High-purity fine-grain vanadium target blank and preparation method thereof

Abstract

The invention belongs to the technical field of preparation of high-purity metal sputtering target materials, and particularly discloses a high-purity fine-grain vanadium target blank and a preparation method thereof. Firstly, high-purity vanadium pentoxide is prepared into a high-purity vanadium-aluminum alloy through an aluminothermic method, crude vanadium is obtained through electron beam melting, then electrolytic refining is conducted to obtain high-purity vanadium, electron beam refining is conducted again after acid pickling is conducted to obtain a low-oxygen-content high-purity vanadium cast ingot, then vacuum room-temperature three-way forging and vacuum annealing treatment are conducted, grains are preliminarily refined, and the high-purity vanadium-aluminum alloy is obtained. And then rolling is conducted, graded vacuum annealing is conducted after rolling, nitrogen is introduced for cooling in the graded vacuum annealing, and finally the high-purity vanadium target blank with the grain size smaller than 50 micrometers is prepared. According to the method, high-vacuum electron beam smelting and electrolytic refining are adopted, the oxygen content is reduced, the plasticity of the vanadium ingot is improved, vacuum room-temperature three-way forging can be borne, and the phenomena of cracking and skin overlapping in the vanadium ingot forging process are reduced; the production method can reduce production environment pollution, realize green production and improve the utilization rate of the vanadium material.

Description

Technical Field

[0001] The invention relates to the technical field of high-purity metal sputtering target materials, and in particular to a high-purity fine-grained vanadium target blank and a preparation method thereof. Background Art

[0002] High-purity vanadium targets are mainly used in the field of magnetron sputtering film preparation. The vanadium oxide film prepared by high-purity vanadium targets has the characteristics of thermal semiconductor-metal phase transition. Therefore, high-purity sputtering vanadium targets have broad application prospects in the fields of intelligent infrared temperature control materials, photoelectric switches, high-performance sensors, advanced optical storage manufacturing, etc.

[0003] High-purity vanadium has a high melting point and is a refractory metal. However, compared with other refractory metals, high-purity vanadium has a lower ductile-brittle transition temperature and better plasticity. Therefore, high-purity fine-grained vanadium targets can be prepared by plastic processing combined with heat treatment annealing process. Traditional technical means for the production and processing of fine-grained vanadium targets, such as patents CN116555713A and CN112779508A, use high-purity vanadium ingots preheated, hot forged, and then annealed, rolled, and re-annealed to obtain fine-grained vanadium target blanks.

[0004] However, high-purity vanadium easily reacts with oxygen to form vanadium oxide during preheating and hot forging, which not only reduces the utilization rate of high-purity vanadium materials and increases the production cost of enterprises, but also causes serious pollution to the production environment. Therefore, the production of vanadium targets urgently needs to solve the problem of how to produce efficiently and greenly and achieve fine grains. Summary of the invention

[0005] The present invention aims to provide a method for efficiently and greenly producing a high-purity fine-grained vanadium target blank, the production method comprising: using high-purity vanadium pentoxide as a raw material, preparing a high-purity vanadium aluminum alloy by aluminothermic method under an argon atmosphere, then using an electron beam to melt the high-purity vanadium aluminum alloy to remove aluminum and iron impurities to obtain crude vanadium, then electrolytically refining the crude vanadium and then using an electron beam to melt and purify it again to obtain a high-purity low-oxygen vanadium ingot, and then performing vacuum room temperature three-way forging, vacuum annealing, multi-pass cold rolling and vacuum graded annealing to prepare a high-purity fine-grained vanadium target blank. To achieve this purpose, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for preparing a high-purity fine-grained vanadium target blank, comprising the following steps:

[0007] 1) Using high-purity vanadium pentoxide, a high-purity vanadium aluminum alloy is prepared by aluminothermic method under argon atmosphere;

[0008] In some preferred embodiments, in step 1), the purity of the high-purity vanadium aluminum alloy is 95-99%;

[0009] In some preferred embodiments, the specific operation steps of the aluminothermic method are as follows: adding aluminum powder as a reducing agent to vanadium pentoxide, heating in an argon atmosphere, and performing metal thermal reduction; when the aluminum powder reacts with the metal oxide vanadium pentoxide, heat is generated to obtain a high-purity vanadium aluminum alloy;

