Rare earth AB2 type hydrogen storage alloy as well as preparation method and application thereof

Abstract

The invention relates to a rare earth AB2 type hydrogen storage alloy and a preparation method and application thereof, the preparation method of the rare earth AB2 type hydrogen storage alloy comprises the following steps: (1) refining a rare earth component and a Cr component and / or a VFe component in a Ti-Zr-Cr-Mn-VFe raw material to obtain an alloy ingot; and (2) after the alloy ingot obtained in the step (1) is subjected to surface treatment, the alloy ingot and remaining components in the Ti-Zr-Cr-Mn-VFe raw materials are subjected to smelting treatment, and the rare earth AB2 type hydrogen storage alloy is obtained. The Cr and / or VFe components and the rare earth elements are refined to improve the purity, and then the refined alloy is used as the raw material for smelting, so that the purposes of reducing the impurity content of the alloy and improving the hydrogen storage performance are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state hydrogen storage, and in particular to a rare earth AB2 type hydrogen storage alloy and a preparation method and application thereof. Background Art

[0002] With the development of society and the growth of population, human demand for energy has gradually increased, and the excessive consumption of fossil energy has caused serious environmental pollution problems. In order to achieve sustainable development, finding new clean energy has become the focus of the energy industry. Hydrogen energy, as a clean energy with high energy density and abundant sources, is expected to become a substitute for fossil energy to solve the problems of energy shortage and environmental pollution. At present, the development of hydrogen energy is mainly concentrated in the fields of hydrogen fuel cell vehicles and hydrogen energy storage. As one of the important means of hydrogen energy storage, solid-state hydrogen storage technology has the advantages of high hydrogen storage density and good safety, and has attracted much attention from researchers.

[0003] Solid-state hydrogen storage technology refers to storing hydrogen in solid materials through physical or chemical adsorption, chemical reaction and other methods. Among them, AB2 type hydrogen storage alloy is a common solid-state hydrogen storage material with low cost, high hydrogen storage capacity and cycle stability, and is widely used in the field of hydrogen energy. AB2 type hydrogen storage alloy is mainly composed of two major categories: Ti series and Zr series, and is considered to be the second generation of solid-state hydrogen storage alloys with high energy density. For example, CN115377433A discloses a method for preparing a high-performance AB2 type hydrogen storage alloy, comprising the following steps: (1) mixing the various metal raw materials constituting the AB2 type hydrogen storage alloy and then smelting to obtain an alloy ingot; (2) crushing the alloy ingot and preparing alloy flakes by belt spinning; (3) mixing graphene with the alloy flakes and high-energy ball milling to obtain an AB2 type hydrogen storage alloy; wherein the various metal raw materials of the hydrogen storage alloy are two or three of Ti, Cr and Mn; the linear speed of belt spinning is 5-20m / s; and the speed of high-energy ball milling is 600-900r / min.

[0004] However, the hydrogen storage performance of AB2 type hydrogen storage alloy is greatly affected by the purity of raw materials. The alloy is usually smelted with raw materials such as titanium, chromium, manganese, and ferrovanadium alloys. The purity of these raw materials is relatively low, among which chromium and ferrovanadium are the most serious, containing a large amount of impurities such as Al, Si, C, S, and P. The incorporation of these impurities will reduce the hydrogen storage performance and cycle stability of the hydrogen storage alloy.

[0005] CN117286378A discloses a TiMnV-based hydrogen storage alloy and its preparation method and application. The chemical composition of the alloy is Ti a Mn b V x Fe y Zr c, where a, b, c and x, y represent the mass percentage of each element, 25≤a≤28, 50≤b≤52.5, 2.5≤c<4, 12≤x≤16, 2≤y≤4.5, x+y+c≤22.5, x / y≥4.5, a+b+c+x+y=100. The alloy is prepared by combining vacuum aluminothermic method, vacuum consumable melting method and vacuum induction melting method. The alloy has high uniformity and low impurity content, but it uses raw materials with higher purity, which will result in higher product cost and is not conducive to mass production.

