Superfine high-uniformity W-based solid solution powder and preparation method thereof

Abstract

The invention provides superfine high-uniformity W-based solid solution powder and a preparation method thereof, and relates to the technical field of powder metallurgy, the preparation method of the superfine high-uniformity W-based solid solution powder comprises the following steps: (a) mixing a tungsten-containing oxide, a rhenium-containing oxide and / or molybdenum-containing oxide and a reducing agent to obtain a mixed raw material; (b) carrying out reduction treatment on the mixed raw material to obtain the superfine high-uniformity W-based solid solution powder, wherein the reduction treatment comprises a first stage and a second stage, and the treatment temperature of the second stage is higher than that of the first stage. According to the method, the superfine W-based solid solution powder with the particle size of 100-500 nm is finally obtained by combining low-cost raw materials with a short-process reduction process. According to the method, on the basis of ensuring that the powder with the superfine particle size and uniform components is obtained, the energy consumption is remarkably reduced, and the method is particularly suitable for large-scale production of the W-Re and W-Mo solid solution powder.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of powder metallurgy, in particular to a kind of ultrafine high uniformity W base solid solution powder and preparation method thereof. BACKGROUND

[0002] Tungsten has important applications in aerospace, nuclear power and electronics due to its high melting point, high strength and excellent thermal shock resistance. To further improve the brittleness and processing performance of pure tungsten at low temperature, studies have attempted to form tungsten-based solid solution alloys by adding elements such as rhenium (Re) or molybdenum (Mo), which can form body-centered cubic structure solid solution (W-Re / W-Mo). This alloying not only significantly improves the low temperature brittleness of pure tungsten, effectively reduces its DBTT, and improves its plasticity and processing performance at medium and low temperatures, but also balances the high temperature strength of the material, reduces the recrystallization temperature, and enhances the creep resistance and long-term stability at high temperatures while maintaining the high melting point and excellent heat resistance of the tungsten matrix.

[0003] Currently, W-based solid solution powders are mostly prepared using powder metallurgy processes, in which the properties of the powder determine the overall performance of the material. There are various methods for preparing ultrafine / nano tungsten alloy powders, including high-energy ball milling, hydrogen reduction, sol-gel, spray drying, and chemical vapor deposition. High-energy ball milling can achieve mechanical alloying, but the prepared powder has a coarse particle size and poor composition uniformity. In traditional hydrogen reduction processes, gas phase chemical transport (CVT) often occurs, leading to particle coarsening and uneven particle size distribution. Although many researchers have optimized the process, changed the gas flow direction, and other strategies to effectively alleviate the CVT problem to varying degrees, it is difficult to use for large-scale production. Wet chemical methods such as sol-gel or spray drying can obtain precursor with uniform composition, but the process steps are complicated, the raw material cost is high, and it is difficult to meet the demand for large-scale continuous production.

[0004] Therefore, the present application is proposed. SUMMARY

[0005] One of the purposes of the present application is to provide a method for preparing ultrafine high uniformity W base solid solution powder to at least solve one of the technical problems existing in the prior art.

[0006] The second purpose of the present application is to provide an ultrafine high uniformity W base solid solution powder.

[0007] In order to achieve the above purposes of the present application, the following technical solutions are adopted: In a first aspect, the present application provides a method for preparing ultrafine high uniformity W base solid solution powder, comprising the following steps: (a) mixing tungsten-containing oxide, rhenium-containing oxide and / or molybdenum-containing oxide, and reducing agent to obtain mixed raw materials; (b) performing a reduction treatment on the mixed raw material to obtain the ultrafine high-uniformity W-based solid solution powder; The reduction treatment comprises a first stage and a second stage, and the processing temperature of the second stage is higher than that of the first stage.

[0008] Further, the mass ratio of the rhenium-containing oxide or the molybdenum-containing oxide to the tungsten-containing oxide to the reducing agent is 1:3-33:1-13.

[0009] Further, the mass ratio of the tungsten-containing oxide, the rhenium-containing oxide, the molybdenum-containing oxide and the reducing agent is 8.02:1:1.06:4.

