Tungsten powder coated with nano-amorphous layer, preparation method and application thereof

Abstract

A tungsten powder coated with a nano-amorphous layer, a preparation method and its application, belonging to the field of powder metallurgy, wherein the surface of the tungsten powder particles is covered with a layer of amorphous alloy film with a nano-thickness, and the chemical composition formula of the amorphous coating is Y 100‑a M a , including rare earth metal Y and post-transition metal M, M is one or more of Fe, Co, Ni, 25≤a≤55, which is the atomic percentage composition. The present invention first prepares Y by arc melting combined with melt atomization technology. 100‑a M a alloy powder; after mixing it with tungsten powder and high-energy ball milling, Y 100‑a M a The alloy adheres and spreads on the surface of the tungsten powder, undergoing amorphization simultaneously, forming a nanometer-thick amorphous coating on the surface of the tungsten powder particles. By adjusting the amount of the coating matrix material added, the present invention can achieve amorphous coatings of varying thicknesses on the surface of the tungsten powder particles. This allows for liquid-solid sintering of the tungsten powder material, significantly reducing the sintering temperature and significantly increasing the density of the sintered body. It also has the potential to achieve pressureless sintering of tungsten-based materials.

Description

Technical Field

[0001] The invention belongs to the technical field of powder metallurgy, and relates to a tungsten powder coated with a nano-amorphous layer, a preparation method and an application thereof. Background Art

[0002] Due to its high melting point, high thermal conductivity, sputtering resistance, high high-temperature strength and low tritium retention, tungsten and tungsten-based composites are widely used in industrial fields such as aerospace, national defense, nuclear fusion devices, and large scientific facilities. In industry, tungsten and tungsten-based composites are mainly prepared by powder metallurgy. The large-scale preparation of large-scale tungsten materials usually adopts pressureless hydrogen sintering, the sintering temperature is higher than 2000℃, and long-term heat preservation is required. For pure tungsten, the grain size control of the sintered body is a key issue; for tungsten-based composites, the size of the matrix grains and the ceramic dispersion-strengthened phase, and the grain boundary segregation of the ceramic phase need to be controlled simultaneously. Specifically, it is found that in oxide dispersion-strengthened tungsten composites, the size and distribution control of the oxide particles significantly affect the subsequent thermoplastic processing performance and the microstructure and mechanical properties of the final material.

[0003] Preparation of raw powders is a key process step for effectively controlling oxide size and distribution. Currently, the main methods for preparing sintered powders are ball milling and wet chemical methods. Wet chemical methods can produce ultrafine powders containing nano-oxide particles. Another process involves preparing oxide- or metal-coated tungsten powder particles. For example, Xu Xiangyang et al. employed a wet chemical reaction method, using ammonium metatungstate and aluminum sulfate as raw materials. After spray pre-freezing and vacuum freeze-drying, they obtained a W / Al mixed salt precursor. From this precursor, they used a stepwise reduction method to obtain an Al2O3-coated composite powder. Chen Wenge et al. used electroless plating to coat tungsten powder with a 0.45μm thick Cu coating. Crystalline coatings of varying thickness have been successfully obtained on tungsten powder surfaces. These tungsten powder coating processes commonly suffer from numerous control parameters, complex production processes, long cycle times, and poor process controllability and reproducibility. Furthermore, the thickness control and microstructure uniformity of the surface coating have not been fully addressed, impacting the sintering performance of the powder.

[0004] Compared with crystalline alloys, amorphous alloys have better uniformity of structure and composition, as well as characteristics such as low melting point and instantaneous melting. If it is used as a coating layer on the surface of tungsten powder, the advantages of liquid phase sintering can be introduced at a lower temperature, which is beneficial to reduce the sintering temperature of tungsten-based material powder and improve the sintering density. This process is different from the powder preparation method described above. The former does not contain a liquid phase sintering process. The inventor has used melt atomization technology to prepare an amorphous coated oxide composite powder material (ZL2022106313269) that can be used for the manufacture of ODS-W alloys, but this technology is mostly suitable for materials with similar specific gravity. Due to the high specific gravity of tungsten (19.25g / cm 3), and metals or alloys with similar specific gravity are refractory materials and difficult to form into an amorphous state. Therefore, the patented technology of ZL2022106313269 cannot be widely applied to the preparation of amorphous coatings on the surface of tungsten-based powder materials. Summary of the Invention