[0010] 2) Electron beam melting of high purity vanadium aluminum alloy to obtain crude vanadium;

[0011] Electron beam bombards high-purity vanadium aluminum alloy to melt and evaporate to remove impurity elements such as aluminum, iron, and part of oxygen;

[0012] In some preferred embodiments, a high vacuum electromagnetic focusing electron beam furnace is used for melting;

[0013] In some preferred embodiments, in step 2), the maximum smelting power is 180-200KW, the maximum smelting temperature is 1900°C-1950°C; the pressure in the furnace is controlled at 10 -3 Below Pa;

[0014] Electron beam bombards high-purity vanadium aluminum alloy to melt and evaporate to remove impurity elements such as aluminum and iron;

[0015] 3) Using crude vanadium as an electrolytic anode, electrolyzing under the protection of an inert atmosphere, obtaining re-precipitated high-purity vanadium at the cathode, acid-washing the obtained high-purity vanadium to remove surface impurities, and performing secondary electron beam melting to obtain a high-purity vanadium low-oxygen ingot;

[0016] In some preferred embodiments, in step 3), the electrolysis temperature is 700°C to 800°C, and the electrolysis power is 3KW to 5KW;

[0017] In some preferred embodiments, in step 3), the maximum melting power of the secondary electron beam melting is 210KW, the maximum melting temperature is 2000°C, and the vacuum degree is controlled at 10 -3 Below Pa;

[0018] In some preferred embodiments, in step 3), the oxygen content of the high-purity vanadium low-oxygen ingot is ≤200 ppm;

[0019] 4) Forging the high-purity low-oxygen vanadium ingot in vacuum at room temperature along the X, Y and Z directions respectively;

[0020] The vacuum room temperature three-way forging treatment described in the present invention can eliminate the inevitable casting defects such as shrinkage and keyhole during solidification of the raw materials of high-purity low-oxygen vanadium ingots, and at the same time can break up the visually coarse grains formed by slow solidification of the cast state, provide nucleation points and driving force for subsequent heat treatment to promote the recrystallization of high-purity metal vanadium, and achieve the effect of preliminary grain refinement. At the same time, the use of vacuum room temperature forging can avoid oxidation of the vanadium ingot during the forging process and reduce production environmental pollution.

[0021] In some preferred embodiments, in step 4), the deformation amounts of forging along the three directions of X, Y and Z are 40-60% respectively;

[0022] The first step is to perform X-direction forging at room temperature, and the deformation amount achieved after the X-direction forging is 40-60%.

[0023] Further, room temperature Y-direction forging is performed, and the deformation amount achieved after the Y-direction forging is 40 to 60%.

[0024] Further, Z-direction forging is performed at room temperature, and the deformation amount achieved after the Z-direction forging is 40 to 60%.

[0025] In some preferred embodiments, in step 4), the dynamic vacuum degree is controlled at 10 -1 Below Pa;

[0026] In some preferred embodiments, in step 4), the forging process is completed in a closed vacuum forging machine, and / or the forging process is performed at room temperature; the forging die is equipped with a water cooling device, and the maximum temperature of the die forging sealing area is ≤50°C; to avoid failure of the sealing area due to high temperature;

[0027] In some preferred embodiments, the forging process is first drawing and then upsetting; wherein X and Y are radial directions and perpendicular to each other, and Z is axial direction;

[0028] 5) vacuum annealing the vanadium ingot obtained by vacuum room temperature forging in step 4);

[0029] The post-forging annealing of the present invention is a vacuum annealing treatment, and the vacuum degree is better than 10 -3 Pa can not only eliminate the work hardening, residual stress and structural defects caused by room temperature plastic deformation of vanadium ingots, but also avoid the oxidation impurities produced by annealing at high temperature by vacuum annealing, complete recrystallization and achieve preliminary grain refinement effect for subsequent rolling processing.