[0010] Further, the tungsten-containing oxide comprises WO3 and / or WO 2.9 ; Preferably, the rhenium-containing oxide comprises ReO3; Preferably, the molybdenum-containing oxide comprises MoO2; Preferably, the reducing agent comprises one or more of nano-carbon powder, sucrose and glucose.

[0011] Further, the mixing mode of the tungsten-containing oxide, the rhenium-containing oxide and / or the molybdenum-containing oxide and the reducing agent is ball milling; Preferably, the rotation speed of the ball milling is 100-500 r / min, and the ball milling time is 10-40 h; Preferably, the mass ratio of the milling ball to the sum of the tungsten-containing oxide, the rhenium-containing oxide and / or the molybdenum-containing oxide and the reducing agent is 3:1-10:1.

[0012] Further, after step (a), the mixed raw material before the reduction treatment is pressed to obtain a green compact; Preferably, the pressing mode is preferably cold isostatic pressing, and the pressure is 10-100 MPa.

[0013] Further, the first stage comprises: heating at a rate of 5-10 ℃ / min to 500-800 ℃, and holding for 0.5-1 h.

[0014] Further, the second stage comprises: heating to 850-1200 ℃, holding for 1-3 h, and then cooling to room temperature.

[0015] In a second aspect, the present application provides an ultrafine high-uniformity W-based solid solution powder, which is prepared by the method for preparing an ultrafine high-uniformity W-based solid solution powder.

[0016] Further, the particle size of the ultrafine high-uniformity W-based solid solution powder is 100-500 nm. Preferably, the mass percentage content of Re or Mo elements in the ultrafine high-uniformity W-based solid solution powder is 3-25 wt.%.

[0017] Compared with the prior art, the present application has the following beneficial effects: The preparation method of the ultrafine high-uniformity W-based solid solution powder provided by the present application comprises the following steps: subjecting tungsten-containing oxides and rhenium-containing and / or molybdenum-containing oxides to a staged reduction treatment in the presence of a reducing agent, promoting solid-phase diffusion between the multi-component oxides and forming a uniform composite oxide precursor in a first stage at a lower temperature, effectively inhibiting element segregation; and then realizing carbothermal reduction and in-situ alloying in a second stage at a higher temperature, promoting W, Re and / or Mo atoms to fully diffuse and form a single solid solution phase. This process path not only guarantees that the obtained W-based solid solution powder has an ultrafine particle size and excellent composition uniformity, but also avoids the particle coarsening problem caused by gas-phase migration (CVT) in the traditional hydrogen reduction process. In addition, the use of low-cost oxide raw materials and carbon sources, combined with a short process reaction, significantly reduces the process energy consumption and equipment cost, which is conducive to realizing large-scale stable preparation of high-performance W-based solid solution powder. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the specific embodiments or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0019] Figure 1 The morphology (b), particle size distribution (c) and XRD pattern (a) of the ultrafine W-based solid solution powder prepared in Example 1 of the present application are shown in the following figure: Figure 2 The morphology (b), particle size distribution (c) and XRD pattern (a) of the ultrafine W-based solid solution powder prepared in Example 2 of the present application are shown in the following figure: Figure 3 The morphology (b), particle size distribution (c) and XRD pattern (a) of the ultrafine W-based solid solution powder prepared in Example 3 of the present application are shown in the following figure: Figure 4 The morphology (b), particle size distribution (c) and XRD pattern (a) of the ultrafine W-based solid solution powder prepared in Example 4 of the present application are shown in the following figure: Figure 5 The morphology (b), particle size distribution (c) and XRD pattern (a) of the ultrafine W-based solid solution powder prepared in Example 5 of the present application are shown in the following figure: Figure 6 The morphology (b), particle size distribution (c) and XRD pattern (a) of the ultrafine W-based solid solution powder prepared in Example 6 of the present application are shown in the following figure: Figure 7 The morphology and particle size distribution of the ultrafine W-based solid solution powder prepared in Example 7 of the present application are shown in the following table: Figure 8 The morphology and particle size distribution of the ultrafine W-based solid solution powder prepared in Comparative Example 1 of the present application are shown in the following table. DETAILED DESCRIPTION

