Spherical tantalum powder, products containing the same, and methods for producing the same.

Abstract

To provide a method for forming articles by additive manufacturing using tantalum powder.SOLUTION: There is provided a method for forming an article, wherein the method comprises a step of additive manufacturing to form the article by utilizing the tantalum powder to form the shape of the article or part thereof, and wherein the tantalum powder has following characteristics: a. spherical shape with an average aspect ratio of from 1.0 to 1.25; b. a purity of tantalum of at least 99.99 wt.% Ta based on total weight of the tantalum powder, excluding gas impurities; c. an average particle size of from about 0.5 micron to about 250 microns; d. an apparent density of from about 4 g / cc to about 12.3 g / cc; e. a true density of from 16 g / cc to 16.6 g / cc; and f. a Hall flow rate of 20 seconds or less.SELECTED DRAWING: Figure I

Description

[Technical Field]

[0001] This application asserts the interests under Section 119(e) of the preceding U.S. Provisional Patent Application No. 62 / 638,328, filed on 5 March 2018, and U.S. Provisional Patent Application No. 62 / 793,418, filed on 17 January 2019, the entirety of which this application constitutes part of this specification by reference.

[0002] The present invention relates to metals, particularly tantalum, and also to products made from tantalum, as well as to methods for producing and processing tantalum. [Background technology]

[0003] Valve metal powders such as tantalum powder are widely used in the manufacture of capacitor electrodes, among many other applications. However, they also have other uses in industries such as sputtering target manufacturing, military applications, and the aerospace industry. Given their properties, tantalum is also promising in the fields of medical and dental implants.

[0004] Currently, tantalum powder is typically produced by one of two methods: a mechanical process or a chemical process. The mechanical process involves electron beam melting tantalum to form an ingot, hydrogenating the ingot, milling the hydride, and then dehydrogenating, crushing, and heat-treating it. This process usually produces high-purity powder.

[0005] Another commonly used process for producing tantalum powder is a chemical process. Several chemical methods for producing tantalum powder are known in the art. U.S. Patent No. 4,067,736 by Vartanian and U.S. Patent No. 4,149,876 by Rerat relate to a chemical production process involving the sodium reduction of potassium tantalate fluoride (K2TaF7). A typical technical description is also provided in the background sections of U.S. Patent No. 4,684,399 by Bergman et al. and U.S. Patent No. 5,234,491 by Chang. All of these patents and documents, in whole, constitute part of this specification by reference.

[0006] Tantalum powder produced by chemical methods typically has a larger surface area than powder produced by mechanical methods, making it well-suited for use in applications such as capacitors. Chemical methods usually involve the chemical reduction of tantalum compounds with reducing agents. Typical reducing agents include hydrogen, as well as active metals such as sodium, potassium, magnesium, and calcium. Typical tantalum compounds include, but are not limited to, potassium tantalate fluoride (K2TaF7), sodium tantalate fluoride (Na2TaF7), tantalum pentachloride (TaCl5), tantalum pentafluoride (TaF5), and mixtures thereof. The most widely used chemical process is the reduction of K2TaF7 with liquid sodium.

[0007] In the chemical reduction of valve metal powders such as tantalum powder, potassium tantalate fluoride is recovered, melted, and reduced to metallic tantalum powder by sodium reduction. The dried tantalum powder is then recovered and optionally crushed by thermal agglomeration under vacuum to avoid oxidation of the tantalum. Since the oxygen concentration of the valve metal material can be important in the manufacture of capacitors, the granular powder is then typically deoxygenated by heating (e.g., to about 1000°C or higher) in the presence of a getter material with a higher affinity for oxygen than the valve metal, such as an alkaline earth metal (e.g., magnesium). Before further processing of the material, a post-deoxygenation process, acid leaching under standard atmospheric conditions (e.g., about 760 mm Hg), can be performed using a mineral acid solution containing, for example, sulfuric acid or nitric acid, to dissolve metal contaminants and refractory oxide contaminants (e.g., magnesium contaminants and magnesium oxide contaminants). The acid-leached powder can be washed and dried, and then compressed, sintered, and anodized by conventional methods to produce a sintered porous body such as an anode for a capacitor.

[0008] Most of the efforts toward the development of tantalum powder have been made in the capacitor anode industry, where the powder has been manufactured solely for this specific application. However, one or more properties of tantalum powder used in the capacitor industry are often undesirable in other industries such as additive manufacturing. Such "capacitor-grade" tantalum powder may not be suitable, or may be less suitable, for such additive manufacturing. Therefore, there is a demand and desire for the development of tantalum powder that can be useful in additive manufacturing and / or other industries. [Overview of the project]

[0009] The present invention is characterized by providing tantalum powder that can be very useful in additive manufacturing, i.e., 3D printing.

[0010] The present invention is otherwise characterized by providing articles, products, and / or parts by additive manufacturing, i.e., 3D printing, using tantalum powder that is easier to use, and / or by improving one or more properties in such a process.

[0011] The present invention is further characterized by providing a process for producing tantalum powder, and a process for producing articles, products, and / or parts containing the tantalum powder.

[0012] Further features and advantages of the present invention are described in part in the following specification, are partially apparent herein, or can be recognized through the practice of the present invention. The object and other advantages of the present invention are realized and achieved using the elements and combinations specifically indicated herein and in the appended claims.

[0013] To achieve these and other advantages, and in accordance with the objectives of the present invention, the present invention relates to tantalum powder, as embodied and outlined herein. This tantalum powder has a spherical shape with an average aspect ratio of 1.0 to 1.25, a tantalum purity of at least 99.9% by weight Ta relative to the total weight of the tantalum powder excluding gas impurities, an average particle size of about 0.5 microns to about 250 microns, a true density of 16 g / cc to 16.6 g / cc, an apparent density of about 4 g / cc to about 12.6 g / cc, and a hole flow rate of 20 seconds or less. The above tantalum powder may, and preferably, be plasma heat-treated.

[0014] Furthermore, the present invention relates to an article or product (or a part or component thereof) made from or formed of the tantalum powder of the present invention. Examples of such an article or its part or component include, but are not limited to, a boss of a coil set for a physical vapor deposition process, a boss including a continuous bubble structure and a solid structure, a coil set for a physical vapor deposition process or a component thereof, an orthopedic implant or a component thereof, a dental implant or a component thereof, and other medical implants or parts thereof.

[0015] Furthermore, the present invention relates to a method for producing the tantalum powder of the present invention. The method includes subjecting starting tantalum powder to plasma heat treatment in an inert atmosphere to at least partially melt at least the outer surface of the starting tantalum powder to obtain heat-treated tantalum powder, and cooling the heat-treated tantalum powder in an inert atmosphere to obtain tantalum powder. The starting tantalum powder can be sodium-reduced tantalum powder, tantalum powder reduced by other salts, or tantalum powder reduced by other processes and techniques such as electrolytic reduction and hydrogen reduction. The starting tantalum powder can be basic lot tantalum powder.

[0016] The present invention also relates to a method for forming an article, the method including a step of forming an article by additive manufacturing by using the tantalum powder of the present invention to form the shape of the article or its component. The additive manufacturing can include laser powder bed fusion, electron beam powder bed fusion, directed energy deposition, laser cladding via powder or wire, material jetting, sheet lamination, and / or vat photopolymerization.

[0017] It is understood that both the above general description and the following detailed description are exemplary and explanatory only, and are intended to further explain the present invention as claimed.

Brief Description of the Drawings

[0018] [Figure I]Figure 1A: SEM image of the starting base lot tantalum powder used in Example 1. Figure 1B: SEM image of the finished tantalum powder after plasma treatment in Example 1. Figure 2A: SEM image of the starting base lot tantalum powder (after crushing and sieving) used in Example 2. Figure 2B: SEM image of the finished tantalum powder after plasma treatment in Example 2. [Figure II] Figures 3 to 8 are SEM images showing the microstructure of tensile bars made from the spherical tantalum powder of the present invention. Figure 3 is an SEM image showing the microstructure of a sintered powder metallurgy bar made by pressing and sintering the spherical tantalum powder of the present invention. Figures 4 to 8 are SEM images showing the microstructure of various tensile bar samples made by additive manufacturing of the spherical tantalum powder of the present invention. Compared to the microstructure of the sintered bar, all printed parts had a density of over 99%, and the laser powder and other printing parameters were sufficiently optimized to completely melt the supplied powder. [Figure III] Figures 9 and 10 are SEM images showing the microstructure of tensile bars fabricated from the spherical tantalum powder of the present invention. Figures 9 and 10 are SEM images showing the microstructure of various tensile bar samples fabricated by additive manufacturing of the spherical tantalum powder of the present invention. Compared to the microstructure of sintered bars, all printed parts had a density of over 99%, and the laser powder and other printing parameters were sufficiently optimized to completely melt the supplied powder. [Figure IV] Figure 11: A diagram of a cylindrical bar or rod, showing the 3D printing directions and orientation of this bar / rod in the z, x, and y directions. [Modes for carrying out the invention]

[0019] This invention relates to a novel tantalum powder and an article (or a part thereof) formed from the tantalum powder of the present invention. Furthermore, this invention relates to a method for producing a novel tantalum powder and a method for forming an article (or a part thereof) using additive manufacturing technology and processes.

[0020] Unlike other spheroidizing techniques, plasma spheroidizing provides the energy necessary to rapidly melt tantalum, producing perfectly spherical powder with high purity, and / or low oxygen, and / or minimal gas encapsulation, and / or a controlled particle size distribution (PSD).

[0021] More specifically, the tantalum powder of the present invention has a spherical shape with an average aspect ratio of 1.0 to 1.25; a tantalum purity of at least 99.9% by weight Ta relative to the total weight of the tantalum powder excluding gas impurities; an average particle size of about 0.5 microns to about 250 microns; a true density of 16 g / cc to 16.6 g / cc; an apparent density of about 4 g / cc to about 12.6 g / cc; and a whole flow rate of 20 seconds or less, which either comprises, essentially consists of, or includes.

[0022] Aside from the properties of tantalum powder described above with respect to spherical shape, purity, average particle size, density, and whole flow rate, it is understood that there are no other significant restrictions on the types of tantalum powder that can be used in the additive manufacturing method of the present invention as described herein.

[0023] The tantalum powder of the present invention is considered to be sodium-reduced tantalum powder, or it can be reduced tantalum powder, or it can be gas-phase reduced tantalum, or ingot-derived tantalum powder.

[0024] As described above, the tantalum powder of this disclosure has a spherical shape. Its shape is defined by its average aspect ratio. In this specification, the average aspect ratio of tantalum powder, i.e., the aspect ratio, is defined as the ratio of the maximum linear dimension of a particle (i.e., tantalum powder) to the minimum linear dimension of the same particle (i.e., tantalum powder), based on random measurements of 50 or 100 particles, or random measurements of about 1% to about 2% by weight of a powder batch. The tantalum particles are measured using scanning electron microscope (SEM) images. A perfectly spherical particle has an aspect ratio of 1.0. For the purposes of the present invention, tantalum powder is considered spherical if it has an average aspect ratio of 1.0 to 1.25, or 1.0 to 1.2, or 1.0 to 1.15, or 1.0 to 1.1, or 1.0 to 1.05, or about 1.05 to about 1.25, or 1.05 to about 1.2, or 1.05 to about 1.1, or about 1.0.

