Tantalum powder and method for preparing same

Abstract

Tantalum powder, comprising pure tantalum powder or tantalum alloy powder, wherein the particle size distribution of the tantalum powder has the following characteristics: (1) Dv90 < 5 μm; and (2) Dv10 > 0.5 μm. The tantalum powder has a narrow particle size distribution and does not contain nanoscale ultrafine particles, and has high stability and a high utilization rate. The present invention further relates to a method for preparing tantalum powder.

Description

A tantalum powder and its preparation method

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411186700.4, filed on August 27, 2024, entitled “A Tantalum Powder and a Method for Preparing the Same”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of rare metal technology, specifically to a tantalum powder and its preparation method. Background Technology

[0004] Ultrafine tantalum powder, with its superior physicochemical properties such as high strength, high specific surface area, high dispersibility, excellent electrical insulation, and resistance to liquid metals and acid / alkali corrosion, has become one of the main raw materials for sputtering targets. Low-oxygen, high-purity, ultrafine tantalum powder is in high demand in the manufacturing fields of integrated circuits, dielectric materials, and optical components. Currently, taking tantalum-silicon alloy targets as an example, these targets are mainly made from tantalum powder through powder metallurgy. The more uniform and fine the grains in the target, the better it is to obtain a uniform and dense thin film. However, the thermal sintering process of powder metallurgy does not refine the grains, therefore, the desired grain size must be obtained from the beginning, which places high demands on the quality of the tantalum powder.

[0005] Typically, particle size distribution, particle morphology, and impurity content are used to evaluate the quality of metallurgical-grade tantalum powder. Tantalum powder prepared by chemical methods, such as sodium-reduced tantalum powder, consists of coral-like porous aggregates formed by numerous primary particles, making it difficult to disperse into individual particles. Therefore, it exhibits a wide particle size distribution and a polydisperse distribution. Physical methods, such as hydrogenating high-purity tantalum raw materials followed by ball milling and post-processing, yield high-purity solid granular powder. However, this method also results in a wide particle size distribution, requiring further classification to achieve a more concentrated particle size distribution to meet requirements. Consequently, powder utilization is low and costs are relatively high.

[0006] Chinese patent application CN103447544A discloses a method for preparing high-purity tantalum powder with a concentrated and controllable particle size distribution. The resulting tantalum powder has an oxygen content of 620 ppm, but the particle size is relatively coarse, ranging from 10 μm to 100 μm. Chinese patent application CN1223695A discloses a technical solution that can control the size of tantalum powder within certain limits, obtaining pulverized clumps with a size of 0.01 μm to 20 μm. The "ultrafine particles" with a particle size of less than 100 nm have high surface energy and oxygen content, making them prone to ignition during processing and posing a significant safety hazard. Summary of the Invention

[0007] This application provides a tantalum powder and its preparation method to obtain ultrafine tantalum powder with narrow particle size distribution while improving the utilization rate of tantalum powder.

[0008] The first aspect of this application provides a tantalum powder, which includes pure tantalum powder or tantalum alloy powder, and the particle size distribution of the tantalum powder has the following characteristics: (1) Dv90 < 5 μm, preferably Dv90 < 4.7 μm; (2) Dv10 > 0.5 μm, preferably Dv10 > 0.9 μm.

[0009] In any embodiment of the first aspect, the Dv50 particle size of the tantalum powder is between 1.5 μm and 3 μm.

[0010] In any embodiment of the first aspect, the oxygen content of the tantalum powder is less than or equal to 5000 ppm, preferably less than or equal to 4000 ppm.

[0011] In any embodiment of the first aspect, the BET specific surface area of ​​the tantalum powder is less than or equal to 1.5 m². 2 / g.

[0012] The second aspect of this application provides a method for preparing tantalum powder, comprising: hydrogenating a tantalum metal raw material to obtain a tantalum metal hydride TaH. x More than 99% of the tantalum metal raw materials are hydrogenated into tantalum metal hydride TaH. x ; tantalum hydride TaH x Crushing and grinding are carried out; among which, tantalum metal hydride TaH x The value of x is 0.9 to 1.0, preferably 0.9 to 0.97.

[0013] In any embodiment of the second aspect, the above-described process of hydrogenating tantalum metal raw material includes: step S1, placing the tantalum metal raw material in a hydrogenation container, heating the hydrogenation container to temperature T0 and holding it at that temperature for time t0 to obtain hot tantalum metal, where 300℃≤T0≤500℃ and 0.5h≤t0≤5h; step S2, introducing hydrogen gas into the hydrogenation container and heating the hydrogenation container from temperature T0 to temperature T1, and holding it at temperature T1 for time t1 to obtain initial hydrogenation. For the bulk material, the temperature is 700℃≤T1≤1000℃, and the temperature is 0.5h≤t1≤10h; Step S3: While maintaining the hydrogen flow, the hydrogenation container is cooled in a stepped manner, with the first step temperature being T' and the last step temperature being T”, 200℃≤T'≤400℃, and 60℃≤T”≤200℃, preferably 60℃≤T”≤100℃; Step S4: While maintaining the hydrogen flow, the hydrogenation container is cooled to the cavitation temperature T. end Afterwards, the hydrogen gas flow was stopped, and tantalum metal hydride TaH was obtained. x T end ≤60℃.

[0014] In any embodiment of the second aspect, the aforementioned tantalum metal raw material is pure tantalum or a tantalum alloy with the surface oxide film removed.

[0015] In any embodiment of the second aspect, the hydrogen pressure inside the hydrogenation container in steps S2 to S4 is 0.05 to 0.2 MPa.

[0016] In any embodiment of the second aspect, step S3 of hydrogenating the tantalum metal raw material includes: step S31, cooling the hydrogenation container to a first step temperature T' while maintaining hydrogen gas supply, and holding it at the first step temperature T' for a time t' to obtain an intermediate hydrogenated block, 0.5h≤t'≤10h; optional step S32, cooling the hydrogenation container to a temperature T2 while maintaining hydrogen gas supply, and holding it at the temperature T2 for a time t2, 100℃≤T2≤300℃, 0.5h≤t2≤10h; step S33, cooling the hydrogenation container to a final step temperature T” while maintaining hydrogen gas supply, and holding it at the final step temperature T' for a time t” to obtain tantalum metal hydride TaH. x Precursor, 0.5h≤t”≤10h.

[0017] Preferably, the cooling rate in steps S31 to S33 is 40℃ / h to 80℃ / h.

[0018] In any embodiment of the second aspect, crushing and grinding includes: processing tantalum metal hydride TaH x The tantalum hydride powder is obtained by crushing and screening. The mass of the tantalum hydride powder is tantalum metal hydride TaH. x The purity of the tantalum hydride powder is 95% to 99.9%; the tantalum hydride powder is acid-washed to remove impurities, and then the impurity-removed tantalum hydride powder is dehydrogenated and deoxygenated to obtain the tantalum powder product.

[0019] In any embodiment of the second aspect, tantalum metal hydride TaH x The process of crushing and screening to obtain tantalum hydride powder includes the crushing and screening of tantalum metal hydride TaH x The process involves mechanical crushing, primary screening, and secondary crushing.

[0020] In any embodiment of the second aspect, the above-mentioned secondary crushing method includes wet stirred ball milling or air jet milling.

[0021] In any embodiment of the second aspect, the wet stirred ball mill satisfies one or more of the following conditions: (1) the grinding media balls of the wet stirred ball mill are tantalum balls, preferably tantalum balls with a diameter of 0.3 to 3 mm, and more preferably tantalum balls with a diameter of 0.5 to 2 mm; (2) the dispersion medium used in the wet stirred ball mill includes ethanol; (3) the ball milling time is 6 to 9 hours; and (4) the grinding aid includes one or more of oleic acid, cyclohexanol, and polyethylene glycol.