[0005] The purpose of the present invention is to provide a tungsten powder coated with a nano-amorphous layer and a preparation method thereof, so as to solve the following problems existing in the current surface coating modification treatment of tungsten powder: (1) the coating layers are all crystalline, and the crystalline coating layers have a high melting point and poor fluidity, which leads to a high sintering temperature, low density and coarse grains in the subsequent sintered body; (2) the crystalline coating layer composition has a narrow applicability, the coating layer composition and thickness are difficult to accurately control, and the coating layer structure uniformity and reproducibility are poor; (3) the crystalline coating layer has low activity and poor compatibility with the matrix, This can easily lead to problems such as weak interfacial bonding of tungsten grains in sintered bodies; (4) the particle size distribution range of the powder is narrow, and the density and strength of the cold-pressed embryo are insufficient, which is not conducive to the subsequent pressureless hydrogen sintering problem; (5) The tungsten powder coated with a nano-amorphous layer prepared by this patent can be used as a new type of powder metallurgy raw material. During the sintering process, the oxides nucleate and grow in situ in the tungsten matrix, achieving uniform distribution within the grains and grain boundaries; impurities such as oxygen are segregated at the grain boundaries, and the oxide dispersed phase is formed in situ to consume the oxygen adsorbed in the powder, playing a role in purifying the grain boundaries. The pressureless sintering preparation of high-performance and dense ODS-tungsten-based alloy materials is achieved.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A tungsten powder coated with a nano-amorphous layer, that is, the surface of the tungsten powder particles is covered with a layer of amorphous alloy film with a thickness of nanometers. The chemical composition formula of the nano-thick amorphous coating layer is Y 100-a M a , including rare earth metal Y and post-transition metal M. Wherein, M is one or more of Fe, Co, and Ni, 25≤a≤55, which is the atomic percentage composition.

[0008] Furthermore, the thickness of the nano-amorphous coating layer (ie, the alloy film) is between 10 and 30 nm, and the particle size of the tungsten powder can vary in the range of 1 to 15 μm.

[0009] A method for preparing tungsten powder coated with a nano-amorphous layer, the present invention first prepares Y by arc melting combined with melt atomization technology 100-a M a The alloy powder is used as the parent material of the nano-amorphous coating layer; it is then mixed with tungsten powder and subjected to high-energy ball milling in an anhydrous ethanol medium environment. 100-a M aThe alloy is bonded and spread on the surface of the tungsten powder through high-energy ball milling, and amorphization occurs simultaneously, ultimately forming a nanometer-thick amorphous coating on the surface of the tungsten powder particles. When the tungsten powder, coating layer alloy raw materials, and ball milling process are fixed, the thickness of the amorphous coating on the surface of the tungsten powder particles can be controlled by adjusting the amount of coating layer alloy raw materials added. The specific steps are as follows:

[0010] (1) The first step is to prepare the powder parent material of the coating layer

[0011] First, industrial pure metal is used as raw material, and the atomic percentage composition is Y 100-a M a Secondly, the raw materials are mixed and placed in a water-cooled copper crucible of a non-consumable arc melting furnace, and then vacuumed to ≤9×10 -3 Pa, filled with 0.01 ~ 0.02MPa of industrial pure Ar gas for melting, the working current of arc melting is 150 ~ 180A; the alloy is turned upside down and repeatedly melted many times to obtain an alloy ingot with uniform composition, and the weight loss of the alloy before and after melting is one thousandth; then the alloy ingot is crushed and placed in a graphite crucible of a vacuum melting gas atomization powder making device, and heated by medium frequency induction to a certain temperature (slightly higher than Y 100-a M a The mixture is then cooled by spraying (the atomizing gas pressure is 3-10 MPa and the nozzle aperture of the guide rod is 1-2 mm) to obtain a spherical powder material with a controllable particle size ranging from 3 μm to 50 μm.

