A method for producing atomized metal powders

Abstract

To provide a reactive metal powder atomization manufacturing process.SOLUTION: For example, such a process includes the step of providing a heated metal source and, during execution of the atomization process, the heated metal source is contacted with at least one additive gas. Such a process provides a raw reactive metal powder having improved flowability. The at least one additive gas can be mixed together with an atomization gas to obtain an atomization mixture, and the heated metal source can be contacted with the atomization mixture during the atomization process. A reactive metal powder spheroidizing manufacturing process is also provided.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims priority based on U.S. Patent Application No. 62 / 247,794, filed on October 29, 2015, the entire content of which is incorporated herein by reference.

[0002] This disclosure relates to the field of production of spherical powders such as reactive metal powders. More particularly, this disclosure relates to methods and apparatus for preparing reactive metal powders having improved flowability.

Background Art

[0003] Generally, the characteristics desired for high - quality reactive metal powders are a combination of high sphericity, density, purity, flowability, and a low amount of gas - entrapped voids. Fine powders are useful for applications such as 3D printing, powder injection molding, hot isostatic pressing, and coating. Such fine powders are used in aerospace, biomedical, and industrial applications.

[0004] Powders with poor flowability may tend to form aggregates with lower density and larger surface area. These aggregates can have an adverse effect when used in applications that require fine reactive metal powders. Further, reactive powders with poor flowability can cause pipe blockages and / or adhere to the walls of the spray chamber of a spraying device or the walls of a transport pipe. Additionally, aggregated powders are more difficult to screen when separating the powder into different size distributions. The larger surface area leads to higher reactivity, so operating with aggregated powders also increases safety risks.

[0005] On the other hand, metal powders with improved flowability are desirable for various reasons. For example, metal powders with improved flowability can be more easily used in powder metallurgy processes as additive manufacturing and coating.

Summary of the Invention

[0006] Therefore, it is highly desirable to provide a device, system, or method that at least partially addresses the poor fluidity of reactive metal powders in relation to their susceptibility to static electricity. Highly fluid powders typically lead to higher apparent densities and can be more easily dispersed to produce a uniform powder layer.

[0007] According to one embodiment, a method for atomizing reactive metal powder, The process of supplying a heated metal source, and During the atomization method described above, a step of bringing the heated metal source into contact with at least one additive gas. A method for atomizing reactive metal powders is provided.

[0008] In another embodiment, a method for atomizing reactive metal powder, The process of supplying a heated metal source, and During the atomization method described above, the heated metal source is brought into contact with at least one additive gas, thereby, A particle size distribution of approximately 10 to 53 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 10 to 45 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 15 to 45 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 15 to 53 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 25 to 45 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 25 to 53 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 45 to 75 μm with a flow rate of less than 28 seconds, as measured according to ASTM B213. A particle size distribution of approximately 45 to approximately 106 μm with a flow rate of less than 28 seconds, as measured according to ASTM B213. A particle size distribution of approximately 45 to approximately 150 μm, with a flow rate of less than 28 seconds as measured according to ASTM B213, and / or Particle size distribution of approximately 45 to 180 μm with a flow rate of less than 28 seconds, as measured according to ASTM B213. A process for obtaining a reactive metal powder raw material composed of the above. A method for atomizing reactive metal powders is provided.

[0009] In another embodiment, a method for atomizing reactive metal powder, The process of supplying a heated metal source, A step of mixing the spray gas with at least one additive gas to obtain a spray mixture, During the atomization method, a step of bringing the heated metal source into contact with the atomized mixture. A method for atomizing reactive metal powders is provided.

[0010] In another embodiment, a method for atomizing reactive metal powder, The process of supplying a heated metal source, A step of mixing the spray gas with at least one additive gas to obtain a spray mixture, During the atomization method described above, the heated metal source is brought into contact with the atomized mixture, thereby, A particle size distribution of approximately 10 to 53 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 10 to 45 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 15 to 45 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 15 to 53 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 25 to 45 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 25 to 53 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A reactive metal powder raw material having a particle size distribution of about 45 to about 75 μm and a fluidity measured according to ASTM B213 of less than 28 seconds, A reactive metal powder raw material having a particle size distribution of about 45 to about 106 μm and a fluidity measured according to ASTM B213 of less than 28 seconds, A reactive metal powder raw material having a particle size distribution of about 45 to about 150 μm and a fluidity measured according to ASTM B213 of less than 28 seconds, and / or A reactive metal powder raw material having a particle size distribution of about 45 to about 180 μm and a fluidity measured according to ASTM B213 of less than 28 seconds A method for spray-producing reactive metal powder is provided, which includes the step of obtaining a reactive metal powder raw material composed of

