A6B 23 Preparation method of single-phase hydrogen storage alloy

Abstract

This application relates to the field of hydrogen storage alloy technology, and in particular to A6B. 23 Preparation method of single-phase hydrogen storage alloy, A6B 23 The chemical formula of the rare earth iron-based single-phase hydrogen storage alloy is Y6Fe. 23 or Gd6Fe 23 The preparation method includes: selecting a metallic element, and preparing it according to Y6Fe 23 The chemical composition is determined by batching, with an excess of Y element, and alloy ingots are prepared using an electric arc melting method; alternatively, a metallic element is selected and prepared according to the formula Gd6Fe. 23 The chemical composition was determined by batching, with an excess of Gd. Alloy ingots were prepared using an electric arc melting method. The alloy ingots were annealed under an argon atmosphere. After annealing, the alloy ingots were subjected to room temperature water quenching. This preparation method successfully eliminated impurity phases, yielding A6B alloy. 23 Y6Fe type 23 Gd6Fe 23 Single-phase hydrogen storage alloys have high reversible hydrogen storage capacity and stable structure after hydrogen absorption and desorption.

Description

Technical Field

[0001] This application relates to the field of hydrogen storage alloy technology, and in particular to A6B. 23 Preparation method of single-phase hydrogen storage alloy. Background Technology

[0002] Rare-earth nickel-based alloys, represented by AB5-type LaNi5, can absorb and release hydrogen under mild conditions, making them the earliest discovered type of rare-earth hydrogen storage material. They have been widely used in nickel-metal hydride battery anodes, hydrogen purification, compression, and storage. However, the high cost of nickel has limited their large-scale application in these fields. Rare-earth iron-based hydrogen storage alloys have a significant advantage in raw material cost, and because iron atoms have atomic radii similar to nickel, they are better suited to achieving similar tetrahedral interstitial spaces and hydrogen absorption / desorption equilibrium pressures. Therefore, rare-earth iron-based alloys hold promise for achieving better reversible hydrogen storage performance.

[0003] However, the unique electronic structure of iron determines that rare earth-iron systems have different phase formation thermodynamics and alloy hydride thermodynamics, such as A6B. 23 The rare earth-iron phase structure is complex and has poor phase-forming ability, making it difficult to obtain single-phase rare earth iron-based alloys by conventional smelting processes. Summary of the Invention

[0004] Based on this, this application provides an A6B 23 A method for preparing A6B single-phase hydrogen storage alloy was presented, which successfully eliminated impurity phases and prepared the alloy. 23 Y6Fe type 23 Gd6Fe 23 Single-phase hydrogen storage alloys have high reversible hydrogen storage capacity and stable structure after hydrogen absorption and desorption.

[0005] This application provides an A6B 23 Preparation method of single-phase rare earth iron-based hydrogen storage alloy, A6B 23 The chemical formula of the rare earth iron-based single-phase hydrogen storage alloy is Y6Fe. 23 or Gd6Fe 23 ;

[0006] The preparation method includes the following steps:

[0007] Select a metallic element, according to Y6Fe 23 The chemical composition is determined by batching, with an excess of Y element, and alloy ingots are prepared using an electric arc melting method; alternatively, a metallic element is selected and prepared according to the formula Gd6Fe. 23 The chemical composition was determined by batching, with an excess of Gd, and alloy ingots were prepared using an electric arc melting method.

[0008] The alloy ingot was annealed under an argon atmosphere.

[0009] The annealed alloy ingots were subjected to room temperature water quenching.

[0010] In some implementations, the amount of Y element is in excess by 1 wt.% to 3 wt.%; or the amount of Gd element is in excess by 1 wt.% to 3 wt.%.

[0011] In some implementations, the alloy ingot is flipped at least three times during the preparation of the alloy ingot using the electric arc melting method.

[0012] In some embodiments, the process of preparing alloy ingots by electric arc melting is carried out under an argon atmosphere at a pressure of -0.07 to -0.03 MPa.