[0022] In any embodiment of the second aspect, the process of dehydrogenating and deoxygenating the tantalum hydride powder includes: step A1, heating a mixture comprising the tantalum hydride powder and magnesium shavings to an oxygen deoxygenation temperature T under an inert gas atmosphere. A And at the deoxygenation temperature T A The lower part is insulated, and the insulation time is t. A Step A2: Under vacuum conditions, continue to keep the above mixture at a constant temperature and perform evacuation to remove magnesium for a duration of t. B Step A3: Cool the mixture to the passivation temperature T. C Air is introduced into the reaction vessel for a duration of t. C This yields tantalum powder that has undergone dehydrogenation and oxygen reduction.

[0023] In any embodiment of the second aspect, the process of dehydrogenating and deoxygenating the tantalum hydride powder satisfies one or more of the following conditions: (1) deoxygenation temperature T A (1) Temperature range: 700℃~900℃; (2) Insulation time: t A (3) Evacuation and magnesium removal time t B (3) Passivation temperature T C ≤30℃; (5) Inflation duration t C (6) The amount of magnesium chips used is 1.5% to 5% by weight.

[0024] In any embodiment of the second aspect, the acid used for pickling and impurity removal includes one or more of sulfuric acid, nitric acid, hydrochloric acid, and hydrofluoric acid.

[0025] Any of the tantalum powders in the first aspect of this application can be prepared by the preparation method provided in the second aspect of this application.

[0026] The tantalum powder provided in this application does not include nano-sized ultrafine particles. The tantalum powder particles are not prone to agglomeration, exhibiting high stability and a concentrated volumetric particle size distribution. Subsequent applications do not require particle size screening, and metal films with uniform grain size can be obtained, resulting in high powder utilization. The tantalum powder product possessing these characteristics is achieved through precise control and overall improvement of tantalum metal raw materials and preparation processes. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of this application, the accompanying drawings used in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. The drawings described herein are used to provide a further understanding of this application and constitute a part of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and not to limit it. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] In the attached diagram:

[0029] Figure 1 shows the tantalum metal hydride TaH obtained in Example 1 of this application. 0.93 XRD pattern.

[0030] Figure 2 shows the tantalum metal hydride TaH obtained in Comparative Example 1 of this application. 0.5 XRD pattern.

[0031] Figure 3 shows the volume particle size distribution curve of the tantalum powder sample obtained in Example 1 of this application.

[0032] Figure 4 shows the volume particle size distribution curve of the tantalum powder sample obtained in Example 2 of this application.

[0033] Figure 5 shows the volume particle size distribution curve of the tantalum powder sample obtained in Example 3 of this application.

[0034] Figure 6 shows the volumetric particle size distribution curve of the tantalum powder sample obtained in Comparative Example 1 of this application.

[0035] Figure 7 shows the volumetric particle size distribution curve of the tantalum powder sample obtained in Comparative Example 2 of this application.

[0036] Figure 8 shows the volumetric particle size distribution curve of the tantalum powder sample obtained in Comparative Example 3 of this application.

[0037] Figure 9 shows the volumetric particle size distribution curve of the tantalum powder sample obtained in Comparative Example 4 of this application. Detailed Implementation

[0038] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. The detailed description of the following embodiments is used to illustrate the principles of this application, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0039] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0040] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0041] As analyzed in the background section of this application, the utilization rate of tantalum powder in the preparation of ultrafine tantalum powder needs to be further improved, while ultrafine tantalum powder is required to have the narrowest possible particle size distribution. At the same time, the particle size of tantalum powder should not be too small; nanoscale ultrafine powders have high surface free energy, are often prone to oxidation or even spontaneous combustion, and can also cause adhesion and agglomeration between powder particles. To obtain ultrafine tantalum powder with a narrow particle size distribution while improving tantalum powder utilization, this application provides a tantalum powder and its preparation method.

[0042] In the first embodiment of this application, a tantalum powder is provided, which includes pure tantalum powder or tantalum alloy powder, and the particle size distribution of the tantalum powder has the following characteristics: (1) Dv90<5μm, preferably Dv90<4.7μm; (2) Dv10>0.5μm, preferably Dv10>0.9μm.

[0043] Tantalum powder with the aforementioned volumetric particle size distribution is an ultrafine tantalum powder with an extremely narrow particle size distribution. It does not include easily oxidized or spontaneously combustible nano-sized ultrafine particles. Therefore, tantalum powder particles are less prone to agglomeration and exhibit high stability. Subsequent applications do not require particle size screening to obtain metal films with uniform grain size, resulting in high powder utilization.

[0044] In some embodiments, in order to further increase the proportion of ultrafine powder in tantalum powder, the Dv50 particle size of tantalum powder is between 1.5 μm and 3 μm.

[0045] Unless otherwise specified in this application, Dv90 is the particle size corresponding to a cumulative volume distribution of 90% in the system, Dv10 is the particle size corresponding to a cumulative volume distribution of 10% in the system, and Dv50 is the particle size corresponding to a cumulative volume distribution of 50% in the system.

[0046] The degree of concentration in particle size distribution can be represented by the span S = (Dv90 - Dv10) / Dv50. The smaller the value of the span S, the more uniform the particle size distribution and the higher the size consistency of the system. In some embodiments, S is between 0.7 and 3.0.

[0047] As described in the background section, the narrower the particle size distribution and the smaller the particle size of the tantalum powder used to prepare the target material, the more uniform and fine the grains in the target material, which is beneficial for obtaining a uniform and dense thin film. Through overall improvements in raw materials and processes, the tantalum powder provided in some embodiments of this application has high purity and a particle size distribution range as low as 0.7. This ultrafine tantalum powder with a narrow particle size distribution is more suitable as a tantalum powder raw material for multiple applications, including targets for integrated circuits.

[0048] Oxygen, an unavoidable component in tantalum powder, mainly exists in the form of tantalum oxide and affects its performance. Therefore, the performance of tantalum powder can be optimized by controlling its oxygen content. In some embodiments, the oxygen content of the tantalum powder is less than or equal to 5000 ppm, preferably less than or equal to 4000 ppm. Under the same preparation conditions, the smaller the particle size of the tantalum powder, the larger its specific surface area, the higher its surface activity in reacting with oxygen, and the greater its oxygen content.

[0049] The definition of BET specific surface area is well known to those skilled in the art, and its determination method can be found in standard GB / T19587-2004, "Determination of Specific Surface Area of ​​Solid Substances by Gas Adsorption BET Method". In some embodiments, the BET specific surface area of ​​tantalum powder is less than or equal to 1.5 m². 2 / g. This avoids particle agglomeration caused by excessively large specific surface area of ​​tantalum powder, and the surface energy of tantalum powder with the above-mentioned BET specific surface area is effectively controlled. Therefore, the oxidation or reaction with other gases of tantalum powder at high temperatures is effectively controlled, thereby improving the stability of tantalum powder under high-temperature conditions.

[0050] The second embodiment of this application provides a method for preparing tantalum powder, the method comprising: hydrogenating tantalum metal raw material to obtain tantalum metal hydride TaH. x More than 99% of the tantalum metal raw materials are hydrogenated into tantalum metal hydride TaH. x ; tantalum hydride TaH x Crushing and grinding are carried out; among which, tantalum metal hydride TaH x The value of x is 0.9 to 1.0, preferably 0.9 to 0.97.

[0051] This application controls the degree of hydrogenation of tantalum metal raw materials, especially the uniformity of hydrogenation, so that more than 99% of the tantalum metal raw materials are hydrogenated into tantalum metal hydride TaH. x Then it is crushed and powdered. The principle is that tantalum undergoes lattice expansion during hydrogenation, forming porous tantalum metal hydride. The higher the hydrogen absorption, the greater the volume expansion, and the higher the brittleness of the tantalum metal hydride. Precise control of tantalum metal hydride TaH... x In the range of x (0.9–1.0), over 99% of the tantalum metal raw materials are hydrogenated to tantalum metal hydride TaH. x This allows tantalum metal hydride to maintain excellent and uniform brittleness, which is beneficial for preparing tantalum powder with a narrow particle size distribution. In some embodiments, tantalum metal hydride TaH... x When x is in the range of 0.9 to 0.97, the particle size distribution concentration can be further improved.

