A small-particle-size nano-W-Re-Y2O3 alloy powder and its preparation method

Abstract

The application relates to a small-particle-diameter nano W-Re-Y2O3 alloy powder and a preparation method thereof. The small-particle-diameter nano W-Re-Y2O3 alloy powder comprises 79-94 wt.% of W, 10-20 wt.% of Re and 1-5 wt.% of Y2O3 according to mass percentage. The small-particle-diameter nano W-Re-Y2O3 alloy powder is prepared by a sol-gel method. Specifically, citric acid is dissolved in deionized water, then ammonium metatungstate, ammonium perrhenate and yttrium nitrate are added respectively, and water bath heating and stirring are carried out until a colloid is formed. After the colloid is dried and calcined, a nano oxide powder is obtained. The nano oxide powder is placed in a reaction furnace, and hydrogen reduction is carried out to obtain W-Re-Y2O3 powder. The application realizes the combination of W and Re at an atomic scale by using the sol-gel method, and Y2O3 particles are generated in situ during calcination, so that Y2O3 is uniformly mixed in the powder. The average particle diameter of the prepared alloy powder is about 12 nm, and the reduced powder does not need subsequent treatment. The preparation method is simple, the raw material cost is low, and the method is easy to realize large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of powder metallurgy technology, specifically relating to a small-particle-size nano-W-Re-Y2O3 alloy powder and its preparation method. Background Technology

[0002] Friction stir welding (FSW) is a solid-state welding technology with advantages such as minimal weld deformation and high joint strength, and is widely used in welding materials such as aluminum alloys, steel, and titanium alloys. However, the high-speed rotation of the stirring head during welding makes it prone to wear, significantly impacting the quality of the weld joint and the lifespan of the stirring head. Therefore, the stirring head needs excellent wear resistance and high-temperature mechanical properties. Tungsten (W), due to its high strength, high hardness, high melting point, and good thermal and electrical conductivity, is the optimal tool material for friction stir welding of steel and other high-temperature alloys. However, tungsten is brittle at room temperature (the ductile-brittle transition temperature of pure tungsten is approximately 400°C) and recrystallizes at high temperatures (the recrystallization temperature of pure tungsten is 1100–1300°C). This can lead to brittle fracture of the tungsten stirring head in the initial stages of welding, and the high temperatures during welding can further degrade the stirring head's performance, limiting the application and lifespan of tungsten in friction stir welding. Therefore, improving the strength, toughness, high-temperature stability, and wear resistance of tungsten materials is of great significance for engineering applications.

[0003] Adding rhenium to tungsten can form tungsten-rhenium solid solution alloys. The addition of rhenium causes lattice distortion in tungsten, increasing the resistance to dislocation movement, which greatly improves the toughness and recrystallization temperature of the tungsten alloy and mitigates low-temperature brittleness. Furthermore, the addition of rhenium can refine the grains, increasing the alloy's hardness and high-temperature stability, thus enhancing its wear resistance. However, rhenium is a very expensive rare metal, significantly increasing production costs and severely limiting the application of tungsten-rhenium alloys. Yttrium oxide (Y₂O₃) particles possess high melting points (up to 2410℃) and stable physical properties. Studies have shown that adding trace amounts of second-phase Y₂O₃ particles to tungsten-rhenium alloys can pin grain boundaries and refine the grains during sintering, significantly improving the alloy's resistance to deformation and recrystallization temperature. Additionally, the addition of Y₂O₃ promotes the densification process during sintering and increases the alloy's hardness, which also improves its wear resistance. Therefore, using trace amounts of Y2O3 particles to replace some of the rhenium element in tungsten-rhenium alloys to prepare W-Re-Y2O3 alloys can improve the strength, toughness, and wear resistance of the alloys, reduce production costs, and broaden the application prospects of tungsten-rhenium alloys.

[0004] Existing technologies disclose several methods for preparing tungsten-rhenium alloy powders. For example, patent number CN119140825A discloses a method for preparing high-rhenium, low-oxygen spherical tungsten-rhenium alloy powder. This method involves ball milling tungsten powder and rhenium powder in a specific ratio, followed by spray drying and plasma spheroidization treatment to obtain uniform spherical alloy powder with low oxygen content. While these methods offer advantages such as short preparation processes, high density, and good sphericity, the significant differences in the physical properties of tungsten and rhenium during ball milling can lead to uneven distribution of rhenium in the alloy powder. Furthermore, the powder may be contaminated by the milling media during ball milling, affecting the performance of the powder after sintering.