[0025] The tantalum powder of the present invention is a high-purity tantalum powder, meaning that the tantalum powder has a purity of at least 99.9 wt% Ta with respect to the total weight of the tantalum powder excluding gas impurities. The purity level can be measured by X-ray fluorescence, inductively coupled plasma atomic emission spectrometry (ICP-AES), i.e., ICP atomic emission spectrometry, or inductively coupled plasma mass spectrometry (ICP-MS), i.e., ICP mass spectrometry, or glow discharge mass spectrometry (GDMS), spark source mass spectrometry (SSMS), or any combination thereof. The tantalum purity can be at least 99.95 wt% Ta, at least 99.99 wt% Ta, at least 99.995 wt% Ta, or about 99.9 wt% Ta to 99.9995 wt% Ta, or about 99.95 wt% Ta to 99.9995 wt% Ta, or about 99.99 wt% Ta to 99.9995 wt% Ta, or other purity values ​​or ranges.

[0026] Tantalum powder has an average particle size of approximately 0.5 microns to approximately 250 microns. This average particle size is determined by randomly measuring 50 particles using laser diffraction technology, dynamic light scattering technology, or dynamic image analysis technology, such as a HORIBA LA-960 laser particle size distribution analyzer, a HORIBA LA-300 laser particle size distribution analyzer, a HORIBA SZ-100 nanoparticle analyzer, a HORIBA Camsizer dynamic image analyzer, or a HORIBA Camsizer X2 dynamic image analyzer. The average particle size can be approximately 0.5 microns to approximately 10 microns, or approximately 5 microns to approximately 25 microns, or approximately 15 microns to approximately 45 microns, or approximately 35 microns to approximately 75 microns, or approximately 55 microns to approximately 150 microns, or approximately 105 microns to approximately 250 microns.

[0027] The apparent density of tantalum powder can be approximately 4 g / cc to 12.6 g / cc, for example, approximately 4.5 g / cc to 12 g / cc, or approximately 5 g / cc to 10 g / cc, or approximately 6 g / cc to 12.5 g / cc, or other apparent density values ​​within these ranges. The apparent density is measured according to the ASTM B212 standard.

[0028] The tantalum powder has a whole flow rate of 20 seconds or less. The whole flow test is performed according to the ASTM B213 standard, which measures the time it takes for the tantalum powder to flow through the funnel opening of a whole flow meter. The whole flow rate of the tantalum powder of the present invention may be 19 seconds or less, 15 seconds or less, 10 seconds or less, or 4 to 20 seconds, or 5 to 20 seconds, or 6 to 20 seconds, or 4 to 15 seconds, or 4 to 12 seconds, or 5 to 15 seconds, or other values ​​within these ranges.

[0029] The tantalum powder may be plasma heat-treated, and is preferably plasma heat-treated.

[0030] Tantalum powder can have a variety of oxygen levels. For example, tantalum powder can have oxygen levels of 2500 ppm or less, or 1000 ppm or less, or less than 500 ppm, or less than 400 ppm, or less than 300 ppm, or less than 250 ppm, or less than 200 ppm, or less than 100 ppm, or less than 50 ppm, for example, about 20 ppm to 500 ppm, about 40 ppm to 400 ppm, about 50 ppm to 300 ppm, about 100 ppm to 495 ppm, or about 150 ppm to about 400 ppm.

[0031] The tantalum powder of the present invention may optionally be an alloy. The alloy contains a) at least metallic tantalum, and b)i) one or more other metals and / or ii) a nonmetallic element and / or iii) a metalloid element.

[0032] Tantalum or tantalum alloy may further optionally be doped, or may contain one or more gaseous elements present as part of a metal or alloy, and / or on the surface of a metal and / or alloy. The alloy may be single-phase or have two or more phases.

[0033] One or more of the following metals can be part of the tantalum alloy powder and therefore can be the tantalum alloy powder of the present invention: Ti, Nb, Si, W, Mo, Re, Rh, Ta, V, Th, Zr, Hf, Cr, Mn, Sc, Y, C, B, Ni, Fe, Co, Al, Sn, Au, Th, U, Pu, and / or rare earth elements (there may be more than one). For example, the tantalum powder can be a Ta-Ti alloy, or a Ta-Si alloy, or a Ta-W alloy, or a Ta-Mo alloy, or a Ta-Nb alloy, or another Ta-metal alloy. In the alloy, the proportion of Ta can be 30% to 99.9% by weight of the total weight of the alloy, and the weight percentage of other non-Ta elements, such as metals or nonmetals in the alloy, can be 0.1% to 70% by weight. The Ta-metal alloy can be tantalum in which one, two, or three or more other metals are present (but not as impurities). In a Ta-metal alloy, tantalum may be the dominant metal (for example, tantalum may be the metal present in the highest proportion relative to the weight of the alloy). The tantalum alloy may contain one, two, or three or more other metals or elements that are not present as impurities.

[0034] The tantalum powder of the present invention may have one or more other properties selected from the following: D10 diameter of approximately 5 microns to approximately 25 microns. Approximately 20 microns to approximately 80 microns in diameter, D90, and / or Oxygen content of approximately 20 ppm to 1000 ppm (relative to the weight of the powder), for example, approximately 100 ppm to 1000 ppm, or 100 ppm to 250 ppm.

[0035] The tantalum powder of the present invention can be a non-aggregated powder, and the properties / parameters described herein apply to the non-aggregated powder.

[0036] The tantalum powder of the present invention can be a non-agglomerated powder, and the properties / parameters described herein apply to the non-agglomerated powder.

[0037] The tantalum powder may optionally be doped with phosphorus. For example, the phosphorus doping level can be at least 10 ppm, at least 50 ppm, or at least 100 ppm, or, for example, about 50 ppm to about 500 ppm. Possible forms of phosphorus include phosphoric acid or ammonium hexafluorophosphate.

[0038] Tantalum powder may optionally be doped with other elements such as yttrium and silica, or with one or more other dopants such as gas dopants and / or metal dopants. The doping level may be at least 5 ppm, at least 10 ppm, at least 25 ppm, at least 50 ppm, or at least 100 ppm, or for example, about 5 ppm to about 500 ppm. One or more dopants may be used to improve the particle stability of the powder or articles made from the powder, and / or to enhance other properties.

[0039] The tantalum powder of the present invention can be used to form an article or a part or component thereof.

[0040] For example, the articles may be orthopedic implants, other medical implants, or dental implants. Orthopedic implants may be replacements for hands, ankles, shoulders, hips, knees, bones, total joint reconstruction (arthroplasty), craniofacial reconstruction, or spines, or other parts of the human or animal body. Dental implants may be for facial reconstruction, which may include, but is not limited to, the mandible or maxilla. Medical or dental implants are useful in humans, as well as in other animals such as dogs, cats, and other animals.

[0041] The article may be a tracer or a medical marker, such as a radiation Ta marker.

[0042] The articles may be surgical instruments or their components. The articles may be reinforcement materials.

[0043] The items may be aerospace components.

[0044] The articles can be bosses, such as bosses on coil sets used in physical vapor deposition processes. The bosses may include open-cell structures and solid structures.

[0045] The article can be any article used in a metal deposition process, such as a sputtering target or a part thereof, or a structure used to hold a sputtering target, etc. For example, the article can be a coil set or a component thereof for a physical deposition process.

[0046] The tantalum powder of the present invention can be used in tantalum spraying (e.g., cold spraying) for coating and / or repairing articles or surfaces.

[0047] The tantalum powder of the present invention can be used in metal injection molding applications and processes.

[0048] The tantalum powder of the present invention can be produced using a plasma heat treatment process. For example, a process for producing the tantalum powder of the present invention may include, essentially consist of, or include the following steps: a) plasma heat treatment of a starting tantalum powder in an inert atmosphere to at least partially melt at least the outer surface of the starting tantalum powder to obtain heat-treated tantalum powder; and b) cooling the heat-treated tantalum powder in an inert atmosphere to obtain tantalum powder. The starting tantalum powder may be completely melted or at least 90% by weight by plasma treatment (e.g., in the plasma torch region of a plasma reactor).

[0049] In this process, the starting tantalum powder may be sodium-reduced tantalum powder or other reduced tantalum powder, or any other tantalum powder source described herein. In this process, the starting tantalum powder may be basic lot tantalum powder.

[0050] The starting tantalum powder can be obtained by melt-reduction of potassium tantalate fluoride (K2TaF7) or by sodium reduction of tantalum in the gas phase (also called "secondary particles of gas-phase reduction of tantalum"). Therefore, the starting tantalum powder can be produced by tantalum salt reduction.

[0051] Molten reduced tantalum particles can be obtained by a process that involves reducing potassium tantalate fluoride (K2TaF7) with sodium (or other reducing agent) in a molten salt to produce tantalum particles which may be aggregates of primary particles, and then optionally washing these particles with water, acid washing, and drying.

[0052] Gas-phase reduced tantalum particles can be obtained by contacting and reacting vaporized tantalum chloride with vaporized sodium. These gas-phase reduced tantalum particles may consist of numerous primary tantalum particles formed by the reaction of tantalum chloride with sodium, and coated with the sodium chloride produced by this reaction.

[0053] To produce the tantalum powder of the present invention, the starting tantalum powder used in this process can be considered to be a basic lot powder such as basic lot tantalum. The starting tantalum powder that can be used can be considered to be secondary particles of plasma-treated tantalum powder.

[0054] In this process, the starting tantalum powder can be ingot-induced tantalum. In this process, the starting tantalum powder can be powder-metallurgy-induced tantalum powder.

[0055] The starting tantalum powder may optionally be unhydrogenated or hydrogenated before being introduced into the plasma treatment.

[0056] In the process of producing tantalum powder, prior to step a, the first tantalum powder is sintered to obtain sintered powder (which may be in the form of a compacted log or other shaped sintered block), then the sintered powder or sintered block is electron-beam melted to obtain an ingot, and then the ingot is powdered back into starting tantalum powder to form the starting tantalum powder. Sintering can be carried out at conventional sintering temperatures for tantalum powder. For example, as just one example, tantalum powder can be sintered at a temperature of about 700°C to about 1450°C (or about 800°C to about 1400°C, or about 900°C to about 1300°C). The sintering time can be from 1 minute to several hours, for example, about 10 minutes to 4 hours, or 10 minutes to 3 hours, or about 15 minutes to about 2 hours, or about 20 minutes to about 1 hour, or other times. Optionally, one or more heat treatments or sinterings may be performed, which may be at the same temperature, the same time, or different temperatures and / or different heat treatment times. Sintering can be carried out in an inert atmosphere such as an argon atmosphere. Sintering can also be carried out in a conventional furnace used for sintering metal powders.

[0057] As an option for forming the tantalum ingot that is subsequently powdered, the tantalum ingot can have any volume, diameter, or shape, or can be of any volume, diameter, or shape. The electron beam treatment is approximately 1 × 10⁻⁶ -3 Torr ~ approximately 1 × 10 -6 Under Torr vacuum, at 20,000 volts to 28,000 volts and 15 to 40 amperes, the melting rate can be approximately 300 lbs. to 800 lbs. per hour. The melting rate is approximately 1 × 10⁻⁶. -4 Torr~1×10 -5 It is more preferable that under Torr vacuum, at 24,000 volts to 26,000 volts and 17 to 36 amperes, the melting rate is approximately 400 lbs. to approximately 600 lbs. per hour. For VAR processing, the melting rate is 2 × 10⁻⁶-2 Torr~1×10 -4 Under Torr vacuum, with 25 volts to 45 volts and 12,000 amperes to 22,000 amperes, the pressure is preferably 500 lbs. to 2,000 lbs. per hour, and 2 × 10 -2 Torr~1×10 -4 It is more preferable that the pressure is 800 lbs. to 1200 lbs. per hour under Torr vacuum, with a voltage of 30 volts to 60 volts and a current of 16,000 amperes to 18,000 amperes.