[0052] The aforementioned tantalum metal raw material can be pure tantalum or a tantalum alloy. Following conventional hydrogenation processes in the art, the aforementioned tantalum metal raw material is pure tantalum or a tantalum alloy with the surface oxide film removed.

[0053] The tantalum powder in the first embodiment of this application can be obtained by the preparation method provided in the second embodiment.

[0054] In some embodiments, the hydrogenation process of the tantalum metal raw material in this preparation method includes the following steps:

[0055] Step S1: Place the tantalum metal raw material in a hydrogenation container, heat the hydrogenation container to temperature T0 and hold it at that temperature for time t0 to obtain hot tantalum metal, 300℃≤T0≤500℃, 0.5h≤t0≤5h;

[0056] Step S2: Hydrogen gas is introduced into the hydrogenation container and the temperature of the hydrogenation container is raised from temperature T0 to temperature T1, and the container is kept at temperature T1 for time t1 to obtain the initial hydrogenated block material, 700℃≤T1≤1000℃, 0.5h≤t1≤10h;

[0057] Step S3: While maintaining the hydrogen gas supply, the hydrogenation container is subjected to a stepped cooling process. The first step temperature in the stepped cooling process is T', and the last step temperature is T”. 200℃≤T'≤400℃, 60℃≤T”≤200℃, preferably, 60℃≤T”≤100℃.

[0058] Step S4: While maintaining the hydrogen flow, cool the hydrogenation container to the venting temperature T. end Afterwards, the hydrogen gas flow was stopped, and tantalum metal hydride TaH was obtained. x T end ≤60℃.

[0059] By utilizing the above hydrogenation process, the uniformity and completeness of hydrogenation can be improved as much as possible.

[0060] In the above-mentioned hydrogenation process of tantalum metal raw materials, the tantalum metal raw materials begin to absorb hydrogen from the time they are in the reducing hydrogen atmosphere in step S2. At the same time, the high-temperature hydrogen atmosphere in step S2 can enhance the surface activity of tantalum metal, which is beneficial to improving the rate and efficiency of the reaction between tantalum metal raw materials and hydrogen.

[0061] In some embodiments, in step S3, the hydrogen gas is introduced while the temperature is lowered to the last step temperature T". Since the maximum hydrogen absorption capacity of tantalum metal increases as the hydrogen supply temperature decreases, the hydrogen content in the tantalum ingot can be controlled by adjusting the last step temperature during the hydrogenation process. The inventors have found that the last step temperature is preferably no higher than 200°C, and more preferably no higher than 100°C. Step-by-step cooling, by setting and adjusting multiple temperature levels, holding times, and cooling rates, can more effectively control the hydrogenation process of tantalum metal adsorbing hydrogen, effectively avoiding the formation of incompletely hydrogenated tantalum cores. After the step-by-step cooling is completed, the hydrogenated tantalum metal can still absorb a small amount of hydrogen during the cooling to the cavitation temperature in step S4, thereby further improving the sufficiency and uniformity of hydrogen absorption. In some embodiments, step S3 specifically includes the following steps:

[0062] Step S31: While maintaining the hydrogen gas flow, cool the hydrogenation container to the first step temperature T', and hold it at the first step temperature T' for t' time to obtain intermediate hydrogenated block material, 0.5h≤t'≤10h;

[0063] Optional step S32: While maintaining the hydrogen gas flow, cool the hydrogenation container to temperature T2, and hold it at temperature T2 for time t2, where 100℃≤T2≤300℃ and 0.5h≤t2≤10h.

[0064] Step S33: While maintaining the hydrogen gas flow, cool the hydrogenation container to the last step temperature T'", and hold at the last step temperature T' for t" time to obtain tantalum metal hydride TaH. x Precursor, 0.5h≤t”≤10h.

[0065] Using the aforementioned stepped cooling method, tantalum metal hydrogenation continues under relatively gentle conditions. After high-temperature activation, the outer layer of the tantalum ingot, which has fully absorbed hydrogen, expands and becomes brittle, peeling off layer by layer. Within the stepped temperature range described in this invention, the fresh inner surface can fully contact hydrogen gas for a certain period of time to absorb hydrogen and continue peeling off. This process is repeated until the tantalum metal is completely hydrogenated, effectively avoiding the occurrence of tantalum cores that are not fully hydrogenated, thereby obtaining hydrogenated tantalum with full and uniform hydrogen absorption.

[0066] After the temperature drops to T", hydrogen is continuously passed through and the temperature is maintained for t". This holding time, within the above range, can be appropriately adjusted according to the size of the tantalum metal raw material placed in the hydrogenation container. In some embodiments, the cooling rate of steps S31 to S33 is 40℃ / h to 80℃ / h. By controlling the cooling rate, it is beneficial for the hydrogenation reaction to proceed fully, while avoiding the impact on production efficiency, increased production cycle, and cost caused by a too slow cooling rate.

[0067] In some embodiments, during steps S2 to S4 of the tantalum metal raw material hydrogenation process, the hydrogen pressure inside the hydrogenation container is 0.05 to 0.2 MPa. This pressure allows the hydrogenation reaction rate to be maintained at a high level. Furthermore, based on the load capacity of conventional hydrogen absorption equipment, this pressure range significantly reduces the risk of excessive hydrogen pressure causing hose rupture in the equipment, thereby reducing the probability of hydrogen leakage.

[0068] In some embodiments, the crushing and powdering process in this preparation method includes: processing tantalum metal hydride TaH x The tantalum hydride powder is obtained by crushing and screening. The mass of the tantalum hydride powder is tantalum metal hydride TaH. x The tantalum hydride powder is 95%–99.9% of its mass. It is then acid-washed to remove impurities, yielding impurity-removed tantalum hydride powder. This impurity-removed tantalum hydride powder is then subjected to dehydrogenation and deoxygenation treatment to obtain the final tantalum powder product. This dehydrogenation and deoxygenation treatment effectively reduces the oxygen content in the tantalum powder. Comparative experiments and tests have shown that the oxygen content of the same particle size without the dehydrogenation and deoxygenation process described in this application is generally above 10,000 ppm.

[0069] In some embodiments, tantalum metal hydride TaH x The process of crushing and screening to obtain tantalum hydride powder includes: crushing and screening tantalum metal hydride TaH x The process involves mechanical crushing, primary sieving, and secondary crushing. Secondary crushing methods include wet-mixed ball milling or air jet milling. Mechanical crushing offers various options and is a well-known technique. This application does not specify the exact operation method. Mechanical crushing can be performed multiple times, with each crushing cycle followed by sieving to further crush the powder remaining on the sieve until all the mechanically crushed powder can pass through a sieve with a mesh size of 400 or higher, such as 500 or 600 mesh. Primary sieving efficiently achieves the desired particle size. The powder remaining on the sieve can be further crushed until all powder passes through a pre-selected sieve. While it is desirable for all mechanically crushed powder to pass through a sieve with a mesh size of 400 or higher, to avoid increasing metallic impurities and ultrafine powder due to repeated crushing, the powder remaining on the sieve after the final mechanical crushing and primary sieving can be separately recycled. The powder remaining on the sieve accounts for approximately 0.1% to 5% of the total powder sieved in the first sieving by mass percentage.

[0070] When using wet stirred ball milling for secondary crushing, selecting grinding media with small diameters helps to achieve finer grinding. Smaller grinding media balls have a larger filling volume in the grinding chamber, increasing the impact and friction effects, and simultaneously increasing the contact area with the material to be ground. To improve the purity of the final product, tantalum balls are preferably used as grinding media in this application. The dispersion medium added to the wet stirred ball mill is preferably an anhydrous organic solvent, which fully disperses the powder, reduces powder agglomeration, improves grinding efficiency, and avoids oxidation of tantalum powder due to contact with oxygen in the dispersion medium. In some embodiments, the wet stirred ball mill meets one or more of the following conditions: (1) the grinding media of the wet stirred ball mill are tantalum balls, preferably tantalum balls with a diameter of 0.3 to 3 mm, and more preferably tantalum balls with a diameter of 0.5 to 2 mm; (2) the dispersion medium used in the wet stirred ball mill includes ethanol; (3) the ball milling time of the wet stirred ball mill is 6 to 9 hours; (4) the grinding aid includes oleic acid, cyclohexanol, polyethylene glycol, butanone, benzoic acid, or combinations thereof.

