RU2793680C1 - Method for obtaining material for absorption and desorption of hydrogen - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, in particular to the production of titanium-based materials used for the absorption and desorption of hydrogen, and intended to be used in hydrogen-consuming energy devices and chemical processes. The method for obtaining material for absorption and desorption of hydrogen consists in using a mixture of iron and titanium powders and their high-temperature treatment, while a mixture of powders of one fraction of 57-68 at.% titanium and 42-32 at.% iron is placed on the surface of a steel substrate and subjected to pressing using explosive loading, the pressed material in the presence of additional titanium powder, taken in a volume ratio to the pressed material equal to 1:1, is subjected to reaction sintering in a welded steel ampoule when heated to 1100°C followed by cooling to a temperature of 22-25°C.

EFFECT: increase in the hydrogen-sorption properties of the intermetallic compound is provided.

1 cl, 2 dwg, 2 tbl, 1 ex

Description

The invention relates to the field of metallurgy, in particular to the production of titanium-based materials used for the absorption and desorption of hydrogen, in order to use it in energy devices that consume hydrogen and chemical processes.

A promising battery and source of hydrogen among titanium-based alloys is TiFe intermetallic compound, which is characterized by availability and low cost.

A known method of obtaining hydrogen storage alloys [patent RU 2532788, IPC B22F 3/11, C22C 1/08, publ. November 10, 2014] by mechanical activation of the metal compound powder and processing of the powder in a reactor at a temperature of 100-500°C, followed by pressing into bulk samples at a pressure of at least 500 MPa, and vacuum annealing at a temperature of 0.3-0.5 of the melting point intermetallic.

However, to achieve the onset of hydrogenation without activation, this method assumes the presence of a large number of defects and a porous state in the sample.

The closest is the way to obtain intermetallic [Park KB et al. Characterization of microstructure and surface oxide of Ti _1,2 Fe hydrogen storage alloy // International Journal of Hydrogen Energy. - 2021. - T. 46. - No. 24. - S. 13082-13087], the composition of which is described by the formula Ti _1,2 Fe. Alloy Ti _1,2 Fe contains 54.55 wt.% titanium, the rest is iron. The phase composition of the alloy TiFe, Ti ₂ Fe (2.8 wt.%) and β -Ti (wt. 5.4%). The content of phases rich in titanium in the alloy significantly improved the kinetics of hydrogen absorption in comparison with TiFe, ensured the sorption process without activation, and increased the sorption capacity of hydrogen. The alloy was obtained by vacuum arc melting using a copper crucible and water cooling, to achieve uniformity, the ingot was heated and cooled 5 times, followed by vacuum homogenization annealing at a temperature of 1200°C for 10 hours.

The disadvantage of this method is the long and energy-consuming production technology, as well as the insufficiently high sorption capacity of the intermetallic compound.

The task is to develop a new method for obtaining a material for the absorption and desorption of hydrogen, which makes it possible to increase Ti ₂ Fe and β -Ti in the composition of the phases.

The technical result is to increase the hydrogen-sorption properties of the intermetallic compound.

The technical result is achieved in a method for obtaining a material for the absorption and desorption of hydrogen using a mixture of powders of iron and titanium and high-temperature processing, while the mixture of powders of one fraction of 57-68 at.% titanium and 42-32 at.% iron is placed on the surface of the steel substrate and subjected to pressing using explosive loading, the pressed material in the presence of titanium powder, taken in a volume ratio to the pressed material equal to 1:1, is subjected to reaction sintering in a welded steel ampoule when heated to 1100°C, followed by cooling to a temperature of 22-25°C.

The essence of the method consists in explosive pressing of the initial mixture of titanium and iron powders of one fraction and subsequent heat treatment of the resulting pressed material with an additional portion of titanium powder.

The use of explosive loading leads to the combination of pressing and activation of the powder material before subsequent thermal exposure, which accelerates the diffusion processes. The declared mode of heat treatment and the optimal initial composition of titanium and iron makes it possible to obtain the most effective phase composition of the material, which provides enhanced hydrogen sorption properties.