[0011] According to another aspect, a method for spray-producing metal powder, comprising: Supplying a heated metal source, and During the implementation of the atomization method, contacting the heated metal source with at least one additive gas under conditions sufficient to produce a reactive metal powder having an additive content rate of less than 1000 ppm of electronegative atoms and / or electronegative molecules derived from the additive gas. A method for spray-producing metal powder is provided.

[0012] According to another aspect, a method for spray-producing metal powder, comprising: Supplying a heated metal source, Mixing a spray gas and at least one additive gas to obtain a spray mixture, and During the implementation of the atomization method, contacting the heated metal source with the spray mixture under conditions sufficient to produce a reactive metal powder raw material having an additive content rate of less than 1000 ppm of electronegative atoms and / or electronegative molecules derived from the additive gas. A method for spray-producing metal powder is provided.

[0013] According to another aspect, a method for spray-producing metal powder, comprising: Supplying a heated metal source, Mixing a spray gas and at least one additive gas to obtain a spray mixture, During the implementation of the spray atomization method, a step of contacting the heated metal source with the spray mixture to thereby obtain a metal powder raw material; A step of sieving the reactive metal powder raw material to obtain a powder having a predetermined particle size, and A method for producing metal powder by spray atomization is provided, which includes a step of contacting the powder having the predetermined particle size with water.

[0014] According to another aspect, there is provided a method for spheroidizing a reactive metal powder, comprising: A step of supplying a reactive metal powder source, and A method for spheroidizing a reactive metal powder is provided, which includes a step of contacting the reactive metal powder source with at least one additive gas during the implementation of the spheroidization method.

[0015] According to another aspect, there is provided a method for spheroidizing a reactive metal powder, comprising: A step of supplying a reactive metal powder source, and During the implementation of the spheroidization method, the reactive metal powder source is contacted with at least one additive gas, thereby A particle size distribution of about 10 to about 53 μm with a fluidity of less than 40 seconds measured according to ASTM B213, A particle size distribution of about 10 to about 45 μm with a fluidity of less than 40 seconds measured according to ASTM B213, A particle size distribution of about 15 to about 45 μm with a fluidity of less than 40 seconds measured according to ASTM B213, A particle size distribution of about 15 to about 53 μm with a fluidity of less than 40 seconds measured according to ASTM B213, A particle size distribution of about 25 to about 45 μm with a fluidity of less than 40 seconds measured according to ASTM B213, A particle size distribution of about 25 to about 53 μm with a fluidity of less than 40 seconds measured according to ASTM B213, A particle size distribution of about 45 to about 75 μm with a fluidity of less than 28 seconds measured according to ASTM B213, A particle size distribution of about 45 to about 106 μm with a fluidity of less than 28 seconds measured according to ASTM B213, A particle size distribution of approximately 45 to approximately 150 μm, with a flow rate of less than 28 seconds as measured according to ASTM B213, and / or Particle size distribution of approximately 45 to 180 μm with a flow rate of less than 28 seconds, as measured according to ASTM B213. A method for producing spheroidized reactive metal powder is provided, which includes a step of obtaining a reactive metal powder raw material composed of the above.

[0016] In another embodiment, a method for producing spheroidized reactive metal powder, A process of supplying a reactive metal powder source, A step of mixing a spheroidizing process gas with at least one additive gas to obtain a spheroidizing process gas mixture, and A method for producing spheroidized reactive metal powder is provided, comprising the step of contacting the reactive metal powder source with the spheroidization process gas mixture during the execution of the spheroidization method.