[0006] Therefore, in view of the shortcomings of the prior art, there is an urgent need to provide a method for preparing a hydrogen storage alloy with low impurity content, good hydrogen storage performance and suitable for mass production. Summary of the invention

[0007] The object of the present invention is to provide a rare earth AB2 type hydrogen storage alloy and a preparation method and application thereof, by refining the Cr and / or VFe components to improve their purity, and then using the refined alloy as a raw material for smelting, thereby achieving the purpose of reducing the impurity content of the alloy and improving the hydrogen storage performance.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing a rare earth AB2 type hydrogen storage alloy, the preparation method comprising the following steps:

[0010] (1) refining the rare earth component and the Cr and / or VFe component in the Ti-Zr-Cr-Mn-VFe raw material to obtain an alloy ingot;

[0011] (2) The alloy ingot obtained in step (1) is subjected to surface treatment and then smelted with the remaining components in the Ti-Zr-Cr-Mn-VFe raw material to obtain the rare earth AB2 type hydrogen storage alloy.

[0012] The invention provides a method for preparing a rare earth AB2 type hydrogen storage alloy. The alloy smelting process is changed, and rare earth and Cr and / or VFe components in a Ti-Zr-Cr-Mn-VFe raw material are refined. During the refining process, the high activity of the rare earth element can absorb oxygen in the raw material to form rare earth oxides. The high melting point of the rare earth oxides causes impurities to be enriched around them during smelting, or to form compounds. After refining, the impurities are removed by surface treatment, thereby improving the purity of the Cr and / or VFe components. Further smelting is performed with the remaining components to obtain a rare earth AB2 type hydrogen storage alloy with higher purity and effective hydrogen absorption amount, and the hydrogen absorption and desorption performance and cycle performance of the alloy are significantly improved. The preparation method has the advantages of low cost and simple process, and is suitable for large-scale preparation.

[0013] Preferably, the composition formula of the Cr and / or VFe component and the rare earth component in step (1) is A m B n , wherein the value range of m is 1-2, the value range of n is 0.01-0.03; A represents Cr and / or VFe, and B includes any one of La, Ce, Pr or Y or a combination of at least two of them.

[0014] The value range of m is 1-2, for example, it can be 1, 1.2, 1.5, 1.8 or 2, but is not limited to the listed values, and other values ​​not listed in the value range are also applicable.

[0015] The value range of n is 0.01-0.03, for example, it can be 0.01, 0.02 or 0.03, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] The B includes any one of La, Ce, Pr or Y or a combination of at least two of them. Typical but non-limiting combinations include a combination of La and Ce, a combination of Ce, Pr and Y, or a combination of La, Ce, Pr and Y.

[0017] Preferably, the refining treatment in step (1) is carried out in a vacuum arc furnace.

[0018] Preferably, before the refining treatment in step (1), the vacuum arc furnace is evacuated to a vacuum degree of ≤5×10 -3 Pa, for example, can be 5×10 -3 Pa, 4×10 -3 Pa, 3×10 -3 Pa, 2×10 -3 Pa or 1×10 -3 Pa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] Preferably, the refining treatment in step (1) is carried out under the protection of an inert gas.

[0020] Preferably, the current of the refining treatment in step (1) is 80-200A, for example, 80A, 100A, 120A, 150A or 200A, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] Preferably, the refining treatment time in step (1) is 80-300 s / time, for example, 80 s / time, 120 s / time, 200 s / time, 250 s / time or 300 s / time, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] Preferably, the refining treatment in step (1) is performed 3-5 times, for example, 3 times, 4 times or 5 times.

[0023] Preferably, the surface treatment in step (2) includes mechanical grinding and / or chemical reagent treatment.

[0024] Preferably, the endpoint of the surface treatment in step (2) is to remove oxides and impurities on the surface of the alloy ingot.

[0025] Preferably, the smelting process in step (2) is carried out in an induction melting furnace.

[0026] Preferably, the vacuum degree of the smelting treatment in step (2) is ≤5×10 -3 Pa, for example, can be 5×10 -3 Pa, 4×10 -3 Pa, 3×10 -3 Pa, 2×10 -3 Pa or 1×10 -3 Pa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the smelting treatment time in step (2) is 1.5-2.5 minutes after all components are melted, for example, 1.5 minutes, 1.8 minutes, 2 minutes, 2.2 minutes or 2.5 minutes, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] Preferably, the power of the smelting treatment in step (2) is 18-22 kW, for example, 18 kW, 19 kW, 20 kW, 21 kW or 22 kW, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] The induction melting furnace parameters such as vacuum degree, time and power of the melting process described in the present invention can be changed according to the adjustment of the preparation capacity.