[0020] Unless otherwise defined, scientific and technical terms used in connection with the present application shall have the meanings that are commonly understood by those of ordinary skill in the art. Clear dictates, however, that the definitions of terms in this specification shall be consistent with those of any patents or other external documents that might be cited herein. In the present application, the use of "or" means "and / or" unless otherwise stated. In addition, the use of the term "including" and other forms is not limiting.

[0021] The technical solutions of the present application will be described clearly and completely in connection with the examples below. Obviously, the described examples are part of the examples of the present application, rather than all the examples. Based on the examples in the present application, all other examples obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.

[0022] The first aspect of the present application provides a preparation method of an ultrafine high-uniformity W-based solid solution powder, comprising the following steps: (a) mixing tungsten-containing oxide, rhenium-containing oxide and / or molybdenum-containing oxide, and a reducing agent to obtain a mixed raw material; (b) performing reduction treatment on the mixed raw material to obtain the ultrafine high-uniformity W-based solid solution powder; wherein the reduction treatment comprises a first stage and a second stage, and the treatment temperature of the second stage is higher than that of the first stage.

[0023] The present application proposes a preparation method of an ultrafine high-uniformity W-based solid solution powder. The preparation method of the ultrafine high-uniformity W-based solid solution powder exhibits significant advantages in cost control, powder performance, and industrial application, etc. by optimizing raw material selection and process design. The core is to use low-cost raw materials combined with a short-flow reduction process: tungsten oxide and rhenium oxide or molybdenum oxide first form a composite oxide during the holding process, and then the composite oxide is reduced, and finally an ultrafine W-based solid solution powder with a particle size of 100-500 nm is obtained. This method significantly reduces energy consumption on the basis of ensuring the obtainment of a powder with ultrafine particle size and uniform composition, and is especially suitable for large-scale production of W-Re, W-Mo solid solution powder, providing an ideal key raw material for high-performance hard alloy, high-temperature-resistant coating, high-end electronics, nuclear engineering, etc.

[0024] In some preferred embodiments, the mass ratio of (rhenium oxide-containing or molybdenum oxide-containing):(tungsten oxide-containing):(reducing agent) is 1:(3-33):(1-13). wherein, for example, “3-33” can be 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, etc. wherein, for example, “1-13” can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, etc.

[0025] In some preferred embodiments, the mass ratio of the tungsten oxide-containing, the rhenium oxide-containing, the molybdenum oxide-containing, and the reducing agent is 8.02:1:1.06:4.

[0026] In some preferred embodiments, the tungsten oxide-containing comprises WO3 and / or WO2. 2.9 ; Preferably, the rhenium oxide-containing comprises ReO3. Preferably, the molybdenum oxide-containing comprises MoO2. Preferably, the reducing agent comprises one or more of nano-carbon powder, sucrose, and glucose.

[0027] In some preferred embodiments, the mixing mode of the tungsten oxide-containing, the rhenium oxide-containing, and / or molybdenum oxide-containing, and the reducing agent is ball milling. Preferably, the rotation speed of ball milling is 100-500 r / min, for example, can be 100 r / min, 150 r / min, 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, etc.; the ball milling time is 10-40 h, for example, can be 10 h, 15 h, 20 h, 25 h, 30 h, 35 h, 40 h, etc. Preferably, the mass ratio of the grinding ball to the sum of the tungsten oxide-containing, the rhenium oxide-containing, and / or molybdenum oxide-containing, and the reducing agent is 3:1-10:1, for example, can be 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, etc.

[0028] In some preferred embodiments, after step (a), the mixed raw materials before being subjected to the reduction treatment are subjected to pressing to obtain a powder compact. Preferably, the pressing mode is preferably cold isostatic pressing, and the pressure is 10-100 MPa, for example, can be 10 MPa, 20 MPa, 30 MPa, 40 MPa, 50 MPa, 60 MPa, 70 MPa, 80 MPa, 90 MPa, 100 MPa, etc.