[0017] In another embodiment, a method for producing spheroidized reactive metal powder, A process of supplying a reactive metal powder source, A step of mixing a spheroidization process gas with at least one additive gas to obtain a spheroidization process gas mixture. During the spheroidization method described above, the reactive metal powder source is brought into contact with the spheroidization process gas mixture, thereby, A particle size distribution of approximately 10 to 53 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 10 to 45 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. Flowability measured according to ASTM B213 is less than 40 seconds, and is approximately 15 to 45 μm in size. particle size distribution, A particle size distribution of approximately 15 to 53 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 25 to 45 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 25 to 53 μm with a flow rate of less than 40 seconds, as measured according to ASTM B213. A particle size distribution of approximately 45 to 75 μm with a flow rate of less than 28 seconds, as measured according to ASTM B213. A particle size distribution of approximately 45 to approximately 106 μm with a flow rate of less than 28 seconds, as measured according to ASTM B213. A particle size distribution of approximately 45 to approximately 150 μm, with a flow rate of less than 28 seconds as measured according to ASTM B213, and / or Particle size distribution of approximately 45 to 180 μm with a flow rate of less than 28 seconds, as measured according to ASTM B213. A method for producing spheroidized reactive metal powder is provided, which includes a step of obtaining a reactive metal powder raw material composed of the above.

[0018] In another embodiment, a method for producing spheroidized reactive metal powder, A step of supplying a reactive metal powder source, and A method for producing spheroidized reactive metal powder is provided, which includes, during the execution of the spheroidization method, contacting the reactive metal powder source with at least one additive gas and under conditions sufficient to produce a reactive metal powder raw material having an additive content of less than 1000 ppm each of electronegative atoms and / or electronegative molecules derived from the additive gas.

[0019] In another embodiment, a method for producing spheroidized reactive metal powder, A process of supplying a reactive metal powder source, A step of mixing a spheroidization process gas with at least one additive gas to obtain a spheroidization process gas mixture. A method for producing spheroidized reactive metal powder is provided, which includes, during the execution of the spheroidization method, contacting the reactive metal powder source with the spheroidization process gas mixture under conditions sufficient to produce a reactive metal powder raw material having electronegative atoms and / or electronegative molecules derived from the added gas at an added content of less than 1000 ppm.

[0020] In another embodiment, a method for producing spheroidized metal powder, A process of supplying a reactive metal powder source, A step of mixing a spheroidization process gas with at least one additive gas to obtain a spheroidization process gas mixture. During the atomization method described above, the reactive metal powder source is brought into contact with the spheroidization process gas mixture, thereby obtaining a metal powder raw material. A step of sieving the reactive metal powder raw material to obtain a powder having a predetermined particle size, A method for producing spheroidized metal powder is provided, which includes a step of bringing the powder having the predetermined particle size into contact with water.

[0021] Another example provides a method for preparing a reactive metal powder mixture, which includes the step of mixing a reactive metal powder obtained by a method specified in this disclosure with a reactive metal powder obtained by a method different from that described in this disclosure.

[0022] Other examples include a step of mixing a reactive metal powder obtained by a method specified in this disclosure with a reactive metal powder obtained by a method different from the method described in this disclosure. A method for preparing a reactive metal powder mixture is provided.

[0023] Another example provides a method for preparing a reactive metal powder mixture, which includes the step of mixing a reactive metal powder obtained by a metal powder atomization method specified in this disclosure with a reactive metal powder obtained by a metal powder spheroidization method specified in this disclosure.

[0024] Other examples provide reactive metal powders obtained by the methods specified in this disclosure.

[0025] This disclosure relates to a method, process, system, and apparatus that enables the production of highly fluid reactive metal powders. The method is effective for various particle size distributions, including fine particle sizes that would not flow through a whole flow meter without the described treatment. One advantage of this method is that no foreign particles are added to the powder. The only improvement is due to surface treatment.

[0026] The various technologies described in this disclosure have been shown to reduce the susceptibility of powders to static electricity, thereby improving the flowability of the powders.

[0027] The following diagrams illustrate non-limiting examples. [Brief explanation of the drawing]

[0028] [Figure 1] This is a cross-sectional view of an example of a spraying system. [Figure 2] This is a schematic diagram of reactive metal powder particles formed by an atomization method that does not involve contact between the heated metal source and the additive gas. [Figure 3] This is a schematic diagram of reactive metal powder particles formed by an atomization method in which a heated metal source is brought into contact with an additive gas. [Figure 4] This diagram shows a schematic representation of a particle having radius R, and of multiple particles, each having radius r, formed from the same material mass. [Figure 5] This figure shows the TOF-SIMS properties of particles obtained from various tests. [Figure 6] This is a photograph of a batch of metal powder formed according to an atomization method that does not involve contact with an additive gas. [Figure 7] This is a photograph of a batch of metal powder formed according to an atomization method in which a metal source is brought into contact with an additive gas. [Modes for carrying out the invention]

[0029] The following examples are presented in an unrestricted manner.