[0012] (2) The second step is to prepare tungsten powder coated with nano-amorphous layer

[0013] First, based on the particle size of the selected W powder (commercial, commercially available), sieve and select Y with the same size as the tungsten powder. 100-a M a Weigh and mix the alloy powder according to the desired ratio. Then, place it in a ball mill with grinding balls (a material-to-ball ratio of 1:5-1:10) and perform high-energy ball milling in anhydrous ethanol at a speed of 150-200 rpm for 20-40 hours. Finally, remove the milled powder and dry it in a vacuum drying oven for later use.

[0014] The powder obtained in step 2 was observed and characterized using X-ray diffraction (XRD), scanning electron microscopy, and electron microscopy (with energy spectrum accessories). The results showed that the surface of the tungsten particles was covered with an alloy film, which was amorphous and had a composition close to that of Y. 100-a M a The thickness of the amorphous coating layer is between 10 and 30 nm, and the size of the tungsten particles can vary in the range of 1 to 15 μm.

[0015] Application of tungsten powder coated with nano-amorphous layer, the Y 100-a M a Amorphous coated tungsten powder can be used as raw material for the preparation of ODS-tungsten based alloy powder metallurgy, and has broad application prospects in the fields of fusion materials, high temperature wear-resistant materials, etc.

[0016] The beneficial effects of the present invention are:

[0017] (1) The present invention successfully prepared tungsten powder coated with a nanometer-thick amorphous alloy layer;

[0018] (2) By adjusting the amount of coating layer parent material added, an amorphous coating layer of different thicknesses can be obtained on the surface of the tungsten powder particles;

[0019] (3) This nano-amorphous layer-coated tungsten powder material can achieve liquid-solid sintering of tungsten powder materials, significantly reduce the sintering temperature of tungsten materials, significantly improve the density of sintered bodies, and is expected to achieve pressureless sintering of tungsten-based materials. All of these are conducive to improving the production efficiency and overall performance of sintered bodies when preparing tungsten-based materials by powder metallurgy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the nanometer thickness Y in Example 1 60 Fe 40 XRD spectrum of tungsten powder coated with amorphous layer.

[0021] Figure 2 Y in Example 1 60 Fe 40 SEM morphology of tungsten powder coated with amorphous layer ( Figure 2 (a)) and TEM high-resolution image ( Figure 2 (b)). Where, Figure 2 (b) The dashed line above and below are regular striped W grains and disordered Y grains, respectively. 60 Fe 40 Amorphous film layer. DETAILED DESCRIPTION

[0022] The following describes in detail the nano-amorphous layer-coated tungsten powder and its implementation in the present invention. The specific preparation process and application of this powder are described using five typical components as examples.

[0023] Example 1Y 60 Fe 40 Amorphous layer coated tungsten powder

[0024] Step 1: Prepare the parent material powder of the coating layer - Y 60 Fe 40 alloy powder

[0025] Industrial pure Y (> 99.5%) and Fe (> 99.5%) are used as raw materials, and the atomic percentage composition of Y is weighed and prepared. 60 Fe 40 The raw materials are mixed and placed in a water-cooled copper crucible in a non-consumable arc melting furnace, and then vacuumed to 9×10 -3 Pa, filled with 0.01MPa of industrial-pure Ar gas for melting, with an arc melting current of 150A. The alloy was flipped upside down and repeatedly melted four times to obtain an alloy ingot with uniform composition. The weight loss of the alloy before and after melting was one thousandth. Next, the alloy ingot was crushed and placed in a graphite crucible of a vacuum melting gas atomization powder preparation device. The crucible was placed in an induction heating coil, heated to 1000°C, and held at this temperature for 2 minutes. The ingot was then sprayed and cooled using atomization technology (atomizing gas pressure of 3MPa, guide rod nozzle aperture of 2mm), resulting in a nearly spherical powder material with a particle size ranging from 5μm to 30μm.