[0013] In some embodiments, the annealing process includes a first annealing process, a second annealing process, and a third annealing process performed sequentially.

[0014] The temperatures of the first, second, and third annealing treatments increase sequentially.

[0015] In some embodiments, the first annealing process includes: heating from room temperature to 363 K-383 K and holding at that temperature for 10 min-20 min;

[0016] The second annealing process includes: heating from the final temperature of the first annealing process to 863 K-883 K and holding at that temperature for 1 h-2 h.

[0017] The third annealing process includes heating from the final temperature of the second annealing process to 1173 K - 1323 K and holding at that temperature for 24 h - 30 h.

[0018] In some embodiments, the heating rate of the first annealing treatment is 3 K / min - 4 K / min;

[0019] And / or, the heating rate for the second annealing treatment is 4 K / min - 5 K / min;

[0020] And / or, the heating rate of the third annealing treatment is 1 K / min - 2 K / min.

[0021] In some implementations, the water temperature for room temperature water quenching is 10°C-35°C.

[0022] In some embodiments, the step of preparing alloy ingots by electric arc melting further includes cleaning the electric arc furnace cavity with argon gas to remove oxygen from the electric arc furnace cavity.

[0023] In some implementations, the process further includes the following steps prior to the annealing step:

[0024] Remove the oxide impurity layer from the surface of the alloy ingot, crush it, and prepare an alloy sample;

[0025] Place the alloy sample in the reaction apparatus;

[0026] Argon gas was used to clean the reaction apparatus;

[0027] The reaction apparatus was sealed after cleaning.

[0028] Compared with traditional technologies, this application has at least the following beneficial effects:

[0029] This invention successfully eliminates impurity phases and prepares A6B by combining electric arc melting with annealing and room temperature water quenching. 23 Y6Fe structure 23 Gd6Fe 23 Single-phase alloys have high reversible hydrogen storage capacity, stable structure after hydrogen absorption and desorption, and low cost. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A6B is an embodiment of this application. 23 A schematic diagram of the preparation method of single-phase rare earth iron-based hydrogen storage alloy.

[0032] Figure 2 Y6Fe prepared in Example 1 of this application 23 XRD pattern of a single-phase hydrogen storage alloy.

[0033] Figure 3 Y6Fe prepared in Example 1 of this application 23 PCT hydrogen storage performance diagram of single-phase hydrogen storage alloy.

[0034] Figure 4 Y6Fe prepared in Example 1 of this application 23 XRD comparison images of a single-phase hydrogen storage alloy before and after cycling.

[0035] Figure 5 Gd6Fe prepared in Example 2 of this application 23 XRD pattern of a single-phase hydrogen storage alloy.

[0036] Figure 6 Gd6Fe prepared in Example 2 of this application 23PCT hydrogen storage performance diagram of single-phase hydrogen storage alloy.

[0037] Figure 7 Y6Fe prepared in Example 3 of this application 23 XRD pattern of a single-phase hydrogen storage alloy.

[0038] Figure 8 Y6Fe prepared in Example 4 of this application 23 XRD pattern of a single-phase hydrogen storage alloy.

[0039] Figure 9 Y6Fe prepared for Comparative Example 1 of this application 23 XRD pattern of the alloy.

[0040] Figure 10 Y6Fe prepared for Comparative Example 1 of this application 23 PCT hydrogen storage performance diagram of the alloy. Detailed Implementation

[0041] A detailed reference is now provided to embodiments of this application, one or more of which are described below. Each embodiment is provided for explanation and not for limitation. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to this application without departing from its scope or spirit. For example, features described or illustrated as part of one embodiment may be used in another embodiment to produce further embodiments.

[0042] Therefore, this application is intended to cover such modifications and variations falling within the scope of the appended claims and their equivalents. Other objects, features, and aspects of this application are disclosed in or will be apparent from the following detailed description. It will be understood by those skilled in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of this application.