[0030] In some preferred embodiments, in step 5), the temperature of vacuum annealing is 600-700°C, the holding time of vacuum annealing is 40-50 minutes, and the vacuum degree is controlled at 10 -3 Pa, and when the furnace is cooled to a temperature below 350°C, nitrogen is filled in for rapid cooling;

[0031] 6) rolling the vanadium ingot obtained by vacuum annealing in step 5) to obtain a vanadium target blank;

[0032] In some preferred embodiments, in step 6), the rolling is controlled to have a downward deformation of 10% to 15% per pass, and a total deformation of 60% to 70%;

[0033] In some preferred embodiments, in step 6), the rolling is performed by cold rolling, and the number of rolling is 6 to 10 times, preferably 8 times; more preferably, it is a cross-shaped rolling;

[0034] 7) performing secondary annealing on the vanadium target blank to obtain a high-purity fine-grained vanadium target blank;

[0035] The high-purity vanadium target blank of the present invention has small and elongated grains after rolling, and graded annealing can be used to achieve rapid recrystallization and avoid excessively fast growth of annealed grains, thereby eliminating small and elongated rolled structure.

[0036] In some preferred embodiments, in step 7), the secondary annealing treatment is multi-stage vacuum annealing, preferably three-stage vacuum annealing;

[0037] In some preferred embodiments, in step 7), the annealing temperature of the primary vacuum annealing is 700°C to 800°C, the holding time is 15 to 20 minutes, and the vacuum degree is controlled at 10 -3 Below Pa;

[0038] In some preferred embodiments, in step 7), the annealing temperature of the secondary vacuum annealing is 450-500°C, the holding time is 30-40 minutes, and the vacuum degree is controlled at 10 -3 Below Pa;

[0039] In some preferred embodiments, in step 7), the process of the three-stage vacuum annealing is cooling to a temperature below 350° C., filling with nitrogen, and rapidly cooling;

[0040] In some preferred embodiments, the vanadium target blank is subjected to three-stage vacuum annealing, the first-stage vacuum annealing temperature is 700°C to 800°C, the holding time is 15 to 20 minutes, and the second-stage vacuum annealing temperature is 450 to 500°C and the holding time is 30 to 40 minutes, and the vacuum degree is better than 10 -3 Pa, and the last three stages of vacuum annealing are followed by furnace cooling to a temperature below 350°C, followed by nitrogen filling for rapid cooling.

[0041] The present invention also provides a high-purity fine-grained vanadium target blank obtained by the preparation method, wherein the average grain size of the target blank is ≤50 μm.

[0042] The beneficial effects of the present invention are:

[0043] 1. The present invention adopts electron beam melting-molten salt electrolytic refining-electron beam purification to reduce the oxygen content, thereby increasing the plasticity of the vanadium ingot and preparing a high-purity low-oxygen vanadium ingot.

[0044] 2. The high-purity low-oxygen vanadium ingot of the present invention adopts vacuum room temperature three-way forging during the forging process, which reduces cracking and skin stacking during the forging process of the vanadium ingot; at the same time, it reduces production environmental pollution, improves production efficiency, and improves the utilization rate of high-purity vanadium materials.

[0045] 3. The high-purity vanadium target blank of the present invention uses vacuum annealing to avoid oxidation of vanadium at high temperature, and there is no serious oxidation phenomenon on the surface of the target blank.

[0046] 4. The production process of the present invention can obtain a high-purity fine-grained vanadium target blank structure with a grain size of ≤50μm. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The process flow chart of producing high-purity fine-grained vanadium target blanks of the present invention;

[0048] Figure 2 This is a schematic diagram of vacuum room temperature forging direction;

[0049] Figure 3 Schematic diagram of high-purity vanadium target blank grains. DETAILED DESCRIPTION

[0050] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Embodiment 1:

[0052] This embodiment provides a method for preparing a fine-grained high-purity vanadium target blank from a high-purity low-oxygen vanadium ingot. Figure 1 The process flow chart and the preparation method are as follows:

[0053] 1. Using commercial high-purity vanadium pentoxide (purity of 99.9%), a high-purity vanadium aluminum alloy with a purity of about 99% was prepared by aluminothermic method under argon atmosphere.

[0054] 2. The high-purity vanadium-aluminum alloy obtained in step 1 is directly melted in a high vacuum electromagnetic focusing electron beam furnace to obtain crude vanadium. The maximum melting power is 180KW, the maximum melting temperature is 1900°C, and the pressure in the furnace is better than 10 -3 Pa. Electron beam bombards high-purity vanadium-aluminum alloy to melt and evaporate to remove impurity elements such as aluminum and iron.