[0030] As a preferred technical solution of the preparation method of the present invention, the preparation method comprises the following steps:

[0031] (1) refining the rare earth component and the Cr and / or VFe component in the Ti-Zr-Cr-Mn-VFe raw material in a vacuum arc furnace under the protection of inert gas, with a current of 80-200A, a time of 80-300s / time, and a number of times of 3-5 times to obtain an alloy ingot; before the refining treatment, the vacuum arc furnace is evacuated to a vacuum degree of ≤5×10 -3 Pa;

[0032] The general formula of the composition of the Cr and / or VFe component and the rare earth component is A m B n , wherein m is in the range of 1-2, and n is in the range of 0.01-0.03; A represents Cr and / or VFe, and B includes any one or a combination of at least two of La, Ce, Pr or Y;

[0033] (2) The alloy ingot obtained in step (1) is subjected to surface treatment to remove oxides and impurities on the surface of the alloy ingot, and then smelted with the remaining components in the Ti-Zr-Cr-Mn-VFe raw material in an induction melting furnace with a vacuum degree of ≤5×10 - 3 Pa, the time is 1.5-2.5 minutes after all components are melted, the power supply is 18-22kW, and the rare earth AB2 type hydrogen storage alloy is obtained.

[0034] In a second aspect, the present invention provides a rare earth AB2 type hydrogen storage alloy, wherein the rare earth AB2 type hydrogen storage alloy is prepared by the preparation method of the rare earth AB2 type hydrogen storage alloy described in the first aspect.

[0035] The effective hydrogen absorption capacity and hydrogen absorption and desorption cycle stability of the rare earth AB2 type hydrogen storage alloy prepared by the present invention are significantly improved compared with conventional methods. The maximum hydrogen absorption amount is increased from 1.89wt% to 1.96wt% compared with the direct smelting method. After 300 hydrogen absorption and desorption cycle stability tests, the cycle efficiency is increased from 96.9% to 98.6%. The alloy can better meet the use requirements of the linkage between the solid-state hydrogen storage device and the fuel cell, and has a high application value.

[0036] Preferably, the rare earth AB2 type hydrogen storage alloy has a general formula of Ti a Zr b Cr c Mn d (VFe) f , where the value range of a is 0.6-0.9, the value range of b is 0.1-0.4, the value range of c is 0.5-1.2, the value range of d is 0.8-1.5, and the value range of f is 0.01-0.1.

[0037] The value range of a is 0.6-0.9, for example, it can be 0.6, 0.7, 0.8 or 0.9, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] The value range of b is 0.1-0.4, for example, it can be 0.1, 0.2, 0.3 or 0.4, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0039] The value range of c is 0.5-1.2, for example, it can be 0.5, 0.6, 0.8, 1 or 1.2, but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0040] The value range of d is 0.8-1.5, for example, it can be 0.8, 1, 1.2 or 1.5, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0041] The value range of f is 0.01-0.1, for example, it can be 0.01, 0.02, 0.05, 0.08 or 0.1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0042] In a third aspect, the present invention provides an application of the rare earth AB2 type hydrogen storage alloy as described in the second aspect, wherein the rare earth AB2 type hydrogen storage alloy is used in a solid-state hydrogen energy storage system or hydrogen metallurgy.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The invention provides a method for preparing a rare earth AB2 type hydrogen storage alloy. The alloy smelting process is changed, and rare earth and Cr and / or VFe components in a Ti-Zr-Cr-Mn-VFe raw material are refined. During the refining process, the high activity of the rare earth element can absorb oxygen in the raw material to form rare earth oxides. The high melting point of the rare earth oxides causes impurities to be enriched around them during smelting, or to form compounds. After refining, the impurities are removed by surface treatment, thereby improving the purity of the Cr and / or VFe components. Further smelting is performed with the remaining components to obtain a rare earth AB2 type hydrogen storage alloy with higher purity and effective hydrogen absorption capacity, and the hydrogen absorption and desorption performance and cycle performance of the alloy are significantly improved. Compared with a direct smelting method, the maximum hydrogen absorption capacity is increased from 1.89wt% to 1.96wt%, and after 300 hydrogen absorption and desorption cycle stability tests, the cycle efficiency is increased from 96.9% to 98.6%. The preparation method has the advantages of low cost and simple process, and is suitable for large-scale preparation. DETAILED DESCRIPTION

[0045] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0046] Example 1

[0047] This embodiment provides a rare earth AB2 type hydrogen storage alloy, the composition formula of the rare earth AB2 type hydrogen storage alloy is Ti 0.6 Zr 0.4 Cr 0.8 Mn1.2 (VFe) 0.02 The preparation method of the rare earth AB2 type hydrogen storage alloy comprises the following steps:

