Preparation method of low-cost tantalum-tungsten alloy powder

Abstract

The invention discloses a low-cost tantalum-tungsten alloy powder preparation method which comprises the following steps: degassing treatment: uniformly mixing superfine tantalum powder and tungsten powder according to a required ratio to obtain mixed powder, putting the obtained mixed powder into degassing equipment, vacuumizing and heating to volatilize gas impurities in the mixed powder and discharging the gas impurities; and isostatic pressing forming is conducted, specifically, the powder obtained after degassing treatment is loaded into a rubber mold sheath, isostatic pressing forming is conducted in a high-pressure environment, the powder is densified, and an obtained formed blank is put into a vacuum sintering furnace to be sintered. According to the method, an effective way for manufacturing low-cost, low-oxygen and low-carbon alloy powder is provided for the refractory metal spherical powder for additive manufacturing, low-grade, high-oxygen and unqualified tantalum-tungsten alloy fine powder waste can be recycled and formed, and the tantalum-tungsten alloy spherical powder reaching or exceeding the industrial standard is produced; the powder preparation production cost is greatly reduced, time and labor are saved, and the working efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of tantalum-tungsten alloy powder preparation, in particular to a method for preparing tantalum-tungsten alloy powder at low cost. Background Art

[0002] Tantalum is the 49th most abundant rare metal on earth. It has a body-centered cubic crystal structure, a high melting point and density, good thermal conductivity, electrical conductivity and biocompatibility, and will not undergo phase change during deformation, recovery and recrystallization in a wide temperature range. Adding tungsten to tantalum can play a good role in solid solution strengthening, forming a tantalum-tungsten solid solution alloy with high strength, and the strength increases significantly with the increase of tungsten content. Tantalum-tungsten alloys are widely used in aerospace, electronics and other fields due to their excellent high temperature strength, corrosion resistance and thermal conductivity.

[0003] With the development of additive manufacturing technology, tantalum-tungsten alloy has realized integrated molding manufacturing technology based on functional design. The preparation of spherical tantalum-tungsten alloy powder, the raw material used in additive manufacturing, is a key process. In China, gas atomization and rotating electrode methods are usually used for preparation. The prepared spherical powder is of poor quality, resulting in low powder sphericity, high oxygen, high carbon, and high hollow powder rate, which cannot meet the needs of additive manufacturing. At the same time, the fine powder waste generated in the additive manufacturing process cannot be recycled, and the manufacturing cost of spherical powder is high and the process is complicated, which limits its large-scale application. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above problems and / or the existing problems in the low-cost tantalum-tungsten alloy powder preparation method, the present invention is proposed.

[0006] Therefore, the problem to be solved by the present invention is how to recycle the fine powder waste generated in the tungsten alloy powder manufacturing process to reduce the manufacturing cost.

[0007] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing low-cost tantalum-tungsten alloy powder, comprising the following steps:

[0008] A. Degassing treatment: Ultrafine tantalum powder and tungsten powder are mixed evenly in the required proportion to obtain a mixed powder, and the obtained mixed powder is placed in a degassing device, vacuumed and heated to volatilize and discharge gas impurities in the mixed powder;

[0009] B. Isostatic pressing: The degassed powder is placed in a rubber mold sleeve and isostatically pressed under high pressure to densify the powder.

[0010] C. Sintering: placing the formed embryo body obtained in step B into a vacuum sintering furnace for sintering to form a hard tantalum-tungsten alloy block;

[0011] D. Vertical melting sintering: The sintered tantalum-tungsten alloy block is placed in a vacuum arc furnace to partially melt the tantalum-tungsten alloy block. The melted part sags under the action of gravity to form a uniform and dense tantalum-tungsten alloy material.

