Method for preparing superfine all-solid-solution tungsten-molybdenum composite powder at ultralow temperature
Ultrafine, fully solid-solidified tungsten-molybdenum composite powder was prepared by spray drying and ultra-low temperature reduction processes, which solved the problem of uneven grain size and enabled the production of high-performance and low-cost tungsten-molybdenum alloy materials.
Patent Information
- Application Number
- CN202511740847.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-25
- Publication Date
- 2026-02-27
AI Technical Summary
Existing technologies make it difficult to prepare ultrafine, fully solid-solid-solid tungsten-molybdenum composite powders with uniform grain size distribution, resulting in poor material performance and high production costs.
Tungsten-molybdenum precursor mixed powder was prepared by spray drying technology, and then calcined and reduced at ultra-low temperature in a tube furnace. The mixing ratio and process parameters of the tungsten-molybdenum precursor were controlled to ensure uniform mixing and reduction effect.
Ultrafine, fully solid-solidified tungsten-molybdenum composite powder with a grain size of less than 0.3 μm, an oxygen content of less than 0.4 wt.%, and a purity of greater than 99.9% was obtained, which improved the strength and plasticity of the material and reduced production costs.
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Figure CN121571635A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of powder metallurgy technology, and relates to tungsten-molybdenum composite powder, specifically to a method for preparing ultrafine fully solid-solid-solid tungsten-molybdenum composite powder at ultra-low temperatures. Background Technology
[0002] With the rapid development of aerospace and nuclear industries, ultra-high temperature alloys, represented by nickel and cobalt, are gradually failing to meet industrial production demands. These alloys, due to their poor high-temperature strength and low thermal diffusivity, become ineffective in environments above 1300K. Therefore, it is necessary to seek an alloy material with high strength and excellent high-temperature resistance for high-temperature environments. Molybdenum, with its high melting point, good corrosion resistance, low coefficient of thermal expansion, and good thermal conductivity, is widely used as a high-temperature structural material. In recent years, the important role of molybdenum alloys in nuclear thermal propulsion has rekindled interest in them. However, at room temperature, pure molybdenum also suffers from low strength and poor ductility. To improve its strength and toughness, researchers have explored various methods, such as adding tungsten to form a solid solution to enhance the mechanical properties of molybdenum-based alloys. Tungsten-molybdenum alloys not only inherit the excellent properties of metallic molybdenum but also possess the high strength and good high-temperature resistance of metallic tungsten. They show broad application prospects in aerospace, high-temperature nuclear reactors, and military industries, making them one of the most promising alloy materials for both military and civilian applications.
[0003] With the development of modern science and technology, higher requirements have been placed on the performance of tungsten-molybdenum alloys. Lowering the ductile-brittle transition temperature of tungsten-molybdenum alloys can improve their strength and plasticity, which is an important means to broaden the application fields of tungsten-molybdenum alloys. Industrially, strength and toughness are generally improved simultaneously through grain refinement strengthening. In addition, the mechanical properties of alloys can be improved by forming tungsten-molybdenum solid solutions, thereby enhancing the alloy's adaptability at low and high temperatures. Therefore, the preparation of ultrafine-grained tungsten-molybdenum-based alloy materials with high density and solid solution degree has become one of the research hotspots. Using nanocomposite powders as raw materials can improve sintering activity, lower sintering temperature, and refine microstructure, which is the key to preparing fine-grained tungsten-molybdenum alloy materials.
[0004] Currently, in industry, tungsten powder and molybdenum powder are commonly used as raw materials, mixed and sintered to obtain tungsten-molybdenum alloys. However, the alloys have low solid solution levels, making it difficult to precisely control grain size and distribution, resulting in uneven microstructure and poor material properties, as well as susceptibility to cracking during rolling. Therefore, how to prepare ultrafine, fully solid-solidified tungsten-molybdenum composite powder with uniform grain size distribution has become an urgent technical problem to be solved in the industry, and is also key to improving the performance of tungsten-molybdenum-based alloy materials and reducing production costs. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this invention proposes a method for preparing ultrafine fully solid-solid-solid tungsten-molybdenum composite powder at ultra-low temperatures, thereby solving the technical problem of uneven grain size distribution in existing technologies.
[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A method for preparing ultrafine fully solid-solid-solid tungsten-molybdenum composite powder at ultra-low temperatures, the method specifically includes the following steps: Step 1: Preparation of tungsten-molybdenum precursor mixed powder: Soluble ammonium metatungstate and ammonium molybdate tetrahydrate are mixed in a certain mass ratio to form a homogeneous solution, and the tungsten-molybdenum precursor mixed powder is obtained by spray drying technology. The particle size of the tungsten-molybdenum precursor mixed powder is ≤10μm. Step 2, prepare tungsten-molybdenum oxide mixed powder: The tungsten-molybdenum precursor mixed powder from step one is placed in a tube furnace and calcined in an air atmosphere to obtain tungsten-molybdenum oxide mixed powder. Step 3: Preparation of ultrafine fully solid-solid-solid tungsten-molybdenum composite powder: The tungsten-molybdenum oxide mixed powder from step two was placed in a tube furnace and subjected to ultra-low temperature reduction under a hydrogen atmosphere. After cooling to room temperature, ultrafine fully solid-solid tungsten-molybdenum composite powder was obtained.