[0048] (1) CrLa 0.03 、(VFe)La 0.03 The refining treatment was carried out under the protection of argon in a vacuum arc furnace, with a current of 150A, a time of 120s / time, and a number of times of 4 times to obtain an alloy ingot; before the refining treatment, the vacuum arc furnace was evacuated to a vacuum degree of 5×10 -3 Pa;

[0049] (2) The alloy ingot obtained in step (1) is mechanically polished to remove oxides and impurities on the surface of the alloy ingot, and then smelted with the remaining components in the Ti-Zr-Cr-Mn-VFe raw material in an induction melting furnace with a vacuum degree of 5×10 - 3 Pa, the time is to continue smelting for 2 minutes after all components are melted, the power supply is 20kW, and the rare earth AB2 type hydrogen storage alloy is obtained.

[0050] Example 2

[0051] This embodiment provides a rare earth AB2 type hydrogen storage alloy, the composition formula of the rare earth AB2 type hydrogen storage alloy is Ti 0.6 Zr 0.4 Cr 0.8 Mn 1.2 (VFe) 0.02 The preparation method of the rare earth AB2 type hydrogen storage alloy comprises the following steps:

[0052] (1) CrLa 0.03 、(VFe)La 0.03 The refining treatment was carried out under the protection of argon in a vacuum arc furnace, with a current of 80A, a time of 300s / time, and a number of times to obtain an alloy ingot; before the refining treatment, the vacuum arc furnace was evacuated to a vacuum degree of 4×10 -3 Pa;

[0053] (2) The alloy ingot obtained in step (1) is mechanically polished to remove oxides and impurities on the surface of the alloy ingot, and then smelted with the remaining components in the Ti-Zr-Cr-Mn-VFe raw material in an induction melting furnace with a vacuum degree of 4×10 - 3 Pa, the time is to continue smelting for 1.5 minutes after all components are melted, the power supply power is 18kW, and the rare earth AB2 type hydrogen storage alloy is obtained.

[0054] Example 3

[0055] This embodiment provides a rare earth AB2 type hydrogen storage alloy, the composition formula of the rare earth AB2 type hydrogen storage alloy is Ti 0.6 Zr 0.4 Cr 0.8 Mn 1.2 (VFe) 0.02 The preparation method of the rare earth AB2 type hydrogen storage alloy comprises the following steps:

[0056] (1) CrLa 0.03 、(VFe)La 0.03 The refining treatment was carried out under the protection of argon in a vacuum arc furnace, with a current of 200A, a time of 80s / time, and a number of times of 5 times to obtain an alloy ingot; before the refining treatment, the vacuum arc furnace was evacuated to a vacuum degree of 3×10 -3 Pa;

[0057] (2) The alloy ingot obtained in step (1) was treated with a hydrochloric acid solution having a concentration of 0.1 mol / L to remove oxides and impurities on the surface of the alloy ingot, and then smelted with the remaining components in the Ti-Zr-Cr-Mn-VFe raw material in an induction melting furnace with a vacuum degree of 3×10 -3 Pa, the time is to continue smelting for 2.5 minutes after all components are melted, the power supply is 22kW, and the rare earth AB2 type hydrogen storage alloy is obtained.

[0058] Example 4

[0059] This embodiment provides a rare earth AB2 type hydrogen storage alloy. The preparation method of the rare earth AB2 type hydrogen storage alloy is different from that of embodiment 1 in that, in addition to the CrLa 0.03 、(VFe)La 0.03 Adjusted to a single CrLa 0.03 Except for this, the rest are the same as in Example 1.

[0060] Example 5

[0061] This embodiment provides a rare earth AB2 type hydrogen storage alloy. The preparation method of the rare earth AB2 type hydrogen storage alloy is different from that of embodiment 1 in that, in addition to the CrLa 0.03 、(VFe)La 0.03 Adjusted to a single (VFe)La 0.03 Except for this, the rest are the same as in Example 1.

[0062] Example 6

[0063] This embodiment provides a rare earth AB2 type hydrogen storage alloy. The preparation method of the rare earth AB2 type hydrogen storage alloy is different from that of embodiment 1 in that, in addition to the CrLa 0.03、(VFe)La 0.03 Adjust to CrCe 0.03 、(VFe)Ce 0.03 Except for this, the rest are the same as in Example 1.