[0058] Tantalum ingots can have a diameter of at least 4 inches, or at least 8 inches, or at least 9.5 inches, at least 11 inches, or at least 12 inches or larger. For example, tantalum ingots can have a diameter of about 10 inches to about 20 inches, or about 9.5 inches to about 13 inches, or 10 inches to 15 inches, or 9.5 inches to 15 inches, or 11 inches to 15 inches. The height, i.e., length, of the ingot can be any size, such as at least 5 inches, or at least 10 inches, or at least 20 inches, at least 30 inches, at least 40 inches, or at least 45 inches. For example, the length, i.e., height, of the ingot can be about 20 inches to about 120 inches, or about 30 inches to about 45 inches. Ingots can have a cylindrical shape, but other shapes can also be used. After the ingot is formed, it can optionally be mechanically cleaned using conventional techniques. For example, mechanical cleaning (of the surface) can reduce the diameter of the ingot, achieving a diameter reduction of approximately 1% to 10%. Specifically, an ingot that has an as-cast nominal diameter of 12 inches can have a diameter of 10.75 inches to 11.75 inches after mechanical cleaning.

[0059] Tantalum ingots can be pulverized into starting tantalum powder by first making the ingot brittle, then crushing the ingot, or by subjecting the ingot to a particle powdering process such as milling, jaw crushing, roll crushing, or crossbeating. To make the ingot brittle, it can be hydrogenated by, for example, placing it in a furnace with a hydrogen atmosphere.

[0060] Regarding plasma heat treatment, this is also known as plasma treatment or plasma processing. In the present invention, RF plasma treatment or induction plasma treatment can be used. For example, an RF thermal plasma system or induction plasma reactor such as the PL-35LS, PL-50, TEK-15, or other models from Tekna in Sherbrooke, Quebec, Canada can be used. The central gas for the plasma can be argon, a mixture of argon and other gases, or other gases such as helium. The supply rate of the central gas can be a suitable flow rate such as about 10 L / min to about 100 L / min, or about 15 L / min to about 60 L / min, or other flow rates. The sheath gas for the plasma can be argon, a mixture of argon and other gases, or other inert gases or other gases such as helium. The sheath gas supply rate can be set to a suitable rate such as approximately 10 L / min to approximately 120 L / min, or approximately 10 L / min to approximately 100 L / min, or other flow rates. The carrier gas for the starting tantalum powder can be argon, a mixture of argon and other gases (for example, hydrogen can be added to increase plasma intensity), or other inert gases or other gases such as helium. The carrier gas supply rate can be set to a suitable rate such as approximately 1 L / min to approximately 15 L / min, or approximately 2 L / min to approximately 10 L / min, or other flow rates. The rate at which the starting tantalum powder is supplied to the plasma torch area can be any flow rate, for example, approximately 1 g / min to approximately 120 g / min of tantalum powder, or approximately 5 g / min to approximately 80 g / min of starting tantalum powder. Generally, the lower the supply rate of the starting tantalum powder, the more uniform and completely spherical the starting tantalum powder will be processed. After leaving the plasma torch region, a cooling gas can be optionally used through one or more cooling ports. The cooling gas can be any suitable non-reactive gas, such as helium or argon. When using a cooling gas, it can be supplied at various flow rates.For example, the flow rate of the cooling gas can be approximately 25 L / min to 300 L / min, or approximately 50 L / min to approximately 200 L / min, or other magnitudes. Instead of using a cooling gas, or in addition to using a cooling gas, a gravity and / or water-cooled cooling jacket may be optionally used. Designs described in U.S. Patent No. 5,200,595 and International Publication No. 92 / 19086 may be used. A passivation gas may optionally be used after cooling the powder, or after cooling the powder has begun. The passivation gas may be oxygen, air, or a combination of air and oxygen. The flow rate of the passivation gas may be any velocity, such as approximately 0.1 L / min to approximately 1 L / min, or other magnitudes. The plasma torch chamber pressure may be any suitable pressure, such as approximately 0.05 MPa to approximately 0.15 MPa. The anode voltage may be approximately 5 kV to approximately 7.5 kV. The frequency of the RF plasma system may be 3 MHz, or other values. The anode current can be approximately 2.5 A to 4.5 A. The power can be approximately 15 kW to 35 kW. The distance from the plasma torch to the supply nozzle or probe position can be adjusted or changed. This distance can be 0 cm, approximately 0 cm, or approximately 0 cm to approximately 8 cm. The greater the distance, the less surface evaporation occurs from the starting powder. Therefore, if the starting tantalum powder has a very irregular shape and an aspect ratio greater than 2 or 3, there is an option to bring the supply nozzle distance closer to 0 cm. If the starting tantalum powder has a more regular shape, such as an aspect ratio of approximately 1.3 to 2, the supply nozzle distance can be arbitrarily increased from the plasma torch. In addition, a higher plasma powder setting can be used to handle starting tantalum powder with a more irregular shape.

[0061] The plasma-treated powder can optionally be recovered, for example, under a protective atmosphere such as an inert gas like argon. The recovered powder can be passivated using a water tank or similar method. The recovered powder can be introduced into a water tank (for example, by submerging it in water).

[0062] To remove small particles such as nanomaterials deposited on the tantalum surface of the tantalum spheres (for example, to remove adjuncts and other free materials on the spheres), the recovered powder can optionally be subjected to ultrasonic treatment or other powder vibration methods. The recovered tantalum spheres can optionally be dried under a protective gas such as an inert gas like argon. This drying can be carried out at any temperature, for example, 50°C to 100°C, for 10 minutes to 24 hours, or 1 hour to 5 hours. The recovered powder can be placed in a sealed bag, such as an aluminum-lined antistatic bag, for further use.

[0063] The plasma treatment used in this invention allows efforts to create a particle size distribution and / or other characteristics of the starting tantalum powder up to the finished tantalum powder exiting the plasma process. By other methods, the particle size can be substantially maintained except for removing sharp edges and / or surface roughness and / or making the starting tantalum powder spherical or more spherical. Thus, prior to introducing the starting tantalum powder into the plasma treatment, one or more steps can be performed on the starting tantalum powder to achieve a desired particle size distribution and / or other particle characteristics. For example, the particle size distribution of the starting tantalum powder can be such that its D10 and / or D90 are within 50%, 40%, 30%, 25%, 20%, 15%, 10%, or 5% of the D50 of the starting tantalum powder.

[0064] Before introducing the starting tantalum powder into plasma treatment, one or more sieving processes or other particle screening processes can be performed to obtain, for example, the particle size distribution described above, or to remove other sieving components. Examples of removing other sieving components include, but are not limited to, mesh cuts of 200 or less, 225 or less, 250 or less, 275 or less, 300 or less (mesh is US mesh size).

[0065] The starting tantalum powder before plasma treatment may have one of the following particle size ranges: the average particle size may be approximately 0.5 microns to approximately 10 microns, or approximately 5 microns to approximately 25 microns, or approximately 15 microns to approximately 45 microns, or approximately 35 microns to approximately 75 microns, or approximately 55 microns to approximately 150 microns, or approximately 105 microns to approximately 250 microns.

[0066] In the process of producing tantalum powder, the starting tantalum powder may have a first particle size distribution, and the obtained (i.e., finished) tantalum powder (e.g., after plasma treatment) may have a second particle size distribution. The first and second particle size distributions may be within 15% of each other, within 10% of each other, within 5% of each other, within 2.5% of each other, or within 1% of each other.

[0067] The starting tantalum powder can be deoxygenated before being introduced into plasma processing to remove oxygen from the tantalum powder.

[0068] The starting tantalum powder before plasma treatment can be classified or sieved to remove particles of various sizes, for example, particles smaller than 20 microns, 15 microns, 10 microns, or 5 microns.

[0069] After plasma treatment, the plasma-treated tantalum powder can undergo one or more post-treatment steps.

[0070] For example, as a post-processing step, the plasma-treated tantalum powder can be passed through one or more sieves to remove plasma-treated tantalum powder of a certain size.

[0071] For example, as a post-processing step, imperfections can be removed from the tantalum spheres using ultrasonic treatment or other vibration techniques. For instance, tantalum spheres obtained by plasma treatment can be placed in a water tank and subjected to ultrasonic treatment to remove nanomaterials from the tantalum spheres, after which the tantalum spheres can be recovered.

[0072] For example, as one post-treatment step, at least one deoxygenation step, or "deox" step, may be optionally performed on the plasma-treated tantalum. Deoxygenation may involve heating the plasma-treated tantalum to a temperature of about 500°C to about 1000°C or higher in the presence of at least one type of oxygen getter. For example, the oxygen getter may be magnesium metal or a magnesium compound. The magnesium metal may be in the form of plates, pellets, or powder. Other oxygen getter materials may also be used.

[0073] For example, as a post-processing step, one or more heat treatment or slow cooling steps may be optionally performed on the plasma-treated tantalum. Regarding the heat treatment step for plasma-treated tantalum, this heat treatment can be performed in a conventional furnace under vacuum or at an inert temperature. The heat treatment temperature is typically at least 800°C, or at least 1000°C, or about 800°C to about 1450°C, or about 1000°C to about 1450°C. Any heat treatment time can be used, but is not limited to, examples of which include at least 10 minutes, at least 30 minutes, or about 10 minutes to about 2 hours or more. Optionally, one or more heat treatments may be performed, which may be at the same temperature, the same time, or different temperatures and / or different heat treatment times. When heat treatment is used, after the heat treatment, the plasma-treated tantalum may maintain the hole flow rate achieved before the heat treatment, or it may be within 20%, 10%, or 5% of the hole flow rate.

[0074] For example, as a post-treatment step, acid leaching can be performed on plasma-treated tantalum using conventional techniques or other suitable methods. Various processes described in U.S. Patent Nos. 6,312,642 and 5,993,513 can be used herein, for example, and the whole thereof constitutes part of this specification by reference. Acid leaching can be performed using an aqueous acid solution containing strong mineral acids, such as nitric acid, sulfuric acid, or hydrochloric acid, as the main acid. Hydrofluoric acid (e.g., HF) can also be used in small amounts (e.g., less than 10% by weight, less than 5% by weight, or less than 1% by weight relative to the total weight of the acid). The mineral acid concentration (e.g., HNO3 concentration) can be in the range of about 20% by weight to about 75% by weight in the acid solution. Acid leaching can be performed at elevated temperatures (above room temperature to about 100°C) or at room temperature using acid compositions and techniques such as those shown in U.S. Patent No. 6,312,642. The acid leaching process is typically carried out under standard atmospheric conditions (e.g., approximately 760 mm Hg). By using the conventional acid compositions and pressure conditions described above, soluble metal oxides can be removed from the deoxygenated powder under these conditions.