[0029] In some preferred embodiments, the first stage comprises: heating up to 500-800℃, for example, 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, etc., at a rate of 5-10℃ / min, for example, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, etc., and holding for 0.5-1h, for example, 30min, 40min, 50min, 60min, etc.

[0030] In some preferred embodiments, the second stage comprises: heating up to 850-1200℃, for example, 850℃, 900℃, 1000℃, 1100℃, 1200℃, etc., and holding for 1-3h, for example, 1h, 2h, 3h, etc., and then cooling to room temperature.

[0031] In the present application, during the 500-800℃ holding stage, tungsten oxide forms a composite oxide with rhenium oxide or molybdenum oxide; then during the 850-1200℃ holding stage, the composite oxide is reduced to form a superfine W-based solid solution powder with a particle size of 100-500nm.

[0032] Further, in the present application, the use of tungsten oxide, rhenium oxide and molybdenum oxide in combination can reduce the reduction reaction temperature to some extent, so as to obtain a W-Re-Mo alloy powder with a finer particle size. Fine-grain strengthening can improve strength and plasticity. Among them, the addition of Mo mainly helps to improve the strength and hardness of tungsten alloy, but has limited improvement on toughness; Re can significantly enhance the toughness of tungsten. The final W-Re-Mo alloy powder exhibits higher strength, higher hardness and better toughness compared with binary alloy powder.

[0033] In an optional embodiment of the present application, preferably, the preparation method of the superfine high-uniformity W-based solid solution powder comprises the following steps: (1) using tungsten oxide (WO3 or WO 2.9 ), rhenium oxide (ReO3) or molybdenum oxide (MoO2) as raw materials, and nanometer carbon powder, sucrose or glucose as reducing agent, ball-milling the tungsten oxide, rhenium oxide or molybdenum oxide and carbon source. The ball-milling parameters are as follows: the mass ratio of grinding ball to powder is (3:1)-(10:1), the grinding medium is anhydrous ethanol and the volume ratio of grinding medium to material is 1:1, the rotation speed of the ball mill is 100-500r / min, and the ball-milling time is 10-40h. (2) After drying in step (1), the powder is pressed into a block and then pressed into a powder blank using cold isostatic pressing at 10-100 MPa. The obtained powder blank is placed in a furnace, such as a muffle furnace, tube furnace, or vacuum sintering furnace, and a reduction reaction is carried out under an argon atmosphere: first, the temperature is raised to 500-800℃ at a rate of 5-10℃ / min and held for 0.5-1h; then the temperature is raised to 850-1200℃ and held for 1-3h, and then cooled to room temperature to obtain an ultrafine, highly uniform W-based solid solution powder.

[0034] This invention provides an ultrafine, highly uniform W-based solid solution powder, which is prepared using the aforementioned ultrafine, highly uniform W-based solid solution powder.

[0035] In some preferred embodiments, the particle size of the ultrafine, highly uniform W-based solid solution powder is 100-500 nm; Preferably, the mass percentage content of Re or Mo elements in the ultrafine, highly uniform W-based solid solution powder is 3-25 wt.%, for example, it can be 3 wt.%, 5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.%, etc.

[0036] The present invention will be further illustrated below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0037] Example 1 This embodiment provides an ultrafine, highly uniform W-based solid solution powder, which is an ultrafine W-3wt.%Re solid solution powder. The preparation process is as follows: (1) Using WO3 and ReO3 as raw materials and sucrose as a reducing agent, the ingredients were prepared according to a mass ratio of ReO3:WO3:sucrose of 1:32.42:12.26. WO3, ReO3, and sucrose were then ball-milled and mixed. The ball milling parameters were as follows: the mass ratio of grinding balls to powder was 10:1; the grinding medium was anhydrous ethanol with a volume ratio of 1:1 to the material; the ball mill speed was 100 r / min; and the ball milling time was 10 h. (2) After drying the powder obtained in step (1), press it into a block and press the powder into a powder blank using cold isostatic pressing at 100 MPa. The powder blank is placed in a muffle furnace and a reduction reaction is carried out under an argon atmosphere: first, the temperature is raised to 800℃ at a rate of 10℃ / min and held for 0.5h; then the temperature is raised to 900℃ and held for 3h, and then cooled to room temperature to obtain ultrafine W-Re solid solution powder.