[0064] Example 7

[0065] This embodiment provides a rare earth AB2 type hydrogen storage alloy. The preparation method of the rare earth AB2 type hydrogen storage alloy is different from that of embodiment 1 in that, in addition to the CrLa 0.03 、(VFe)La 0.03 Adjust to single CrCe 0.03 Except for this, the rest are the same as in Example 1.

[0066] Example 8

[0067] This embodiment provides a rare earth AB2 type hydrogen storage alloy. The preparation method of the rare earth AB2 type hydrogen storage alloy is different from that of embodiment 1 in that, in addition to the CrLa 0.03 、(VFe)La 0.03 Adjusted to a single (VFe)Ce 0.03 Except for this, the rest are the same as in Example 1.

[0068] Example 9

[0069] This embodiment provides a rare earth AB2 type hydrogen storage alloy. The preparation method of the rare earth AB2 type hydrogen storage alloy is different from that of embodiment 1 in that, in addition to the CrLa 0.03 、(VFe)La 0.03 Adjusted to CrLa 0.01 、(VFe)La 0.01 Except for this, the rest are the same as in Example 1.

[0070] Example 10

[0071] This embodiment provides a rare earth AB2 type hydrogen storage alloy. The preparation method of the rare earth AB2 type hydrogen storage alloy is different from that of embodiment 1 in that, in addition to the CrLa 0.03 、(VFe)La 0.03 Adjusted to a single CrLa 0.01 Except for this, the rest are the same as in Example 1.

[0072] Embodiment 11

[0073] This embodiment provides a rare earth AB2 type hydrogen storage alloy. The preparation method of the rare earth AB2 type hydrogen storage alloy is different from that of embodiment 1 in that, in addition to the CrLa 0.03 、(VFe)La 0.03Adjusted to a single (VFe)La 0.01 Except for this, the rest are the same as in Example 1.

[0074] Example 12

[0075] This embodiment provides a rare earth AB2 type hydrogen storage alloy. The preparation method of the rare earth AB2 type hydrogen storage alloy is different from that of embodiment 1 in that, in addition to the CrLa 0.03 、(VFe)La 0.03 Adjust to CrCe 0.01 、(VFe)Ce 0.01 Except for this, the rest are the same as in Example 1.

[0076] Example 13

[0077] This embodiment provides a rare earth AB2 type hydrogen storage alloy. The preparation method of the rare earth AB2 type hydrogen storage alloy is different from that of embodiment 1 in that, in addition to the CrLa 0.03 、(VFe)La 0.03 Adjust to single CrCe 0.01 Except for this, the rest are the same as in Example 1.

[0078] Embodiment 14

[0079] This embodiment provides a rare earth AB2 type hydrogen storage alloy. The preparation method of the rare earth AB2 type hydrogen storage alloy is different from that of embodiment 1 in that, in addition to the CrLa 0.03 、(VFe)La 0.03 Adjusted to a single (VFe)Ce 0.01 Except for this, the rest are the same as in Example 1.

[0080] Comparative Example 1

[0081] This comparative example provides a rare earth AB2 type hydrogen storage alloy. The difference between the preparation method of the rare earth AB2 type hydrogen storage alloy and that of Example 1 is that the refining treatment described in step (1) is omitted, and the Ti-Zr-Cr-Mn-VFe raw material is directly smelted. The rest is the same as that of Example 1.

[0082] The purity of the rare earth AB2 type hydrogen storage alloys provided in Examples 1-14 and Comparative Example 1 was tested for the alloy ingots using an X-ray fluorescence spectrometer, and the results obtained are shown in Table 1; the hydrogen storage performance was tested using a PCT testing device, and the results obtained are shown in Table 1.

[0083] Table 1

[0084]

[0085]

[0086] It can be seen from Table 1 that the preparation method of the rare earth AB2 type hydrogen storage alloy provided by the present invention can significantly reduce the impurity content of the alloy and improve the hydrogen storage performance. The maximum hydrogen absorption capacity of the smelted rare earth AB2 type hydrogen storage alloy is increased from 1.89wt% to 1.96wt% compared with the direct smelting method. After 300 hydrogen absorption and desorption cycle stability tests, its cycle efficiency is increased from 96.9% to 98.6%, and the hydrogen absorption and desorption capacity and cycle performance are significantly improved.