[0071] Pickling the product after secondary crushing can significantly reduce impurities introduced during the crushing process. After dehydrogenation and oxygen reduction, pickling of tantalum powder can further remove magnesium or magnesium oxide shavings. In some embodiments, the acid used for pickling to remove impurities includes one or more of sulfuric acid, nitric acid, hydrochloric acid, and hydrofluoric acid. For example, nitric acid or hydrochloric acid alone can be used, or a mixture of nitric acid and hydrofluoric acid can be selected. The pure water filtration and drying after pickling can be carried out using conventional techniques and will not be described in detail here.

[0072] The dehydrogenation and deoxygenation of tantalum hydride powder is preferably carried out under the protection of an inert gas. Typically, the dehydrogenation and deoxygenation processes can be performed consecutively, or one can be performed first as part of another process before the other. In some embodiments, the dehydrogenation and deoxygenation process includes:

[0073] Step A1: The mixture comprising impurity-removed tantalum hydride powder and magnesium shavings is heated to the deoxygenation temperature T under an inert gas atmosphere. A and at temperature T A The lower part is insulated, and the insulation time is t. A ;

[0074] Step A2: Continue to keep the mixture warm under vacuum conditions and perform evacuation to remove magnesium for a duration of t. B ;

[0075] Step A3: Cool the mixture to the passivation temperature T. C To passivate, air is introduced into the reaction vessel for a duration of t. C .

[0076] In step A1, under an inert gas atmosphere, the mixture comprising the above-mentioned impurity-removed tantalum hydride powder and magnesium shavings is placed in a sealed furnace and heated to the oxygen-reducing temperature T.A and at temperature T A Lower insulation t A Time is allowed for the magnesium to fully react with the oxygen in the tantalum powder; step A2, followed by vacuuming, the mixture is kept at a constant temperature under vacuum for a duration of t. B The process involves evacuating and removing magnesium, specifically extracting hydrogen from the magnesium oxide and tantalum hydride reaction products of the deoxygenation treatment; step A3 involves cooling the mixture to the passivation temperature T. C Air is introduced into the reaction vessel in small amounts multiple times at low temperature, and the priming time is t. C Passivation treatment of tantalum powder forms a dense oxide film on its surface, which helps to increase the stability of tantalum powder after it leaves the furnace and prevents it from oxidizing, heating up or even spontaneously combusting due to large-area contact with air after leaving the furnace.

[0077] In some implementations, dehydrogenation and deoxygenation satisfy one or more of the following conditions: (1) deoxygenation temperature T A (1) Temperature range: 700℃~900℃; (2) Insulation time: t A (3) Evacuation and magnesium removal time t B (3) Passivation temperature T C ≤30℃; (5) Inflation duration t C (6) The amount of magnesium shavings used is 1.5% to 5% by weight.

[0078] While maintaining high production efficiency, selecting the lowest possible deoxygenation temperature and the longest possible holding time can promote the full progress of each reaction and also help the ultrafine tantalum powder maintain good dispersibility.

[0079] In some embodiments, the crushing and grinding process also includes a classification process after dehydrogenation and deoxygenation to separate the ultrafine powder with extremely small particle size, making the particle size distribution more concentrated; optionally, the classification process includes water overflow classification or airflow classification.

[0080] The beneficial effects of this application will be further illustrated below with reference to embodiments and comparative examples, but the scope of the present invention is not limited to these embodiments.

[0081] Example 1

[0082] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0083] Step 1: Select a high-purity tantalum ingot with a purity of 99.99%. After removing the oxide layer from the surface of the tantalum ingot by acid washing, place it in a hydrogenation container and heat it to 400°C for preheating. After holding it at this temperature for 1 hour, start introducing hydrogen gas.

[0084] Step 2: Continue to raise the temperature to 900℃ and keep it at that temperature for 4 hours to carry out the activation treatment;

[0085] Step 3: After the activation process is completed, lower the temperature to 200℃ and keep it at that temperature for 3 hours. Then, continue to lower the temperature to 100℃ and keep it at that temperature for 4 hours. The cooling rate during the cooling process is 55℃ / hour.

[0086] Step 4: Reduce the temperature to 30℃, stop hydrogen supply before unloading from the furnace, and remove the product from the furnace to obtain tantalum metal hydride TaH. x The hydrogenation ratio of tantalum ingots is 100%, and the hydrogen pressure inside the furnace during the above hydrogenation process is about 0.1 MPa.

[0087] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The above mechanical crushing and sieving are repeated 3 times. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 2.02% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0088] Step 6: The primary tantalum hydride powder is subjected to secondary crushing using a wet stirred ball mill. The ball milling medium is tantalum balls with a diameter of 2 mm, and the dispersion medium is ethanol. The ball milling is carried out continuously for 8 hours to obtain tantalum hydride powder.

[0089] Step 7: The tantalum hydride powder is acid-washed with a mixture of HNO3 and HF to remove impurities (the volume ratio of HNO3, HF and water is 4:1:20, and the solid-liquid mass ratio of tantalum powder to acid is 1:2). After stirring for 60 minutes, the mixture is filtered to remove waste acid. After drying, it is passed through a 200-mesh sieve to obtain impurity-removed tantalum hydride powder.

[0090] Step 8: After mixing with 2% magnesium shavings, place in a sealed furnace and heat to 850°C under an argon atmosphere. Hold for 2 hours, then remove magnesium by vacuum and continue holding under vacuum for 3 hours. After holding, lower the temperature to 25°C and passivate for 15 hours. Remove from the furnace to obtain dehydrogenated and deoxygenated tantalum powder.

[0091] Step 9: Acid wash the dehydrogenated and deoxygenated tantalum powder to remove impurities, mix it with 10% HNO3 (solid-liquid mass ratio of tantalum powder to acid solution of 1:1), stir for 60 minutes to fully dissolve magnesium and magnesium oxide in tantalum powder, then filter to remove waste acid solution, dry and pass through a 500-mesh sieve to obtain tantalum powder sample.

[0092] Example 2

[0093] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0094] Step 1: Select a high-purity tantalum ingot with a purity of 99.99%. After removing the oxide layer from the surface of the tantalum ingot by acid washing, place it in a hydrogenation container and heat it to 400°C for preheating. After holding it at this temperature for 1 hour, start introducing hydrogen gas.

[0095] Step 2: Continue to raise the temperature to 900℃ and keep it at that temperature for 4 hours to carry out the activation treatment;

[0096] Step 3: After the activation process is completed, the temperature is lowered to 300℃ and kept at that temperature for 1 hour. Then, the temperature is lowered to 200℃ and kept at that temperature for 2 hours. Finally, the temperature is lowered to 100℃ and kept at that temperature for 6 hours. The cooling rate during the cooling process is 55℃ / hour.

[0097] Step 4: Reduce the temperature to 30℃, stop hydrogen supply before unloading from the furnace, and remove the product from the furnace to obtain tantalum metal hydride TaH. x The hydrogenation ratio of tantalum ingots is 100%, and the hydrogen pressure inside the furnace during the above hydrogenation process is about 0.1 MPa.

[0098] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The mechanical crushing and sieving are repeated twice. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 1.05% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0099] Step 6: The primary tantalum hydride powder is subjected to secondary crushing using a wet stirred ball mill. The ball milling medium is tantalum balls with a diameter of 2 mm, and the dispersion medium is ethanol. The ball milling is carried out continuously for 8 hours to obtain tantalum hydride powder.

[0100] Step 7: The tantalum hydride powder is acid-washed with a mixture of HNO3 and HF to remove impurities (the volume ratio of HNO3, HF and water is 4:1:20, and the solid-liquid mass ratio of tantalum powder to acid is 1:2). After stirring for 60 minutes, the mixture is filtered to remove waste acid. After drying, it is passed through a 200-mesh sieve to obtain impurity-removed tantalum hydride powder.