[0012] E. Hydrogenation treatment: The tantalum-tungsten alloy material obtained in step D is placed in a hydrogenation furnace for high-temperature activation treatment, and hydrogen absorption and dehydrogenation are repeated many times to open the hydrogenation channel, so that hydrogen atoms penetrate into the interior of the ingot to cause a continuous hydrogenation reaction until complete hydrogenation and cracking;

[0013] F. Crushing treatment: using a jaw crusher to grade and crush the product after hydrogenation in step E to obtain a coarse powder;

[0014] G. Powder screening: The coarse powder obtained in step F is graded and screened using a gas shielded sieve to screen out non-spherical powder with a particle size of 15 to 63 μm;

[0015] H. Dehydrogenation and oxygen reduction treatment: the non-spherical powder obtained in step G is subjected to a dehydrogenation heat treatment under vacuum, and then magnesium powder is added to the product after the dehydrogenation heat treatment to perform an oxygen reduction heat treatment;

[0016] I. Acid washing: The alloy powder treated in step H is placed in a drum mixer, and HCI and water are added for pickling. During the pickling process, the drum is continuously rotated to ensure that the alloy powder is fully in contact with the acid solution to achieve the purpose of removing impurities and oxidation. After the pickling is completed, the alloy powder is rinsed with pure water, filtered and dried;

[0017] J. Powder spheroidization: The product after the treatment in step I is placed in a plasma spheroidization device, and the plasma spheroidization device shapes the powder to obtain a tantalum-tungsten alloy powder product with an oxygen content of ≤300ppm, a carbon content of ≤80ppm, and a particle size distribution of 15 to 53um.

[0018] As a preferred solution of the low-cost tantalum-tungsten alloy powder preparation method of the present invention, wherein: in step A, the amount of tantalum powder is 85-95wt%, the amount of tungsten powder is 5-15wt%, the pressure value of the vacuum pumping of the degassing equipment is 0.9-1.6MPa, the degassing equipment is heated from 0 to 600°C for 90min, kept at 600°C for 60min, heated from 600 to 930°C for 90min, kept at 930°C for 240min, and then the degassing equipment is cooled to 40°C and taken out of the furnace

[0019] As a preferred solution of the method for preparing low-cost tantalum-tungsten alloy powder of the present invention, the pressure value of the isostatic pressing in step B is 150-210 MPa, and the pressure is maintained for 10 minutes.

[0020] As a preferred solution of the low-cost tantalum-tungsten alloy powder preparation method of the present invention, wherein: in the step C, the sintering temperature is 1650-1950° C., and the holding time is 240-840 min.

[0021] As a preferred solution of the low-cost tantalum-tungsten alloy powder preparation method of the present invention, wherein: in the step D, the vertical melting sintering temperature is 2200-2600° C., and the holding time is 240-720 min.

[0022] As a preferred scheme of the low-cost tantalum-tungsten alloy powder preparation method described in the present invention, wherein: in step E, the hydrogenation furnace is heated to 500-800°C for 60 minutes, hydrogen pressure of 160-190 MPa is passed, and the temperature is maintained at 800°C for 600-800 minutes, and then the temperature is reduced to absorb hydrogen, and the temperature is reduced to 800-100°C for 3100-3500 minutes.

[0023] As a preferred embodiment of the low-cost tantalum-tungsten alloy powder preparation method of the present invention, the dehydrogenation and deoxidation heat treatment temperature in step H is 700-920°C, heating at 0-400°C for 120 min, heating at 400-500°C for 60 min, heating at 500-750°C for 120 min, heating at 750-800°C for 120 min, and heating at 800-920°C for 60 min.

[0024] As a preferred scheme of the low-cost tantalum-tungsten alloy powder preparation method described in the present invention, wherein: in the step I, the volume ratio of HCl (36% to 38%): water is 1: (1.5 to 2), the drum pickling time is 120 to 180 minutes, and the conductivity of the product after pure water rinsing, filtration and drying is less than 5uS / cm.

[0025] The beneficial effects of the present invention are: it provides an effective way to manufacture low-cost, low-oxygen, low-carbon alloy powder for refractory metal spherical powder for additive manufacturing, and can recycle and reuse low-grade, high-oxygen, unqualified tantalum-tungsten alloy fine powder waste to produce tantalum-tungsten alloy spherical powder that meets or exceeds industry standards, greatly reducing the production cost of powder preparation, saving time and labor, and improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0027] Figure 1 The figure is a flow chart of the method for preparing low-cost tantalum-tungsten alloy powder. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0030] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0031] Example 1