[0075] Plasma-treated tantalum can optionally be nitrogen-doped. The nitrogen may be in any state, such as gas, liquid, or solid. The powder of the present invention may contain any amount of nitrogen, either as a dopant or in other forms. Nitrogen may be present in any proportion in crystalline and / or solid solution forms. The nitrogen doping level can be 5 ppm to 5000 ppm or more.

[0076] The plasma-treated tantalum of the present invention can be used in many ways. For example, the plasma-treated tantalum can be used in additive manufacturing or additive manufacturing processes, also known as 3D printing, to form articles or parts of articles. The plasma-treated tantalum powder of the present invention can be used in processes or apparatus that can use metal powders. The plasma-treated powder of the present invention facilitates the implementation of additive manufacturing. In addition, or instead, the plasma-treated powder of the present invention improves the supply of powder to the additive manufacturing apparatus and / or, through a programmed design in the printing apparatus, more precise articles can be obtained.

[0077] Additive manufacturing processes that can utilize the plasma-treated tantalum powder of the present invention include laser powder bed fusion, electron beam powder bed fusion, directed energy deposition, laser cladding via powder or wire, material jetting, sheet lamination, or vat photopolymerization.

[0078] These additive manufacturing processes include laser metal melting, laser sintering, metal laser melting, or direct metal printing or direct metal laser sintering. In this process, a high-power laser beam is scanned over a powder bed, sintering the powder into the desired shape along the path of the laser beam. After each layer, the powder bed is lowered a short distance to apply a new layer of powder. The entire process is carried out in a sealed chamber with an inert (e.g., argon) or active controlled gas atmosphere to fine-tune the properties of the material / product.

[0079] One of the additive manufacturing processes described above is called laser metal deposition (LMD) or near-net shape. In this process, a high-power laser beam connected to a robot or gantry system is used to form a molten pool on a metal substrate, which is supplied with powder or metal wire. In LMD, the powder is contained in a carrier gas and directed onto the substrate through a nozzle concentric with the laser beam. Alternatively, wire may be supplied from the side. The powder or wire is melted to form a molten pool, which adheres to the substrate and grows layer by layer. Additional gas jets concentric with the laser beam can provide further shielding or process gas protection.

[0080] The additive manufacturing processes described above include gas metal arc welding and plasma welding, which involve melting metal powder to form 3D shapes layer by layer. In these processes, metal wire is added as an electrode molten material in the arc, and its droplets form layers on the substrate. Considering the thermal sensitivity of most materials used in additive manufacturing, low heat input processes such as controlled short-circuit metal transfer are preferred. A shielding gas protects the layers from the ambient air.

[0081] Plasma additive manufacturing is similar to laser metal deposition, in which powder is guided onto a substrate in a gas stream and melted by plasma heating.

[0082] One of the additive manufacturing processes described above is called thermal spraying. In this process, droplets obtained from molten and heated powder particles or molten wire are accelerated onto the substrate by a gas stream, ensuring local adhesion through kinetic energy and heat. When used in additive manufacturing, thermal spraying is applied layer by layer to construct parts with no geometric complexity, such as tubes or reducers. The process gas protects the hot material from the ambient atmosphere gas and helps to fine-tune the properties of the material.

[0083] The above additive manufacturing process includes an electron beam melting or powder bed melting process using an electron beam in a vacuum, which is called. This process is similar to laser sintering.

[0084] The additive manufacturing apparatus or process used to form an article can have one or more of the following settings: a laser output of 150 W to about 175 W, or 155 W to 165 W; a scanning speed of about 100 mm / s to about 500 mm / s, such as about 300 mm / s to about 400 mm / s; a hatch spacing of about 30 microns to about 100 microns, such as about 80 microns to about 90 microns; a layer thickness of about 10 microns to about 50 microns, such as about 30 microns to about 40 microns; and / or an energy density of about 3 J / mm 2 ~ about 20 J / mm 2 For example, about 4 J / mm 2 ~ about 6 J / mm 2 In some cases, settings lower than the maximum laser settings may be utilized to reduce heat input and / or minimize thermal stress and / or minimize part deformation.

[0085] In additive manufacturing, it is preferred to use a tantalum-based plate, but other base plates such as stainless steel or stainless steel alloys can also be used. The tantalum-based plate can minimize the difference in coefficient of thermal expansion (CTE) and / or the difference in thermal conductivity between the part and the base plate. As a result, the residual thermal stress in the part can be minimized and / or the part can be prevented from lifting off the plate.

[0086] It has been discovered that by using the additive manufacturing process with the tantalum powder of the present invention, an article formed from the tantalum powder of the present invention can achieve desirable tensile properties. When the article is slowly cooled at a temperature of about 800°C to about 2000°C (e.g., for 10 minutes to 10 hours, or 30 minutes to 3 hours, or 1 hour to 2 hours), one or more of these properties can be enhanced.

[0087] In the formation of additively manufactured (AM) objects or articles, the present invention can achieve one or more of the following properties: The maximum tensile strength (UTS) can be at least 50% or at least 100% greater than that of a processed Ta having the same shape. The UTS can be greater than 50 KSI, greater than 70 KSI, greater than 80 KSI, or greater than 90 KSI, for example, about 50 KSI to about 100 KSI. The yield stress can be at least 50% or at least 100% greater than that of a processed Ta having the same shape. The yield stress can be greater than 35 KSI, greater than 40 KSI, greater than 50 KSI, or greater than 80 KSI, for example, about 35 KSI to about 90 KSI. The slow-cooled AM articles of the present invention showed improved yield stress. The slow-cooled AM articles of the present invention showed improved yield stress without impairing the UTS. The elongation can be about 1% to about 50%, for example, about 3% to 40%, or 5% to 35%. The slow-cooled AM article of the present invention showed improved elongation. The present invention enables an acceptable and / or good balance of UTS, yield stress, and elongation.

[0088] Plasma-treated tantalum powder used in additive manufacturing enables the creation of a wide variety of articles, resulting in superior quality and precision. For example, articles can be orthopedic implants, other medical implants, or dental implants. Orthopedic implants can replace parts of the hand, ankle, shoulder, hip, knee, bone, complete joint reconstruction (arthroplasty), craniofacial reconstruction, or spine, or other parts of the human or animal body. Dental implants can be used for facial reconstruction, including, but not limited to, the mandible or maxilla. Medical or dental implants are useful in humans and other animals such as dogs or cats.

[0089] The articles can be bosses, such as bosses on coil sets used in physical vapor deposition processes. The bosses may include open-cell structures and solid structures.

[0090] The article can be any article used in a metal deposition process, such as a sputtering target or a part thereof, or a structure used to hold a sputtering target, etc. For example, the article can be a coil set or a component thereof for a physical deposition process.

[0091] As an alternative, the plasma-treated tantalum powder can be further processed to form capacitor electrodes (e.g., capacitor anodes). This can be done, for example, by compressing the plasma-treated powder to form a pressed body, sintering the pressed body to form a porous body, and then anodizing the porous body. Powder pressing can be achieved by any conventional method, for example, by placing the powder in a mold and compressing the powder by pressing to form a pressed body, i.e., a compacted powder. Various pressing densities can be used, with a pressing density of approximately 1.0 g / cm³ being typical. 3 ~7.5 g / cm 3Examples include, but are not limited to, the following. The powder can be sintered, anodized, and / or impregnated with an electrolyte by any conventional method. For example, the sintering, anodizing, and impregnation techniques described in U.S. Patents 6,870,727, 6,849,292, 6,813,140, ​​6,699,767, 6,643,121, 4,945,452, 6,896,782, 6,804,109, 5,837,121, 5,935,408, 6,072,694, 6,136,176, 6,162,345, and 6,191,013 can be used herein. These patents, in whole, constitute part herein by reference. Sintered anode pellets can be deoxygenated, for example, by a process similar to that described above for powders. The anodized porous body can be further impregnated with a manganese nitrate solution and fired to form a manganese oxide film on the porous body. In wet valve metal capacitors, a liquid electrolyte can be used as the cathode in combination with its housing. A cathode plate can be applied by thermally decomposing manganese nitrate into manganese dioxide. The pellets can be immersed, for example, in an aqueous manganese nitrate solution and then fired in a furnace at approximately 250°C or another suitable temperature to produce a manganese dioxide film. This process can be repeated several times while changing the specific gravity of the nitrate to create a thin film on all inner and outer surfaces of the pellet. The pellets can then be optionally immersed in graphite and silver to improve the connection with the manganese dioxide cathode plate. For example, an electrical connection can be achieved by depositing carbon on the cathode surface. The carbon can then be coated with a conductive material to facilitate connection with external cathode terminals. From this perspective, capacitor packaging can be carried out by conventional methods, such as chip manufacturing, resin encapsulation, mold molding, and lead wires.

[0092] As part of anode formation, for example, camphor (C 10 H 16A binder such as O) can be added to the powder in an amount of 3% to 5% by weight, for example, with the powder being 100% by weight. The mixture is then placed in a mold, compressed, and sintered by heating at 1000°C to 1400°C for 0.3 to 1 hour while still compressed. This molding method makes it possible to obtain pellets made of a sintered porous body.

[0093] When using pellets obtained using the molding process described above as a capacitor anode, it is preferable to embed the lead wires in the powder before compression molding in order to integrate the lead wires with the pellets.

[0094] Capacitors can be manufactured using the pellets described above. A capacitor with an anode can be obtained by oxidizing the surface of the pellet, the cathode facing the anode, and the solid electrolyte layer placed between the anode and cathode.

[0095] The cathode terminals are connected to the cathode by soldering or other means. A resin shell is formed around the component, which consists of the anode, cathode, and solid electrolyte layer. Examples of materials used to form the cathode include graphite and silver. Examples of materials used to form the solid electrolyte layer include manganese dioxide, lead oxide, and conductive polymers.

[0096] To oxidize the surface of the pellets, for example, a method can be used that involves treating the pellets for 1 to 3 hours at a temperature of 30°C to 90°C in an electrolyte solution such as nitric acid or phosphoric acid with a concentration of 0.1 wt% by current density of 40 mA / g to 120 mA / g, while increasing the voltage from 20 V to 60 V. A dielectric oxide film is formed on the oxidized portion during such a time.

[0097] As described above, the plasma-treated tantalum of the present invention can be used to form capacitor anodes (e.g., wet anodes or solid anodes). Capacitor anodes and capacitors (wet electrolytic capacitors, solid capacitors, etc.) can be used, for example, in U.S. Patent Nos. 6,870,727, 6,813,140, ​​6,699,757, 7,190,571, 7,172,985, 6,804,109, 6,788,523, 6,527,937, 6,462,934, 6,420,043, 6,375,704, 6,338,816, 6,322,912, and 6,616,6 The material can be formed in any way described in U.S. Patent No. 23, U.S. Patent No. 6,051,044, U.S. Patent No. 5,580,367, U.S. Patent No. 5,448,447, U.S. Patent No. 5,412,533, U.S. Patent No. 5,306,462, U.S. Patent No. 5,245,514, U.S. Patent No. 5,217,526, U.S. Patent No. 5,211,741, U.S. Patent No. 4,805,704, and U.S. Patent No. 4,940,490 (all of these documents, in whole, constitute a part of this specification by reference) and / or may have one or more of the components / designs described in these documents. The powder can typically be formed into compacts and sintered to form a sintered body, which can then be anodized by the prior art. Capacitor anodes made from powder produced according to the present invention are considered to have improved leakage characteristics. The capacitor of the present invention can be used in a variety of end applications, including automotive electronics, mobile phones, smartphones, computers such as monitors and motherboards, consumer electronics including TVs and CRTs, printers / copiers, power supplies, modems, notebook computers, and disk drives.