[0026] Step 2: Preparation of Y 60 Fe 40 Tungsten powder coated with amorphous layer

[0027] Use 1000 mesh and 1340 mesh sieves to separate the Y particles with a particle size of 10-13 μm. 60 Fe 40 The powder was weighed and mixed with commercially available W powder with a particle size of 10-15 μm at a mass ratio of 1:100. The mixed powder and grinding balls (material-to-ball ratio of 1:10) were placed in a ball mill and subjected to high-energy ball milling in anhydrous ethanol medium at a ball mill speed of 180 rpm for 20 hours.

[0028] The powder after high-energy ball milling was taken out and dried in a vacuum drying oven. The powder was observed and characterized by X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy (with energy spectrum attachment). Figure 1 The X-ray diffraction spectrum of the powder shows that its main body is body-centered cubic tungsten, and no other crystal phases are found. Figure 2 (a) The scanning electron microscope (SEM) morphology of the powder is shown, indicating that the particle size of the powder is between 5 and 10 μm. Further transmission electron microscope (TEM) analysis shows that the powder has a shell structure. The main body of the particle is a well-ordered tungsten grain, which is covered with a layer of film with a thickness of about 10 nm and is disordered and amorphous. The atomic percentage composition of the film measured by energy spectrum is close to that of Y 60 Fe 40 Attached Figure 2 (b) shows the TEM high-resolution image of the powder material. The part above the dotted line is crystalline W particles with regular stripes, and the part below the dotted line is disordered Y 60 Fe40 Amorphous film.

[0029] The above results show that the powder finally obtained in this embodiment has a nanometer thickness of Y 60 Fe 40 Tungsten particle powder material coated with amorphous layer, which is a special nano-amorphous layer coated tungsten powder, is made of low melting point Y 60 Fe 40 The alloy becomes amorphous after high-energy ball milling and spreads evenly on the surface of tungsten powder particles.

[0030] Example 2Y 45 Co 55 Amorphous coated tungsten powder

[0031] Step 1: Preparation of Y 45 Co 55 alloy powder

[0032] Industrial pure Y (> 99.5%) and Co (> 99.5%) are used as raw materials, and the atomic percentage composition of Y is weighed and prepared. 45 Co 55 The raw materials are mixed and placed in a water-cooled copper crucible in a non-consumable arc melting furnace, and then vacuumed to 8×10 -3 Pa, filled with 0.02MPa of industrial-pure Ar gas for melting, with an arc melting current of 180A. The alloy was flipped upside down and repeatedly melted four times to obtain an alloy ingot with uniform composition. The weight loss of the alloy before and after melting was one thousandth. Next, the alloy ingot was crushed and placed in a graphite crucible of a vacuum melting gas atomization powder preparation device. The crucible was placed in an induction heating coil, heated to 1050°C, and kept at this temperature for 5 minutes. It was then sprayed and cooled using atomization technology (atomizing gas spray pressure of 10MPa, guide rod nozzle aperture of 2mm), resulting in a spherical powder material with a particle size distribution between 20μm and 50μm.

[0033] Step 2: Preparation of Y 45 Co 55 Amorphous coated tungsten powder

[0034] Use 500 mesh and 800 mesh sieves to separate Y with a particle size of 18 to 25 μm. 45 Co 55 The powder was weighed and mixed with commercially available W powder with a particle size of 15-25 μm at a mass ratio of 1:60. The mixed powder and grinding balls (material-to-ball ratio of 1:5) were placed in a ball mill and subjected to high-energy ball milling in anhydrous ethanol medium at a ball mill speed of 200 rpm for 20 hours.

[0035] The powder after high-energy ball milling was taken out and dried in a vacuum drying oven. The obtained powder was observed and characterized by X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy (with energy spectrum accessories). The XRD results showed that the main body was body-centered cubic tungsten, and no other crystal phases were found. The SEM morphology showed that the particle size of the powder particles was between 10 and 15 μm; TEM analysis showed that the main body of the powder particles was tungsten grains with an orderly structure, which was wrapped with a layer of amorphous alloy film with a thickness of about 20 nm. The measured atomic percentage composition of the film layer was Y 45 Co 55 Nearby. The final product obtained in this embodiment is Y 45 Co 55 Tungsten powder material coated with nano-amorphous layer.