[0032] Reference Figure 1, which is the first embodiment of the present invention, and provides a low-cost tantalum-tungsten alloy powder preparation method, comprising the following steps: uniformly mixing ultrafine tantalum powder and tungsten powder in a desired proportion to obtain a mixed powder, placing the obtained mixed powder into a degassing device, evacuating and heating to volatilize and discharge gas impurities in the mixed powder, placing the degassed powder into a rubber mold sleeve, and isostatically pressing the powder under high pressure to densify the powder, placing the obtained molded embryo into a vacuum sintering furnace for sintering to form a hard tantalum-tungsten alloy block, placing the obtained tantalum-tungsten alloy block in a vacuum arc furnace, partially melting the tantalum-tungsten alloy block, and allowing the melted part to sag under gravity to form a uniform and dense tantalum-tungsten alloy material, placing the obtained tantalum-tungsten alloy material in a hydrogenation furnace for high-temperature activation treatment, and repeatedly performing hydrogen absorption and dehydrogenation three times to open the hydrogenation channel, so that hydrogen atoms penetrate into the interior of the ingot to cause it to undergo sustained The hydrogenation reaction is continued until the hydrogenation cracking is completely completed. The hydrogenation product is graded and crushed by a jaw crusher to obtain a coarse powder. The coarse powder is graded and screened by a gas protection screen to screen out a non-spherical powder with a particle size of 15um. The obtained non-spherical powder is subjected to a dehydrogenation heat treatment under vacuum. Then, magnesium powder is added to the product after the dehydrogenation heat treatment to perform an oxygen reduction heat treatment. The alloy powder after the dehydrogenation and oxygen reduction treatment is placed in a drum mixer, and HCI and water are added for pickling. During the pickling process, the drum is continuously rotated to ensure that the alloy powder is fully in contact with the acid solution to achieve the purpose of removing impurities and oxidation. After the pickling is completed, the alloy powder is rinsed with pure water, filtered and dried, and the treated product is placed in a plasma spheroidizing device. The plasma spheroidizing device shapes the powder to obtain a tantalum-tungsten alloy powder product with an oxygen content of 300ppm, a carbon content of 80ppm, and a particle size distribution of 15um.

[0033] Example 2

[0034] Reference Figure 1 , which is the second embodiment of the present invention. This embodiment is based on the previous embodiment, and the following steps are added: in step A, the amount of tantalum powder is 85-95wt%, the amount of tungsten powder is 5-15wt%, the pressure value of the vacuum pumping of the degassing equipment is 0.9-1.6MPa, the degassing equipment is heated at 0-600℃ for 90min, kept at 600℃ for 60min, heated at 600-930℃ for 90min, kept at 930℃ for 240min, and then the degassing equipment is cooled to 40℃ and taken out of the furnace.

[0035] First, ultrafine tantalum powder and tungsten powder are mixed evenly in a ratio of 85wt% tantalum powder and 15wt% tungsten powder to obtain a mixed powder. The obtained mixed powder is placed in a degassing device. The vacuum pressure value of the degassing device is 0.9MPa. The degassing device is heated from 0 to 600°C for 90min, kept at 600°C for 60min, heated from 600 to 930°C for 90min, and kept at 930°C for 240min to volatilize and discharge gas impurities in the mixed powder. Then the degassing device is cooled to 40°C and discharged. The degassed powder is placed in a rubber mold sleeve and isostatically pressed under high pressure to densify the powder. The formed embryo is placed in a vacuum sintering furnace for sintering to form a hard tantalum-tungsten alloy block. The obtained tantalum-tungsten alloy block is placed in a vacuum arc furnace to partially melt the tantalum-tungsten alloy block. The melted part sags under gravity to form a uniform and dense tantalum-tungsten alloy material. The obtained tantalum-tungsten alloy material is placed in a hydrogenation furnace for high-temperature activation treatment, which is repeated four times. Hydrogen absorption and dehydrogenation are performed to open the hydrogenation channel. Hydrogen atoms penetrate into the ingot to cause a continuous hydrogenation reaction until it is completely hydrogenated and cracked. A jaw crusher is used to grade and crush the hydrogenated product to obtain a coarse powder. A gas protection screen is used to grade and screen the obtained coarse powder to screen out a non-spherical powder with a particle size of 15um. The obtained non-spherical powder is subjected to a dehydrogenation heat treatment under vacuum, and then magnesium powder is added to the product after the dehydrogenation heat treatment to perform an oxygen reduction heat treatment. The alloy powder after the dehydrogenation and oxygen reduction treatment is placed in a drum mixer, and HCI and water are added for pickling. During the pickling process, the drum rotates continuously to ensure that the alloy powder is fully in contact with the acid solution to achieve the purpose of removing impurities and oxidation. After the pickling is completed, the alloy powder is rinsed with pure water, filtered and dried, and the treated product is placed in a plasma spheroidizing device. The plasma spheroidizing device shapes the powder to obtain a tantalum-tungsten alloy powder product with an oxygen content of 250ppm, a carbon content of 80ppm, and a particle size distribution of 15um.

