A method for preparing a tungsten-rhenium-tantalum pre-alloyed powder

Abstract

The application discloses a preparation method of tungsten-rhenium-tantalum pre-alloy powder, and specifically comprises the following steps: preparing a wet gelatin of a tungsten-rhenium-tantalum precursor by a sol-gel method; drying the obtained wet gelatin of the tungsten-rhenium-tantalum precursor by heating to a certain temperature, and then calcining for a certain time to obtain a calcined powder; and reducing the obtained calcined powder in a protective atmosphere to obtain the tungsten-rhenium-tantalum pre-alloy powder with a particle size of 0.1-100 mu m. The wet chemical sol-gel method is used to mix the precursors of tungsten, rhenium and tantalum into a gel through liquid-liquid mixing, the net framework of the gel enables the three elements of tungsten, rhenium and tantalum to be mixed together at an atomic level, realizes the atomic-level mixing of rhenium and tantalum in the tungsten matrix, and has the advantages of uniform composition, small powder size and certain pre-alloying effect, and higher sintering activity.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy technology, specifically to a method for preparing tungsten-rhenium-tantalum pre-alloyed powder. Background Technology

[0002] Pure metallic tungsten has a high ductile-brittle transition temperature (DBTT) and exhibits significant brittleness at room temperature, making it highly susceptible to brittle fracture during processing and use, thus limiting its widespread adoption and application. Alloying tungsten-based materials with other elements is a common method to improve their DBTT and enhance their toughness.

[0003] Numerous studies have shown that introducing rhenium (Re) to form solid-solution rhenium tungsten-rhenium alloys (such as W-3Re) alters the dislocation energy of metallic tungsten, optimizes its dislocation structure, and improves its dislocation mobility. This not only increases the material's recrystallization temperature, strength, and toughness but also significantly reduces its processing difficulty. However, metallic rhenium has a lower thermal conductivity than tungsten (47.9 W·m). -1 ·K -1 The high cost and excessive addition of tungsten-rhenium alloys not only reduce their overall thermal conductivity but also significantly increase production costs, limiting their application in certain fields. Tantalum (Ta), a refractory metal, has a melting point as high as 2996℃ and a theoretical density of 16.6 g / cm³. 3 Tantalum possesses strong corrosion resistance and shares some physical properties with tungsten, but the two differ significantly in strength and toughness. Tungsten exhibits room-temperature brittleness, while tantalum possesses excellent ductility. Referring to the W-Ta binary phase diagram, both are infinitely soluble in solid solution. Therefore, the alloying of tungsten and tantalum has attracted considerable attention from researchers. Research results show that the introduction of tantalum can refine grains and improve the ductility of materials, thus strengthening and toughening tungsten alloys. Furthermore, metallic tantalum has a higher thermal conductivity (57.5 W·m⁻¹) compared to metallic rhenium. -1 ·K -1 Therefore, by using tantalum to replace part of the rhenium element in tungsten-rhenium alloys to prepare tungsten-rhenium-tantalum ternary alloys, the strength and toughness of the material can be improved, suitable thermal conductivity can be ensured, and the production and manufacturing costs can be reduced, thus broadening the application fields of this type of material.

[0004] Currently, research on the preparation of tungsten-rhenium-tantalum alloys is limited. Drawing on research experience with tungsten-rhenium and tungsten-tantalum alloys, methods such as arc melting and powder metallurgy can be used for their preparation. Among these, powder metallurgy is widely used due to its advantages of simple process, ease of operation, low cost, and ease of industrialization and large-scale production. In existing technologies, the preparation of tungsten-rhenium-tantalum alloys using powder metallurgy typically involves mixing tungsten powder, rhenium powder, and tantalum powder through ball milling to obtain a mixed powder. There are also reports of preparing composite powders by mechanically alloying the mixed powders through high-energy ball milling. The main problems with current methods for preparing tungsten, rhenium, and tantalum mixed powders are that the three elements are difficult to mix uniformly, resulting in weak pre-alloying effects. In the subsequent sintering process for preparing tungsten-rhenium-tantalum alloys, this can easily lead to low sintering activity and easy segregation of rhenium and tantalum, affecting the final mechanical properties of the material. Summary of the Invention

[0005] This invention discloses a method for preparing tungsten-rhenium-tantalum pre-alloyed powder to solve any of the above-mentioned and other potential problems in the prior art.