[0043] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0044] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0045] Unless otherwise specified herein, all embodiments and optional embodiments of this application can be combined with each other to form new technical solutions. Similarly, all technical features and optional technical features of this application can be combined with each other to form new technical solutions.

[0046] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0047] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0048] Unless otherwise stated or in case of conflict, the terms or phrases used in this application shall have the following meanings:

[0049] In this application, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" or "at least one" means one or more of two.

[0050] In this application, terms such as "further" and "especially" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0051] In this application, "room temperature" generally refers to 10℃ to 35℃, for example, 20℃ ± 5℃. In some embodiments of this application, "room temperature" or "normal temperature" refers to 10℃ to 30℃. In some embodiments of this application, "room temperature" or "normal temperature" refers to 20℃ to 30℃.

[0052] like Figure 1 As shown, this application provides an A6B 23 A method for preparing a single-phase rare-earth iron-based hydrogen storage alloy, wherein A6B 23 The chemical formula of the rare earth iron-based single-phase hydrogen storage alloy is Y6Fe. 23 or Gd6Fe 23 ;

[0053] The preparation method includes the following steps:

[0054] Select a metallic element, according to Y6Fe 23 The chemical composition is determined by batching, with an excess of Y element, and alloy ingots are prepared using an electric arc melting method; alternatively, a metallic element is selected and prepared according to the formula Gd6Fe. 23 The chemical composition was determined by batching, with an excess of Gd, and alloy ingots were prepared using an electric arc melting method.

[0055] The alloy ingot was annealed under an argon atmosphere.

[0056] The annealed alloy ingots were subjected to room temperature water quenching.

[0057] This invention successfully eliminates impurity phases and prepares A6B by combining electric arc melting with annealing and room temperature water quenching. 23 Y6Fe structure 23 Gd6Fe 23 Single-phase alloys have high reversible hydrogen storage capacity, stable structure after hydrogen absorption and desorption, and low cost.

[0058] In some implementations, the Y element is in excess by 1 wt.% to 3 wt.%.

[0059] Optionally, the excess of Y element is 1 wt.%, 1.5 wt.%, 2 wt.%, 2.5 wt.%, or 3 wt.%, or the excess of Y element may be within the range of any two of the above values.

[0060] In some implementations, Gd is used in excess of 1 wt.% to 3 wt.%.

[0061] Optionally, the excess of Gd is 1 wt.%, 1.5 wt.%, 2 wt.%, 2.5 wt.%, or 3 wt.%, or the excess of Gd can be within any two of the above values.

[0062] During the arc melting of mixed metallic materials, considering the volatilization loss of yttrium (Y) during the melting process, an excess of Y is added at a ratio of 1wt.%-3wt.% to effectively compensate for its volatilization loss and ensure that the final alloy composition meets the design requirements. Similarly, considering the volatilization loss of gadolinium (Gd) during the melting process, an excess of gadolinium (Gd) is added at a ratio of 1wt.%-3wt.% to effectively compensate for its volatilization loss and ensure that the final alloy composition meets the design requirements.

[0063] In this application, excess Y element means that the mass ratio of Y element in the actual feed is based on Y6Fe. 23 The stoichiometric calculation yields a 1% to 3% higher theoretical mass of element Y.

[0064] Similarly, in this application, "Gd excess" means that the mass ratio of Gd in the actual feed is based on Gd6Fe. 23 The stoichiometric calculations yielded a theoretical mass of Gd that was 1% to 3% higher than the actual mass.

[0065] In some embodiments, the alloy ingot is prepared by arc melting at least three times. By turning the ingot formed during arc melting, the alloy melt is fully convected and mixed, ensuring the uniformity of the alloy melting and avoiding compositional segregation defects.

[0066] In some embodiments, the process of preparing alloy ingots by electric arc melting is carried out under an argon atmosphere at a pressure of -0.07 to -0.03 MPa.

[0067] In some implementations, the pressure inside the electric arc furnace is stabilized at -0.07 to -0.03 MPa by introducing argon gas into the furnace cavity.