[0038] Example 2 This embodiment provides an ultrafine, highly uniform W-based solid solution powder, which is an ultrafine W-15wt.%Re solid solution powder. The preparation process is as follows: (1) Using WO3 and ReO3 as raw materials and nano-carbon black as a reducing agent, the materials were prepared according to a mass ratio of ReO3:WO3:nano-carbon black of 1:5.67:1.01, and the WO3, ReO3 and nano-carbon black were ball-milled and mixed. The ball milling parameters were as follows: the mass ratio of grinding balls to powder was 7:1, the grinding medium was anhydrous ethanol and the volume ratio of ethanol to material was 1:1, the ball mill speed was 300 r / min, and the ball milling time was 20 h. (2) After drying the powder obtained in step (1), press it into a block and press the powder into a powder blank using cold isostatic pressing at 50 MPa. The obtained powder blank is placed in a vacuum sintering furnace and a reduction reaction is carried out under an argon atmosphere: first, the temperature is raised to 700℃ at a rate of 10℃ / min and held for 0.5h; then the temperature is raised to 1000℃ and held for 2h, and then cooled to room temperature to obtain ultrafine W-Re solid solution powder.

[0039] Example 3 This embodiment provides an ultrafine, highly uniform W-based solid solution powder, which is an ultrafine W-25wt.%Re solid solution powder. The preparation process is as follows: (1)With WO 2.9 Using ReO3 as a raw material and glucose as a reducing agent, according to the ReO3:WO3 ratio... 2.9 The ingredients were prepared with glucose in a mass ratio of 1:3:1.52, and WO3 was added. 2.9 ReO3 and glucose were ball-milled and mixed. The ball milling parameters were as follows: the mass ratio of grinding balls to powder was 3:1, the grinding medium was anhydrous ethanol with a volume ratio of 1:1 to the material, the ball mill speed was 500 r / min, and the ball milling time was 40 h. (2) After drying the powder obtained in step (1), press it into a block and press the powder into a powder blank using cold isostatic pressing at 30 MPa. The obtained powder blank is placed in a tube furnace and a reduction reaction is carried out under an argon atmosphere: first, the temperature is raised to 600℃ at a rate of 5℃ / min and held for 1h; then the temperature is raised to 1100℃ and held for 1h, and then cooled to room temperature to obtain ultrafine W-Re solid solution powder.

[0040] Example 4 This embodiment provides an ultrafine, highly uniform W-based solid solution powder, which is an ultrafine W-10wt.%Mo solid solution powder. The preparation process is as follows: (1)With WO 2.9 Using MoO2 as raw material and glucose as reducing agent, according to the MoO2:WO3 ratio... 2.9 The ingredients were prepared with glucose at a mass ratio of 1:11.83:4.94, and WO3 was added. 2.9 MoO2 and glucose were ball-milled and mixed. The ball milling parameters were as follows: the mass ratio of grinding balls to powder was 5:1, the grinding medium was anhydrous ethanol with a volume ratio of 1:1 to the material, the ball mill speed was 300 r / min, and the ball milling time was 30 h. (2) The powder obtained in step (1) is dried and then pressed into a block, and the powder is pressed into a green compact by cold isostatic pressing at 10 MPa. The green compact is placed in a tube furnace and subjected to a reduction reaction in an argon atmosphere: first, the temperature is raised to 500°C at a rate of 10°C / min, and held for 1 h; then the temperature is raised to 1200°C, and held for 1 h, and then cooled to room temperature, to obtain a superfine W-Mo solid solution powder.