[0036] Example 3Y 65 Ni 35 Amorphous coated tungsten powder

[0037] Step 1: Preparation of Y 65 Ni 35 alloy powder

[0038] Industrial pure Y (> 99.5%) and Ni (> 99.5%) are used as raw materials, and the atomic percentage composition of Y is weighed and prepared. 65 Ni 35 The raw materials are mixed and placed in a water-cooled copper crucible in a non-consumable arc melting furnace, and then vacuumed to 5×10 -3 Pa, filled with 0.01MPa of industrial-pure Ar gas for melting, with an arc melting current of 170A. The alloy was flipped upside down and repeatedly melted four times to obtain an alloy ingot with uniform composition. The weight loss of the alloy before and after melting was one thousandth. Next, the alloy ingot was crushed and placed in a graphite crucible of a vacuum melting gas atomization powder preparation device. The crucible was placed in an induction heating coil, heated to 900°C, and kept at this temperature for 3 minutes. The ingot was then sprayed and cooled using atomization technology (atomizing gas pressure of 10MPa, guide rod nozzle aperture of 1mm), resulting in a spherical powder material with a particle size distribution between 5μm and 25μm.

[0039] Step 2: Preparation of Y 65 Ni 35 Amorphous coated tungsten powder

[0040] Use 1000 mesh and 1340 mesh sieves to separate the Y particles with a particle size of 10-13 μm. 65 Ni 35The powder was weighed and mixed with commercially available W powder with a particle size of 10-15 μm at a mass ratio of 1:20. The mixed powder and grinding balls (material-to-ball ratio of 1:10) were placed in a ball mill and subjected to high-energy ball milling in anhydrous ethanol medium at a speed of 150 rpm for 40 hours.

[0041] The powder after high-energy ball milling was taken out and dried in a vacuum drying oven. The powder was observed and characterized by X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy (with energy spectrum accessories). The XRD results showed that the main body was body-centered cubic tungsten, and no other crystal phases were found. The SEM morphology showed that the particle size of the powder particles was between 3 and 8 μm; further TEM analysis showed that the powder had a shell structure, the main body was tungsten particles, and its surface was covered with a layer of amorphous film with a thickness of about 30 nm. The atomic percentage composition of the film measured by energy spectrum was close to Y 65 Ni 35 This shows that: this embodiment finally obtained Y 65 Ni 35 The nano-amorphous layer is coated with tungsten powder material.

[0042] Example 4Y 75 Fe 12.5 Ni 12.5 Amorphous coated tungsten powder

[0043] Step 1: vacuum atomization to prepare Y 75 Fe 12.5 Ni 12.5 alloy powder

[0044] Industrial pure Y (>99.5%), Fe (>99.5%) and Ni (>99.5%) are used as raw materials, and the atomic percentage composition of Y is weighed and prepared. 75 Fe 12.5 Ni 12.5 The raw materials are mixed and placed in a water-cooled copper crucible in a non-consumable arc melting furnace, and then vacuumed to 6×10 -3 Pa, filled with 0.02MPa of industrial-pure Ar gas for melting, with an arc melting current of 180A. The alloy was flipped upside down and repeatedly melted four times to obtain an alloy ingot with uniform composition. The weight loss of the alloy before and after melting was one thousandth. Next, the alloy ingot was crushed and placed in a graphite crucible of a vacuum melting gas atomization powder preparation device. The crucible was placed in an induction heating coil, heated to 950°C, and kept at this temperature for 5 minutes. It was sprayed and cooled using atomization technology (atomizing gas spray pressure of 10MPa, guide rod nozzle aperture of 1mm), resulting in a spherical powder material with a particle size ranging from 3μm to 15μm.