[0055] 3. Then, the crude vanadium is used as an electrolytic anode and electrolyzed under inert atmosphere protection at a temperature of 700°C and a power of 3KW. The precipitated vanadium is pickled and then purified by electron beam melting again at a maximum melting power of 210KW and a maximum melting temperature of 2000°C. The purity is further improved and the oxygen content is reduced to obtain a high-purity vanadium low-oxygen ingot with an oxygen content of ≤200ppm.

[0056] 4. Such as Figure 2 As shown in the figure, the high-purity low-oxygen vanadium ingot was forged in vacuum at room temperature along the X / Y / Z directions, and the dynamic vacuum degree was better than 10 -1 Pa, the maximum temperature of the die forging sealing area does not exceed 50°C, and the forging process is first drawing and then upsetting; where X and Y are radial and perpendicular to each other, Z is axial, and the deformation of each drawing and upsetting is 40%.

[0057] 5. The vanadium ingot obtained by vacuum room temperature forging in step 4 is subjected to vacuum annealing treatment, wherein the annealing temperature is 600°C, the holding time is 40 minutes, and the vacuum degree is better than 10 -3 Pa, and then use nitrogen to quickly cool when the temperature is below 350°C;

[0058] 6. The vanadium ingot obtained by annealing in step 5 is rolled, and the deformation amount of each pass is controlled to be 10%. Eight passes of cross-shaped rolling are performed, and the total deformation amount is 60%.

[0059] 7. The vanadium target blank obtained by rolling in step 5 is subjected to a second annealing treatment to obtain a high-purity fine-grained vanadium target blank. The temperature of the first-stage vacuum annealing is 700°C, the holding time is 15 minutes, and the furnace is cooled to the second-stage vacuum annealing temperature of 450°C, the holding time is 30 minutes, and the vacuum degree is better than 10 -3 Pa, and then cooled to 350°C in the furnace by nitrogen filling for rapid cooling to obtain a fine-grained vanadium target blank with a grain size of ≤50μm and an oxygen content of less than 200ppm.

[0060] Embodiment 2:

[0061] 1. Using commercial high-purity vanadium pentoxide (purity of 99.9%), a high-purity vanadium aluminum alloy with a purity of about 95% was prepared by aluminothermic method under argon atmosphere.

[0062] 2. The high-purity vanadium-aluminum alloy obtained in step 1 is directly melted in a high vacuum electromagnetic focusing electron beam furnace to obtain crude vanadium. The maximum melting power is 200W, the maximum melting temperature is 1950°C, and the pressure in the furnace is better than 10 -3 Pa. Electron beam bombards high-purity vanadium-aluminum alloy to melt and evaporate to remove impurity elements such as aluminum and iron.

[0063] 3. Then, the crude vanadium is used as an electrolytic anode and electrolyzed under the protection of an inert atmosphere, and vanadium is re-precipitated at an inert cathode. The electrolysis temperature is 800°C and the electrolysis power is 5KW. The precipitated vanadium is pickled and then electron beam smelted and purified again. The maximum smelting power is 210KW and the maximum smelting temperature is 2000°C. The purity is further improved and the oxygen content is reduced to obtain a high-purity vanadium low-oxygen ingot with an oxygen content of ≤200ppm.

[0064] 4. The high-purity low-oxygen vanadium ingot is forged in vacuum at room temperature along the X / Y / Z directions. The dynamic vacuum degree is better than 10 - 1 Pa, the maximum temperature of the die forging sealing area does not exceed 50°C, and the forging process is first drawing and then upsetting; where X and Y are radial and perpendicular to each other, Z is axial, and the deformation of each drawing and upsetting is 60%.

[0065] 5. The vanadium ingot obtained by vacuum room temperature forging in step 4 is subjected to vacuum annealing treatment, wherein the annealing temperature is 700°C, the holding time is 50 minutes, and the vacuum degree is better than 10 -3 Pa, and then use nitrogen to quickly cool when the temperature is below 350°C;

[0066] 6. The vanadium ingot obtained by annealing in step 5 is rolled, and the deformation amount of each pass is controlled to be 15%. Eight passes of cross-shaped rolling are performed, and the total deformation amount is 70%.

[0067] 7. The vanadium target blank obtained by rolling in step 6 is subjected to a second annealing treatment, wherein the temperature of the second vacuum annealing is 800°C, the holding time is 20 minutes, and the second vacuum annealing is carried out with the furnace at 500°C, the holding time is 40 minutes, and the vacuum degree is better than 10 -3 Pa, and then cooled to 350°C in the furnace by nitrogen filling for rapid cooling to obtain a high-purity fine-grained vanadium target blank with a grain size of ≤50μm and an oxygen content of less than 200ppm.