[0006] To achieve the above objectives, the technical solution of the present invention is: a method for preparing tungsten-rhenium-tantalum pre-alloyed powder, which specifically includes the following steps:

[0007] S1) Tungsten-rhenium-tantalum precursor wet gel was prepared by sol-gel method;

[0008] S2) The wet gel of the tungsten-rhenium-tantalum precursor obtained in S1) is first heated to a certain temperature and dried, and then calcined for a certain time to obtain calcined powder;

[0009] S3) The calcined powder obtained in S2) is reduced under a protective atmosphere to obtain tungsten-rhenium-tantalum pre-alloyed powder with a particle size of 0.1-100μm.

[0010] The specific steps of S1) are as follows:

[0011] S1.1) Weigh the tungsten-containing raw material, ammonium perrhenate, and tantalum-containing raw material according to the designed ratio, dissolve them in water, add a certain proportion of complexing agent, and stir thoroughly under a water bath at 60-95℃ to obtain a solution;

[0012] S1.2) Adjust the pH of the solution obtained in S1.1) to between 1 and 3;

[0013] S1.3) Keep the water bath heating and stirring until the solution becomes a viscous gel, thus obtaining the wet gel of tungsten-rhenium-tantalum precursor.

[0014] Furthermore, in step S1.1), the design ratio of tungsten-containing raw material, ammonium perrhenate, and tantalum-containing raw material is W-xRe-yTa, where x is 0.1%-25wt%, y is 0.1%-10wt%, and the remainder is tungsten;

[0015] The ratio of the number of moles of the complexing agent to the total number of moles of tungsten, rhenium, and tantalum is 1:(0.5-3).

[0016] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the tungsten-containing raw material is one or more of ammonium tungstate, ammonium metatungstate, or ammonium paratungstate; and the tantalum-containing raw material is one or more of tantalum ethoxide, tantalum isopropoxide, or a solution of tantalum oxalate.

[0017] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the complexing agent is one or more of maleic acid, oxalic acid, or citric acid.

[0018] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the drying temperature in S2) is 100℃-150℃, the calcination temperature is 200℃-230℃, and the calcination time is 5h-10h.

[0019] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the protective atmosphere in S3) is hydrogen, the reduction temperature is 800-1000°C, and the reduction time is 1-3 hours.

[0020] In the tungsten-rhenium-tantalum pre-alloy powder, rhenium and tantalum are completely or partially dissolved in the tungsten matrix, forming a tungsten-rhenium-tantalum ternary pre-alloy powder with tungsten as the main phase.

[0021] A tungsten-rhenium-tantalum pre-alloyed powder, wherein the tungsten-rhenium-tantalum pre-alloyed powder is prepared by the above-described preparation method.

[0022] This invention offers the following advantages: It utilizes a wet chemical sol-gel method to form a gel from tungsten, rhenium, and tantalum precursors through liquid-liquid mixing. The gel's network framework allows the three elements to be mixed at an atomic level, resulting in a highly uniform elemental distribution from macroscopic to microscopic levels. This overcomes the elemental agglomeration issues that often occur during solid-liquid and solid-solid powder mixing. Furthermore, the calcined powder obtained through sol-gel drying and calcination exhibits fine particle size and uniform elemental distribution, leading to better pre-alloying during hydrogen reduction. The prepared pre-alloyed powder also has a fine particle size, with primary particle sizes reaching the nanoscale, resulting in higher sintering activity. Attached Figure Description

[0023] Figure 1 This is a flowchart of a method for preparing tungsten-rhenium-tantalum pre-alloyed powder according to the present invention.

[0024] Figure 2 The particle size distribution diagram is shown for the W-1wt%Re-1wt%Ta pre-alloyed powder prepared in this invention.

[0025] Figure 3The particle size distribution diagram is shown for the W-1wt%Re-2wt%Ta pre-alloyed powder prepared in this invention.

[0026] Figure 4 The particle size distribution diagram is shown for the W-2wt%Re-2wt%Ta pre-alloyed powder prepared in this invention.

