Tungsten particles, method for producing the same, and use thereof

Abstract

The application provides a tungsten particle and a preparation method and application thereof, and the preparation method comprises the following steps: growing tungsten particles in a nickel-iron alloy system to obtain a tungsten-nickel-iron alloy; then preparing the tungsten-nickel-iron alloy into an alloy powder; then heating the alloy powder to 1550-1800 DEG C for melting, and then carrying out solid-liquid separation or static stratification, crushing to obtain the tungsten particles; the tungsten particles are obtained by growing tungsten powder in a nickel-iron alloy system first, and then separating the tungsten and the nickel-iron binder phase by density stratification or through a special device, so that the tungsten and the nickel-iron binder phase are separated, and the tungsten particles with uniform particle size are obtained; compared with the prior art, the method of the application overcomes the problems of environmental pollution and separation efficiency in the preparation process of the tungsten particles in the prior art, and can efficiently prepare the tungsten particles with uniform particle size.

Description

Technical Field

[0001] This invention relates to the field of tungsten particle preparation, and more specifically, to a tungsten particle, its preparation method, and its application. Background Technology

[0002] Tungsten is a very important refractory metal. Tungsten 3D printing technology places new and stringent technical requirements on tungsten powder, such as the difficulty in preparing coarse-grained (20-40μm) spherical or quasi-spherical tungsten powder. Currently, there are no suitable dedicated powders for tungsten 3D printing, either domestically or internationally. Currently, it is possible to first grow tungsten particles in a tungsten-nickel-iron alloy system using specialized techniques, and then further separate the tungsten particles from the nickel-iron binder phase to prepare spherical or quasi-spherical tungsten powder. However, separating the tungsten particles from the binder phase in the tungsten-nickel-iron alloy remains a significant challenge with current technology.

[0003] In existing technologies, ball milling or acid electrolysis is used to separate tungsten particles from the binder phase. However, ball milling is difficult to use for separating tungsten particles and the binder phase in tungsten-nickel-iron alloys, and it is time-consuming and inefficient. Acid electrolysis is also slow and inefficient, and it is difficult to solve the environmental pollution problem. Summary of the Invention

[0004] To address the aforementioned technical issues, this application provides a method for preparing tungsten particles. This method can separate tungsten particles from the binder phase using physical means, which is not only highly efficient and can produce coarse tungsten particles in batches, but also produces spherical or near-spherical tungsten particles with uniform particle size.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A method for preparing tungsten particles includes the following steps:

[0007] Tungsten particles are grown in a nickel-iron alloy system to obtain a tungsten-nickel-iron alloy; then the tungsten-nickel-iron alloy is made into alloy powder; then the alloy powder is heated to 1550-1800℃ for melting, and then the solid and liquid are separated or allowed to stand and separate into layers, and then crushed to obtain the tungsten particles.

[0008] In some embodiments, the method for preparing the tungsten particles includes the following steps:

[0009] S1. Tungsten particle growth: Tungsten powder and nickel-iron powder are mixed evenly, then molded and pre-sintered at 700-900℃, and then sintered at 1480-1600℃ under hydrogen atmosphere or vacuum conditions to obtain tungsten-nickel-iron alloy.

[0010] S2. Preparation of tungsten alloy powder: The tungsten-nickel-iron alloy is prepared into tungsten alloy powder;

[0011] S3. Under a protective atmosphere or vacuum, heat the tungsten alloy powder to 1550-1800℃, let it stand to allow the binder phase to completely melt, then filter it while hot, separate the solid and liquid, and crush it to obtain the tungsten particles; or after the binder phase is completely melted, let it stand to separate into layers, and crush and classify it after cooling to obtain the tungsten particles.

[0012] In some implementations, in step S1, the mass ratio of tungsten, nickel, and iron is 85-90:5-8:2-10.

[0013] In some embodiments, in step S3, the device used for filtration and separation includes a first crucible and a second crucible, the first crucible being fitted inside the second crucible, the bottom of the first crucible having a through hole and being covered with a sieve with a mesh size of 150-200; and the bottom surface of the first crucible having a support portion.