[0068] Embodiment 3:

[0069] 1. Using commercial high-purity vanadium pentoxide (purity of 99.9%), a high-purity vanadium aluminum alloy with a purity of about 97% was prepared by aluminothermic method under argon atmosphere.

[0070] 2. The high-purity vanadium-aluminum alloy obtained in step 1 is directly melted in a high vacuum electromagnetic focusing electron beam furnace to obtain crude vanadium. The maximum melting power is 190W, the maximum melting temperature is 1930°C, and the pressure in the furnace is better than 10 -3 Pa. Electron beam bombards high-purity vanadium-aluminum alloy to melt and evaporate to remove impurity elements such as aluminum and iron.

[0071] 3. Use crude vanadium as electrolytic anode, carry out electrolysis under the protection of inert atmosphere, and re-precipitate vanadium at inert cathode, the electrolysis temperature is 750°C, and the electrolysis power is 4KW; the precipitated vanadium is pickled and then electron beam smelted and purified again, the maximum smelting power is 210KW, and the maximum smelting temperature is 2000°C, so as to further improve the purity and reduce the oxygen content to obtain high-purity vanadium low-oxygen ingot with oxygen content ≤200ppm.

[0072] 4. The high-purity low-oxygen vanadium ingot is forged in vacuum at room temperature along the X / Y / Z directions. The dynamic vacuum degree is better than 10 - 1 Pa, the maximum temperature of the die forging sealing area does not exceed 50°C, and the forging process is first drawing and then upsetting; where X and Y are radial and perpendicular to each other, Z is axial, and the deformation of each drawing and upsetting is 50%.

[0073] 5. The vanadium ingot obtained by vacuum room temperature forging in step 4 is subjected to vacuum annealing treatment, wherein the annealing temperature is 650°C, the holding time is 45 minutes, and the vacuum degree is better than 10 -3 Pa, and then use nitrogen to quickly cool when the temperature is below 350°C;

[0074] 6. The vanadium ingot obtained by annealing in step 5 is rolled, and the deformation amount of each pass is controlled to be 12%. Eight passes of cross-shaped rolling are performed, and the total deformation amount is 65%.

[0075] 7. The vanadium target blank obtained by rolling in step 6 is subjected to a second annealing treatment, wherein the temperature of the second vacuum annealing is 750°C, the holding time is 15 minutes, and the second vacuum annealing is carried out with the furnace cooling to 475°C, the holding time is 35 minutes, and the vacuum degree is better than 10 -3 Pa, and then cooled to 350°C in the furnace by nitrogen filling for rapid cooling to obtain a high-purity fine-grained vanadium target blank with a grain size of ≤50μm and an oxygen content of less than 200ppm.

[0076] Comparative Example 1:

[0077] Compared with Example 3, in Comparative Example 1, the maximum smelting power of the vanadium after electrolytic refining did not reach 210KW when subjected to electron beam smelting, and the maximum smelting temperature was lower than 2000°C. In the vanadium low-oxygen ingot obtained in step 3), the oxygen content exceeded 200ppm, and the other conditions were basically the same. After the subsequent three-way vacuum room temperature forging was completed, the ingot cracked.

[0078] Comparative Example 2:

[0079] Compared with Example 3, Comparative Example 2 did not perform three-way vacuum room temperature forging, but only performed radial and axial forging, and the other conditions were the same, and the grain size distribution was uneven.

[0080] Comparative Example 3:

[0081] Compared with Example 3, Comparative Example 3 does not use graded vacuum annealing after cold rolling, the annealing system is consistent with that after forging, and the other conditions are the same. The edge grain structure is coarse and uneven.

[0082] like Figure 3 As shown, it is a schematic diagram of the high-purity vanadium target blank grains of Examples 1 to 3 and Comparative Examples 1 and 2, from which it can be seen that the high-purity vanadium target blank examples produced within the process range of the present invention have the characteristics of small grain size and uniform distribution compared with the comparative examples, meeting the requirements for the preparation of high-performance vanadium oxide films.