[0027] Figure 5 The morphology and microstructure of the W-1wt%Re-2wt%Ta pre-alloyed powder prepared according to this invention are shown in the figure. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention.

[0029] like Figure 1 As shown, the present invention discloses a method for preparing tungsten-rhenium-tantalum pre-alloyed powder, which specifically includes the following steps:

[0030] S1) Tungsten-rhenium-tantalum precursor wet gel was prepared by sol-gel method;

[0031] The specific process is as follows:

[0032] S1.1) Weigh the tungsten-containing raw material, ammonium perrhenate, and tantalum-containing raw material according to the designed ratio, dissolve them in water, add a certain proportion of complexing agent, and stir thoroughly under a water bath at 60-95℃ to obtain a solution;

[0033] S1.2) Adjust the pH of the solution obtained in S1.1) to between 1 and 3;

[0034] S1.3) Keep the water bath heating and stirring until the solution becomes a viscous gel, thus obtaining the wet gel of tungsten-rhenium-tantalum precursor.

[0035] Preferably, the design ratio of the tungsten-containing raw material, ammonium perrylate, and tantalum-containing raw material is W-xRe-yTa, where x is 0.1%-25wt% and y is 0.1%-10wt%.

[0036] Preferably, the amount of complexing agent added is in a ratio of 1:(0.5-3) to the total number of moles of tungsten, rhenium, and tantalum.

[0037] Preferably, the tungsten-containing raw material is one or more of ammonium tungstate, ammonium metatungstate, or ammonium paratungstate; the tantalum-containing raw material is one or more of tantalum ethoxide, tantalum isopropoxide, or a solution of tantalum oxalate.

[0038] Preferably, the complexing agent is one or more of maleic acid, oxalic acid, or citric acid.

[0039] S2) The wet gel of the tungsten-rhenium-tantalum precursor obtained in S1) is first heated to a certain temperature and dried, and then calcined for a certain time to obtain calcined powder;

[0040] Preferably, the drying temperature is 100℃-150℃, the calcination temperature is 200℃-230℃, and the calcination time is 5h-10h.

[0041] S3) The calcined powder obtained in S2) is reduced under a protective atmosphere to obtain tungsten-rhenium-tantalum pre-alloyed powder with a particle size of 0.1-100 μm. The morphology and microstructure of the tungsten-rhenium-tantalum pre-alloyed powder are as follows: Figure 2 As shown, it utilizes a wet chemical sol-gel method to form a gel by liquid-liquid mixing of tungsten, rhenium, and tantalum precursors. The network framework of the gel allows the three elements of tungsten, rhenium, and tantalum to be mixed together at an atomic level, with a very uniform element distribution from macroscopic to microscopic. This overcomes the problem of element segregation that easily occurs during solid-liquid mixing and solid-solid powder mixing.

[0042] Preferably, the protective atmosphere is hydrogen, the reduction temperature is 800–1000°C, and the reduction time is 1–3 hours.

[0043] In the tungsten-rhenium-tantalum pre-alloy powder, rhenium and tantalum are completely or partially dissolved in the tungsten matrix, forming a tungsten-rhenium-tantalum ternary pre-alloy powder with tungsten as the main phase.

[0044] A tungsten-rhenium-tantalum pre-alloyed powder, wherein the tungsten-rhenium-tantalum pre-alloyed powder is prepared by the above preparation method.

[0045] In addition, the pre-alloyed powder has a fine particle size, and rhenium and tantalum can form a certain degree of solid solution pre-alloying effect in the tungsten matrix. When sintering tungsten-rhenium-tantalum alloy, it often has higher sintering activity than physically mixed powders.

[0046] Example 1

[0047] The preparation of 200g of W-1wt%Re-1wt%Ta pre-alloyed powder specifically includes the following steps:

[0048] S1) Weigh 262.65g of ammonium metatungstate and 2.88g of ammonium rheniumate, measure 200ml of tantalum oxalate solution (10g / L), dissolve in deionized water, add 209.01g of citric acid, and place in an 85℃ water bath and stir thoroughly until homogeneous; adjust the pH value to 1; continue stirring and evaporating until the above solution becomes a viscous gel, thus obtaining the tungsten-rhenium-tantalum precursor wet gel.