[0068] In some embodiments, the annealing process includes a first annealing process, a second annealing process, and a third annealing process performed sequentially; the temperatures of the first annealing process, the second annealing process, and the third annealing process are increased sequentially.

[0069] This application employs a segmented annealing process, employing a stepped temperature control and holding method involving low-temperature stress relief, medium-temperature recrystallization and microstructure reconstruction, and high-temperature long-term composition homogenization. This gradually eliminates dendritic segregation and compositional inhomogeneity in the as-cast alloy, provides sufficient diffusion conditions for elements in the rare-earth hydrogen storage alloy, effectively dissolves the primary second phase, avoids the formation and precipitation of non-equilibrium impurities, and smoothly completes the solid solution homogenization process. This maximizes the production of a high-temperature single-phase solid solution with uniform composition and pure microstructure, laying a good microstructural foundation for the stable retention of the room-temperature single-phase microstructure during subsequent water quenching.

[0070] In some embodiments, the first annealing process includes: heating from room temperature to 363 K-383 K and holding at that temperature for 10 min-20 min;

[0071] The second annealing process includes: heating from the final temperature of the first annealing process to 863 K-883 K and holding at that temperature for 1 h-2 h.

[0072] The third annealing process includes heating from the final temperature of the second annealing process to 1173 K-1323 K and holding at that temperature for 24 h-30 h.

[0073] In some embodiments, the heating rate of the first annealing treatment is 3 K / min - 4 K / min;

[0074] And / or, the heating rate for the second annealing treatment is 4 K / min - 5 K / min;

[0075] And / or, the heating rate of the third annealing treatment is 1 K / min - 2 K / min.

[0076] In some implementations, the water temperature for room temperature water quenching is 10°C-35°C.

[0077] This application utilizes room temperature water quenching, which, after obtaining a high-temperature stable single-phase solid solution through segmented high-temperature annealing, rapidly crosses the temperature range for the precipitation of the second phase and the ordered phase transformation of the alloy at an extremely high cooling rate. This significantly suppresses solute atom diffusion, grain boundary second-phase nucleation, and compositional segregation regeneration, effectively preventing the decomposition, precipitation of secondary phases, and ordered transformation of the high-temperature single-phase structure during the cooling process. It can directly freeze and preserve a uniform and pure high-temperature single-phase structure to room temperature. At the same time, the process is simple and controllable with moderate thermal shock, making it the most ideal cooling method for preparing high-purity single-phase alloys.

[0078] In some embodiments, the step of preparing alloy ingots using the electric arc melting method further includes: cleaning the electric arc furnace cavity with argon gas to remove oxygen from the furnace cavity. Cleaning the electric arc furnace cavity with argon gas before electric arc melting removes as much residual oxygen as possible, preventing oxidation contamination during alloy melting.

[0079] In some embodiments, the process prior to the annealing step includes: removing the oxide impurity layer from the surface of the alloy ingot, crushing it, and preparing an alloy sample; placing the alloy sample in a reaction apparatus; cleaning the reaction apparatus with argon gas; and sealing the cleaned reaction apparatus.

[0080] In some embodiments, the alloy sample is encapsulated in a quartz tube under an argon atmosphere and annealed in a muffle furnace.

[0081] Optionally, the mass of the alloy sample in the quartz tube is 3g-7g. Further, the mass of the alloy sample in the quartz tube is 4g-5g.

[0082] The implementation schemes of this application will be described in detail below with reference to specific embodiments. It should be understood that these embodiments are only for illustrating this application and are not intended to limit the scope of this application. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this application, or follow experimental manuals or conventional conditions in the field, or follow the conditions recommended by the manufacturer, or refer to experimental methods known in the field. Unless otherwise specified, the raw materials used in the following experiments can be routinely purchased from the market. "Room temperature" refers to 25°C.