[0101] Step 8: After mixing with 2% magnesium shavings, place in a sealed furnace and heat to 850°C under an argon atmosphere. Hold for 2 hours, then remove magnesium by vacuum and continue holding under vacuum for 3 hours. After holding, lower the temperature to 30°C for 12 hours of passivation treatment, and remove from the furnace to obtain dehydrogenated and deoxygenated tantalum powder.

[0102] Step 9: Acid wash the dehydrogenated and deoxygenated tantalum powder to remove impurities, mix it with 10% HNO3 (solid-liquid mass ratio of tantalum powder to acid solution of 1:1), stir for 60 minutes to fully dissolve magnesium and magnesium oxide in tantalum powder, then filter to remove waste acid solution, dry and pass through a 500-mesh sieve to obtain tantalum powder sample.

[0103] Example 3

[0104] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0105] Step 1: Select a high-purity tantalum ingot with a purity of 99.99%. After removing the oxide layer from the surface of the tantalum ingot by acid washing, place it in a hydrogenation container and heat it to 400°C for preheating. After holding it at this temperature for 1 hour, start introducing hydrogen gas.

[0106] Step 2: Continue to raise the temperature to 900℃ and keep it at that temperature for 4 hours to carry out the activation treatment;

[0107] Step 3: After the activation process is completed, lower the temperature to 200℃ and keep it at that temperature for 3 hours. Then, continue to lower the temperature to 100℃ and keep it at that temperature for 4 hours. The cooling rate during the cooling process is 70℃ / hour.

[0108] Step 4: Reduce the temperature to 60℃, stop hydrogen supply before unloading from the furnace, and remove the product from the furnace to obtain tantalum metal hydride TaH. x The hydrogenation ratio of tantalum ingots is 99.58%, and the hydrogen pressure in the furnace during the above hydrogenation process is about 0.1 MPa.

[0109] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The above mechanical crushing and sieving are repeated 5 times. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 3.12% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0110] Step 6: The primary tantalum hydride powder is subjected to secondary crushing using a wet stirred ball mill. The ball milling medium is tantalum balls with a diameter of 2 mm, and the dispersion medium is ethanol. The ball milling is carried out continuously for 8 hours to obtain tantalum hydride powder.

[0111] Step 7: The tantalum hydride powder is acid-washed with a mixture of HNO3 and HF to remove impurities (the volume ratio of HNO3, HF and water is 4:1:20, and the solid-liquid mass ratio of tantalum powder to acid is 1:2). After stirring for 60 minutes, the mixture is filtered to remove waste acid. After drying, it is passed through a 200-mesh sieve to obtain impurity-removed tantalum hydride powder.

[0112] Step 8: After mixing with 2% magnesium shavings, place in a sealed furnace and heat to 850°C under an argon atmosphere. Hold for 2 hours, then remove magnesium by vacuum and continue holding under vacuum for 3 hours. After holding, lower the temperature to 30°C for 18 hours of passivation treatment, and remove from the furnace to obtain dehydrogenated and deoxygenated tantalum powder.

[0113] Step 9: Acid wash the dehydrogenated and deoxygenated tantalum powder to remove impurities, mix it with 10% HNO3 (solid-liquid mass ratio of tantalum powder to acid solution of 1:1), stir for 60 minutes to fully dissolve magnesium and magnesium oxide in tantalum powder, then filter to remove waste acid solution, dry and pass through a 500-mesh sieve to obtain tantalum powder sample.

[0114] Example 4

[0115] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0116] Steps one and two are the same as in Example 1;

[0117] Step 3: After the activation process is completed, lower the temperature to 400℃, keep it at that temperature for 2 hours, continue to lower the temperature to 300℃, keep it at that temperature for 2 hours, continue to lower the temperature to 200℃, keep it at that temperature for 10 hours. The cooling rate during the cooling process is 55℃ / hour.

[0118] Step four is the same as in Example 1, with the hydrogenation ratio of the tantalum ingot being 100%.

[0119] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The mechanical crushing and sieving are repeated twice. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 0.92% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0120] Steps six through nine are the same as in Example 1.

[0121] Example 5

[0122] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0123] Steps one and two are the same as in Example 1;

[0124] Step 3: After the activation process is completed, the temperature is lowered to 200℃ and kept at that temperature for 3 hours. Then, the temperature is lowered to 100℃ and kept at that temperature for 1 hour. Finally, the temperature is lowered to 60℃ and kept at that temperature for 5 hours. The cooling rate during the cooling process is 55℃ / hour.

[0125] Step 4: Reduce the temperature to 25°C, stop hydrogen supply before unloading from the furnace, and remove the product from the furnace to obtain tantalum metal hydride TaH. x The hydrogenation ratio of tantalum ingots is 99.23%, and the hydrogen pressure inside the furnace during the above hydrogenation process is about 0.1 MPa.

[0126] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The above mechanical crushing and sieving are repeated 4 times. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 2.18% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0127] Steps six through nine are the same as in Example 1.

[0128] Example 6

[0129] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0130] Step one is the same as in Example 1;

[0131] Step 2: Continue to raise the temperature to 700℃ and keep it at that temperature for 4 hours to carry out the activation treatment;

[0132] Step 3: After the activation process is completed, the temperature is lowered to 300℃ and kept at that temperature for 10 hours. Then, the temperature is lowered to 200℃ and kept at that temperature for 5 hours. Finally, the temperature is lowered to 100℃ and kept at that temperature for 0.5 hours. The cooling rate during the cooling process is 55℃ / hour.

[0133] Step 4: Reduce the temperature to 30℃, stop hydrogen supply before unloading from the furnace, and remove the product from the furnace to obtain tantalum metal hydride TaH. x The hydrogenation ratio of tantalum ingots is 99.16%, and the hydrogen pressure inside the furnace during the above hydrogenation process is about 0.1 MPa.

[0134] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The above mechanical crushing and sieving are repeated 4 times. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 2.35% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0135] Steps six through nine are the same as in Example 1.

[0136] Example 7

[0137] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0138] Step one is the same as in Example 1;

[0139] Step 2: Continue to raise the temperature to 1000℃ and keep it at that temperature for 4 hours to carry out the activation treatment;

[0140] Step 3: After the activation process is completed, lower the temperature to 300℃ and keep it at that temperature for 0.5 hours. Then, continue to lower the temperature to 200℃ and keep it at that temperature for 2 hours. Finally, continue to lower the temperature to 100℃ and keep it at that temperature for 4 hours. The cooling rate during the cooling process is 55℃ / hour.

[0141] Step 4: Reduce the temperature to 30℃, stop hydrogen supply before unloading from the furnace, and remove the product from the furnace to obtain tantalum metal hydride TaH. x The hydrogenation ratio of tantalum ingots is 100%, and the hydrogen pressure inside the furnace during the above hydrogenation process is about 0.1 MPa.

[0142] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The above mechanical crushing and sieving are repeated twice. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 1.02% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0143] Steps six through nine are the same as in Example 1.

[0144] Example 8

[0145] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0146] Steps one through four are the same as in Example 3, with the hydrogenation ratio of the tantalum ingot being 99.53%.

[0147] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The above mechanical crushing and sieving are repeated 5 times. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 3.75% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0148] Steps six and seven are the same as in Example 3;

[0149] Step 8: After mixing with 2% magnesium shavings, place in a sealed furnace and heat to 700°C under an argon atmosphere. Hold for 5 hours, then remove magnesium by vacuum and continue holding under vacuum for 3 hours. After holding, lower the temperature to 25°C and passivate for 15 hours. Remove from the furnace to obtain dehydrogenated and deoxygenated tantalum powder.

[0150] Step nine is the same as in Example 3.

[0151] Example 9

[0152] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0153] The procedures in steps one through four are the same as in Example 1, and the hydrogenation ratio of the tantalum ingot is 100%.

[0154] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The above mechanical crushing and sieving are repeated 3 times. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 2.22% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0155] Step 6: The primary tantalum hydride powder is subjected to secondary crushing using a wet stirred ball mill. The ball milling medium is tantalum balls with a diameter of 3 mm, and the dispersion medium is ethanol. The ball milling is carried out continuously for 6 hours to obtain tantalum hydride powder.