[0049] S2) The above wet gel was dried at 100°C and calcined at 200°C for 6 hours to obtain calcined powder.

[0050] S3) The calcined powder was reduced in a hydrogen atmosphere at a reduction temperature of 900℃ for 3 hours to obtain W-1wt%Re-1wt%Ta pre-alloyed powder.

[0051] The particle size distribution test results of the W-1wt%Re-1wt%Ta pre-alloyed powder obtained above are as follows: Figure 2 As shown, the particle size ranges from nanometer to micrometer, and its Dv(50) is approximately 5.61 μm. Multiple samples of this powder were taken, and the Re and Ta content was determined by ICP-OES. The results are shown in Table 1.

[0052] Table 1. ICP-OES test results of Re and Ta elements in W-1wt%Re-1wt%Ta pre-alloyed powder.

[0053]

[0054] Example 2

[0055] The preparation of 200g of W-1wt%Re-2wt%Ta pre-alloyed powder specifically includes the following steps:

[0056] S1) Weigh 269.13g of ammonium paratungstate, 2.88g of ammonium rhenium, and 8.98g of tantalum ethoxide, dissolve them in deionized water, add 195.86g of oxalic acid, and stir thoroughly in a 70℃ water bath; adjust the pH to 1.5; continue stirring and evaporating until the above solution becomes a viscous gel, thus obtaining the wet gel of tungsten-rhenium-tantalum precursor.

[0057] S2) The above wet gel was dried at 120°C and calcined at 250°C for 8 hours to obtain calcined powder.

[0058] S3) The calcined powder was reduced in a hydrogen atmosphere at a reduction temperature of 1000℃ for 2 hours to obtain W-1wt%Re-2wt%Ta pre-alloyed powder. The XRD structure spectrum of the pre-alloyed powder is shown in the figure. Figure 2 As shown.

[0059] The particle size distribution test results of the W-1wt%Re-2wt%Ta pre-alloyed powder obtained above are as follows: Figure 3 As shown, similar to Example 1, its particle size is distributed from nanometer to micrometer scale, and its Dv(50) is approximately 5.57 μm. Multiple samples of this powder were taken, and the Re and Ta content was detected by ICP-OES. The results are shown in Table 2.

[0060] Table 2 shows the ICP-OES test results of Re and Ta elements in W-1wt%Re-2wt%Ta pre-alloyed powder.

[0061]

[0062] Example 3

[0063] The preparation of 200g of W-2wt%Re-2wt%Ta pre-alloyed powder specifically includes the following steps:

[0064] S1) Weigh 257.29g of ammonium metatungstate, 5.76g of ammonium rhenium, and 10.53g of tantalum isopropoxide, dissolve them in deionized water, add 63.14g of maleic acid, and stir thoroughly in an 80℃ water bath; adjust the pH to 2; continue stirring and evaporating until the above solution becomes a viscous gel, thus obtaining the wet gel of tungsten-rhenium-tantalum precursor.

[0065] S2) The above wet gel was dried at 150°C and calcined at 230°C for 10 hours to obtain calcined powder.

[0066] S3) The calcined powder was reduced in a hydrogen atmosphere at a reduction temperature of 950℃ for 2.5h to obtain W-2wt%Re-2wt%Ta pre-alloyed powder.

[0067] The particle size distribution test results of the W-2wt%Re-2wt%Ta pre-alloyed powder obtained above are as follows: Figure 4 As shown, similar to Examples 1 and 2, the particle size ranges from nanometer to micrometer, with a Dv(50) of approximately 5.91 μm. Multiple samples of the powder were taken, and the Re and Ta content was determined by ICP-OES. The results are shown in Table 3.

[0068] Table 3. ICP-OES test results of Re and Ta elements in W-2wt%Re-2wt%Ta pre-alloyed powder.