[0083] Example 1

[0084] A type of A6B 23 Type Y6Fe23 The preparation method of single-phase rare earth iron-based hydrogen storage alloy includes:

[0085] 1) Select high-purity yttrium (Y) and iron (Fe) metal elements as raw materials, and follow the Y6Fe... 23 Chemical composition was determined by batching, with 1 wt.% of element Y added in excess to effectively compensate for its volatilization loss. After batching, alloy ingots were prepared using an electric arc melting process. Before melting, the electric arc furnace cavity was cleaned three times with argon gas to remove residual oxygen. After the final cleaning, argon gas was added to the electric arc furnace cavity to stabilize the furnace pressure at -0.05 MPa. Then, electric arc melting was started. During the melting process, the ingot was flipped three times.

[0086] 2) First, remove the oxide impurity layer on the surface of the alloy ingot prepared by electric arc melting, and then crush it. Then, weigh 4 g of the crushed alloy sample and place it in a quartz tube with an inner diameter of 10 mm. Use a vacuum sealing machine to clean the atmosphere inside the quartz tube with argon gas 3 times to ensure the purity of the sample during the heat treatment process. Finally, use small quartz blocks to seal the quartz tube.

[0087] 3) Anneal the alloy sample inside the quartz tube. Specifically, heat the sample from room temperature to 373 K at a heating rate of 4 K / min and hold for 15 min, then heat it to 873 K at a rate of 5 K / min and hold for 60 min, then heat it to 1173 K at a rate of 1 K / min and hold for 24 h. Finally, remove the quartz tube directly from the muffle furnace and quench it in water at room temperature, taking care to prevent the quartz tube from breaking during the quenching process.

[0088] The alloy material prepared above was ground and crushed. The alloy powder that passed through a 300-mesh sieve was used for XRD testing. The test angle range was set to 10°~90°. The resulting alloy XRD pattern is shown below. Figure 2 As shown. Test results indicate that this alloy is Y6Fe. 23 It has a single-phase structure with a phase abundance of 100 wt.%.

[0089] Alloy powder sieved through a 300-mesh sieve was selected, and its PCT hydrogen storage performance was tested using a Zhejiang University ZDMH-4 hydrogen storage device. The test temperature was set at 573 K and the pressure at 13 MPa. The PCT test curve of the alloy is shown below. Figure 3 As shown. Test results show that the alloy's maximum hydrogen storage capacity reaches 1.63 wt.%; the XRD patterns of the alloy before and after cycling are shown in the figure. Figure 4 As shown, the results indicate that the alloy can still maintain a stable crystal structure after 5 weeks of hydrogen absorption and desorption cycles.

[0090] Example 2

[0091] A type of A6B 23 Type Gd6Fe 23 The preparation method of single-phase rare earth iron-based hydrogen storage alloy includes:

[0092] 1) High-purity gadolinium (Gd) and iron (Fe) metallic elements are selected as raw materials, Gd6Fe 23 The chemical composition was determined by batching, with Gd added in excess at a ratio of 2 wt.% to effectively compensate for its volatilization loss. After batching, alloy ingots were prepared using an electric arc melting process. Before melting, the electric arc furnace cavity was cleaned three times with argon gas to remove residual oxygen. After the final cleaning, argon gas was added to the electric arc furnace cavity to stabilize the furnace pressure at -0.05 MPa. Then, electric arc melting was started. During the melting process, the ingots were flipped three times.

[0093] 2) First, remove the oxide impurity layer on the surface of the alloy ingot prepared by electric arc melting, and then crush it. Then, weigh 5 g of the crushed alloy sample and place it in a quartz tube with an inner diameter of 10 mm. Use a vacuum sealing machine to clean the atmosphere inside the quartz tube with argon gas three times to ensure the purity of the sample during the heat treatment process. Finally, use small quartz blocks to seal the quartz tube.