[0098] Further details of the starting tantalum powder, plasma-treated tantalum powder, and components formed from the tantalum powder are described below. These further details constitute a selective embodiment of the present invention.

[0099] According to the method of the present invention, tantalum powder having the following properties can be produced: a) Apparent density of approximately 4 g / cc to approximately 12.3 g / cc b) D10 particle size of approximately 5 microns to approximately 25 microns, c) D50 particle size of approximately 20 microns to approximately 50 microns, d) D90 particle size of approximately 30 microns to approximately 100 microns, and / or e) Approximately 0.05 m 2 / g ~ approx. 20 m 2 BET surface area per g. Tantalum powder may have at least one of the following properties: a) Apparent density of approximately 9 g / cc to approximately 12.3 g / cc b) D10 particle size of approximately 12 microns to approximately 25 microns, c) D50 particle size of approximately 20 microns to approximately 40 microns, d) D90 particle size of approximately 30 microns to approximately 70 microns, and / or e) Approximately 0.1 m 2 / g ~ approx. 15 m 2 BET surface area per g.

[0100] For the purposes of the present invention, at least one, at least two, at least three, at least four, or all five of these properties may be present.

[0101] In at least one embodiment of the present invention, plasma-treated tantalum powder (or starting tantalum powder), or any article formed from the tantalum powder of the present invention, may have the following properties, although it is understood that the powder or article may also have properties outside of these ranges: Purity level: The oxygen content is approximately 20 ppm to 60,000 ppm, or approximately 100 ppm to 60,000 ppm, for example, approximately 20 ppm to 1,000 ppm, or approximately 40 ppm to 500 ppm, or approximately 50 ppm to 200 ppm, or approximately 250 ppm to 50,000 ppm, or approximately 500 ppm to 30,000 ppm, or approximately 1,000 ppm to 20,000 ppm. BET(m 2 The ratio of oxygen (ppm) to (g) can be approximately 2000 to 4000, for example, approximately 2200 to 3800, approximately 2400 to 3600, approximately 2600 to 3400, or approximately 2800 to 3200. The carbon content is approximately 1 ppm to 100 ppm, more preferably approximately 10 ppm to 50 ppm, or approximately 20 ppm to 30 ppm. The nitrogen content is approximately 5 ppm to approximately 20,000 ppm, or approximately 100 ppm to approximately 20,000 ppm or more, more preferably approximately 1,000 ppm to approximately 5,000 ppm, or approximately 3,000 ppm to approximately 4,000 ppm, or approximately 3,000 ppm to approximately 3,500 ppm. The hydrogen content is approximately 1 ppm to 1000 ppm, approximately 10 ppm to 1000 ppm, and more preferably approximately 300 ppm to 750 ppm, or approximately 400 ppm to 600 ppm. The iron content is approximately 1 ppm to 50 ppm, more preferably approximately 5 ppm to 20 ppm. The nickel content is approximately 1 ppm to 150 ppm, more preferably approximately 5 ppm to 100 ppm, or approximately 25 ppm to 75 ppm. The chromium content is approximately 1 ppm to 100 ppm, more preferably approximately 5 ppm to 50 ppm, or approximately 5 ppm to 20 ppm. The sodium content is approximately 0.1 ppm to approximately 50 ppm, and more preferably approximately 0.5 ppm to approximately 5 ppm. The potassium content is approximately 0.1 ppm to approximately 100 ppm, more preferably approximately 5 ppm to approximately 50 ppm, or approximately 30 ppm to approximately 50 ppm. The magnesium content is approximately 1 ppm to 50 ppm, more preferably approximately 5 ppm to 25 ppm. The phosphorus (P) content is approximately 1 ppm to approximately 500 ppm, or approximately 5 ppm to approximately 500 ppm, and more preferably approximately 100 ppm to approximately 300 ppm. The fluoride (F) content is approximately 1 ppm to approximately 500 ppm, more preferably approximately 25 ppm to approximately 300 ppm, or approximately 50 ppm to approximately 300 ppm, or approximately 100 ppm to approximately 300 ppm.

[0102] Plasma-treated powder (or starting tantalum powder) (primary, secondary, or tertiary) can have the following particle size distribution (as a percentage of the total) based on the mesh size: The +60# is present in approximately 0.0% to 1%, preferably approximately 0.0% to 0.5%, and more preferably 0.0% or approximately 0.0%. 60 / 170 is approximately 45% to 70%, preferably approximately 55% to 65%, or approximately 60% to 65%. The proportion of 170 / 325 is approximately 20% to 50%, preferably 25% to 40%, or 30% to 35%. The 325 / 400 content is approximately 1.0% to 10%, preferably approximately 2.5% to 7.5%, for example, approximately 4% to 6%. -400 is present in an amount of approximately 0.1% to 2.0%, preferably approximately 0.5% to 1.5%.

[0103] When the powder is formed into an anode by sintering at 1150°C for 10 minutes, with a conversion temperature of 60°C, a press density of 4.5 g / cc, and a conversion voltage of 6 V, it has a capacitance of approximately 20,000 CV / g to approximately 800,000 CV / g, for example, approximately 100,000 CV / g to approximately 300,000 CV / g, or approximately 150,000 CV / g to approximately 400,000 CV / g. Furthermore, the leakage current can be less than 20 nA / μFV, and can be approximately 2.5 nA / μFV to approximately 15 nA / μFV, or approximately 3.0 nA / μFV to approximately 10 nA / μFV. These capacitance and / or leakage current values ​​or ranges can also be obtained by sintering at 1200°C or 1250°C for 10 minutes, and / or by a conversion voltage of 5 volts to 16 volts. Furthermore, any individual value within the range of capacitance and leakage current can be used for the purposes of the present invention.

[0104] The plasma-treated tantalum powder of the present invention may have a pore size distribution that is monomodal or multimodal, such as bimodal.

[0105] The plasma-treated tantalum powder of the present invention is approximately 0.01 m 2 / g ~ approx. 20 m 2 / g, more preferably about 0.05 m 2 / g ~ approx. 5 m 2 / g, for example, about 0.1 m 2 / g ~ approx. 0.5 m 2 It can have a BET surface area of ​​ / g.

[0106] As described above, the starting tantalum powder can be obtained by various processes used to obtain tantalum powder. As described above, the starting tantalum powder to be plasma treated can be the raw material tantalum powder. The raw material tantalum powder (e.g., basic lot powder) is at least 0.1 m 2 / g, or at least 0.5 m 2The powder having a surface area of ​​1 / g can be obtained or manufactured by a process capable of providing such a powder. In this regard, any tantalum powder can be used. Specific examples of raw material tantalum manufacturing processes include sodium / halide flame encapsulation (SFE), sodium reduction process of potassium tantalate fluoride, magnesium reduction process of tantalum oxide, gas-phase hydrogen reduction process of tantalum pentachloride, and grinding process of metallic tantalum. In the SFE process, gaseous sodium is reacted with a gaseous metal halide such as gaseous tantalum halide to produce an aerosol core material and a salt. The techniques employed in the SFE process applicable to the preparation of the raw material tantalum powder of the present invention are described in U.S. Patents 5,498,446 and 7,442,227, which in whole form constitute part of this specification by reference. See also "Processingsalt-encapsulated tantalum nanoparticles for high purity, ultra high surfacearea applications" by Barr, JL et al., J. Nanoparticle Res. (2006), 8:11-22. An example of a chemical structure used in the production of metal powders by the SFE process, U.S. Patent No. 5,498,446, is given below, where "M" refers to a metal such as Ta: MCl x +XNa+Inert→M+XNaCl+Inert. In this chemical structure, the reactant MCl xAn example of a tantalum halide that can be used is tantalum pentachloride, and argon gas can be used as the inert gas and carrier gas. Initially, core particles (e.g., Ta) are produced by the flame with salt remaining in the gas phase, and grow by aggregation. As the heat-dissipated salt condenses on the core particles and the salt-encapsulated particles grow, uncoated core particles are captured by the salt particles. The salt capsules allow for control of size and shape and protect the core particles from oxidation and / or hydrolysis during storage and handling before use in the production of plasma-treated tantalum powder. The capsules can be removed by known methods such as vacuum sublimation and / or water washing before using the tantalum powder in the production of plasma-treated tantalum powder.

[0107] Alternatively, the starting tantalum powder can be obtained by sodium reduction of tantalum salts such as diluted sodium tantalate fluoride, or by other chemical treatment methods, or by ingot processing methods.

[0108] The raw material or starting tantalum powder may contain primary particles having an average particle size in the range of 1 nm to about 500 nm, or 10 nm to 300 nm, or 15 nm to 175 nm, or 20 nm to 150 nm, or 25 nm to 100 nm, or 30 nm to 90 nm, or other sizes. The average particle size and particle size distribution of the primary particles may depend on the preparation method. The primary particles may tend to form clusters or agglomerates with larger particle sizes than the primary particles. The shape of the raw material or starting tantalum powder particles may be flake-shaped, angular, nodular, or spherical, or any combination thereof, or variations thereof, but are not limited thereto. The raw material powder used to carry out the present invention may have any purity with respect to tantalum metal, but higher purity is preferred. For example, the tantalum purity (e.g., by weight) of the raw material or starting powder can be 95%Ta or higher, or 99%Ta or higher, for example, about 99.5%Ta or higher, more preferably 99.95%Ta or higher, even more preferably 99.99%Ta or higher, or 99.995%Ta or higher, or 99.999%Ta or higher.

[0109] As part of the plasma-treated tantalum powder manufacturing process of the present invention, the tantalum powder can be passivated using an oxygen-containing gas such as air at any stage before or after plasma treatment. Passivation is typically used to form a stable oxide film on the powder during treatment and before forming a sintered body using the powder. Therefore, the powder manufacturing process of the present invention may include hydrogen doping and passivation operations.

[0110] Passivation of tantalum powder can be carried out by any suitable method. Passivation can be achieved in any suitable container, such as a retort, furnace, vacuum chamber, or vacuum furnace. Passivation can be achieved in any equipment used for processing metal powders, such as heat treatment, deoxygenation, nitriding, de-oiling (delubing), granulation, milling, and / or sintering. Passivation of metal powder can be achieved under vacuum. Passivation may include filling a container with an oxygen-containing gas to a specific gas pressure and holding the gas in the container for a specific time. The oxygen content level of the gas used for passivating the powder can be 1% to 100% by weight, or 1% to 90% by weight, or 1% to 75% by weight, or 1% to 50% by weight, or 1% to 30% by weight, or 20% to 30% by weight, or the same or higher oxygen content as air or atmosphere, or other levels. Oxygen can be used in combination with an inert gas such as nitrogen, argon, or a combination thereof, or with other inert gases. Inert gases do not react with tantalum during the passivation process. Preferably, an inert gas such as nitrogen and / or argon may constitute all or essentially all (e.g., more than 98%) of the remaining passivation gas excluding oxygen. Air can be used as the passivation gas. Air may refer to atmospheric air or dry air. The composition of dry air is typically nitrogen (about 75.5% by weight), oxygen (about 23.2% by weight), argon (about 1.3% by weight), and the remainder of less than about 0.05% in total. The hydrogen content level in dry air is about 0.00005% by volume.