[0156] Step seven is the same as in Example 1;

[0157] Step 8: After mixing with 1.5% magnesium shavings, place the mixture in a sealed furnace and heat it to 900°C under an argon atmosphere. Hold the temperature for 1.5 hours, then remove the magnesium by vacuum and continue to hold the temperature under vacuum for 2.5 hours. After holding the temperature, lower the temperature to 30°C and passivate for 18 hours. Remove the powder from the furnace to obtain dehydrogenated and deoxygenated tantalum powder.

[0158] Step nine is the same as in Example 1.

[0159] Example 10

[0160] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0161] Steps one through four are the same as in Example 3, with the hydrogenation ratio of the tantalum ingot being 99.65%.

[0162] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The above mechanical crushing and sieving are repeated 4 times. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 4.38% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0163] Steps six and seven are the same as in Example 3;

[0164] Step 8: After mixing with 2% magnesium shavings, place in a sealed furnace and heat to 850°C under an argon atmosphere. Hold for 2 hours, then remove magnesium by vacuum and continue holding under vacuum for 2.5 hours. After holding, lower the temperature to 30°C and passivate for 18 hours. Remove from the furnace to obtain dehydrogenated and deoxygenated tantalum powder.

[0165] Step nine is the same as in Example 3.

[0166] Example 11

[0167] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0168] Steps one through four are the same as in Example 2, and the hydrogenation ratio of the tantalum ingot is 100%.

[0169] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The above mechanical crushing and sieving are repeated twice. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 1.26% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0170] Step 6: The primary tantalum hydride powder is subjected to secondary crushing using a wet-stirred ball mill. The milling medium is tantalum balls with a diameter of 0.5 mm, and the dispersion medium is ethanol. The ball milling is carried out continuously for 9 hours to obtain tantalum hydride powder.

[0171] Step seven is the same as in Example 2;

[0172] Step 8: After mixing with 2% magnesium shavings, place in a sealed furnace and heat to 850°C under an argon atmosphere. Hold for 2 hours, then remove magnesium by vacuum and continue holding under vacuum for 3 hours. After holding, lower the temperature to 25°C and passivate for 8 hours. Remove from the furnace to obtain dehydrogenated and deoxygenated tantalum powder.

[0173] Step nine is the same as in Example 2.

[0174] Example 12

[0175] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0176] Steps one through four are the same as in Example 2, and the hydrogenation ratio of the tantalum ingot is 100%.

[0177] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The above mechanical crushing and sieving are repeated twice. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 1.38% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0178] Step 6: The primary tantalum hydride powder is subjected to secondary crushing using a wet-stirred ball mill. The milling medium is tantalum balls with a diameter of 1 mm, and the dispersion medium is ethanol. The ball milling is carried out continuously for 8 hours to obtain tantalum hydride powder.

[0179] Step seven is the same as in Example 2;

[0180] Step 8: After mixing with 2% magnesium shavings, place in a sealed furnace and heat to 850°C under an argon atmosphere. Hold for 2 hours, then remove magnesium by vacuum and continue holding under vacuum for 4 hours. After holding, lower the temperature to 30°C for 20 hours of passivation treatment, then remove from the furnace to obtain dehydrogenated and deoxygenated tantalum powder.

[0181] Step nine is the same as in Example 2.

[0182] Comparative Example 1

[0183] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0184] Step 1: Select a high-purity tantalum ingot with a purity of 99.99%. After removing the oxide layer from the surface of the tantalum ingot by acid washing, place it in a hydrogenation container and heat it to 400°C for preheating. After holding it at this temperature for 1 hour, start introducing hydrogen gas.

[0185] Step 2: Continue to raise the temperature to 900℃ and keep it at that temperature for 4 hours to carry out the activation treatment;

[0186] Step 3: After the activation process is completed, lower the temperature to 300℃ and stop the hydrogen supply. The cooling rate during the cooling process is 70℃ / hour.

[0187] Step 4: Cool the temperature to 30℃, break the air chamber, and remove from the furnace to obtain tantalum metal hydride TaH. x The hydrogenation ratio of tantalum ingots is 98.7%, and the hydrogen pressure inside the furnace during the above hydrogenation process is about 0.1 MPa.

[0188] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The above mechanical crushing and sieving are repeated 5 times. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 8.5% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0189] Step 6: The primary tantalum hydride powder is subjected to secondary crushing using a wet stirred ball mill. The ball milling medium is tantalum balls with a diameter of 2 mm, and the dispersion medium is ethanol. The ball milling is carried out continuously for 8 hours to obtain tantalum hydride powder.

[0190] Step 7: The tantalum hydride powder is acid-washed with a mixture of HNO3 and HF to remove impurities (the volume ratio of HNO3, HF and water is 4:1:20, and the solid-liquid mass ratio of tantalum powder to acid is 1:2). After stirring for 60 minutes, the mixture is filtered to remove waste acid. After drying, it is passed through a 200-mesh sieve to obtain impurity-removed tantalum hydride powder.

[0191] Step 8: After mixing with 2% magnesium shavings, place in a sealed furnace and heat to 850°C under an argon atmosphere. Hold for 2 hours, then remove magnesium by vacuum and continue holding under vacuum for 3 hours. After holding, lower the temperature to 30°C and passivate for 10 hours. Remove from the furnace to obtain dehydrogenated and deoxygenated tantalum powder.

[0192] Step 9: Acid wash the dehydrogenated and deoxygenated tantalum powder to remove impurities, mix it with 10% HNO3 (solid-liquid mass ratio of tantalum powder to acid solution of 1:1), stir for 60 minutes to fully dissolve magnesium and magnesium oxide in tantalum powder, then filter to remove waste acid solution, dry and pass through a 500-mesh sieve to obtain tantalum powder sample.

[0193] Comparative Example 2

[0194] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0195] Steps one through four are the same as in Comparative Example 1, and the hydrogenation rate of the tantalum ingot is 98.64%.

[0196] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The above mechanical crushing and sieving are repeated 5 times. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 8.5% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0197] Step 6: The primary tantalum hydride powder is subjected to secondary crushing using a wet stirred ball mill. The milling medium is tantalum balls with a diameter of 2 mm, and the dispersion medium is ethanol. The ball milling is carried out continuously for 12 hours to obtain tantalum hydride powder.

[0198] Step seven is the same as in Comparative Example 1;

[0199] Step 8: After mixing with 2% magnesium shavings, place in a sealed furnace and heat to 850°C under an argon atmosphere. Hold for 2 hours, then remove magnesium by vacuum and continue holding under vacuum for 3 hours. After holding, lower the temperature to 40°C and passivate for 10 hours. Remove from the furnace to obtain dehydrogenated and deoxygenated tantalum powder.

[0200] Step nine is the same as in Comparative Example 1.

[0201] Comparative Example 3

[0202] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0203] Step 1: Select a high-purity tantalum ingot with a purity of 99.99%. After removing the oxide layer from the surface of the tantalum ingot by acid washing, place it in a hydrogenation container and heat it to 400°C for preheating. After holding it at this temperature for 1 hour, start introducing hydrogen gas.

[0204] Step 2: Continue to raise the temperature to 900℃ and keep it at that temperature for 4 hours to carry out the activation treatment;

[0205] Step 3: After the activation process is completed, lower the temperature to 200℃ and stop the hydrogen supply. The cooling rate during the cooling process is 70℃ / hour.

[0206] Step 4: Reduce the temperature to 30℃, stop hydrogen supply before unloading from the furnace, and remove the product from the furnace to obtain tantalum metal hydride TaH. x The hydrogenation ratio of tantalum ingots is 99.1%, and the hydrogen pressure inside the furnace during the above hydrogenation process is about 0.1 MPa.

[0207] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The above mechanical crushing and sieving are repeated 5 times. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 6.8% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0208] Step 6: The primary tantalum hydride powder is subjected to secondary crushing using a wet stirred ball mill. The ball milling medium is tantalum balls with a diameter of 2 mm, and the dispersion medium is ethanol. The ball milling is carried out continuously for 8 hours to obtain tantalum hydride powder.