[0094] 3) Anneal the alloy sample inside the quartz tube. Specifically, heat the sample from room temperature to 373 K at a heating rate of 4 K / min and hold for 15 min, then heat it to 873 K at a rate of 5 K / min and hold for 60 min, then heat it to 1173 K at a rate of 1 K / min and hold for 24 h. Finally, remove the quartz tube directly from the muffle furnace and quench it at room temperature with water. Avoid cracking the quartz tube during the quenching process.

[0095] The alloy material prepared above was ground and crushed. The alloy powder that passed through a 300-mesh sieve was used for XRD testing. The test angle range was set to 10°~90°. The resulting alloy XRD pattern is shown below. Figure 5 As shown. Test results indicate that this alloy is Gd6Fe. 23 It has a single-phase structure with a phase abundance of 100 wt.%.

[0096] Alloy powder sieved through a 300-mesh sieve was selected, and its PCT hydrogen storage performance was tested using a Zhejiang University ZDMH-4 hydrogen storage device. The test temperature was set at 573 K and the pressure at 13 MPa. The PCT test curve of the alloy is shown below. Figure 6 As shown in the figure. Test results show that the alloy's maximum hydrogen storage capacity reaches 1.48 wt.%.

[0097] Example 3

[0098] A type of A6B 23 Type Y6Fe 23 The preparation method of single-phase rare earth iron-based hydrogen storage alloy includes:

[0099] 1) Select high-purity yttrium (Y) and iron (Fe) metal elements as raw materials, and follow the Y6Fe... 23 Chemical composition was determined by batching, with 1 wt.% of element Y added in excess to effectively compensate for its volatilization loss. After batching, alloy ingots were prepared using an electric arc melting process. Before melting, the electric arc furnace cavity was cleaned three times with argon gas to remove residual oxygen. After the final cleaning, argon gas was added to the electric arc furnace cavity to stabilize the furnace pressure at -0.05 MPa. Then, electric arc melting was started. During the melting process, the ingot was flipped three times.

[0100] 2) First, remove the oxide impurity layer on the surface of the alloy ingot prepared by electric arc melting, and then crush it. Then, weigh 4 g of the crushed alloy sample and place it in a quartz tube with an inner diameter of 10 mm. Use a vacuum sealing machine to clean the atmosphere inside the quartz tube with argon gas 3 times to ensure the purity of the sample during the heat treatment process. Finally, use small quartz blocks to seal the quartz tube.

[0101] 3) Anneal the alloy sample inside the quartz tube. Specifically, heat the sample from room temperature to 373 K at a heating rate of 4 K / min and hold for 15 min, then heat it to 873 K at a rate of 5 K / min and hold for 60 min, then heat it to 1273 K at a rate of 1 K / min and hold for 24 h. Finally, remove the quartz tube directly from the muffle furnace and quench it in water at room temperature, taking care to prevent the quartz tube from breaking during the quenching process.

[0102] The alloy material prepared above was ground and crushed. The alloy powder that passed through a 300-mesh sieve was used for XRD testing. The test angle range was set to 10°~90°. The resulting alloy XRD pattern is shown below. Figure 7 As shown. Test results indicate that this alloy is Y6Fe. 23 It has a single-phase structure with a phase abundance of 100 wt.%.

[0103] Example 4

[0104] A type of A6B 23 Type Y6Fe 23 The preparation method of single-phase rare earth iron-based hydrogen storage alloy includes:

[0105] 1) Select high-purity yttrium (Y) and iron (Fe) metal elements as raw materials, and follow the Y6Fe... 23Chemical composition was determined by batching, with 1 wt.% of element Y added in excess to effectively compensate for its volatilization loss. After batching, alloy ingots were prepared using an electric arc melting process. Before melting, the electric arc furnace cavity was cleaned three times with argon gas to remove residual oxygen. After the final cleaning, argon gas was added to the electric arc furnace cavity to stabilize the furnace pressure at -0.05 MPa. Then, electric arc melting was started. During the melting process, the ingot was flipped three times.