[0005] Currently, the main methods for preparing W-Re-Y2O3 alloy powder include mechanical alloying of tungsten powder, rhenium powder, and yttrium oxide powder through high-energy ball milling. However, the main problem is that these three powders are difficult to mix uniformly, and rhenium tends to agglomerate during sintering, ultimately affecting the material's performance. Therefore, it is necessary to explore a method that can achieve complete solid solution of tungsten and rhenium while uniformly introducing Y2O3 particles. Summary of the Invention

[0006] The purpose of this invention is to address the problem of uneven distribution of tungsten, rhenium, and yttrium oxide powders during mixing, and to provide a small-particle-size nano-W-Re-Y2O3 alloy powder and its preparation method.

[0007] The present invention achieves the above objectives through the following technical solutions:

[0008] As a first aspect of the present invention, a small-particle-size nano-W-Re-Y2O3 alloy powder is provided, wherein the small-particle-size nano-W-Re-Y2O3 alloy powder is prepared by a sol-gel method; wherein the small-particle-size nano-W-Re-Y2O3 alloy powder comprises, by mass percentage, 79-94 wt.% W, 10-20 wt.% Re and 1-5 wt.% Y2O3.

[0009] As a further optimization of the present invention, the average particle size of the small-diameter nano-W-Re-Y2O3 alloy powder is 12-17 nm.

[0010] As a second aspect of the present invention, a method for preparing small-particle-size nano-W-Re-Y2O3 alloy powder is also provided, comprising the following steps:

[0011] (1) First, dissolve citric acid in deionized water to obtain a citric acid solution. Then, dissolve ammonium metatungstate, ammonium perrhenate and yttrium nitrate as raw materials in the citric acid solution. Then, heat and stir in a water bath until a colloid is formed.

[0012] (2) First, dry the colloid obtained in step (1) to obtain a precursor, and then calcine the precursor to obtain nano-oxide powder.

[0013] (3) The nano-oxide powder obtained in step (2) is reduced in a hydrogen environment to obtain the small-particle-size nano-W-Re-Y2O3 alloy powder.

[0014] As a further optimization of the present invention, in step (1), the molar ratio of ammonium metatungstate and citric acid is 1 to 2:30.

[0015] As a further optimization of the present invention, in step (1), the temperature of the water bath heating is 60-90℃, the stirring speed is 300-500r / min, and the stirring time is 4-6h.

[0016] As a further optimization of the present invention, in step (2), the colloid is dried in a drying oven at 100-140°C for 6-12 hours.

[0017] As a further optimization of the present invention, in step (2), the calcination temperature of the precursor is 400-500°C and the calcination time is 6-12h.

[0018] As a further optimization of the present invention, in step (3), the reduction temperature is 600-900℃ and the reduction time is 2-4h.

[0019] As a third aspect of the present invention, a nano-W-Re-Y2O3 alloy bulk material is also provided, which is prepared by sintering of any of the small-particle-size nano-W-Re-Y2O3 alloy powders described above, wherein the density of the nano-W-Re-Y2O3 alloy bulk material is 98.9%.

[0020] As a further optimization of the present invention, the sintering preparation step is specifically as follows: in a vacuum environment, the small-particle-size nano W-Re-Y2O3 alloy powder is densified by sintering at a sintering temperature of 1700℃, a sintering pressure of 30MPa, and a sintering time of 2h.

[0021] The beneficial effects of this invention are as follows:

[0022] (1) The present invention uses the sol-gel method to prepare nano-W-Re-Y2O3 alloy powder, which achieves uniform mixing and dispersion of tungsten, rhenium and yttrium oxide at the molecular level. By controlling the reaction conditions, the average particle size of the prepared powder can be refined to a minimum of about 12 nm. Compared with traditional mechanical mixing methods, the sol-gel method can ensure the uniform distribution of all components in the entire powder, which helps to improve the sintering activity of the powder and makes it easier to achieve sintering densification at a lower temperature (1700℃).

[0023] (2) When preparing nano W-Re-Y2O3 alloy powder using the sol-gel method in this invention, citric acid is added to the preparation system first. Citric acid reacts with water molecules to form citric acid molecules in advance. The carboxyl groups in the citric acid molecules then form stable complexes with the metal ions added later, which helps to control the uniform distribution of metal ions. Subsequently, a more uniform sol and alloy powder with a finer particle size will be obtained.