[0041] Example 5 This example provides a superfine high-uniformity W-based solid solution powder, which is a superfine W-10 wt.% Re-10 wt.% Mo solid solution powder, and the difference between the preparation process thereof and that of Example 5 is that: MoO2, WO 2.9 , ReO3 are used as raw materials, and glucose is used as a reducing agent, and the mass ratio of WO 2.9 : ReO3: MoO2: glucose is 8.02: 1: 1.06: 4. In step (2), a reduction reaction is performed in an argon atmosphere: first, the temperature is raised to 800°C at a rate of 10°C / min, and held for 0.5 h; then the temperature is raised to 850°C, and held for 3 h, and then cooled to room temperature, to obtain a superfine W-Re-Mo solid solution powder.

[0042] Example 6 This example provides a superfine high-uniformity W-based solid solution powder, which is a superfine W-10 wt.% Re-10 wt.% Mo solid solution powder, and the difference between the preparation process thereof and that of Example 5 is that: In step (2), a reduction reaction is performed in an argon atmosphere: first, the temperature is raised to 800°C at a rate of 10°C / min, and held for 0.5 h; then the temperature is raised to 825°C, and held for 3 h, and then cooled to room temperature.

[0043] Example 7 This example provides a superfine high-uniformity W-based solid solution powder, which is a superfine W-10 wt.% Re-10 wt.% Mo solid solution powder, and the difference between the preparation process thereof and that of Example 5 is that: In step (2), a reduction reaction is performed in an argon atmosphere: first, the temperature is raised to 800°C at a rate of 10°C / min, and held for 0.5 h; then the temperature is raised to 1250°C, and held for 3 h, and then cooled to room temperature.

[0044] Comparative Example 1 This comparative example provides a superfine high-uniformity W-based solid solution powder, and the difference between the preparation process thereof and that of Example 5 is that: In step (2), a reduction reaction is performed in an argon atmosphere: the temperature is directly raised to 850°C, and held for 3.5 h, and then cooled to room temperature.

[0045] Test Example Test Method: The phase composition of the sample was analyzed by X-ray diffraction (XRD, D8 Advance, Bruker) in the range of 20°-90° 2θ diffraction angle at a scanning rate of 2° / min. The morphology and particle size distribution of the powder after reduction were observed by field emission scanning electron microscopy (SEM), and the average particle size was calculated by statistically analyzing more than 200 particles randomly selected from the SEM image using Nano-measurer image analysis software. The elemental composition and distribution were qualitatively and semi-quantitatively analyzed by SEM equipped with an energy dispersive spectrometer (EDS).

[0046] The total carbon, free carbon content and oxygen content in the powder were determined by a carbon and sulfur analyzer (CS600) and an oxygen, nitrogen and hydrogen analyzer (TCH600), respectively. The test results are shown in Table 1.

[0047] Table 1

[0048] As can be seen from the data in Table 1, the ultrafine W-based solid solution powder prepared in Examples 1-5 exhibits excellent chemical purity, with the oxygen content controlled between 0.23-0.48 wt.%, the total carbon content as low as 0.033-0.068 wt.%, and the free carbon residue extremely low (as low as 0.019 wt.%), indicating that the staged reduction process can efficiently reduce the oxides and effectively inhibit the carbon residue, ensuring the high purity of the powder. Among them, Example 5 performs best in the control of oxygen and carbon impurities, fully proving that the optimization of process parameters can achieve extremely low impurity residue.

[0049] In comparison, Examples 6-7 deviate from the preferred range of the second stage reduction temperature, resulting in an increase in oxygen content, and a slight increase in total carbon and free carbon content, with the overall purity slightly inferior to Examples 1-5, reflecting that temperature control has a significant impact on impurity removal efficiency and the final quality of the powder. However, the overall purity is still significantly better than that of Comparative Example 1, indicating that even under non-optimal temperature conditions, the staged reduction process still has good impurity control ability.