[0036] Example 3

[0037] Reference Figure 1 , which is the third embodiment of the present invention. This embodiment is based on the previous embodiment, and adds the following steps: the pressure value of the isostatic pressing in step B is 150-210MPa, and the pressure is maintained for 10min; the sintering temperature in step C is 1650-1950℃, and the holding time is 240-840min; the vertical melting sintering temperature in step D is 2200-2600℃, and the holding time is 240-720min.

[0038] First, ultrafine tantalum powder and tungsten powder are mixed evenly in a ratio of 90wt% tantalum powder and 10wt% tungsten powder to obtain a mixed powder. The obtained mixed powder is placed in a degassing device. The vacuum pressure value of the degassing device is 1MPa. The degassing device is heated from 0 to 600°C for 90min, kept at 600°C for 60min, heated from 600 to 930°C for 90min, and kept at 930°C for 240min to volatilize and discharge gas impurities in the mixed powder. Then, the degassing device is cooled to 40°C and taken out of the furnace. The degassed powder is placed in a rubber mold sleeve. The isostatic pressing pressure is 150MPa, and the pressure is maintained for 10 minutes. The isostatic pressing is performed under high pressure to densify the powder. The formed embryo is placed in a vacuum sintering furnace for sintering. The sintering temperature is 1650℃ and the holding time is 240min. The embryo forms a hard tantalum-tungsten alloy block. The obtained tantalum-tungsten alloy block is placed in a vacuum arc furnace. The temperature of the vacuum arc furnace is 2200℃ and the holding time is 240min. The tantalum-tungsten alloy block is partially melted. The melted part sags under gravity to form a uniform and dense Tantalum-tungsten alloy material, the obtained tantalum-tungsten alloy material is placed in a hydrogenation furnace for high-temperature activation treatment, and hydrogen absorption and dehydrogenation are repeated three times to open the hydrogenation channel, and the hydrogen atoms penetrate into the ingot to cause a continuous hydrogenation reaction until it is completely hydrogenated and cracked, and the hydrogenated product is graded and crushed by a jaw crusher to obtain a coarse powder, and the obtained coarse powder is graded and screened by a gas protection screen to screen out a 15um particle size non-spherical powder, and the obtained non-spherical powder is subjected to dehydrogenation heat treatment under vacuum, and then magnesium powder is added to the product after dehydrogenation heat treatment. Oxygen reduction heat treatment: the alloy powder after dehydrogenation and oxygen reduction treatment is placed in a drum mixer, and HCI and water are added for pickling. During the pickling process, the drum rotates continuously to ensure that the alloy powder is fully in contact with the acid solution to achieve the purpose of removing impurities and oxidation. After the pickling is completed, the alloy powder is rinsed with pure water, filtered and dried, and the treated product is placed in a plasma spheroidizing device. The plasma spheroidizing device shapes the powder to obtain a tantalum-tungsten alloy powder product with an oxygen content of 100ppm, a carbon content of 40ppm, and a particle size distribution of 60um.

[0039] Example 4

[0040] Reference Figure 1 , which is the fourth embodiment of the present invention. This embodiment is based on the previous embodiment, and the following steps are added: Step E: the hydrogenation furnace is heated to 500-800°C for 60 minutes, hydrogen pressure of 160-190 MPa is passed, and the temperature is kept at 800°C for 600-800 minutes, then the temperature is lowered to absorb hydrogen, and the temperature is lowered to 800-100°C for 3100-3500 minutes.