[0111] Additional techniques that can be applied to passivation processes may be derived from the techniques disclosed in U.S. Patent No. 7,803,235. This document, in its entirety, constitutes part of this specification by reference.

[0112] The tantalum-containing salt can be any salt that can contain tantalum, such as potassium tantalate fluoride. Regarding agents capable of reducing the salt to tantalum and a second salt in a reaction vessel, any agent capable of performing this reduction is any agent capable of reducing the tantalum-containing salt to just metallic tantalum and other components (e.g., salts (or more)). The other components can be separated from the metallic tantalum, for example, by dissolving the salt in water or another water source. This agent is preferably sodium. Other examples include, but are not limited to, lithium, magnesium, calcium, potassium, carbon, carbon monoxide, and ionized hydrogen. Typically, the second salt formed during the reduction of the tantalum-containing salt is sodium fluoride. For details of reduction processes applicable to the present invention, considering this application, see Kirk-Othmer's Encyclopedia of Chemical Technology, 3. rd This is described in Edition, Vol. 22, pp. 541-564, U.S. Patents 2,950,185, 3,829,310, 4,149,876, and 3,767,456. Further details of tantalum treatment can be found in U.S. Patents 5,234,491, 5,242,481, and 4,684,399. All of these patents and documents, in whole, constitute part of this specification by reference.

[0113] The process described above can be included in a multi-stage process that can begin with low-purity tantalum such as tantalum ore. Niobium is one of the impurities that can substantially be present with tantalum. Other impurities at this stage include tungsten, silicon, calcium, iron, and manganese. More specifically, low-purity tantalum can be purified by mixing low-purity tantalum containing tantalum and impurities with an acid solution. If low-purity tantalum exists as an ore, it must first be crushed before being mixed with the acid solution. The acid solution must be able to substantially dissolve all of the tantalum and impurities, especially when mixed at high temperatures.

[0114] Solid-liquid separation can be performed as soon as sufficient time has elapsed for the acid solution to dissolve substantially all, if not all, of the solid containing tantalum and impurities, and solid-liquid separation usually removes any undissolved impurities. The solution is further purified by liquid-liquid extraction. Methyl isobutyl ketone (MIBK) can be used to contact the tantalum-rich solution, and deionized water can be added to produce a tantalum fraction. A salt is then precipitated from the liquid containing at least tantalum using a liquid tank. Typically, this salt is potassium tantalate fluoride. More preferably, this salt is K2TaF7. This salt is then reacted with 1) tantalum and 2) an agent that can reduce it to the second salt described above. This compound is typically pure sodium, and the reaction is carried out in the reaction vessel described above. As described above, the by-product, the second salt, can be separated from tantalum by dissolving this salt in a water source and washing the dissolved salt.

[0115] The present invention will be further illustrated by the following examples, which are intended to be purely illustrative. [Examples]

[0116] Example 1 Tantalum powder was obtained using commercially available KTa2F7 (KTAF) and sodium, employing a standard industrial process of sodium reduction of KTAF. By-product salts were removed by washing, acid leaching, and drying steps. The resulting tantalum powder was approximately 0.1 m³. 2 It had a BET surface area of ​​1 / g. This tantalum was used as the base lot tantalum powder. Figure 1A shows an SEM image of this starting tantalum powder. The starting tantalum powder was divided into three powder lots, namely lot A, lot B, and lot C, and each was plasma treated separately as follows.

[0117] Next, the base lot tantalum powder was plasma-treated. In particular, the base lot tantalum powder was spheroidized by introducing it into a feeder. The feeder was equipped with an argon feeder (5 LPM) that aerosolized the powder into a plasma spheroidization reactor (TEK15 from Tekna, Canada). The powder supply rate was maintained at 0.75 kg / hr by adjusting the feeder. The aerosolized powder was introduced into the plasma heat source of the plasma reactor. The plasma reactor was equipped with an induction plasma torch using a design described in U.S. Patent No. 5,200,595 and International Publication No. 92 / 19086, which utilizes a concentric tube. The plasma energy used to spheroidize the powder was 15 KW when the anode voltage was set to 6.5 V, the anode current to 2.3 A, and the grid current to 0.4 A. The reactor was inactivated using an argon gas flow with the carrier gas velocity set to 5 LPM, the sheath gas velocity to 30 LPM, the center gas velocity to 10 LPM, and the nozzle gas velocity to 1 LPM. The plasma intensity was increased by adding hydrogen gas (using a flow rate of 4 LPM). The operating conditions are summarized in Table 1. The basic lot of tantalum powder introduced into the plasma torch was at least partially melted and then spherical. The tantalum droplets were carried downstream from the plasma torch, where they were rapidly cooled by an activated water-cooled jacket on the plasma reactor. In this example, the cooled spherical tantalum powder fell to the bottom of the plasma reactor by gravity, where the spherical powder was collected under an argon gas blanket and passedivated in a water tank. Immediately after immersion in water, the slurry was sonicated (with an energy of less than 150 W / gal.) to remove any nanomaterials that may have accumulated on the surface of the spherical powder. The washed tantalum spheres were then dried under argon at 80°C for 4 hours. Next, the dried powder was filled into aluminum-lined antistatic bags until its properties were tested.

[0118] Table 2 shows the results for impurity levels, and Table 3 shows the results for particle size distribution, apparent density, and whole flow rate.

[0119] Figure 1B shows an SEM image of the plasma-treated powder from lot A.

[0120] In each of the lots A, B, and C, the aspect ratio was approximately 1.0 to 1.1.

[0121] [Table A]

[0122] Example 2 In this example, the same basic lot tantalum powder (sodium-reduced powder) as in Example 1 was used. This basic lot tantalum powder was 0.1 m 2 The BET surface area was 1 / g. The base lot of tantalum powder was pressed and sintered into compacted logs at a sintering temperature of approximately 1000°C for 1 hour. The compacted logs were fed into an electron beam furnace, where the metal was melted using a crucible. The molten material was stretched through a mold, causing the tantalum to solidify and form ingots. The tantalum ingots were hydrogenated using a high-temperature furnace with a hydrogen atmosphere and then cooled to room temperature. The hydrogenated ingots were then crushed (using a jaw crusher, then a roll crusher) and screened to a sieve size of -20 #. The crushed ingots were screened to the desired size cut, i.e., 10 to 25 microns for lot A (or 35 to 75 microns for lot B). The powder for each lot after screening was then acid leached. The powder was then deoxygenated using magnesium to reduce the oxygen level to less than 500 ppm. Figure 2A shows an SEM image of the starting tantalum powder. Next, lot A and lot B were plasma-treated separately using the same method as in Example 1.

[0123] Table 4 shows the results for impurity levels, and Table 5 shows the results for particle size distribution, apparent density, and whole flow rate.

[0124] Figure 2B shows SEM images of the plasma-treated powder from Lot A. The aspect ratio was approximately 1.0 to 1.1 for both Lot A and Lot B.

[0125] [Table B]

[0126] Example 3 The tantalum powder from Example 2 was used in a 3D printing process, i.e., an additive manufacturing process. Specifically, tantalum printing was performed on a Trumpf TruPrint 1000 with a build volume of 100 mm in diameter × 100 mm and a maximum laser output of 175 W. The base plate used was austenitic chromium nickel stainless steel of type 316.

[0127] In this experiment, the spheroidized tantalum powder of Example 2 was sufficient for laser powder bed fusion (L-PBF) printing, exhibiting alternating solid and mesh forms with prominent protrusions, and producing sufficiently dense tensile bars and demonstration parts. Specifically, tensile bars were printed 1 mm larger than the standard dimensions (ASTM E8), and these bars were machined to the final dimensions on a lathe. Tensile properties were measured using an Instron 4210 tensile testing machine. The microstructure and hardness of the tensile bars were analyzed. For microstructure analysis, samples were mounted on epoxy and cut with a diamond saw. The mounted samples were polished and etched with acid, and the particles were characterized using a Unition Versamet 2 metal microscope. Microhardness was tested using a LECO LM700-AT testing machine equipped with AMH32 software.

[0128] The preferred parameters described above were used for both the printing and laser parameters. As a result, a density of over 99.5% with good protrusions was obtained in the test prints. In this experiment, a cube (25 mm × 25 mm × 25 mm) with alternating coarse mesh and solid sections was also printed. This demonstration part showed high-resolution (30 μm) features with the ability to successfully print an open-cell structure. This alternating mesh-solid structure is often required in additively manufactured lightweight aerospace and industrial parts, and is also needed in medical implants to improve osseointegration.

[0129] The tensile bar of the present invention had a higher yield strength (YS) and slightly less elongation compared to processed tantalum. After slow cooling, the elongation improved without a decrease in YS.

[0130] Example 4 In this example, the same basic lot tantalum powder (sodium-reduced powder) as in Example 1 was used. This basic lot tantalum powder was 0.1 m 2The BET surface area was 1 / g. The base lot tantalum powder was pressed and sintered into compacted logs at a sintering temperature of 2500°C to 3000°C for 3 hours. The compacted logs were fed into an electron beam furnace, where the metal was melted using a crucible. The molten material was stretched through a mold, causing the tantalum to solidify and form ingots. The tantalum ingots were hydrogenated using a high-temperature furnace with a hydrogen atmosphere and then cooled to room temperature. The hydrogenated ingots were then crushed (using a jaw crusher, then a roll crusher) and screened to a sieve size of -20 #. The crushed ingots were screened to desired size cuts, i.e., 10 to 25 microns for lots A2 and D2, 15 to 40 microns for lots E2 and F2, or 35 to 105 microns for lots B2 and C2. The powder for each screening lot was then acid leached. Next, the powder for each lot was deoxygenated using magnesium chips (at 700°C for 2 hours) to reduce the oxygen level to various levels below 1000 ppm, as shown in Table 6. Standard oxygen-impregnated powders (A2, D2) and low-oxygen-impregnated powders (B2, E2) were produced. Then, lots A2 to F2 were plasma-treated separately in the same manner as in Example 1. For lots C2 and F2, in addition to the initial deoxygenation performed on lots B2 and E2, an additional deoxygenation was performed after spheroidization (using magnesium chips at 700°C for 2 hours) (deoxygenation was performed twice) to obtain ultra-low oxygen-impregnated powders (lots C2 and F2). The difference in oxygen content between A2, D2, B2, and E2 is due to the particle size distribution of each lot, as shown in Table 7.

[0131] Table 6 shows the results for impurity levels, and Table 7 shows the results for particle size distribution, apparent density, and whole flow rate.

[0132] In each of the lots A2 through F2, the aspect ratio was approximately 1.0 to 1.1.

[0133] [Table C]

[0134] Example 5 In this example, several tantalum tensile bars having the shape of cylindrical bars or rods were fabricated. These bars or rods have two flat end faces with a cylindrical shape in between. Sample 5.1 is a comparative example, in which processed tantalum bars were fabricated by vacuum arc melting tantalum prism powder (commercially available as KDEL from Global Advanced Metals USA, Inc.) in a mold.

[0135] As Sample 5.2, a tantalum tensile bar was formed from KDEL tantalum powder. This powder was pressed into a compact log at a pressure of approximately 30,000 psi to 50,000 psi, and sintered at a temperature of 2,500°C to 3,000°C for 3 hours to form a sintered powder metallurgy bar. The SEM image of its microstructure is shown in Figure 3.