[0050] In combination Figures 1-8It can be seen that the W-Re, W-Mo and multi-component W-based solid solution powders prepared in Examples 1-5 all exhibit typical "ultra-fine" and "high uniformity" characteristics. The SEM morphology shows that the particles are small and clear in outline, the average particle size of the samples is distributed in the range of 100-500 nm, the D50 of the samples is highly close to the average particle size, indicating that the particle size distribution is concentrated, the dispersion is small, and the particle size uniformity is excellent. On the basis of the optimized process, the W-Re-Mo solid solution powder prepared in Example 5 realizes the smallest average particle size of only 160.26 nm, which shows the best refinement effect. In contrast, the average particle sizes of Examples 6-7 increase to 325.35 nm and 334.08 nm respectively due to the deviation of temperature parameters from the preferred range, indicating that the process conditions have a significant effect on the particle size. The average particle size of Comparative Example 1 further significantly increases to 417.50 nm due to the absence of the low-temperature holding stage, fully highlighting the key role of this stage in inhibiting particle coarsening.

[0051] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing ultrafine, highly uniform W-based solid solution powder, characterized in that, Includes the following steps: (a) Mixing tungsten oxide, rhenium oxide and / or molybdenum oxide with a reducing agent to obtain a mixed raw material; (b) The mixed raw materials are subjected to reduction treatment to obtain the ultrafine, highly uniform W-based solid solution powder; The reduction process includes a first stage and a second stage, wherein the processing temperature of the second stage is higher than that of the first stage.

2. The method for preparing ultrafine, highly uniform W-based solid solution powder according to claim 1, characterized in that, The mass ratio of the rhenium-containing oxide or molybdenum-containing oxide to the tungsten-containing oxide and the reducing agent is 1:3-33:1-13.

3. The method for preparing ultrafine, highly uniform W-based solid solution powder according to claim 1, characterized in that, The mass ratio of the tungsten oxide, the rhenium oxide, the molybdenum oxide, and the reducing agent is 8.02:1:1.06:

4.

4. The method for preparing ultrafine, highly uniform W-based solid solution powder according to claim 1, characterized in that, The tungsten oxide includes WO3 and / or WO 2.9 ; Preferably, the rhenium-containing oxide includes ReO3; Preferably, the molybdenum-containing oxide comprises MoO2; Preferably, the reducing agent includes one or more of nano-carbon powder, sucrose, and glucose.

5. The method for preparing ultrafine, highly uniform W-based solid solution powder according to claim 1, characterized in that, The tungsten oxide, the rhenium oxide and / or the molybdenum oxide and the reducing agent are mixed by ball milling. Preferably, the ball mill rotation speed is 100-500 r / min, and the ball milling time is 10-40 h; Preferably, the mass ratio of the grinding balls used in the ball mill to the sum of the tungsten oxide, the rhenium oxide and / or the molybdenum oxide and the reducing agent is 3:1 to 10:

1.

6. The method for preparing ultrafine, highly uniform W-based solid solution powder according to claim 1, characterized in that, After step (a), the mixed raw materials before reduction treatment are pressed to obtain a powder blank; Preferably, the pressing method is cold isostatic pressing, with a pressure of 10-100 MPa.

7. The method for preparing ultrafine, highly uniform W-based solid solution powder according to claim 1, characterized in that, The first stage includes: heating to 500-800℃ at a rate of 5-10℃ / min and holding at that temperature for 0.5-1h.

8. The method for preparing ultrafine, highly uniform W-based solid solution powder according to claim 1, characterized in that, The second stage includes: raising the temperature to 850-1200℃, holding it at that temperature for 1-3 hours, and then cooling it to room temperature.

9. An ultrafine, highly uniform W-based solid solution powder, characterized in that, It was prepared using the method described in any one of claims 1-8 for preparing ultrafine, highly uniform W-based solid solution powder.

10. The ultrafine, highly uniform W-based solid solution powder according to claim 9, characterized in that, The particle size of the ultrafine, highly uniform W-based solid solution powder is 100-500 nm. Preferably, the mass percentage content of Re or Mo elements in the ultrafine, highly uniform W-based solid solution powder is 3-25 wt.%.

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