[0041] First, ultrafine tantalum powder and tungsten powder are mixed evenly in a ratio of 95wt% tantalum powder and 5wt% tungsten powder to obtain a mixed powder. The obtained mixed powder is placed in a degassing device. The pressure value of the vacuum pumping of the degassing device is 1.2MPa. The degassing device is heated from 0 to 600°C for 90min, kept at 600°C for 60min, heated from 600 to 930°C for 90min, and kept at 930°C for 240min to volatilize and discharge gas impurities in the mixed powder. Then, the degassing device is cooled to 40°C and taken out of the furnace. The degassed powder is placed in a rubber mold sleeve. The pressure value of isostatic pressing is 170MPa. a. Maintain the pressure for 10 minutes and perform isostatic pressing under high pressure to densify the powder. Place the formed embryo body in a vacuum sintering furnace for sintering at a temperature of 1800°C for 400 minutes to form a hard tantalum-tungsten alloy block. Place the obtained tantalum-tungsten alloy block in a vacuum arc furnace at a temperature of 2400°C for 500 minutes to partially melt the tantalum-tungsten alloy block. The melted part sags under gravity to form a uniform and dense tantalum-tungsten alloy material. Place the obtained tantalum-tungsten alloy material in a hydrogenation furnace for high-temperature activation treatment. The furnace is heated to 500-800℃ for 60min, hydrogen pressure of 160MPa is passed, and the temperature is kept at 800℃ for 600min, then the temperature is lowered to absorb hydrogen, and the temperature is lowered to 800-100℃ for 3100min. The hydrogen absorption and dehydrogenation are repeated five times to open the hydrogenation channel. The hydrogen atoms penetrate into the ingot to cause a continuous hydrogenation reaction until it is completely hydrogenated and cracked. The hydrogenated product is graded and crushed by a jaw crusher to obtain a coarse powder. The obtained coarse powder is graded and screened by a gas protection screen to screen out a non-spherical powder with a particle size of 15um. The obtained non-spherical powder is subjected to dehydrogenation heat treatment under vacuum, and then Magnesium powder is added to the product after dehydrogenation heat treatment to carry out oxygen reduction heat treatment. The alloy powder after dehydrogenation and oxygen reduction treatment is placed in a drum mixer, and HCI and water are added for pickling. During the pickling process, the drum rotates continuously to ensure that the alloy powder is fully in contact with the acid solution to achieve the purpose of removing impurities and oxidation. After the pickling is completed, the alloy powder is rinsed with pure water, filtered and dried, and the treated product is placed in a plasma spheroidizing device. The plasma spheroidizing device shapes the powder to obtain a tantalum-tungsten alloy powder product with an oxygen content of 150ppm, a carbon content of 60ppm, and a particle size distribution of 50um.

[0042] Example 5

[0043] Reference Figure 1, which is the fifth embodiment of the present invention. This embodiment is based on the previous embodiment, and the following steps are added: in step H, the dehydrogenation and oxygen reduction heat treatment temperature is 700-920°C, heating at 0-400°C for 120min, heating at 400-500°C for 60min, heating at 500-750°C for 120min, heating at 750-800°C for 120min, and heating at 800-920°C for 60min. In step I, the volume ratio of HCl (36%-38%): water is 1:(1.5-2), the drum pickling time is 120-180min, and the conductivity of the product after pure water rinsing, filtration and drying is less than 5uS / cm.