[0106] 2) First, remove the oxide impurity layer on the surface of the alloy ingot prepared by electric arc melting, and then crush it. Then, weigh 4 g of the crushed alloy sample and place it in a quartz tube with an inner diameter of 10 mm. Use a vacuum sealing machine to clean the atmosphere inside the quartz tube with argon gas 3 times to ensure the purity of the sample during the heat treatment process. Finally, use small quartz blocks to seal the quartz tube.

[0107] 3) Anneal the alloy sample inside the quartz tube. Specifically, heat the sample from room temperature to 373 K at a heating rate of 4 K / min and hold for 15 min, then heat it to 873 K at a rate of 5 K / min and hold for 60 min, then heat it to 1323 K at a rate of 1 K / min and hold for 24 h. Finally, remove the quartz tube directly from the muffle furnace and quench it at room temperature with water, taking care to prevent the quartz tube from breaking during the quenching process.

[0108] The alloy material prepared above was ground and crushed. The alloy powder that passed through a 300-mesh sieve was used for XRD testing. The test angle range was set to 10°~90°. The resulting alloy XRD pattern is shown below. Figure 8 As shown. Test results indicate that this alloy is Y6Fe. 23 It has a single-phase structure with a phase abundance of 100 wt.%.

[0109] Comparative Example 1

[0110] A type of A6B 23 Type Y6Fe 23 Methods for preparing hydrogen storage alloys with phase structures include:

[0111] High-purity yttrium (Y) and iron (Fe) metallic elements were selected as raw materials, and the process was carried out according to Y6Fe 23Chemical composition was determined by batching; element Y was added in excess at a ratio of 1 wt.% to effectively compensate for its volatilization loss. After batching, alloy ingots were prepared using an electric arc melting process. Before melting, the electric arc furnace cavity was cleaned three times with argon gas to remove residual oxygen. After the final cleaning, argon gas was added to the furnace cavity to stabilize the furnace pressure at -0.05 MPa. Electric arc melting was then initiated, and the ingot was flipped three times during the melting process. The alloy material obtained above was ground and crushed. Alloy powder sieved through a 300-mesh sieve was subjected to XRD testing. The testing angle range was set to 10°~90°. The XRD pattern of the alloy is shown below. Figure 9 As shown, the results indicate that the alloy is composed of Y6Fe 23 Y2Fe 17 It consists of YFe3 and YFe2 phases, with phase abundances of 62.0 wt.%, 24.2 wt.%, 5.1 wt.% and 8.7 wt.%, respectively.

[0112] Alloy powder sieved through a 300-mesh sieve was selected, and its PCT hydrogen storage performance was tested using a Zhejiang University ZDMH-4 hydrogen storage device. The test temperature was set at 573 K and the pressure at 13 MPa. The PCT test curve of the alloy is shown below. Figure 10 As shown in the figure. Test results show that the alloy's maximum hydrogen storage capacity reaches 1.21 wt.%.

[0113] By comparing the results of the above embodiments with those of the comparative examples, it can be found that the Y6Fe prepared by the preparation method provided in this application... 23 and Gd6Fe 23 The alloy possesses Th6Mn 23 - Type single-phase structure, space group Fm-3m. Y6Fe 23 and Gd6Fe 23 The single-phase alloy exhibits reversible hydrogen storage properties, with maximum hydrogen storage capacities of 1.63 wt.% and 1.48 wt.% at 573 K.

[0114] The preparation method provided in this application successfully prepared single-phase A6B23 type Y-Fe and Gd-Fe based hydrogen storage alloys, and their hydrogen storage performance was tested, revealing that A6B23... 23 (A=Y, Gd, B=Fe) single-phase alloys exhibit high hydrogen storage performance and good structural stability. Among them, Y6Fe... 23 The alloy has a maximum hydrogen storage capacity of 1.63 wt.% Gd6Fe 23 The alloy has a maximum hydrogen storage capacity of 1.48 wt.%, and its structure remains stable after hydrogen absorption and desorption cycles.