[0045] Step 2: Preparation of Y 75 Fe12.5 Ni 12.5 Amorphous coated tungsten powder

[0046] Use 1340 mesh to screen out Y particles with a size of less than 10 μm 75 Fe 12.5 Ni 12.5 The powder was weighed and mixed with commercially available W powder with a particle size of 1-5 μm at a mass ratio of 1:50. The mixed powder and grinding balls (material-to-ball ratio of 1:10) were placed in a ball mill and subjected to high-energy ball milling in anhydrous ethanol medium at a ball mill speed of 200 rpm for 35 hours.

[0047] The powder after high-energy ball milling was taken out and dried in a vacuum drying oven. The obtained powder was observed and characterized using X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy (with energy spectrum attachment). The results showed that the particle size of the powder was between 1 and 5 μm, and the main body was tungsten grains with a body-centered cubic structure, which was covered with an amorphous alloy film with a thickness of about 15 nm. The measured amorphous film composition was close to Y 75 Fe 12.5 Ni 12.5 , indicating that this embodiment finally obtains Y 75 Fe 12.5 Ni 12.5 Tungsten powder material coated with nano-amorphous layer.

[0048] Example 5Y 60 Fe 20 Co 10 Ni 10 Amorphous coated tungsten powder

[0049] Step 1: Preparation of Y 60 Fe 20 Co 10 Ni 10 alloy powder

[0050] Industrial pure Y (>99.5%), Fe (>99.5%), Co (>99.5%) and Ni (>99.5%) are used as raw materials, and the atomic percentage composition of Y is weighed and prepared. 60 Fe 20 Co 10 Ni 10 The raw materials are mixed and placed in a water-cooled copper crucible in a non-consumable arc melting furnace, and then vacuumed to 7×10 -3Pa, filled with 0.01MPa of industrial-pure Ar gas for melting, with an arc melting current of 150A. The alloy was flipped upside down and repeatedly melted four times to obtain an alloy ingot with uniform composition. The weight loss of the alloy before and after melting was one thousandth. Next, the alloy ingot was crushed and placed in a graphite crucible of a vacuum melting gas atomization powder preparation device. The crucible was placed in an induction heating coil, heated to 1050°C, and kept at this temperature for 4 minutes. It was sprayed and cooled using atomization technology (atomizing gas spray pressure of 10MPa, guide rod nozzle aperture of 1mm), resulting in a nearly spherical powder material with a particle size distribution between 5μm and 25μm.

[0051] Step 2: Preparation of Y 60 Fe 20 Co 10 Ni 10 Amorphous coated tungsten powder

[0052] Use 1000 mesh and 1340 mesh sieves to separate the Y particles with a particle size of 10-13 μm. 60 Fe 20 Co 10 Ni 10 The powder was weighed and mixed with commercially available W powder with a particle size of 10-15 μm at a mass ratio of 1:30. The mixed powder and grinding balls (material-to-ball ratio of 1:8) were placed in a ball mill and subjected to high-energy ball milling in anhydrous ethanol medium at a speed of 200 rpm for 35 hours.

[0053] The powder after high-energy ball milling was removed and dried in a vacuum drying oven. The obtained powder was observed and characterized using X-ray diffraction (XRD), scanning electron microscopy, and transmission electron microscopy (with energy spectrum accessories). The results showed that the main body of the powder particles was body-centered cubic tungsten, which was covered with an amorphous film with a thickness of about 25nm. The measured atomic percentage composition of the amorphous film was close to that of Y 60 Fe 20 Co 10 Ni 10 ; The overall particle size of the powder is between 3 and 6 μm.