[0044] First, ultrafine tantalum powder and tungsten powder are mixed evenly in a ratio of 95wt% tantalum powder and 5wt% tungsten powder to obtain a mixed powder. The obtained mixed powder is placed in a degassing device. The vacuum pressure value of the degassing device is 1.6MPa. The degassing device is heated from 0 to 600°C for 90min, kept at 600°C for 60min, heated from 600 to 930°C for 90min, and kept at 930°C for 240min to volatilize and discharge gas impurities in the mixed powder. Then, the degassing device is cooled to 40°C and taken out of the furnace. The degassed powder is placed in a rubber mold sleeve. The isostatic pressing pressure value is 210MPa, and the pressure is maintained for 10min. The isostatic pressing is performed under high pressure to densify the powder. The embryo is placed in a vacuum sintering furnace for sintering at a temperature of 1950°C and a holding time of 840 minutes to form a hard tantalum-tungsten alloy block. The obtained tantalum-tungsten alloy block is placed in a vacuum arc furnace at a temperature of 2600°C and a holding time of 720 minutes to partially melt the tantalum-tungsten alloy block. The melted part sags under gravity to form a uniform and dense tantalum-tungsten alloy material. The obtained tantalum-tungsten alloy material is placed in a hydrogenation furnace for high-temperature activation treatment. The hydrogenation furnace is heated at 500-800°C for 60 minutes, and a hydrogen pressure of 190MPa is passed. The temperature is kept at 800°C for 600 minutes, and then the temperature is lowered to absorb hydrogen. The temperature is lowered at 800-100°C for 3500 minutes, and the hydrogen absorption and dehydrogenation are repeated five times. , to open the hydrogenation channel, hydrogen atoms penetrate into the ingot to make it undergo a continuous hydrogenation reaction until it is completely hydrogenated and cracked, a jaw crusher is used to grade and crush the hydrogenated product to obtain a coarse powder, a gas protection screen is used to grade and screen the obtained coarse powder, and a non-spherical powder with a particle size of 15um is screened out, and the obtained non-spherical powder is subjected to dehydrogenation heat treatment under vacuum, and then magnesium powder is added to the product after the dehydrogenation heat treatment for oxygen reduction heat treatment, the dehydrogenation and oxygen reduction heat treatment temperature is 700-920°C, 0-400°C heating for 120min, 400-500°C heating for 60min, 500-750°C heating for 120min, 750-800°C heating for 120min, 800-920°C heating 60min, the alloy powder after dehydrogenation and oxygen reduction treatment is placed in a drum mixer, HCI and water are added for pickling, the volume ratio of 36% HCI: water is 1:1.5, the drum pickling time is 120min, and the conductivity of the product after pure water rinsing, filtration and drying is 4uS / cm. During the pickling process, the drum rotates continuously to ensure that the alloy powder is fully in contact with the acid solution to achieve the purpose of removing impurities and oxidation. After the pickling is completed, the alloy powder is rinsed with pure water, filtered and dried, and the treated product is placed in a plasma spheroidizing device, which shapes the powder to obtain a tantalum-tungsten alloy powder product with an oxygen content of 200ppm, a carbon content of 70ppm, and a particle size distribution of 25um.

[0045] Through degassing treatment, the gas molecules adsorbed on the surface of fine powder, such as oxygen, nitrogen and water vapor, are effectively removed. If these gases are not effectively removed before sintering, the residual gas may cause the material density to decrease, the mechanical properties to decrease, and the electrical conductivity to deteriorate. It will react chemically with the powder at high temperature to produce oxides or other impurity phases, thereby affecting the performance of the alloy. Therefore, the degassing treatment of tantalum-tungsten alloy fine powder is a key step to improve the quality of the final product. Through the isostatic pressing step, the pressure is evenly transmitted using the principle of fluid mechanics to ensure that the density of the formed part is uniform and there are no internal defects. Through the sintering process, the bonding between the powder particles is gradually strengthened, and finally a hard tantalum-tungsten alloy block is formed. The core of vertical melting sintering lies in the strict control of temperature and time. During the heating process, extremely high temperatures must be reached to melt it, and maintaining temperature stability is the key to ensuring product quality. The advantage of the vertical melting sintering process of tantalum-tungsten alloy is that it can significantly improve the density and consistency of the material. Vertical melting sintering can effectively solve the problems of porosity and unevenness in the traditional sintering process. The internal pores are eliminated by melting and sagging, ensuring the high density and excellent mechanical properties of the material. The spherical powder after hydrogenation, crushing, screening, dehydrogenation and oxygen reduction, acid washing and powder spheroidization can meet the use requirements, and the recycling of 3D printing tantalum, tantalum niobium and their alloy waste materials not only reduces costs, but also effectively solves the problems of resource waste and environmental pollution.