[0014] In some embodiments, the first crucible is a zirconium oxide crucible; the sieve is a tungsten sieve; and the second crucible is an alumina crucible.

[0015] In some embodiments, in step S3, the ratio of the bottom diameter to the height of the crucible used for static layering is 1:2-5.

[0016] In some implementations, the pre-sintering time in step S1 is 60-120 min.

[0017] In some embodiments, the sintering time in step S1 is 100-300 min. A suitable time facilitates the growth of tungsten particles.

[0018] In some embodiments, the settling time in step S3 is ≥120 min. A longer settling time helps to separate or separate the binder phase and tungsten particles.

[0019] In some embodiments, a ball mill is used for crushing, with a ball-to-material ratio of 1-4:1, and the grinding beads are zirconia grinding beads.

[0020] The present invention also provides tungsten particles obtained by the preparation method of any of the above embodiments, wherein the tungsten particles are spherical or near-spherical and have a particle size of 20-40 μm.

[0021] The present invention also provides the application of the above-mentioned tungsten particles in the preparation of tungsten alloy materials.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] This invention involves first growing tungsten powder in a nickel-iron alloy system, then separating or sedimenting the tungsten particles from the binder phase using physical methods. Finally, spherical or near-spherical tungsten particles are obtained through crushing and grading. The tungsten particles obtained by this method are uniform in size (20-40 μm), have high purity, and low impurity content (nickel-iron binder phase content <1%), and can be directly used in the preparation of tungsten alloy materials.

[0024] The method of this invention creatively separates tungsten and the binder phase metal using a physical method, which not only enables the batch preparation of tungsten particles, but also has high efficiency, low preparation cost, and short cycle, effectively solving the problems of environmental pollution or low separation efficiency in existing technologies. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the filtration device in the embodiment;

[0026] Figure 2 This is a schematic diagram of the crucible used for settling in Example 2;

[0027] Among them, 1-zirconia crucible, 2-pure tungsten screen, 3-through hole, 4-support part, 5-alumina crucible Detailed Implementation

[0028] Numerous specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and similar modifications can be made by those skilled in the art without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0029] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0031] Example 1

[0032] A method for preparing tungsten particles includes the following steps:

[0033] (1) Weighing raw materials: Weigh tungsten powder, nickel powder and iron powder according to the mass ratio of tungsten powder, nickel powder and iron powder of 90:7:3. Add tungsten powder, nickel powder and iron powder to a ball mill and mix for 6 hours. Then use a fully automatic powder molding machine to complete the molding and obtain the pressed blank.

[0034] (2) Pre-sintering: The pressed blank is pre-sintered at a temperature of 800℃ and a holding time of 120min.

[0035] (3) Sintering: Sintering is carried out in a vacuum atmosphere at a temperature of 1500℃ and a holding time of 210min. After natural cooling, tungsten-nickel-iron alloy is obtained.

[0036] (4) Preparation of alloy powder: Plasma rotating electrode atomization powder preparation technology (PREP) is used to make tungsten nickel iron alloy into dispersed alloy powder with a particle size of 30-60μm.

[0037] (5) Filtration: Place the tungsten alloy powder in a container such as... Figure 1 In the crucible apparatus shown, the temperature is raised to 1700℃ and then held for 120 minutes to allow the molten nickel-iron binder phase to be filtered through the mesh, while the tungsten particles remain on the mesh. The crucible apparatus used for heating and filtering in this embodiment includes an outer alumina crucible 5 and an inner zirconia crucible 1. The bottom of the inner zirconia crucible has through-holes 3 with a diameter of 20-40 μm, and the bottom of the inner zirconia crucible 1 is covered with a tungsten mesh 2 with a mesh size of 200. A support portion 4 is provided at the bottom edge of the inner zirconia crucible 1. After heating to the melting temperature and holding for 120 minutes, the molten nickel-iron binder phase flows out through the mesh and through-holes into the outer zirconia crucible 5, while the tungsten particles remain on the tungsten mesh, thus completing the filtration and separating the tungsten particles from the nickel-iron binder phase.