[0054] In order to reveal and verify the technical effect of the amorphous coated W powder provided by the present invention, the present invention uses it as the final powder to prepare ODS-W alloy. Specifically, the tungsten powder obtained in the second step of Example 1 is used to prepare an ODS-tungsten-based alloy sintered body through hot pressing sintering technology. The sintering temperature is 1800°C and the heat preservation is 2h. During the sintering process, the amorphous coating layer melts into a liquid phase, fully filling the gaps between the W powder particles, and Y can adsorb the free O impurities in the tungsten matrix to generate submicron oxides in situ, which plays a role in purifying the grain boundaries. The final density of the ODS-W alloy sintered body is as high as 99%. Further microstructural characterization results show that the grain size of the ODS-W sintered body is between 3 and 6μm, and Y2O3 particles are evenly dispersed in the crystals and on the grain boundaries, and the oxide particle size is between 10 and 60nm. This shows that Y 100-a M a Amorphous-coated tungsten powder facilitates the liquid-solid sintering of tungsten materials, significantly reducing the sintering temperature during powder metallurgy production of tungsten materials, maintaining fine grains, and increasing the density of the sintered body. These advantages contribute to improving the production efficiency and overall performance of tungsten-based materials produced by powder metallurgy. Furthermore, the invention of this new material facilitates the realization of pressureless sintering of tungsten-based materials. This invention can provide a new powder material for the development of ODS-tungsten-based alloys, with broad application prospects in fields such as fusion and high-temperature wear-resistant materials.

[0055] The above-described embodiments merely express the implementation methods of the present invention, but should not be understood as limiting the scope of the patent of the present invention. It should be pointed out that for those skilled in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A method for preparing tungsten powder coated with a nano-amorphous layer, characterized in that: First, a Y 100-a M a The alloy powder is used as the parent material of the nano-amorphous coating layer; it is then mixed with tungsten powder and subjected to high-energy ball milling in anhydrous ethanol medium environment. The ball mill speed is 150~200 rpm and the ball milling time is 20~40h. 100-a M a The alloy is bonded and spread on the surface of the tungsten powder through high-energy ball milling, and amorphization occurs at the same time, eventually forming a nanometer-thick amorphous coating on the surface of the tungsten powder particles. When the tungsten powder, coating layer alloy raw materials and ball milling process are constant, the thickness of the amorphous coating on the surface of the tungsten powder particles can be controlled by adjusting the amount of coating layer alloy raw materials added. The tungsten powder is a tungsten powder particle surface covered with a layer of nanometer-thick amorphous alloy film, and the chemical composition formula of the nanometer-thick amorphous coating layer is Y 100-a M a , including rare earth metal Y and post-transition metal M elements; wherein M is one or more of Fe, Co, and Ni elements, 25≤a≤55, which is the atomic percentage composition.

2. The method for preparing tungsten powder coated with a nano-amorphous layer according to claim 1, characterized in that: The specific steps are as follows: (1) The first step is to prepare the powder parent material of the coating layer First, industrial pure metal is used as raw material, and the atomic percentage composition is Y 100-a M a The raw materials are mixed and placed in a water-cooled copper crucible of a non-consumable arc melting furnace, which is then evacuated and filled with industrial-pure Ar gas for melting. The alloy is flipped upside down and repeatedly melted multiple times to obtain an alloy ingot with uniform composition. The weight loss of the alloy before and after melting is one thousandth. The alloy ingot is then crushed and placed in a graphite crucible of a vacuum melting gas atomization powder making device, where it is heated by medium-frequency induction heating. The ingot is then sprayed out and cooled using atomization technology to obtain a spherical powder material with a controllable particle size ranging from 3 μm to 50 μm. (2) The second step is to prepare tungsten powder coated with nano-amorphous layer First, based on the selected W powder particle size, screen and select Y with the same size as the tungsten powder. 100-a M a The alloy powder is weighed and mixed according to the required proportion; then, it is placed in a ball mill with grinding balls and subjected to high-energy ball milling in an anhydrous ethanol medium environment. The ball mill speed is 150-200 rpm and the ball milling time is 20-40 h. Finally, the ball-milled powder is taken out and dried in a vacuum drying oven for later use.

3. The method for preparing tungsten powder coated with a nano-amorphous layer according to claim 1, characterized in that: The thickness of the nano-amorphous coating layer is between 10 and 30 nm, and the particle size of the tungsten powder varies in the range of 1 to 15 μm.

4. An application of tungsten powder coated with a nano-amorphous layer obtained by the preparation method according to any one of claims 1, 2 or 3, characterized in that: The tungsten powder coated with the nano-amorphous layer is used as a raw material for preparing ODS-tungsten-based alloy powder metallurgy.

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