[0046] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for preparing low-cost tantalum-tungsten alloy powder, characterized in that: The following steps are involved: A. Degassing treatment: Ultrafine tantalum powder and tungsten powder are mixed evenly in the required proportion to obtain a mixed powder, and the obtained mixed powder is placed in a degassing device, vacuumed and heated to volatilize and discharge gas impurities in the mixed powder; B. Isostatic pressing: The degassed powder is placed in a rubber mold sleeve and isostatically pressed under high pressure to densify the powder. C. Sintering: placing the formed embryo body obtained in step B into a vacuum sintering furnace for sintering to form a hard tantalum-tungsten alloy block; D. Vertical melting sintering: The sintered tantalum-tungsten alloy block is placed in a vacuum arc furnace to partially melt the tantalum-tungsten alloy block. The melted part sags under the action of gravity to form a uniform and dense tantalum-tungsten alloy material. E. Hydrogenation treatment: The tantalum-tungsten alloy material obtained in step D is placed in a hydrogenation furnace for high-temperature activation treatment, and hydrogen absorption and dehydrogenation are repeated many times to open the hydrogenation channel, so that hydrogen atoms penetrate into the interior of the ingot to cause a continuous hydrogenation reaction until complete hydrogenation and cracking; F. Crushing treatment: using a jaw crusher to grade and crush the product after hydrogenation in step E to obtain a coarse powder; G. Powder screening: The coarse powder obtained in step F is graded and screened using a gas shielded sieve to screen out non-spherical powder with a particle size of 15 to 63 μm; H. Dehydrogenation and oxygen reduction treatment: the non-spherical powder obtained in step G is subjected to a dehydrogenation heat treatment under vacuum, and then magnesium powder is added to the product after the dehydrogenation heat treatment to perform an oxygen reduction heat treatment; I. Acid washing: The alloy powder treated in step H is placed in a drum mixer, and HCI and water are added for pickling. During the pickling process, the drum is continuously rotated to ensure that the alloy powder is fully in contact with the acid solution to achieve the purpose of removing impurities and oxidation. After the pickling is completed, the alloy powder is rinsed with pure water, filtered and dried; J. Powder spheroidization: The product after the treatment in step I is placed in a plasma spheroidization device, and the plasma spheroidization device shapes the powder to obtain a tantalum-tungsten alloy powder product with an oxygen content of ≤300ppm, a carbon content of ≤80ppm, and a particle size distribution of 15 to 53um.

2. The method for preparing low-cost tantalum-tungsten alloy powder according to claim 1, characterized in that: In step A, the amount of tantalum powder is 85-95wt%, the amount of tungsten powder is 5-15wt%, the vacuum pressure of the degassing equipment is 0.9-1.6MPa, the degassing equipment heats up at 0-600°C for 90min, keeps at 600°C for 60min, heats up at 600-930°C for 90min, keeps at 930°C for 240min, then cools down to 40°C and takes out of the furnace.

3. The method for preparing low-cost tantalum-tungsten alloy powder according to claim 1, characterized in that: The pressure value of the isostatic pressing in step B is 150-210 MPa, and the pressure is maintained for 10 minutes.

4. The method for preparing low-cost tantalum-tungsten alloy powder according to claim 1, characterized in that: In the step C, the sintering temperature is 1650-1950° C., and the holding time is 240-840 minutes.

5. The method for preparing low-cost tantalum-tungsten alloy powder according to claim 1, characterized in that: In the step D, the vertical melting sintering temperature is 2200-2600° C., and the heat preservation time is 240-720 minutes.

6. The method for preparing low-cost tantalum-tungsten alloy powder according to claim 1, characterized in that: In step E, the hydrogenation furnace is heated to 500-800°C for 60 minutes, hydrogen pressure of 160-190 MPa is passed, the temperature is maintained at 800°C for 600-800 minutes, and then the temperature is lowered to absorb hydrogen, and the temperature is lowered to 800-100°C for 3100-3500 minutes.

7. The method for preparing low-cost tantalum-tungsten alloy powder according to claim 1, characterized in that: The dehydrogenation and oxygen reduction heat treatment temperature in step H is 700-920° C., heating at 0-400° C. for 120 min, heating at 400-500° C. for 60 min, heating at 500-750° C. for 120 min, heating at 750-800° C. for 120 min, and heating at 800-920° C. for 60 min.

8. The method for preparing low-cost tantalum-tungsten alloy powder according to claim 1, characterized in that: In step I, the volume ratio of HCI (36% to 38%) to water is 1: (1.5 to 2), the drum pickling time is 120 to 180 minutes, and the conductivity of the product after pure water washing, filtration and drying is less than 5uS / cm.

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