[0024] (3) The entire preparation process of this invention is carried out at a relatively low temperature, which can significantly reduce the oxidation and impurity incorporation of the powder during the preparation process, thereby obtaining high-purity and low-oxygen-content W-Re-Y2O3 powder, which helps the powder maintain excellent mechanical properties in subsequent sintering.

[0025] (4) When preparing nano-W-Re-Y2O3 alloy powder using the sol-gel method in this invention, dispersed Y2O3 particles can be generated in situ during calcination, which helps the Y2O3 particles to be uniformly distributed in the alloy block after powder sintering. As a stable oxide, Y2O3 can effectively inhibit the oxidation of tungsten and rhenium at high temperatures. The prepared W-Re-Y2O3 has broad application potential in many fields such as friction stir welding, nuclear energy industry, and high-temperature structural materials.

[0026] (5) The preparation method of the present invention is simple, has low production cost, and is easy to scale up. Attached Figure Description

[0027] Figure 1 These are TEM images and particle size distribution diagrams of the oxide powder prepared in step 2 of Example 1 of this invention;

[0028] Figure 2 These are TEM images and particle size distribution diagrams of the nano-79wt.%W-20wt.%Re-1wt.%Y2O3 alloy powder prepared in Example 1 of this invention;

[0029] Figure 3 This is the XRD pattern of the nano-79wt.%W-20wt.%Re-1wt.%Y2O3 alloy powder prepared in Example 1 of this invention;

[0030] Figure 4 These are surface SEM images of the 79wt.%W-20wt.%Re-1wt.%Y2O3 alloy block prepared in Example 2 of this invention;

[0031] Figure 5 These are TEM images of the 79wt.%W-20wt.%Re-1wt.%Y2O3 alloy bulk prepared in Example 2 of this invention;

[0032] Figure 6These are TEM images and particle size distribution diagrams of the oxide powder prepared in step 2 of Example 3 of this invention;

[0033] Figure 7 These are TEM images and particle size distribution diagrams of the nano-89wt.%W-10wt.%Re-1wt.%Y2O3 alloy powder prepared in Example 3 of this invention;

[0034] Figure 8 This is the XRD pattern of the nano-89wt.%W-10wt.%Re-1wt.%Y2O3 alloy powder prepared in Example 3 of this invention;

[0035] Figure 9 These are TEM images and particle size distribution diagrams of the oxide powder prepared in step 2 of Example 4 of this invention;

[0036] Figure 10 These are TEM images and particle size distribution diagrams of the nano-94wt.%W-5wt.%Re-1wt.%Y2O3 alloy powder prepared in Example 4 of this invention;

[0037] Figure 11 This is the XRD pattern of the nano-94wt.%W-5wt.%Re-1wt.%Y2O3 alloy powder prepared in Example 4 of this invention.

[0038] Figure 12 These are TEM images and particle size distribution diagrams of the oxide powder prepared in step 2 of Example 5 of the present invention;

[0039] Figure 13 These are TEM images and particle size distribution diagrams of the nano-93wt.%W-5wt.%Re-2wt.%Y2O3 alloy powder prepared in Example 5 of this invention;

[0040] Figure 14 This is the XRD pattern of the nano-93wt.%W-5wt.%Re-2wt.%Y2O3 alloy powder prepared in Example 5 of this invention. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above application content.

[0042] Unless otherwise specified, all methods used in this invention are conventional methods known to those skilled in the art. Where specific conditions are not specified, they shall be performed according to conventional conditions or conditions recommended by the manufacturer. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0043] Example 1

[0044] The small-particle-size nano-79wt.%W-20wt.%Re-1wt.%Y2O3 alloy powder disclosed in this embodiment is prepared by the following steps:

[0045] (1) Add 15g of citric acid to deionized water and stir until the citric acid is completely dissolved. Then, add 10.59g of ammonium metatungstate, 2.88g of ammonium perrhenate, and 0.34g of yttrium nitrate to the solution in sequence. During this period, place the solution in a water bath at 70℃ and stir thoroughly at 300r / min for 5 hours until a colloid is formed.

[0046] (2) The colloid obtained in step (1) was dried at 130°C for 6 hours, and then calcined at 500°C for 6 hours to obtain nano-sized oxide powder. All reactions in this step were carried out in air.