[0209] Step 7: The tantalum hydride powder is acid-washed with a mixture of HNO3 and HF to remove impurities (the volume ratio of HNO3, HF and water is 4:1:20, and the solid-liquid mass ratio of tantalum powder to acid is 1:2). After stirring for 60 minutes, the mixture is filtered to remove waste acid. After drying, it is passed through a 200-mesh sieve to obtain impurity-removed tantalum hydride powder.

[0210] Step 8: After mixing with 2% magnesium shavings, place in a sealed furnace and heat to 850°C under an argon atmosphere. Hold for 2 hours, then remove magnesium by vacuum and continue holding under vacuum for 3 hours. After holding, lower the temperature to 35°C and passivate for 10 hours. Remove from the furnace to obtain dehydrogenated and deoxygenated tantalum powder.

[0211] Step 9: Acid wash the dehydrogenated and deoxygenated tantalum powder to remove impurities, mix it with 10% HNO3 (solid-liquid mass ratio of tantalum powder to acid solution of 1:1), stir for 60 minutes to fully dissolve magnesium and magnesium oxide in tantalum powder, then filter to remove waste acid solution, dry and pass through a 500-mesh sieve to obtain tantalum powder sample.

[0212] Comparative Example 4

[0213] The preparation process in this embodiment can be simply divided into two parts: tantalum metal hydrogenation treatment and tantalum metal hydride crushing and powdering. The specific steps are as follows:

[0214] Steps one through four are the same as in Comparative Example 3, and the hydrogenation rate of the tantalum ingot is 99.42%.

[0215] Step 5: The tantalum metal hydride is crushed by mechanical crushing and sieved once (through a 500-mesh sieve). The above mechanical crushing and sieving are repeated 4 times. The powder on the sieve after the last sieve is recovered separately. The powder on the sieve accounts for 6.8% of the total powder processed by sieve by mass percentage. The powder under the sieve is mixed to form tantalum hydride powder.

[0216] Step 6: The primary tantalum hydride powder is subjected to secondary crushing using a wet stirred ball mill. The ball milling medium is tantalum balls with a diameter of 2 mm, and the dispersion medium is ethanol. The ball milling is carried out continuously for 15 hours to obtain tantalum hydride powder.

[0217] Step seven is the same as in Comparative Example 3;

[0218] Step 8: After mixing with 2% magnesium shavings, place in a sealed furnace and heat to 850°C under an argon atmosphere. Hold for 2 hours, then remove magnesium by vacuum and continue holding under vacuum for 3 hours. After holding, lower the temperature to 35°C and passivate for 10 hours. Remove from the furnace to obtain dehydrogenated and deoxygenated tantalum powder.

[0219] Step nine is the same as in Comparative Example 3.

[0220] Following step four of the above embodiments and comparative examples, the tantalum metal hydride TaH obtained after furnace tapping x Phase analysis was performed using X-ray diffraction to obtain TaH from Example 1. 0.93 The XRD patterns are recorded in Figure 1, and the TaH obtained in Comparative Example 1 is shown in Figure 1. 0.5 The XRD pattern is shown in Figure 2.

[0221] The oxygen content, BET specific surface area, and particle size parameters of the tantalum powder samples of the above examples and comparative examples were measured and analyzed. The volume particle size distribution curves of the tantalum powder samples of Examples 1 to 3 and Comparative Examples 1 to 4 are recorded in Figures 3 to 9.

[0222] The equipment and models used to measure each parameter are shown in Table 1.

[0223] Table 1

[0224] Table 2 shows the composition of tantalum metal hydrides in Examples 1-12 and Comparative Examples 1-4, as well as the oxygen content, BET specific surface area, particle size, and distribution span S of the tantalum powder samples.

[0225] Table 2

[0226] With tantalum hydride TaH x The value of x is used to represent the degree of hydrogenation of tantalum ingots. The tantalum hydrides in the above embodiments have a higher degree of hydrogenation, falling within the range of x = 0.9 to 1.0 as defined in this application. The tantalum hydrides in Comparative Examples 1 to 4 have a relatively lower degree of hydrogenation, with x values ​​of 0.5 or 0.8. Comparing the volume particle sizes Dv10, Dv50, and Dv90 of the embodiments and the span S of the particle size distribution curves of the comparative examples, it can be found that the tantalum powder in the embodiments has a finer overall particle size and a more concentrated particle size distribution. This eliminates the need for complex separation and screening post-processing, making it more suitable for preparing thin films with uniform grain size and improving powder utilization.

[0227] Next, we will further analyze the preparation methods of each embodiment.

[0228] The differences between Example 3 and Example 1 are: (a) the cavitation temperature and cooling rate during hydrogenation; and (b) the passivation temperature and gas charging duration during dehydrogenation and deoxygenation. Specifically, the cavitation temperature and cooling rate during hydrogenation in Example 3 are higher than those in Example 1, which to some extent reduces the uniformity and sufficiency of hydrogenation, resulting in a lower degree of hydrogenation in Example 3 compared to Example 1. This can be seen from the value of tantalum hydride x and the hydrogenation ratio of the tantalum ingot. Correspondingly, the Dv10, Dv50, and Dv90 particle sizes and the particle size distribution span S of Example 3 are all larger than those of Example 1.

[0229] Using the hydrogenation treatment of Example 2 as a baseline, Example 4 increased the temperature (and holding time) of each stage in the stepped cooling process, resulting in a finer particle size than Example 2, while the particle size distribution span S was similar to that of Example 2. Comparing the tantalum powder preparation processes of Examples 6 and 7, the ball milling, acid washing, sieving, and dehydrogenation (steps six to nine) processes were the same. The parameters of the hydrogenation treatment stage, including the preheating temperature and the temperatures of each stage of the stepped cooling, were also the same. The main difference lay in the selection of temperature T1 and the step cooling time. Example 6 used a lower temperature T1, resulting in a lower activation degree of the tantalum ingot. Even with increased holding time in the stepped cooling process, the degree of hydrogenation was still lower than in Example 7, resulting in a larger particle size and a wider particle size distribution. Conversely, Example 7 used a higher temperature T1, increasing the activation degree of the tantalum ingot. Slightly reducing the holding time in the stepped cooling process also yielded a narrower particle size distribution.

[0230] It can be found that hydrogenation treatment parameters such as activation temperature, temperature of individual stages of stepped cooling, holding time, cooling rate, and cavitation temperature all affect the degree of hydrogenation of tantalum ingots. By selecting various hydrogenation treatment parameters, the particle size and particle size distribution of tantalum powder products can be precisely controlled.

[0231] The only difference between the preparation methods of Examples 8 and 10 is the dehydrogenation and deoxygenation process; the hydrogenation treatment and crushing / ball milling operations are the same in both. Measurements showed that the Dv10, Dv50, and Dv90 particle sizes of both were quite similar, and the span S, representing the degree of particle size distribution, was also similar. This indicates that the hydrogenation treatment and ball milling processes dominate in adjusting particle size and distribution, while the dehydrogenation and deoxygenation treatment has a relatively low impact on the tantalum powder particle size and distribution.

[0232] The difference between Example 2 and Example 11 lies only in steps six and eight, where the ball milling time and the diameter of the grinding balls affect the particle size and distribution of the obtained tantalum powder. Example 11 has a longer ball milling time and a smaller grinding ball diameter, which is beneficial for obtaining finer tantalum powder. Comparing the Dv10, Dv50, and Dv90 particle sizes of the two examples, they conform to the above-mentioned pattern. In addition, the hydrogenation process of Examples 2 and 11 is the same, and the particle size distribution span S is similar. Similarly, compared with Example 1, Example 9 has a shorter ball milling time and a larger grinding ball diameter. The hydrogenation process of the two examples is the same, and the Dv10, Dv50, and Dv90 particle sizes of Example 9 are significantly larger than those of Example 1, while the span S values ​​are the same. It can be concluded that: (1) the higher the degree of hydrogenation, the longer the ball milling time, and the smaller the grinding ball diameter, the more beneficial it is to obtain fine tantalum powder; (2) the particle size distribution of tantalum powder mainly depends on the degree of hydrogenation of the tantalum ingot, and the influence of the ball milling process is relatively small.