[0136] Furthermore, as will be explained below, tantalum powder was used in the 3D printing process, i.e., the additive manufacturing process. Specifically, tantalum fabrication was performed in a laser powder bed fusion machine with a maximum laser output of 400W. Various base plates were used, including 316 type austenitic chromium nickel stainless steel and Ti alloy (Ti-6V-4Al).

[0137] In this example, spheroidized tantalum powder (various lots) from Example 4 was used in laser powder bed fusion (L-PBF) printing to form sufficiently dense tensile bars. Specifically, tensile bars were printed 1 mm larger than the standard dimensions (ASTME8). Tensile bars T1 to T6 were printed using powder from lot A2, tensile bar T13 was printed using powder from lot E2, and tensile bar T14 was printed using powder from lot F2 (see Table 6). These bars were machined to their final dimensions on a lathe. Tensile properties were measured using an Instron 4210 tensile testing machine. The microstructure and hardness of the tensile bars were analyzed. For microstructure analysis (Figures 3 to 10), samples were mounted on epoxy and cut with a diamond saw. The mounted samples were polished and etched with acid, and the particles were characterized using a Unition Versamet 2 metal microscope. Microhardness was tested using a LECO LM700-AT testing machine with AMH32 software.

[0138] Optimized printing and laser parameters were used to manufacture sufficiently dense parts. As a result, the test prints achieved a density of over 99.5% with good protrusions. In this experiment, a cube (25 mm × 25 mm × 25 mm) with alternating coarse mesh and solid sections was also printed. This demonstration part showed high-resolution (less than 30 μm) features with the ability to successfully print open-cell structures. This alternating mesh-solid structure is often required in lightweight aerospace and industrial parts, and is also needed in medical implants to improve osseointegration.

[0139] As Sample 5.3 (Sample T1 in Table 8), a tantalum tensile bar was formed using a 3D printing process, i.e., an additive manufacturing process. Specifically, tantalum printing was performed on a Trumpf TruPrint 1000 with a build volume of 100 mm diameter × 100 mm and a maximum laser power of 175 W. A 316 type austenitic chromium-nickel stainless steel was used as the base plate. In Sample 5.3, a cylindrical bar or rod was printed in the z direction (see Figure 11). This means that a flat end face was formed on the base plate, ensuring that the bar or rod stands upright upon completion, with one flat end face serving as the base for the support plate. No heat treatment was performed on Sample 5.3 after printing. An SEM image of its microstructure is shown in Figure 4.

[0140] As Sample 5.4 (Sample T2 in Table 8), a tantalum tensile bar was formed using a 3D printing process, i.e., an additive manufacturing process. Specifically, tantalum fabrication was performed on a Trumpf TruPrint 1000 with a build volume of 100 mm in diameter × 100 mm and a maximum laser output of 175 W. A 316 type austenitic chromium-nickel stainless steel was used as the base plate. In Sample 5.4, a cylindrical bar or rod was printed in the z direction. After printing, Sample 5.4 was heat-treated (stress relaxation) in an air furnace at 850°C for 1 hour. An SEM image of its microstructure is shown in Figure 5.

[0141] As Sample 5.5 (Sample T4 in Table 8), a tantalum tensile bar was formed using a 3D printing process, i.e., an additive manufacturing process. Specifically, tantalum fabrication was performed on a Trumpf TruPrint 1000 with a build volume of 100 mm diameter × 100 mm and a maximum laser output of 175 W. A 316 type austenitic chromium-nickel stainless steel was used as the base plate. In Sample 5.5, a cylindrical bar or rod was printed in the z direction. After printing, Sample 5.5 was heat-treated (stress-relieving) in an air furnace at 1300°C for 1 hour. A SEM image of its microstructure is shown in Figure 6.

[0142] As Sample 5.6 (Sample T5 in Table 8), a tantalum tensile bar was formed using a 3D printing process, i.e., an additive manufacturing process. Specifically, tantalum fabrication was performed on a Trumpf TruPrint 1000 with a build volume of 100 mm diameter × 100 mm and a maximum laser power of 175 W. A 316 type austenitic chromium-nickel stainless steel was used as the base plate. In Sample 5.6, a cylindrical bar or rod was printed in the z direction. After printing, Sample 5.6 was heat-treated (stress relaxation) in an air furnace at 1700°C for 2 hours. A SEM image of its microstructure is shown in Figure 7.

[0143] As Sample 5.7 (Sample T6 in Table 8), a tantalum tensile bar was formed using a 3D printing process, i.e., an additive manufacturing process. Specifically, tantalum fabrication was performed on a Trumpf TruPrint 1000 with a build volume of 100 mm diameter × 100 mm and a maximum laser power of 175 W. A 316 type austenitic chromium-nickel stainless steel was used as the base plate. In Sample 5.7, a cylindrical bar or rod was printed in the z direction. After printing, Sample 5.7 was heat-treated (stress relaxation) in an air furnace at 2000°C for 2 hours. A SEM image of its microstructure is shown in Figure 8.

[0144] As Sample 5.8 (Sample T13 in Table 8), a tantalum tensile bar was formed using a 3D printing process, i.e., additive manufacturing. Specifically, tantalum fabrication was performed on an EOS M290 with a build volume of 250 mm × 250 mm × 325 mm and a maximum laser output of 400 W. A titanium alloy (Ti-6Al-4V) was used as the base plate. In Sample 5.8, a cylindrical bar or rod was printed in the z direction. No heat treatment was performed on Sample 5.8 after printing. An SEM image of its microstructure is shown in Figure 9.

[0145] As Sample 5.9 (Sample T14 in Table 8), a tantalum tensile bar was formed using a 3D printing process, i.e., additive manufacturing. Specifically, tantalum fabrication was performed on an EOS M290 with a build volume of 250 mm × 250 mm × 325 mm and a maximum laser output of 400 W. A titanium alloy (Ti-6Al-4V) was used as the base plate. In Sample 5.9, a cylindrical bar or rod was printed in the x-direction. No heat treatment was performed on Sample 5.9 after printing. An SEM image of its microstructure is shown in Figure 10.

[0146] Further details for each sample are shown in Table 8 below. In addition, the tensile properties were measured using an Instron 4210 tensile testing machine.

[0147] As can be seen from Table 8, samples 5.3 to 5.9 of the present invention had significantly higher (Vickers) hardness than samples 5.1 and 5.2. Furthermore, the results in Table 8 show how tensile strength, yield strength, and elongation can change depending on the 3D printing direction (x, y, or z direction), and / or how heat treatment (stress relaxation) is performed, and / or the oxygen content of the powder.

[0148] The tensile bar of the present invention, when using a high-oxygen-supplied powder, exhibited higher yield strength (YS) and slightly lower elongation compared to processed tantalum and sintered bars (Table 8). After slow cooling, elongation improved without a decrease in YS (T4-T6). By reducing oxygen impurities (T14), elongation significantly improved without substantially reducing UTS. The elongation data for T14 showed a cup-cone fracture surface characteristic of the ductile fracture mode (Figure 10).

[0149] [Table D]

[0150] The present invention encompasses the following aspects / embodiments / features in any order and / or any combination. 1. a. It has a spherical shape with an average aspect ratio of 1.0 to 1.25. b. The tantalum powder, excluding gas impurities, has a tantalum purity of at least 99.99% by weight Ta, c. It has an average particle size of approximately 0.5 microns to approximately 250 microns. d. It has a true density of 16 g / cc to 16.6 g / cc. e. It has an apparent density of approximately 4 g / cc to approximately 12.3 g / cc, and Tantalum powder having a whole flow rate of f.20 seconds or less. 2. Tantalum powder having been plasma heat-treated, according to any of the above or below embodiments / features / aspects. 3. Tantalum powder having an oxygen level of less than 400 ppm, according to any of the above or below embodiments / features / aspects. 4. Tantalum powder having an oxygen level of 20 ppm to 250 ppm, according to any of the above or below embodiments / features / appearances. 5. Tantalum powder of any of the above or below embodiments / features / models, wherein the average aspect ratio is 1.0 to 1.1. 6. Tantalum powder of any of the above or below embodiments / features / models, wherein the average aspect ratio is 1.0 to 1.05. 7. Tantalum powder according to any of the above or below embodiments / features / models, wherein the purity is at least 99.995% by weight of Ta. 8. Tantalum powder according to any of the above or below embodiments / features / appearances, wherein the average particle size is approximately 0.5 microns to approximately 10 microns. 9. Tantalum powder according to any of the above or below embodiments / features / appearances, wherein the average particle size is approximately 5 microns to approximately 25 microns. 10. Tantalum powder according to any of the above or below embodiments / features / appearances, wherein the average particle size is approximately 15 microns to approximately 45 microns. 11. Tantalum powder according to any of the above or below embodiments / features / appearances, wherein the average particle size is approximately 35 microns to approximately 75 microns. 12. Tantalum powder according to any of the above or below embodiments / features / appearances, wherein the average particle size is approximately 55 microns to approximately 150 microns. 13. Tantalum powder according to any of the above or below embodiments / features / appearances, wherein the average particle size is approximately 105 microns to approximately 250 microns. 14. Tantalum powder of any of the above or below embodiments / features / appearances having at least one of the following properties: a. D10 diameter of approximately 5 microns to 25 microns, b. D90 diameter of approximately 20 microns to 80 microns, and / or c. Oxygen content of approximately 100 ppm to 1000 ppm, for example, approximately 100 ppm to 250 ppm. 15. An article comprising tantalum powder in any of the above or below embodiments / features / appearances. 16. An article having any of the above or below embodiments / features / aspects, which is a boss for a coil set for a physical vapor deposition process. 17. Articles of any above or below embodiment / feature / appearance in which the boss includes an open-cell structure and a solid structure. 18. Articles having any of the above or below embodiments / features / appearances, which are coil sets or components thereof for physical vapor deposition processes. 19. Articles relating to any of the above or below embodiments / features / models, which are orthopedic implants or components thereof. 20. An article that is a dental implant, having any of the above or below embodiments / features / appearances. 21. A method for forming an article, comprising additive manufacturing of an article by using tantalum powder of any of the above or below embodiments / features / appearances to form the shape of an article or a part thereof. 22. Any above or below embodiment / feature / appearance of the additive manufacturing method, wherein the additive manufacturing includes laser powder bed melting. 23. Any above or below embodiment / feature / model of the additive manufacturing method, including electron beam powder bed melting. 24. A method of additive manufacturing, any of the above or below embodiments / features / appearances, wherein the additive manufacturing includes directed energy deposition. 25. Any above or below embodiment / feature / aspect of the additive manufacturing method, wherein the additive manufacturing includes laser cladding via powder or wire. 26. The additive manufacturing method, any of the above or below embodiments / features / appearances, including material injection. 27. The additive manufacturing method, any of the above or below embodiments / features / appearances, including sheet lamination. 28. Any above or below embodiment / feature / appearance of the additive manufacturing method, wherein the additive manufacturing includes vat photopolymerization. 29. A method for producing tantalum powder according to any of the above or below embodiments / features / appearances, a. Plasma heat treatment of the starting tantalum powder in an inert atmosphere to partially melt at least the outer surface of the starting tantalum powder, thereby obtaining heat-treated tantalum powder. b. To obtain tantalum powder by cooling the heat-treated tantalum powder in an inert atmosphere, Methods that include... 30. Any above or below embodiment / feature / appearance of the method, wherein the starting tantalum powder is sodium-reduced tantalum powder. 31. Any above or below embodiment / feature / appearance of the method, wherein the starting tantalum powder is basic lot tantalum powder. 32. A method according to any of the above or below embodiments / features / appearances, wherein the starting tantalum powder has a first particle size distribution, the tantalum powder has a second particle size distribution, and the first particle size distribution and the second particle size distribution are within 10% of each other. 33. A method according to any of the above or below embodiments / features / aspects, wherein, prior to step a, a first tantalum powder is sintered to obtain sintered powder, the sintered powder is then electron-beam-melted to obtain an ingot, and the ingot is then powdered back into starting tantalum powder to form the starting tantalum powder.