In FIG. 1 shows a diagram of explosive loading, in which a powder material 2 is placed on a steel substrate 1 (steel base), consisting of a mixture of powders of one (identical) fraction of titanium according to TU 14-22-57-92 and iron according to GOST 9849-86 (the thickness of the placed layer is 7 mm), a piston 3 with a thickness of 1 mm is installed on top of it with a charge 4 of an explosive (HE) from ammonite (6ZhV) (the height of the explosive charge is determined from the condition of ensuring the same heating temperature of the pressed materials in the process of explosive loading), detonator 5 and detonating cord 6. The whole circuit for explosive loading is installed on a sand cushion 7.

After the explosion of the detonator, an explosive charge is initiated, under the action of which a normally incident detonation wave is formed, which ensures the compaction of the mixture to an almost pore-free state. The resulting pressed material is subjected to reaction sintering in a welded steel ampoule when heated to 1100°C, followed by cooling to a temperature of 22-25°C. Sintering is carried out in the presence of titanium powder, taken in a volume ratio to the pressed material equal to 1:1. An additional volume of titanium powder makes it possible to minimize the interaction of sintered samples with the ampoule atmosphere.

In FIG. 2 shows the microstructure and phase composition of the obtained alloy.

The hydrogen sorption properties of the obtained samples were determined by the electrochemical method. Samples obtained by the claimed method of materials were placed in an electrochemical cell for electrolysis.

Hydrogenation was carried out at a temperature of 20°C and atmospheric pressure. The measurements were carried out in a three-electrode cell with a 9 M aqueous KOH solution as an electrolyte, a Ni(OH) ₂ /NiOOH counter electrode, and an Hg/HgO reference electrode on an Electrochemical Instruments P-40X potentiostat. The saturation potential was set as high as possible within the limits associated with the experimentally determined onset of hydrogen gas evolution on the electrode (-1.25 V for a material with 57 at.% Ti and -1.175 V for a material with 68 at.% Ti), the test time was 100 minutes.

Table 1 shows the ratio of titanium and iron powders in the composition of the powder material (the initial ratio of powders).

Table 1 Sample The composition of the initial powder mixture, wt.% Composition of the initial powder mixture, at.% The composition of the material
wt% Height of explosive charge, mm Ti Fe Ti Fe Ti Fe 1 54.2 45.8 57 42 54 46 95 2 60.3 39.7 64 36 60 40 90 3 63.5 36.5 67 33 63.4 36.6 85 4 64.55 35.45 68 32 64.5 35.5 80

Sample 1 is a material obtained by the claimed method with the chemical composition of the prototype.

The phase compositions and sorption properties of the obtained samples are presented in Table 2.

table 2 Sample Phase composition of the obtained material, wt. % Sorption properties, µg/cm² TiFe Ti ₂ Fe β-Ti Ti(N,C,O) 1 74.9 17.4 0.0 7.6 1.1008 2 41.6 44.7 5.1 8.7 3.9904 3 20.7 62.1 2.8 14.4 3.2491 4 9.8 73.3 13.5 3.3 5.3367

It can be seen from the given data that the material contains titanium with impurities of nitrogen and carbon Ti(N,C,O) obtained from the atmosphere during heat treatment and the chemical composition of the powders used.

Thus, a method for obtaining a material for the absorption and desorption of hydrogen, in which a mixture of powders of one fraction of 57-68 at.% titanium and 42-32 at.% iron is placed on the surface of a steel substrate and subjected to pressing using explosive loading, the pressed material in the presence of titanium powder, taken in a volume ratio to the pressed material equal to 1:1, is subjected to reaction sintering in a welded steel ampoule when heated to 1100°C, followed by cooling to a temperature of 22-25°C, which ensures the production of intermetallic compounds with increased hydrogen sorption properties.

Claims (1)

A method for producing a material for the absorption and desorption of hydrogen using a mixture of iron and titanium powders and high-temperature treatment, characterized in that a mixture of powders of one fraction of 57-68 at.% titanium and 42-32 at.% iron is placed on the surface of a steel substrate and subjected to pressing using explosive loading, the pressed material in the presence of additional titanium powder, taken in a volume ratio to the pressed material equal to 1:1, is subjected to reaction sintering in a welded steel ampoule when heated to 1100°C, followed by cooling to a temperature of 22-25°C.

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