[0007] The present invention also includes the following technical features: Specifically, in step one, the mass ratio of ammonium metatungstate and ammonium molybdate tetrahydrate is (3-7):(3-7).
[0008] Specifically, in step one, the inlet air temperature for spray drying is 160℃~220℃.
[0009] Specifically, in step one, the pump speed for spray drying is 20 rpm to 60 rpm.
[0010] Specifically, in step two, the roasting temperature is 400℃~600℃.
[0011] Specifically, in step three, the ultra-low temperature reduction temperature is 700℃~850℃.
[0012] Specifically, in step three, the ultra-low temperature reduction time is 6h to 10h.
[0013] Specifically, in step three, the ultrafine fully solid-solid-solid tungsten-molybdenum composite powder has a grain size of less than 0.3 μm, an oxygen content of less than 0.4 wt.%, and a purity of greater than 99.9%.
[0014] Compared with the prior art, the present invention has the following beneficial technical effects: The method for preparing ultrafine, fully solid-solid-solid-solid-state tungsten-molybdenum composite powder at ultra-low temperatures proposed in this invention can obtain ultrafine, fully solid-solid ... Attached Figure Description
[0015] Figure 1 The XRD patterns of the ultrafine fully solid-solid-solid tungsten-molybdenum composite powders obtained in Examples 1, 2 and 3 are shown.
[0016] Figure 2 This is a SEM image of the ultrafine fully solid-solid-solid tungsten-molybdenum composite powder obtained in Example 1.
[0017] Figure 3 This is a SEM image of the ultrafine fully solid-solid-solid tungsten-molybdenum composite powder obtained in Example 2.
[0018] Figure 4 The image shows the SEM image of the ultrafine fully solid-solid-solid tungsten-molybdenum composite powder provided in Example 3.
[0019] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation
[0020] It should be noted that, unless otherwise specified, all the equipment and materials used in this invention are those known in the prior art.
[0021] Spray drying is a rapid powder production process with advantages such as high production efficiency, uniform composition, and controllable particle size distribution. Its mechanism involves atomizing a solution into mist particles using a high-pressure pump, then directly exchanging these particles with hot air to obtain powder. This technology enables atomically homogeneous mixing of tungsten and molybdenum. Furthermore, compared to heat drying, rapid spray drying avoids phase separation caused by the separate crystallization of ammonium tungstate and ammonium molybdate during the drying process. Additionally, using deionized water as a solvent avoids the use of potentially hazardous substances such as alcohol, and the operation is simple and the process is easy to control. The preparation of ultrafine, fully solid-solution tungsten-molybdenum composite powders is beneficial for lowering sintering temperatures and reducing alloy grain size, thereby improving performance through grain refinement and solid-solution strengthening.
[0022] Following the above technical solutions, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.
[0023] Example 1: This embodiment provides a method for preparing ultrafine fully solid-solid-solid tungsten-molybdenum composite powder at ultra-low temperatures, which specifically includes the following steps: Step 1: Preparation of tungsten-molybdenum precursor mixed powder: Soluble ammonium metatungstate and ammonium molybdate tetrahydrate were mixed into a homogeneous solution at a tungsten:molybdenum mass ratio of 3:7, and spray-dried at an inlet air temperature of 200℃ and a pump speed of 30rpm to obtain a tungsten-molybdenum precursor mixed powder with a particle size ≤10μm. Step 2, prepare tungsten-molybdenum oxide mixed powder: The tungsten-molybdenum precursor mixed powder from step one was placed in a tube furnace and calcined at 500°C in an air atmosphere to obtain tungsten-molybdenum oxide mixed powder. Step 3: Preparation of ultrafine fully solid-solid-solid tungsten-molybdenum composite powder: The tungsten-molybdenum oxide mixed powder from step two was placed in a tube furnace and subjected to ultra-low temperature reduction at 800°C under a hydrogen atmosphere for 8 hours. After cooling to room temperature with the tube furnace, ultrafine fully solid-solid ...
[0024] In this embodiment, the ultrafine fully solid-solid-solid tungsten-molybdenum composite powder was characterized by SEM, such as... Figure 2 As shown, from Figure 2 As can be seen, some of the spherical particles have broken, with a diameter of about 1 to 10 μm. Under high magnification, they appear as strips, composed of near-spherical particles and polyhedral block particles, with an average grain size of less than 100 nm.