[0151] The present invention may encompass any combination of these various features or embodiments described above and / or below in the text and / or paragraphs. Any combination of the features disclosed herein is deemed to be part of the present invention, and no limitation is intended regarding features that can be combined.

[0152] The applicants specifically refer to all cited references in this disclosure. Furthermore, where a quantity, concentration, or other value or parameter is given as a range, a preferred range, or a list of preferred upper and lower limits, this is understood to specifically disclose all ranges consisting of any pair of any upper or preferred value and any lower or preferred value of any range, regardless of whether the range is disclosed separately. Where a numerical range is referred to herein, unless otherwise specified, the range is intended to include its endpoints, as well as all integers and fractions within the range. The range of the present invention is not intended to be limited to any specific value referred to when defining a range.

[0153] Other embodiments of the present invention will be apparent to those skilled in the art from the discussion herein and the practice of the present invention disclosed herein. This specification and these embodiments are merely illustrative, and the true scope and spirit of the invention are intended to be shown by the appended claims and equivalents. [Explanation of symbols]

[0154] Drawing translation Figure 1B Spherical Tantalum Powder Figure 2A T-Powder Figure 2B Spherical Tantalum Powder Figure 11 X-direction Y-direction Z-direction

[0155] This invention encompasses the following: 1.a. It has a spherical shape with an average aspect ratio of 1.0 to 1.25. b. The tantalum powder, excluding gas impurities, has a tantalum purity of at least 99.99% by weight Ta, c. It has an average particle size of approximately 0.5 microns to approximately 250 microns. d. It has an apparent density of approximately 4 g / cc to approximately 12.3 g / cc. It has a true density of e.16 g / cc to 16.6 g / cc, and Tantalum powder having a whole flow rate of f.20 seconds or less. 2. The tantalum powder described in item 1 above, which has been plasma heat-treated. The tantalum powder described in item 1 above, having an oxygen level of less than 3,400 ppm. 4. Tantalum powder as described in item 1 above, having an oxygen level of 4.20 ppm to 250 ppm. 5. The tantalum powder described in item 1 above, wherein the average aspect ratio is 1.0 to 1.1. 6. The tantalum powder described in item 1 above, wherein the average aspect ratio is 1.0 to 1.05. 7. The tantalum powder described in item 1 above, wherein the purity is at least 99.995% by weight of Ta. 8. The tantalum powder described in item 1 above, wherein the average particle size is approximately 0.5 microns to approximately 10 microns. 9. The tantalum powder described in item 1 above, wherein the average particle size is approximately 5 microns to approximately 25 microns. 10. The tantalum powder described in item 1 above, wherein the average particle size is approximately 15 microns to approximately 45 microns. 11. The tantalum powder described in item 1 above, wherein the average particle size is approximately 35 microns to approximately 75 microns. 12. The tantalum powder described in item 1 above, wherein the average particle size is approximately 55 microns to approximately 150 microns. 13. The tantalum powder described in item 1 above, wherein the average particle size is approximately 105 microns to approximately 250 microns. 14. Tantalum powder as described in paragraph 1 above, having at least one of the following properties: a. D10 diameter of approximately 5 microns to 25 microns, b. A D90 diameter of approximately 20 to 80 microns, or c. Oxygen content of 100 ppm to 1000 ppm. 15. Articles containing the tantalum powder described in item 1 above. 16. The article described in item 15 above, which is a boss for a coil set for a physical vapor deposition process. 17. The article according to paragraph 16, wherein the boss includes an open-cell structure and a solid structure. 18. The article described in paragraph 15 above, which is a coil set or component thereof for a physical vapor deposition process. 19. Articles described in item 15 above, which are orthopedic implants or components thereof. 20. The article according to paragraph 19, wherein the orthopedic implant includes an open-cell structure and a solid structure. 21. The article described in item 15 above, which is a dental implant. 22. The article according to paragraph 21, wherein the dental implant includes an open-cell structure and a solid structure. 23. A method for forming an article, comprising additive manufacturing of an article by using the tantalum powder described in paragraph 1 above to form the shape of an article or a part thereof. 24. The method according to item 23, wherein the additive manufacturing includes laser powder bed melting. 25. The method according to item 23, wherein the additive manufacturing includes electron beam powder bed melting. 26. The method according to paragraph 23, wherein the additive manufacturing includes directed energy deposition. 27. The method according to paragraph 23, wherein the additive manufacturing includes laser cladding via powder or wire. 28. The method according to paragraph 23, wherein the additive manufacturing includes material injection. 29. The method according to paragraph 23, wherein the additive manufacturing includes sheet lamination. 30. The method according to paragraph 23, wherein the additive manufacturing includes vat photopolymerization. 31. A method for producing tantalum powder as described in item 1 above, a. Plasma heat treatment of the starting tantalum powder in an inert atmosphere to partially melt at least the outer surface of the starting tantalum powder, thereby obtaining heat-treated tantalum powder. b. To obtain tantalum powder by cooling the heat-treated tantalum powder in an inert atmosphere, Methods that include... 32. The method according to paragraph 31, wherein the starting tantalum powder is sodium-reduced tantalum powder. 33. The method according to paragraph 31, wherein the starting tantalum powder is basic lot tantalum powder. 34. The method according to paragraph 31, wherein the starting tantalum powder has a first particle size distribution, the tantalum powder has a second particle size distribution, and the first particle size distribution and the second particle size distribution are within 10% of each other. 35. The method according to paragraph 31, wherein, prior to step a, a first tantalum powder is sintered to obtain sintered powder, the sintered powder is then electron-beam-melted to obtain an ingot, and the ingot is then powdered back into starting tantalum powder to form the starting tantalum powder.

Claims

1. A method for forming an article, comprising additive manufacturing of the article by using tantalum powder to form the shape of the article or its parts, wherein the powder has at least the following characteristics: a. The powder has a spherical shape with an average aspect ratio of 1.0 to 1.25; b. The purity of the tantalum powder is at least 99.99% by weight of Ta relative to the total weight of the powder excluding gas impurities; c. Average particle size between 0.5 microns and 250 microns; d. Apparent density of 4 g / cc to 12.3 g / cc; e. True density of 16 g / cc to 16.6 g / cc; and It has a whole flow rate of f.20 seconds / 50 g or less. A method for forming the article wherein one or more of the following characteristics are achieved: b) maximum tensile strength (UTS) is greater than 50 KSI, d) yield stress is greater than 35 KSI, and e) elongation is between 1% and 50%.

2. The method according to claim 1, wherein the average particle size is 0.5 microns to 10 microns, 5 microns to 25 microns, 15 microns to 45 microns, 35 microns to 75 microns, 55 microns to 150 microns, or 105 microns to 250 microns.

3. The tantalum powder has the following characteristics: a. D10 diameter of 5 microns to 25 microns; b. The method according to claim 1, having at least one of the D90 diameters ranging from 20 microns to 80 microns.

4. The method according to claim 1, wherein the additive manufacturing includes laser powder bed fusion, electron beam powder bed fusion, directed energy deposition, laser cladding via powder or wire, material jetting, sheet lamination, or vat photopolymerization.

5. The method according to claim 1, wherein the powder has an oxygen level of less than 100 ppm.

6. The method according to claim 1, wherein the article is a medical implant or a dental implant.

7. The method according to claim 1, wherein the article is an orthopedic implant for the hand, ankle, shoulder, buttocks, knee, bone, total joint reconstruction (arthroplasty), craniofacial reconstruction, or spinal replacement, a dental implant for facial reconstruction which is the mandible or maxilla, a medical marker, a surgical instrument or its component, augmentation material, or an aerospace component.

8. The method according to claim 1, wherein the additive manufacturing includes laser metal deposition (LMD), gas metal arc welding, plasma welding, cold spray, metal injection molding, plasma additive manufacturing, thermal spraying, electron beam melting, or a powder bed melting process using an electron beam in a vacuum.

9. The additive manufacturing process is performed with the following settings: laser power of 150 W to 175 W; scanning speed of 100 mm / s to 500 mm / s; hatch spacing of 30 microns to 100 microns; layer thickness of 10 microns to 50 microns; and / or 3 J / mm 2 ~20 J / mm 2 The method according to claim 1, comprising using a device having one or more of the following energy densities.

10. The method according to claim 1, wherein all of characteristics a) to d) are achieved.

11. The aforementioned powder has an oxygen content of 20 ppm to 200 ppm and a BET of 2000 to 4000 m 2 The method according to claim 1, comprising the ratio of oxygen (ppm) to (g), a carbon content of 1 ppm to 100 ppm, a nitrogen content of 5 ppm to 5000 ppm, a hydrogen content of 1 ppm to 1000 ppm, an iron content of 1 ppm to 50 ppm, a nickel content of 1 ppm to 150 ppm, a chromium content of 1 ppm to 100 ppm, a sodium content of 0.1 ppm to 50 ppm, a potassium content of 0.1 ppm to 100 ppm, a magnesium content of 1 ppm to 50 ppm, a phosphorus (P) content of 1 ppm to 500 ppm, and a fluoride (F) content of 1 ppm to 500 ppm.

12. A method for forming an article, comprising additive manufacturing of the article by using tantalum alloy powder to form the shape of the article or its parts, wherein the powder has at least the following properties: a. The powder has a spherical shape with an average aspect ratio of 1.0 to 1.25; b. The purity of the tantalum powder is at least 99.99% by weight of Ta relative to the total weight of the powder excluding gas impurities; c. Average particle size between 0.5 microns and 250 microns; d. Apparent density of 4 g / cc to 12.3 g / cc; and e. A method having a whole flow rate of 20 seconds / 50 g or less.

13. The method according to claim 12, wherein the tantalum alloy powder comprises a) at least tantalum metal and b) i) one or more other metals and / or ii) a nonmetallic element and / or iii) a metalloid element.

14. The method according to claim 13, wherein the one or more other metals are Ti, Nb, Si, W, Mo, Re, Rh, V, Th, Zr, Hf, Cr, Mn, Sc, Y, C, B, Ni, Fe, Co, Al, Sn, Au, Th, U, Pu, and / or rare earth elements (there may be more than one).

15. The tantalum alloy powder is a Ta-Ti alloy, a Ta-Si alloy, a Ta-W alloy, a Ta-Mo alloy, or a Ta-Nb alloy, or The method according to claim 12, wherein tantalum is the metal present in the highest proportion relative to the weight of the tantalum alloy powder.

16. The method according to claim 1, wherein the additive manufacturing includes the use of a base plate.

17. The method according to claim 1, further comprising heat-treating the article at at least 800°C for at least 10 minutes.

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