[0047] (3) Place the oxide powder obtained in step (2) in a mortar and grind for 5 minutes. Then, place the ground powder in a tube furnace and reduce it in a hydrogen environment. The reduction temperature is 900℃ and the reduction time is 2 hours. This will prepare nano 79wt.%W-20wt.%Re-1wt.%Y2O3 alloy powder.

[0048] The nano-79wt.%W-20wt.%Re-1wt.%Y2O3 powder prepared in Example 1 was characterized.

[0049] Figure 1 The TEM image and particle size distribution diagram of the oxide powder prepared in step (2) show that the oxide powder is uniformly distributed, with particle sizes ranging from 30 nm to 110 nm and an average particle size of 55 nm. The ultrafine particle size means that the oxide powder has a larger specific surface area, which will increase the rate of the subsequent reduction reaction and help the reduction reaction to proceed fully.

[0050] Figure 2 TEM images and particle size distribution diagrams of nano-79wt.%W-20wt.%Re-1wt.%Y2O3 powder show that the particle size of the reduced alloy powder is between 5nm and 23nm, with an average particle size of 12nm.

[0051] Figure 3 The XRD pattern of nano-79wt.%W-20wt.%Re-1wt.%Y2O3 powder shows that the reduced powder is a single BCC tungsten phase, and no obvious rhenium or other impurity phases were detected. This indicates that the prepared powder has high purity and that rhenium has been completely dissolved in tungsten.

[0052] Example 2

[0053] Based on Example 1, to demonstrate that the nano-79wt.%W-20wt.%Re-1wt.%Y2O3 powder prepared in Example 1 can be easily sintered and densified at a lower temperature, this example uses a hot press furnace to sinter the nano-79wt.%W-20wt.%Re-1wt.%Y2O3 powder prepared in Example 1. The specific steps are as follows:

[0054] Nano-79wt.%W-20wt.%Re-1wt.%Y2O3 powder was densified and sintered in a vacuum environment using a hot press furnace at a temperature of 1700℃, a pressure of 30MPa, and a sintering time of 2h, resulting in a 79wt.%W-20wt.%Re-1wt.%Y2O3 alloy bulk with a density of 98.9%.

[0055] The alloy bulk was characterized. Figure 4 The SEM image of the alloy block shows that its surface is almost entirely free of pores, indicating a high degree of densification. Statistical analysis of the grain size reveals an average grain size of approximately 3.1 μm.

[0056] Figure 5 The TEM image of the alloy block shows that Y2O3 particles are evenly distributed within the grains, resulting in a good dispersion strengthening effect.

[0057] Example 3

[0058] The small-particle-size nano-89wt.%W-10wt.%Re-1wt.%Y2O3 alloy powder disclosed in this embodiment is prepared by the following steps:

[0059] (1) Add 20g of citric acid to deionized water and stir until the citric acid is completely dissolved. Then add 11.93g of ammonium metatungstate, 1.44g of ammonium perrhenate, and 0.34g of yttrium nitrate to the solution in sequence. During this period, place the solution in a water bath at 80°C and stir thoroughly at 400r / min for 4 hours until a colloid is formed.

[0060] (2) The colloid obtained in step (1) was dried at 140°C for 12 hours, and then calcined at 475°C for 10 hours to obtain nano-sized oxide powder. All reactions in this step were carried out in air.

[0061] (3) Place the oxide powder obtained in step (2) in a mortar and grind for 5 minutes. Then, place the ground powder in a tube furnace and reduce it in a hydrogen environment. The reduction temperature is 800℃ and the reduction time is 3 hours. This will prepare nano 89wt.%W-10wt.%Re-1wt.%Y2O3 alloy powder.

[0062] The 89wt.%W-10wt.%Re-1wt.%Y2O3 alloy powder prepared in Example 3 was characterized.

[0063] Figure 6 The TEM image and particle size distribution of the oxide powder obtained in step (2) show that the oxide powder is uniformly distributed, with particle sizes ranging from 50 nm to 110 nm and an average particle size of 68 nm. The ultrafine particle size means that the oxide powder has a larger specific surface area, which will increase the rate of the subsequent reduction reaction and help the reduction reaction to proceed fully.

[0064] Figure 7 TEM images and particle size distribution diagrams of the reduced 89wt.%W-10wt.%Re-1wt.%Y2O3 powder prepared in step (3) show that the particle size of the reduced alloy powder is between 6nm and 22nm, with an average particle size of 17nm.