[0038] (6) Crushing and grading: After cooling, the particles on the tungsten screen are removed, which are pure tungsten particles or tungsten-nickel-iron alloy particles with very little nickel-iron content (<1%). Then, the particles on the screen are added to a ball mill and ball-milled for 5 hours using zirconia grinding beads at a ball-to-material ratio of 2:1. Next, the particles are sieved and graded using a vibrating screen to obtain tungsten powder. The sphericity of the tungsten powder is 93%, the particle size is between 20 and 40 μm, and the flowability is tested to be 23.6 s / 50 g.

[0039] Example 2

[0040] A method for preparing tungsten particles includes the following steps:

[0041] (1) Weighing raw materials: Weigh tungsten powder, nickel powder and iron powder according to the mass ratio of tungsten powder, nickel powder and iron powder of 90:7:3. Add tungsten powder, nickel powder and iron powder to a ball mill and mix for 6 hours. Use a fully automatic powder molding machine to complete the molding and obtain the pressed blank.

[0042] (2) Pre-sintering: The pressed blank is pre-sintered at a temperature of 800℃ and a holding time of 120min.

[0043] (3) Sintering: Sintering is carried out in a vacuum atmosphere at a temperature of 1500℃ and a holding time of 210min to obtain tungsten-nickel-iron alloy.

[0044] (4) Preparation of alloy powder: Plasma rotating electrode atomization powder preparation technology (PREP) is used to make tungsten nickel iron alloy into dispersed alloy powder with a particle size of 30-60μm.

[0045] (5) Layering: Place the powder in a layer such as Figure 2 The zirconia was melted in a deeper zirconia crucible at 1700°C and left to stand for 180 minutes, then allowed to cool naturally to obtain a layered block; the ratio of the diameter to the height of the zirconia crucible was 3:1.

[0046] (6) Crushing and grading: Take out the obtained blocks, cut off the bottom block and add it to the ball mill. Use zirconia ball milling beads to crush for 5 hours with a ball-to-material ratio of 1:1. Then use a vibrating screen to screen and grade to obtain tungsten powder. The sphericity of the tungsten powder is 91%, the particle size is between 20 and 40 μm, and the flowability is 25.9 s / 50g.

[0047] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0048] The embodiments described above are merely illustrative 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 invention patent. 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 all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing tungsten particles, characterized in that, Includes the following steps: S1. Tungsten particle growth: Tungsten powder and nickel-iron powder are mixed evenly, then molded and pre-sintered at 700-900℃, and then sintered at 1480-1600℃ under hydrogen atmosphere or vacuum conditions to obtain tungsten-nickel-iron alloy. S2. Preparation of tungsten alloy powder: The tungsten-nickel-iron alloy is prepared into tungsten alloy powder; S3. Under a protective atmosphere or vacuum, heat the tungsten alloy powder to 1550-1800℃, let it stand to allow the binder phase to completely melt, then filter it while hot, separate the solid and liquid, and crush it to obtain the tungsten particles; or after the binder phase is completely melted, let it stand to separate into layers, and after cooling, crush and classify it to obtain the tungsten particles. In step S1, the mass ratio of tungsten powder, nickel powder and iron powder is 85-90:5-8:2-10; In step S2, plasma rotating electrode atomization powder preparation technology is used to turn tungsten nickel iron alloy into dispersed alloy powder with a particle size of 30-60μm. In step S3, the device used for filtration and separation includes a first crucible and a second crucible. The first crucible is fitted inside the second crucible. The bottom of the first crucible has a through hole and is covered with a 150-200 mesh screen. The bottom of the first crucible has a support part.

2. The method for preparing tungsten particles according to claim 1, characterized in that, In step S3, the ratio of the bottom diameter to the height of the crucible used for static layering is 1:2-5.

3. The method for preparing tungsten particles according to claim 1, characterized in that, In step S1, the pre-sintering time is 60-120 min.

4. The method for preparing tungsten particles according to claim 1, characterized in that, In step S1, the sintering time is 100-300 min.

5. The method for preparing tungsten particles according to claim 1, characterized in that, In step S3, the settling time is ≥120 min.

6. Tungsten particles prepared by the preparation method according to any one of claims 1-5.

7. The application of the tungsten particles according to claim 6 in the preparation of tungsten alloy materials.

Images