 t / min to 5.0 ÷ 6.0 t / cm ² and, according to the indications of the dial indicator, they monitor the appearance of the extruded rod of thermoelectric material at the exit of the die.

Hot extrusion mode: drawing ratio - ~ 5; temperature - 400 ÷ 500 ° C; specific load - 5.0 ÷ 6.0 t / cm ² ; the exit speed of the extruded rod with a diameter of 20 mm is 2.0 ÷ 3.0 mm / min.

The extrusion process continues until the arrow of the indicator stops moving, indicating the complete use of the material of the billet in the channel of the container. Then the heater is turned off, the equipment is allowed to cool, then the heater is removed, a press ring is placed under the container and the die is squeezed out with the press residue from the briquette under the press washer. Extruded rods of thermoelectric material are sent for annealing.

Group annealing of extruded rods of p-type thermoelectric material is carried out in a protective argon atmosphere in a quartz ampoule with a quasi-hermetic shutter at a temperature of 340 ÷ 370 ° C (i.e., Totz <Tekstr) for 1 to 5 days. At the end of the annealing, the furnace heating is turned off and the ampoule with thermoelectric material rods is cooled to room temperature together with the furnace. After that, the rods are removed from the ampoule and measure the mechanical and thermoelectric properties of the material.

Mechanical strength was determined according to ASTM E9-89a (2000) "Standard Test Methods for the Compression of Metallic Materials at Room Temperature". The authors of the prototype when determining the strength used the same standard.

X-ray diffraction studies of the structure showed that the main texture component after hot extrusion is the favorable annular texture (110), (010), i.e., 65% of the grains of the cleavage plane are oriented parallel to the direction of extrusion. In this case, annealing at a temperature of 340–370 ° С (i.e., at Totz <Text) for 1 to 5 days led to an increase in the fraction of axial texture. A further increase in temperature and annealing duration eroded the texture, which led to a deterioration in thermoelectric parameters.

The following output parameters were measured on extruded samples of thermoelectric material after annealing by the Harman method: electrical conductivity (σ), thermoelectric coefficient (α) and thermoelectric figure of merit Z at room temperature, followed by determination of the thermal conductivity coefficient (æ). It should be noted that after annealing in almost all cases, the electrical conductivity increased on average by ~ 35–45%, and the thermoelectric power by ~ 5–7%.

Table 1 shows the results of the method obtained with various technological parameters.

Table 2 shows the measurement results of the thermoelectric and mechanical properties of the extruded rods Bi _0.4 Sb _1.6 Te ₃ (examples 1 ÷ 4) obtained by the proposed technology, in comparison with the material of the prototype (examples 5 ÷ 7).

Measurements performed at room temperature.

Thus, based on the data of tables 1 and 2, we can conclude that the claimed method allows reproducibly obtain p-type thermoelectric material based on Bi ₂ Te ₃ -Sb ₂ Te ₃ solid solutions with an efficiency of ZT≥1.3 and mechanical strength of at least 150 MPa at room temperature.

table 2 Thermoelectric and mechanical properties of extruded rods after annealing, measured at room temperature 298 K. Examples Ligature wt.% Atmosphere σ, Ohm ^-1 cm ^-1 α, μV / K æ, W / cm · K Z, 10 ⁻³ · K ⁻¹ Zt Strength, MPa Cracks The results of the experiments according to the claimed method one - argon 1061 224 1.16 4,59 1.37 150.3 no 2 - argon 1004 229 1.19 4.42 1.32 161.6 - 3 - argon 1098 223 1.20 4,55 1.35 153.4 - four - argon 908 232 1.06 4.61 1.37 152.1 - The results of the experiments on the prototype method Exp. Number 5 0,055 (Sb) argon 1031 219 1.65 2.99 0.89 114.3 no Exp. Number 6 0,055 (Sb) argon A lot of cracks Exp. Number 7 0,055 (Sb) argon 1176 198 1.68 2.75 0.82 91.8 no

Claims (5)

1. A method of producing a p-type thermoelectric material based on Bi ₂ Te ₃ -Sb ₂ Te ₃ solid solutions, including synthesis of a solid solution, making a powder from it, compacting the obtained powder into a briquette, extruding the material from the briquette obtained in the previous operation, and annealing of the extruded material, characterized in that the solid solution is synthesized by fusion of the initial components taken in a stoichiometric ratio: Bi, Sb, Te in sealed ampoules protected by a layer of pyrocarbon in an argon atmosphere into a three-zone tube furnace that sways near a horizontal position at a temperature exceeding 150–200 ° С the melting point of a solid solution of bismuth and antimony chalcogenides, followed by cooling of the melt at a rate of 200–250 ° С / min, grinding the obtained synthesized material, loading powder in a sealed mold and placing it in a compacting unit, and compaction of the obtained powder is carried out by spark plasma sintering (SPS-sintering) in a vacuum or in an inert atmosphere under temperature 400 ÷ 450 ° С, pressure 50 ÷ 100 MPa for no more than 5 minutes; the extrusion of briquetted material is carried out at a temperature of 400 ÷ 500 ° C and a specific load of 5.0 ÷ 6.0 t / cm ² to ensure the extrusion rate of the extruded rod of thermoelectric material 2.0 ÷ 3.0 mm / min, and annealing of the extruded rod is carried out at a temperature of 340 ÷ 370 ° C for 1 ÷ 5 days. 2. The method according to claim 1, characterized in that the swing of the three-zone tube furnace is carried out at a speed of 5 ÷ 7 Kach / min. 3. The method according to claim 1, characterized in that the grinding of the synthesized solid solution, loading the powder into the mold and placing it in the apparatus for spark plasma sintering is carried out in a box with an atmosphere of argon with a 3% hydrogen content. 4. The method according to claim 1, characterized in that for spark plasma sintering using micron, submicron and nanoscale powder or mixtures thereof from synthesized solid solution. 5. The method according to claim 1, characterized in that before extrusion the inner surface of the container and the briquetted material are treated with a suspension of colloidal graphite in a solution of ammonia "Aquadag" at a temperature of 50 ÷ 100 ° C.

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