[0065] Figure 8 The XRD pattern of the reduced 89wt.%W-10wt.%Re-1wt.%Y2O3 powder prepared in step 3 shows that the reduced powder is a single BCC tungsten phase, and no obvious rhenium or other impurity phases were detected. This indicates that the prepared powder has high purity and that rhenium has been completely dissolved in tungsten.

[0066] Example 4

[0067] This embodiment provides a method for preparing small-particle-size nano-94wt.%W-5wt.%Re-1wt.%Y2O3 alloy powder, the specific steps of which are as follows:

[0068] (1) Add 25g of citric acid to deionized water and stir until the citric acid is completely dissolved. Then add 12.60g of ammonium metatungstate, 0.72g of ammonium perrhenate, and 0.34g of yttrium nitrate to the solution in sequence. During this period, place the solution in a water bath at 90℃ and stir thoroughly at 500r / min for 6 hours until a colloid is formed.

[0069] (2) The colloid obtained in step (1) was dried at 120°C for 8 hours, and then calcined at 450°C for 8 hours to obtain nano-sized oxide powder. All reactions in this step were carried out in air.

[0070] (3) The oxide powder obtained in step (3) is placed in a mortar and ground for 5 minutes. Then, the ground powder is placed in a tube furnace and reduced in a hydrogen environment. The reduction temperature is 700℃ and the reduction time is 4 hours. This will prepare nano 94wt.%W-5wt.%Re-1wt.%Y2O3 alloy powder.

[0071] The 94 wt.% W-5 wt.% Re-1 wt.% Y2O3 alloy powder prepared in Example 4 was characterized.

[0072] Figure 9 The TEM image and particle size distribution of the oxide powder prepared in step (2) show that the oxide powder is uniformly distributed, with particle sizes ranging from 30 nm to 130 nm and an average particle size of 65 nm. The ultrafine particle size means that the oxide powder has a larger specific surface area, which will increase the rate of the subsequent reduction reaction and help the reduction reaction to proceed fully.

[0073] Figure 10 TEM images and particle size distribution diagrams of nano-94wt.%W-5wt.%Re-1wt.%Y2O3 powder show that the particle size of the reduced alloy powder is between 6nm and 18nm, with an average particle size of 13nm.

[0074] Figure 11 The XRD pattern of nano-94wt.%W-5wt.%Re-1wt.%Y2O3 powder shows that the reduced powder is a single BCC tungsten phase, and no obvious rhenium or other impurity phases were detected. This indicates that the prepared powder has high purity and that rhenium has been completely dissolved in tungsten.

[0075] Example 5

[0076] The preparation method of the small-particle-size nano-93wt.%W-5wt.%Re-2wt.%Y2O3 alloy powder disclosed in this embodiment is as follows:

[0077] (1) Add 25g of citric acid to deionized water and stir until the citric acid is completely dissolved. Then add 12.46g of ammonium metatungstate, 0.72g of ammonium perrhenate, and 0.68g of yttrium nitrate to the solution in sequence. During this period, place the solution in a water bath at 60℃ and stir thoroughly at 400r / min for 4h until a colloid is formed.

[0078] (2) The colloid obtained in step (1) was dried at 100°C for 10 h, and then the dried colloid was calcined at 400°C for 12 h to obtain nano-sized oxide powder. All reactions in this step were carried out in air.

[0079] (3) The oxide powder obtained in step (2) is ground in a mortar for 5 minutes. Then the ground powder is placed in a tube furnace and reduced in a hydrogen environment. The reduction temperature is 600℃ and the reduction time is 4 hours. This will prepare nano 93wt.%W-5wt.%Re-2wt.%Y2O3 alloy powder.

[0080] The 93wt.%W-5wt.%Re-2wt.%Y2O3 alloy powder prepared in Example 5 was characterized.

[0081] Figure 12 The TEM image and particle size distribution of the oxide powder prepared in step 2 show that the oxide powder is uniformly distributed, with particle sizes ranging from 30 nm to 90 nm and an average particle size of 46 nm. The ultrafine particle size indicates that the oxide powder has a larger specific surface area, which increases the reduction reaction rate and helps the reduction reaction proceed fully.

[0082] Figure 13 TEM images and particle size distribution diagrams of nano-93wt.%W-5wt.%Re-2wt.%Y2O3 powder show that the particle size of the reduced alloy powder is between 6nm and 18nm, with an average particle size of 14nm.