[0025] Example 2: This embodiment provides a method for preparing ultrafine fully solid-solid-solid tungsten-molybdenum composite powder at ultra-low temperature. The steps of this method are basically the same as those in Example 1, except that soluble ammonium metatungstate and ammonium molybdate tetrahydrate are mixed at a tungsten:molybdenum mass ratio of 5:5.
[0026] In this embodiment, the ultrafine fully solid-solid-solid tungsten-molybdenum composite powder was characterized by SEM, such as... Figure 3 As shown, from Figure 3 As can be seen, the ultrafine fully solid-solid-solid tungsten-molybdenum composite powder still maintains a spherical morphology with pores at low magnification, with a diameter of about 1 to 10 μm. At high magnification, it is observed that it is composed of a large number of near-ellipsoidal tungsten-molybdenum solid solution particles with an average grain size of about 100 nm.
[0027] Example 3: This embodiment provides a method for preparing ultrafine fully solid-solid-solid tungsten-molybdenum composite powder at ultra-low temperature. The steps of this method are basically the same as those in Example 1, except that soluble ammonium metatungstate and ammonium molybdate tetrahydrate are mixed at a tungsten:molybdenum mass ratio of 7:3.
[0028] In this embodiment, the ultrafine fully solid-solid-solid tungsten-molybdenum composite powders obtained in Examples 1, 2, and 3 were subjected to X-ray diffraction analysis, such as... Figure 1 As shown, 30W-70Mo is the ultrafine fully solid-solid ... Figure 1 It can be seen that only W and Mo diffraction peaks are present, with no impurities or oxides, indicating that the reduction reaction proceeded fully.
[0029] In this embodiment, the ultrafine fully solid-solid-solid tungsten-molybdenum composite powder was characterized by SEM, such as... Figure 4 As shown, from Figure 4 As can be seen, the ultrafine fully solid-solidified tungsten-molybdenum composite powder is still a spherical particle containing voids under low magnification, with a diameter of about 1 to 10 μm. Under high magnification, it is observed to be composed of a large number of near-spherical particles, with an average grain size of about 100 nm.
Claims
1. A method for preparing ultrafine fully solid-solid-solid tungsten-molybdenum composite powder at ultra-low temperatures, characterized in that, The method specifically includes the following steps: Step 1: Preparation of tungsten-molybdenum precursor mixed powder: Soluble ammonium metatungstate and ammonium molybdate tetrahydrate are mixed in a certain mass ratio to form a homogeneous solution, and the tungsten-molybdenum precursor mixed powder is obtained by spray drying technology. The particle size of the tungsten-molybdenum precursor mixed powder is ≤10μm. Step 2, prepare tungsten-molybdenum oxide mixed powder: The tungsten-molybdenum precursor mixed powder from step one is placed in a tube furnace and calcined in an air atmosphere to obtain tungsten-molybdenum oxide mixed powder. Step 3: Preparation of ultrafine fully solid-solid-solid tungsten-molybdenum composite powder: The tungsten-molybdenum oxide mixed powder from step two was placed in a tube furnace and subjected to ultra-low temperature reduction under a hydrogen atmosphere. After cooling to room temperature, ultrafine fully solid-solid tungsten-molybdenum composite powder was obtained.
2. The method for preparing ultrafine fully solid-solid-solid tungsten-molybdenum composite powder at ultra-low temperature as described in claim 1, characterized in that, In step one, the mass ratio of ammonium metatungstate and ammonium molybdate tetrahydrate is (3-7):(3-7).
3. The method for preparing ultrafine fully solid-solid-solid tungsten-molybdenum composite powder at ultra-low temperature as described in claim 1, characterized in that, In step one, the inlet air temperature for spray drying is 160℃~220℃.
4. The method for preparing ultrafine fully solid-solid-solution tungsten-molybdenum composite powder at ultra-low temperatures as described in claim 1, characterized in that, In step one, the pump speed for spray drying is 20 rpm to 60 rpm.
5. The method for preparing ultrafine fully solid-solid-solution tungsten-molybdenum composite powder at ultra-low temperature as described in claim 1, characterized in that, In step two, the roasting temperature is 400℃~600℃.
6. The method for preparing ultrafine fully solid-solid-solution tungsten-molybdenum composite powder at ultra-low temperature as described in claim 1, characterized in that, In step three, the ultra-low temperature reduction temperature is 700℃~850℃.
7. The method for preparing ultrafine fully solid-solid-solid tungsten-molybdenum composite powder at ultra-low temperature as described in claim 1, characterized in that, In step three, the ultra-low temperature reduction time is 6h to 10h.
8. The method for preparing ultrafine fully solid-solid-solid tungsten-molybdenum composite powder at ultra-low temperature as described in claim 1, characterized in that, In step three, the ultrafine fully solid-solid-solid tungsten-molybdenum composite powder has a grain size of less than 0.3 μm, an oxygen content of less than 0.4 wt.%, and a purity of greater than 99.9%.