[0083] Table 1 Average grain size of prepared high purity vanadium target blank

[0084] Example Grain size Example 1 40μm Example 2 45μm Example 3 48μm Comparative Example 2 79μm Comparative Example 3 84μm

[0085] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-purity fine-grained vanadium target blank, comprising the following steps: 1) Using high-purity vanadium pentoxide, a high-purity vanadium aluminum alloy is prepared by aluminothermic method under argon atmosphere; 2) Electron beam melting of high purity vanadium aluminum alloy to obtain crude vanadium; 3) Using crude vanadium as an electrolytic anode, electrolyzing under the protection of an inert atmosphere, obtaining re-precipitated high-purity vanadium at the cathode, acid-washing the obtained high-purity vanadium to remove surface impurities, and performing secondary electron beam melting to obtain a high-purity vanadium low-oxygen ingot; 4) Forging the high-purity low-oxygen vanadium ingot in vacuum at room temperature along the X, Y and Z directions respectively; 5) vacuum annealing the vanadium ingot obtained by vacuum room temperature forging in step 4); 6) rolling the vanadium ingot obtained by vacuum annealing in step 5) to obtain a vanadium target blank; 7) The vanadium target blank is subjected to secondary annealing treatment to obtain a high-purity fine-grained vanadium target blank.

2. The method for preparing a high-purity fine-grained vanadium target blank according to claim 1, wherein: The electron beam melting in step 2) is carried out using a high vacuum electromagnetic focusing electron beam furnace; Preferably, in step 2), the maximum smelting power is 180-200KW; and / or the maximum smelting temperature is 1900°C-1950°C; and / or the pressure in the furnace is controlled at 10 -3 Below Pa.

3. The method for preparing a high-purity fine-grained vanadium target blank according to claim 1, wherein: In the step 3), the electrolysis temperature is 700° C. to 800° C., and the electrolysis power is 3KW to 5KW; and / or In step 3), the maximum melting power of the secondary electron beam melting is 210KW, the maximum melting temperature is 2000°C, and the vacuum degree is controlled at 10 -3 Pa or less; and / or In the step 3), the oxygen content of the high-purity vanadium low-oxygen ingot is ≤200 ppm.

4. The method for preparing a high-purity fine-grained vanadium target blank according to claim 1, wherein: In the step 4), the forging process is first drawing and then upsetting; wherein X and Y are radial directions and perpendicular to each other, and Z is axial direction; The deformation along the X, Y and Z directions is 40-60% respectively; and / or In the step 4), the dynamic vacuum degree is controlled at 10 -1 Pa or less; and / or In the step 4), the maximum temperature of the sealing area during the forging process is ≤50°C.

5. The method for preparing a high-purity fine-grained vanadium target blank according to claim 1, wherein: In the step 5), the temperature of vacuum annealing is 600-700°C, the holding time of vacuum annealing is 40-50min, and the vacuum degree is controlled at 10 -3 When the temperature is below 350°C, nitrogen is filled in for rapid cooling.

6. The method for preparing a high-purity fine-grained vanadium target blank according to claim 1, wherein: In step 6), the rolling is controlled so that the pressing deformation of each pass is 10% to 15%, and the total deformation is 60% to 70%; and / or In the step 6), the rolling is performed by cold rolling, and the number of rolling passes is 6 to 10, preferably 8; more preferably, it is a cross-shaped rolling.

7. The method for preparing a high-purity fine-grained vanadium target blank according to claim 1, wherein: In the step 7), the secondary annealing treatment is a multi-stage vacuum annealing, preferably a three-stage vacuum annealing; In the step 7), the annealing temperature of the first-stage vacuum annealing is 700°C to 800°C, the holding time is 15 to 20 minutes, and the vacuum degree is controlled at 10 -3 Below Pa; In step 7), the annealing temperature of the secondary vacuum annealing is 450-500°C, the holding time is 30-40 minutes, and the vacuum degree is controlled at 10 -3 Below Pa; In the step 7), the process of the three-stage vacuum annealing is cooling to a temperature lower than 350° C., filling with nitrogen, and rapidly cooling.

8. The method for preparing a high-purity fine-grained vanadium target blank according to claim 1, wherein: In the step 1), the purity of the high-purity vanadium aluminum alloy is 95-99%.

9. A high-purity fine-grained vanadium target blank obtained by the preparation method according to any one of claims 1 to 8, wherein the average grain size thereof is ≤50 μm.

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