[0083] Figure 14 The XRD pattern of nano-93wt.%W-5wt.%Re-2wt.%Y2O3 powder shows that the reduced powder is a single BCC tungsten phase, and no obvious rhenium or other impurity phases were detected. This indicates that the prepared powder has high purity and that rhenium has been completely dissolved in tungsten.

[0084] Comparative Example 1

[0085] According to the article "Wang Hui, Ding Chenshi, Xie Zhuoming, et al. Study on mechanical properties and thermal stability of W-ZrC / HfC-Re alloy prepared by spark plasma sintering [J]. Rare Metals Materials and Engineering, 2024, 53(05):1321-1331," when W-ZrC / HfC-Re powder was prepared by ball milling, signals of Re and Re2W3C were detected in the powder when the Re addition amount was 3%. This indicates that the ball milling method cannot completely dissolve 3% Re into the tungsten matrix. In addition, carbon impurities are introduced during the ball milling process. With the increase of Re content, the Re(W) signal in the powder prepared by ball milling is enhanced, which means that the solid solution effect of Re in the tungsten matrix is ​​worse. In addition, the literature also observed the SEM morphology of W-ZrC / HfC-Re powder after ball milling. The results showed that the alloy powder prepared by ball milling consisted of many fragmented fine particles (about 100 nm in size) and a relatively large number of larger particles (about 500 nm in size).

[0086] The average particle size of the nano-W-Re-Y2O3 alloy powder prepared by the sol-gel method in Examples 1 and 3-5 of this invention is between 12nm and 17nm, and the powder particles are uniformly distributed. According to structural analysis, rhenium is completely dissolved in the tungsten matrix without any segregation.

[0087] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A small-particle-size nano-W-Re-Y2O3 alloy powder, characterized in that, The small-particle-size nano W-Re-Y2O3 alloy powder comprises, by mass percentage, 79~94 wt.%W, 10~20 wt.%Re and 1~5 wt.%Y2O3; The average particle size of the small-diameter nano-W-Re-Y2O3 alloy powder is 12~17 nm; The small-particle-size nano-W-Re-Y2O3 alloy powder was prepared by the sol-gel method, and the preparation method includes the following steps: (1) First, citric acid is dissolved in deionized water to obtain a citric acid solution. Then, ammonium metatungstate, ammonium perrhenate and yttrium nitrate are dissolved in the citric acid solution as raw materials. Then, water bath heating and stirring are carried out until a colloid is formed. (2) First, dry the colloid obtained in step (1) to obtain the precursor, and then calcine the precursor to obtain nano-oxide powder; (3) The nano-oxide powder obtained in step (2) is reduced in a hydrogen environment. The powder after reduction is a single BCC tungsten phase. No obvious rhenium and other impurity phases were detected, and the small-particle-size nano W-Re-Y2O3 alloy powder was obtained.

2. The small-particle-size nano-W-Re-Y2O3 alloy powder according to claim 1, characterized in that: In step (1), the molar ratio of ammonium metatungstate and citric acid is 1~2:

30.

3. The small-particle-size nano-W-Re-Y2O3 alloy powder according to claim 1, characterized in that: In step (1), the water bath heating temperature is 60~90 ℃, the stirring speed is 300~500 r / min, and the stirring time is 4~6 h.

4. The small-particle-size nano-W-Re-Y2O3 alloy powder according to claim 1, characterized in that: In step (2), the colloid is dried in a drying oven at 100~140 ℃ for 6~12 h.

5. The small-particle-size nano-W-Re-Y2O3 alloy powder according to claim 1, characterized in that: In step (2), the calcination temperature of the precursor is 400~500 ℃ and the calcination time is 6~12 h.

6. The small-particle-size nano-W-Re-Y2O3 alloy powder according to claim 1, characterized in that: In step (3), the reduction temperature is 600~900 ℃ and the reduction time is 2~4 h.

7. A nano-W-Re-Y2O3 alloy bulk, characterized in that, The nano-W-Re-Y2O3 alloy powder with small particle size as described in any one of claims 1 to 6 is prepared by sintering, and the density of the nano-W-Re-Y2O3 alloy bulk is 98.9%.

8. The nano-W-Re-Y2O3 alloy bulk material according to claim 7, characterized in that, The sintering preparation step is as follows: in a vacuum environment, the small-particle-size nano W-Re-Y2O3 alloy powder is densified by sintering at a temperature of 1700 ℃, a sintering pressure of 30 MPa, and a sintering time of 2 h.

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