[0069]

[0070] As can be seen from Tables 1-3 of the sample test results of the above embodiments, the tungsten-rhenium-tantalum pre-alloyed powder prepared by the method of the present invention exhibits a very uniform distribution of component elements from a relatively macroscopic testing (ICP-OES) perspective (the relative deviation of the content of each element is within 3.7%). From a relatively microscopic testing (EDSMapping) perspective, taking the W-1wt%Re-2wt%Ta sample as an example, ... Figure 5 As shown, Re and Ta elements are distributed very uniformly across the entire tungsten matrix, with no obvious agglomeration, and the primary particle size is at the micro-nano scale. This demonstrates that the tungsten-rhenium-tantalum pre-alloyed powder prepared by this invention differs from powders prepared by physical mixing methods, exhibiting a highly uniform composition distribution from macroscopic to microscopic levels. Furthermore, from... Figure 2 , Figure 3 and Figure 4As can be seen, the tungsten-rhenium-tantalum pre-alloy powder prepared by this invention has a fine particle size and is distributed at the micro-nano scale. The laser particle size Dv(50) is within 6μm, which gives it a more significant advantage in the preparation of tungsten-rhenium-tantalum alloys by powder metallurgy.

[0071] The foregoing has provided a detailed description of a tungsten-rhenium-tantalum pre-alloyed powder and its preparation method provided in the embodiments of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this application; furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

[0072] Certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The terms "comprising" and "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising / including but not limited to". "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error. The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of illustrating the general principles of this application and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0073] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0074] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0075] The foregoing description illustrates and describes several preferred embodiments of this application. However, as previously stated, it should be understood that this application is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the application concept described herein through the foregoing teachings or the technology or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this application should be considered in accordance with the appended claims.

Claims

1. A method of producing a tungsten-rhenium-tantalum pre-alloyed powder, characterized by, The preparation method specifically comprises the following steps: S1) preparing a tungsten-rhenium-tantalum precursor wet gel by a sol-gel method; In the tungsten-rhenium-tantalum pre-alloy powder, rhenium and tantalum are all or partially solid-solved in the tungsten matrix to form a tungsten-rhenium-tantalum ternary pre-alloy powder with tungsten as the main phase; S2) drying the tungsten-rhenium-tantalum precursor wet gel obtained in S1) by heating to a certain temperature, and then calcining for a certain time to obtain a calcined powder; S3) reducing the calcined powder obtained in S2) in a protective atmosphere to obtain a tungsten-rhenium-tantalum pre-alloy powder with a particle size of 0.1-100 μm; The specific steps of S1) are as follows: S1.1) weighing tungsten-containing raw materials, ammonium rhenate, and tantalum-containing raw materials according to a designed ratio, dissolving them in water, adding a certain proportion of a complexing agent, and stirring uniformly under the condition of a 60-95 ℃ water bath to obtain a solution; S1.2) adjusting the pH value of the solution obtained in S1.1) to 1-3; S1.3) keeping water bath heating and stirring until the solution becomes a viscous gel, i.e., obtaining a tungsten-rhenium-tantalum precursor wet gel; In S1.1), the designed ratio of the tungsten-containing raw materials, ammonium rhenate, and tantalum-containing raw materials is W-xRe-yTa, x is 0.1%-25wt%, and y is 0.1%-10wt%; In S1.1), the ratio of the number of moles of the added complexing agent to the total number of moles of tungsten, rhenium, and tantalum is 1:(0.5-3); In S1.1), the tungsten-containing raw materials are one or more of ammonium tungstate, ammonium metatungstate, or ammonium paratungstate; and the tantalum-containing raw materials are one or more of a tantalum ethoxide solution, a tantalum isopropyl alcohol solution, or a tantalum oxalate solution.

2. The production method according to claim 1, characterized by, The complexing agent is one or more of maleic acid, oxalic acid, or citric acid.

3. The preparation method according to claim 1, characterized in that, In S2), the drying temperature is 100-150 ℃, the calcining temperature is 200-230 ℃, and the calcining time is 5-10 h.

4. The method of claim 1, wherein, In S3), the protective atmosphere is hydrogen, the reduction temperature is 800-1000 ℃, and the reduction time is 1-3 h.

5. A tungsten-rhenium-tantalum pre-alloyed powder, characterized in that, The tungsten-rhenium-tantalum pre-alloy powder is prepared by the preparation method according to any one of claims 1-4.

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