[0115] The preparation process proposed in this invention involves arc melting followed by annealing, and finally room temperature water quenching. The process flow is clear, simple to operate, and highly repeatable. This is beneficial for A6B. 23 Industrial production of (A=Y, Gd, B=Fe) single-phase hydrogen storage alloy.

[0116] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0117] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A type of A6B 23 A method for preparing a single-phase rare-earth iron-based hydrogen storage alloy, characterized in that, The A6B 23 The chemical formula of the single-phase rare earth iron-based hydrogen storage alloy is Y6Fe. 23 or Gd6Fe 23 ; The preparation method includes the following steps: Select a metallic element, according to Y6Fe 23 The chemical composition is determined by batching, with an excess of Y element, and alloy ingots are prepared using an electric arc melting method; alternatively, a metallic element is selected and prepared according to the formula Gd6Fe. 23 The chemical composition was determined by batching, with an excess of Gd, and the alloy ingot was prepared by electric arc melting. The alloy ingot is annealed under an argon atmosphere. The annealed alloy ingot is then subjected to room temperature water quenching.

2. The A6B according to claim 1 23 A method for preparing a single-phase rare-earth iron-based hydrogen storage alloy, characterized in that, The Y element is in excess by 1 wt.% to 3 wt.%; or the Gd element is in excess by 1 wt.% to 3 wt.%.

3. The A6B according to claim 1 23 A method for preparing a single-phase rare-earth iron-based hydrogen storage alloy, characterized in that, During the process of preparing alloy ingots using the electric arc melting method, at least three flipping processes are performed.

4. The A6B according to claim 1 23 A method for preparing a single-phase rare-earth iron-based hydrogen storage alloy, characterized in that, The process of preparing alloy ingots using the electric arc melting method is carried out under an argon atmosphere at a pressure of -0.07 MPa to -0.03 MPa.

5. The A6B according to claim 1 23 A method for preparing a single-phase rare-earth iron-based hydrogen storage alloy, characterized in that, The annealing process includes a first annealing process, a second annealing process, and a third annealing process performed sequentially. The temperatures of the first annealing treatment, the second annealing treatment, and the third annealing treatment are increased sequentially.

6. The A6B according to claim 5 23 A method for preparing a single-phase rare-earth iron-based hydrogen storage alloy, characterized in that, The first annealing process includes: heating from room temperature to 363 K-383 K and holding at that temperature for 10 min-20 min; The second annealing process includes: raising the temperature from the final temperature of the first annealing process to 863 K-883 K and holding it at that temperature for 1 h-2 h; The third annealing process includes: raising the temperature from the final temperature of the second annealing process to 1173 K-1323 K and holding it at that temperature for 24 h-30 h.

7. The A6B according to claim 5 or 6 23 A method for preparing a single-phase rare-earth iron-based hydrogen storage alloy, characterized in that, The heating rate for the first annealing treatment is 3 K / min - 4 K / min; And / or, the heating rate of the second annealing treatment is 4 K / min - 5 K / min; And / or, the heating rate of the third annealing treatment is 1 K / min - 2 K / min.

8. The A6B according to any one of claims 1-6 23 A method for preparing a single-phase rare-earth iron-based hydrogen storage alloy, characterized in that, The water temperature for the room temperature water quenching treatment is 10℃-35℃.

9. The A6B according to any one of claims 1-6 23 A method for preparing a single-phase rare-earth iron-based hydrogen storage alloy, characterized in that, Before the step of preparing alloy ingots by electric arc melting, the process further includes cleaning the electric arc furnace cavity with argon gas to remove oxygen from the furnace cavity.

10. The A6B according to any one of claims 1-6 23 A method for preparing a single-phase rare-earth iron-based hydrogen storage alloy, characterized in that, The process also includes the following steps before the annealing process: Remove the oxide impurity layer from the surface of the alloy ingot, crush it, and prepare an alloy sample; The alloy sample is placed in the reaction apparatus; The reaction apparatus was cleaned using argon gas; The reaction apparatus, after cleaning, is then sealed.

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