[0087] The invention provides a method for preparing a rare earth AB2 type hydrogen storage alloy. The alloy smelting process is changed, and rare earth and Cr and / or VFe components in a Ti-Zr-Cr-Mn-VFe raw material are refined. During the refining process, the high activity of the rare earth element can absorb oxygen in the raw material to form rare earth oxides. The high melting point of the rare earth oxides causes impurities to be enriched around them during smelting, or to form compounds. After refining, the impurities are removed by surface treatment, thereby improving the purity of the Cr and / or VFe components. Further smelting is performed with the remaining components to obtain a rare earth AB2 type hydrogen storage alloy with higher purity and effective hydrogen absorption amount, and the hydrogen absorption and desorption performance and cycle performance of the alloy are significantly improved. The preparation method has the advantages of low cost and simple process, and is suitable for large-scale preparation.

[0088] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a rare earth AB2 type hydrogen storage alloy, characterized in that: The preparation method comprises the following steps: (1) refining the rare earth component and the Cr and / or VFe component in the Ti-Zr-Cr-Mn-VFe raw material to obtain an alloy ingot; (2) The alloy ingot obtained in step (1) is subjected to surface treatment and then smelted with the remaining components in the Ti-Zr-Cr-Mn-VFe raw material to obtain the rare earth AB2 type hydrogen storage alloy.

2. The preparation method according to claim 1, characterized in that: The general formula of the composition of the Cr and / or VFe component and the rare earth component in step (1) is A m B n , wherein the value range of m is 1-2, the value range of n is 0.01-0.03; A represents Cr and / or VFe, and B includes any one of La, Ce, Pr or Y or a combination of at least two of them.

3. The preparation method according to claim 1 or 2, characterized in that: The refining treatment in step (1) is carried out in a vacuum arc furnace; Preferably, before the refining treatment in step (1), the vacuum arc furnace is evacuated to a vacuum degree of ≤5×10 -3 Pa.

4. The preparation method according to any one of claims 1 to 3, characterized in that The refining treatment in step (1) is carried out under the protection of an inert gas; Preferably, the current of the refining treatment in step (1) is 80-200A; Preferably, the refining treatment time in step (1) is 80-300s / time; Preferably, the refining treatment in step (1) is performed 3-5 times.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The surface treatment in step (2) includes mechanical polishing and / or chemical reagent treatment; Preferably, the endpoint of the surface treatment in step (2) is to remove oxides and impurities on the surface of the alloy ingot.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The smelting process in step (2) is carried out in an induction smelting furnace; Preferably, the vacuum degree of the smelting treatment in step (2) is ≤5×10 -3 Pa; Preferably, the smelting treatment time in step (2) is 1.5-2.5 minutes after all components are melted; Preferably, the power of the smelting process in step (2) is 18-22 kW.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) refining the rare earth component and the Cr and / or VFe component in the Ti-Zr-Cr-Mn-VFe raw material in a vacuum arc furnace under the protection of inert gas, with a current of 80-200A, a time of 80-300s / time, and a number of times of 3-5 times to obtain an alloy ingot; before the refining treatment, the vacuum arc furnace is evacuated to a vacuum degree of ≤5×10 -3 Pa; The general formula of the composition of the Cr and / or VFe component and the rare earth component is A m B n , wherein m is in the range of 1-2, and n is in the range of 0.01-0.03; A represents Cr and / or VFe, and B includes any one or a combination of at least two of La, Ce, Pr or Y; (2) The alloy ingot obtained in step (1) is subjected to surface treatment to remove oxides and impurities on the surface of the alloy ingot, and then smelted with the remaining components in the Ti-Zr-Cr-Mn-VFe raw material in an induction melting furnace with a vacuum degree of ≤5×10 -3 Pa, the time is 1.5-2.5 minutes after all components are melted, the power supply power is 18-22kW, and the rare earth AB2 type hydrogen storage alloy is obtained.

8. A rare earth AB2 type hydrogen storage alloy, characterized in that: The rare earth AB2 type hydrogen storage alloy is prepared by the preparation method of the rare earth AB2 type hydrogen storage alloy according to any one of claims 1-7.

9. The rare earth AB2 type hydrogen storage alloy according to claim 8, characterized in that: The composition formula of the rare earth AB2 type hydrogen storage alloy is Ti a Zr b Cr c Mn d (VFe) f , where the value range of a is 0.6-0.9, the value range of b is 0.1-0.4, the value range of c is 0.5-1.2, the value range of d is 0.8-1.5, and the value range of f is 0.01-0.

1.

10. An application of the rare earth AB2 type hydrogen storage alloy as claimed in claim 8 or 9, characterized in that: The rare earth AB2 type hydrogen storage alloy is used in solid-state hydrogen energy storage systems or hydrogen metallurgy.

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