[0233] In addition, compared with the tantalum powder preparation process in Example 2, the grinding ball diameter in Example 12 is smaller, so the particle sizes of Dv10, Dv50, and Dv90 are slightly smaller than those in Example 2. At the same time, Example 12 utilizes a longer magnesium removal and passivation treatment, which effectively controls the oxygen content of the tantalum powder while controlling the particle size to be small and the distribution to be narrow.

[0234] In summary, by controlling the preparation process, the tantalum metal hydride TaH in Examples 1 to 12... x Meeting the condition of x being 0.9–1.0 ensures sufficient and uniform hydrogen absorption, significantly improving the product performance of tantalum metal hydride powder. On one hand, it effectively controls the oxygen content and BET specific surface area of ​​the tantalum powder; the oxygen content in the tantalum powder can be controlled below 4000 ppm, and the BET specific surface area can be controlled at 1.5 m². 2 The particle size distribution of the ultrafine tantalum powder is below / g, which is comparable to the low-hydrogenated tantalum powder (hydrogenation degree x≤0.8) prepared by conventional methods in Comparative Examples 1-4. This improves the stability of the ultrafine tantalum powder during storage and use. On the other hand, the obtained ultrafine tantalum powder has an extremely narrow particle size distribution, which eliminates the need for particle size screening in subsequent applications. It can also meet the requirements for preparing metal films with uniform grain size, thus greatly improving the utilization rate of the powder.

[0235] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

A tantalum powder, characterized in that, The tantalum powder includes pure tantalum powder or tantalum alloy powder, and the particle size distribution of the tantalum powder has the following characteristics: (1) Dv90 < 5 μm, preferably Dv90 < 4.7 μm; (2) Dv10>0.5μm, preferably Dv10>0.9μm. The tantalum powder according to claim 1 is characterized in that, The tantalum powder has a Dv50 particle size between 1.5 μm and 3 μm. The tantalum powder according to claim 1 or 2 is characterized in that, The oxygen content of the tantalum powder is less than or equal to 5000 ppm, preferably less than or equal to 4000 ppm. The tantalum powder according to any one of claims 1 to 3 is characterized in that, The BET specific surface area of ​​the tantalum powder is less than or equal to 1.5 m². 2 / g. A method for preparing tantalum powder, characterized in that, The preparation method includes: Hydrogenation of tantalum metal raw material yields tantalum metal hydride TaH. x More than 99% of the tantalum metal raw material is hydrogenated into tantalum metal hydride TaH. x ; TaH metal tantalum hydride x Crushing and grinding; Among them, the tantalum metal hydride TaH x The value of x is 0.9 to 1.0, preferably 0.9 to 0.

97. The preparation method according to claim 5 is characterized in that, The process of hydrogenating tantalum metal raw materials includes: Step S1: Place the tantalum metal raw material in a hydrogenation container, heat the hydrogenation container to temperature T0 and hold it at that temperature for time t0 to obtain hot tantalum metal, 300℃≤T0≤500℃, 0.5h≤t0≤5h; Step S2: Hydrogen gas is introduced into the hydrogenation container and the temperature of the hydrogenation container is raised from temperature T0 to temperature T1, and the temperature is held at T1 for time t1 to obtain the initial hydrogenated block material, 700℃≤T1≤1000℃, 0.5h≤t1≤10h; Step S3: While maintaining the hydrogen gas supply, the hydrogenation container is subjected to a stepped cooling process. The first step temperature in the stepped cooling process is T', and the last step temperature is T”. 200℃≤T'≤400℃, 60℃≤T”≤200℃, preferably, 60℃≤T”≤100℃. Step S4: While maintaining the hydrogen flow, cool the hydrogenation container to the venting temperature T. end Afterwards, the hydrogen gas flow was stopped, and tantalum metal hydride TaH was obtained. x T end ≤60℃. The preparation method according to claim 6 is characterized in that, Step S3 includes: Step S31: While maintaining the hydrogen gas flow, cool the hydrogenation container to the first step temperature T', and hold it at the first step temperature T' for t' time to obtain intermediate hydrogenated block material, 0.5h≤t'≤10h; Optional step S32: While maintaining the hydrogen gas flow, the hydrogenation container is cooled to temperature T2, and held at temperature T2 for time t2, where 100℃≤T2≤300℃ and 0.5h≤t2≤10h. Step S33: While maintaining the hydrogen gas flow, cool the hydrogenation container to the last step temperature T' and hold it at the last step temperature T' for t' time to obtain tantalum metal hydride TaH. x Precursor, 0.5h≤t”≤10h; Optionally, the cooling rate in steps S31 to S33 is 40℃ / h to 80℃ / h. The preparation method according to claim 6 is characterized in that, In steps S2 to S4 of the hydrogenation of tantalum metal raw materials, the hydrogen pressure inside the hydrogenation container is 0.05 to 0.2 MPa. The preparation method according to any one of claims 5 to 8 is characterized in that, The crushing and grinding process includes: For the tantalum metal hydride TaH x The tantalum hydride powder is obtained by crushing and sieving, and the mass of the tantalum hydride powder is equal to that of the tantalum metal hydride TaH. x 95% to 99.9% of the quality; The tantalum hydride powder is acid-washed to remove impurities, resulting in impurity-removed tantalum hydride powder. The impurity-removed hydrogenated tantalum powder is dehydrogenated and deoxygenated to obtain tantalum powder product. The preparation method according to claim 9 is characterized in that, The dehydrogenation and oxygen reduction process includes: Step A1: The mixture comprising the impurity-removed tantalum hydride powder and magnesium shavings is heated to the deoxygenation temperature T under an inert gas atmosphere. A And at the oxygen reduction temperature T A The lower part is insulated, and the insulation time is t. A ; Step A2: Under vacuum conditions, the mixture is kept at a constant temperature for evacuation and magnesium removal. The evacuation and magnesium removal time is t. B ; Step A3: Cool the mixture to the passivation temperature T. C Air is introduced into the reaction vessel for a duration of t. C This yields tantalum powder that has undergone dehydrogenation and oxygen reduction. The preparation method according to claim 10 is characterized in that, The dehydrogenation and oxygen reduction meet one or more of the following conditions: (1) The oxygen depletion temperature T A The temperature ranges from 700℃ to 900℃. (2) The heat preservation time t A It takes 1.5 to 5 hours; (3) The evacuation and magnesium removal time t B It takes 2.5 to 4 hours; (4) The passivation temperature T C ≤30℃; (5) The inflation duration t C It takes 8 to 20 hours; (6) The amount of magnesium chips used is 1.5% to 5% by weight. The preparation method according to any one of claims 5 to 11 is characterized in that, The tantalum metal raw material is pure tantalum or tantalum alloy with the surface oxide film removed. The preparation method according to claim 9 is characterized in that, For the tantalum metal hydride TaH x The process of crushing and screening to obtain tantalum hydride powder includes the crushing and screening of the tantalum metal hydride TaH x Mechanical crushing, primary screening, and secondary crushing are performed. The secondary crushing methods include wet stirred ball milling or air jet milling. The preparation method according to claim 13 is characterized in that, The wet stirred ball mill meets one or more of the following conditions: (1) The grinding media balls of the wet stirred ball mill are tantalum balls, preferably tantalum balls with a diameter of 0.3 to 3 mm, and more preferably tantalum balls with a diameter of 0.5 to 2 mm; (2) The dispersion medium used in the wet stirred ball mill includes ethanol; (3) The ball milling time of the wet stirred ball mill is 6 to 9 hours; (4) Grinding aids include one or more of oleic acid, cyclohexanol, and polyethylene glycol. The preparation method according to claim 9 is characterized in that, The acids used for pickling and impurity removal include one or more of sulfuric acid, nitric acid, hydrochloric acid, and hydrofluoric acid.

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