[0030] The words "a" or "an," when used with the term "comprising" in the claims and / or specification, may mean "one," but unless explicitly stated otherwise, they also mean "one or more," "at least one," and "one or more." Similarly, the word "another," unless explicitly stated otherwise, may mean at least a second or more.

[0031] As used herein and in the claims, the terms “comprising” (and all forms of “comprising,” such as “comprise” and “comprises”), “having” (and all forms of “having,” such as “have” and “has”), “including” (and all forms of “including,” such as “include” and “includes”), or “containing” (and all forms of “containing,” such as “contain” and “contains”) are inclusive or open-ended and do not exclude any additional undescribed elements or process steps.

[0032] As used herein, the term "spray zone" refers to the area in which the material is atomized into droplets, when relating to a method, apparatus, or system for preparing metal powders. Those skilled in the art will understand that the dimensions of the spray zone vary depending on various parameters, such as the temperature of the spraying means, the viscosity of the spraying means, the material within the spraying means, the output of the spraying means, the temperature of the material before it reaches the spray zone, the properties of the material, the dimensions of the material, and the electrical resistivity of the material.

[0033] The term “heating region of the atomizer” as used herein means a region that is hot enough to allow the powder to react with the electronegative atoms of the additive gas to form a depletion layer, as described herein.

[0034] The statement "The metal powder has a particle size distribution of X~Y μm" means that less than 5% by weight of the metal powder contains particles larger than Y μm, and this value is measured according to the ASTM B214 standard. This statement also means that less than 6% by weight of the metal powder contains particles smaller than X μm (d6≧X μm), and this value is measured according to the ASTM B822 standard.

[0035] The expression "metal powder having a particle size of 15-45 μm" means that the metal powder contains less than 5% by weight of particles larger than 45 μm (measured according to ASTM B214 standard) and less than 6% by weight of particles smaller than 15 μm (measured according to ASTM B822 standard).

[0036] The "gas-to-metal ratio" used here refers to the ratio of the mass of the introduced gas per unit time (kg / s) to the mass supply rate (kg / s) of the metal source supplied to the spray area.

[0037] The term "reactive metal powder" as used herein refers to metal powders that cannot be efficiently prepared by conventional gas atomization methods using a closed-coupled nozzle. For example, such reactive metal powders may include at least one selected from titanium, titanium alloys, zirconium, zirconium alloys, magnesium, magnesium alloys, aluminum, and aluminum alloys.

[0038] The term "reactive metal powder raw material" as used herein refers to reactive metal powder obtained directly by atomization without any post-processing steps such as sieving or classification.

[0039] Reactive metal powders with fine particle sizes, such as those within a size distribution range of less than 10⁶ μm, have been observed to have a larger surface area and stronger surface interactions. These result in poorer flowability than coarser powders. Powder flowability depends on one or more of various factors, including particle shape, particle size distribution, surface smoothness, moisture concentration, associated inclusions, and the presence of static electricity. Therefore, powder flowability is a complex macroscopic characteristic resulting from the balance between the adhesive forces and gravity acting on the powder particles.

[0040] For example, particle size distribution is The fluidity measured according to ASTM B213 can be approximately 10 to 53 μm, with a flow rate of less than 40 seconds. Flowability measured according to ASTM B213 is less than 40 seconds, approximately 10 to approximately 45 μm. Flowability measured according to ASTM B213 is less than 40 seconds, approximately 15 to 45 μm. Fluidity measured according to ASTM B213 is less than 40 seconds, approximately 15 to 53 μm. Flowability measured according to ASTM B213 is less than 40 seconds, approximately 25 to approximately 45 μm. Fluidity measured according to ASTM B213 is less than 40 seconds, approximately 25 to 53 μm. Flowability measured according to ASTM B213 is less than 28 seconds, approximately 45 to approximately 75 μm. Flowability measured according to ASTM B213 is less than 28 seconds, approximately 45 to approximately 106 μm. Flowability measured according to ASTM B213 is less than 28 seconds, approximately 45 to approximately 150 μm, and / or Flowability measured according to ASTM B213 is less than 28 seconds, approximately 45 to 180 μm.

[0041] For example, the particle size distribution can range from approximately 10 to approximately 53 μm, with a flow rate of less than 36 seconds as measured according to ASTM B213.

[0042] For example, the particle size distribution may be approximately 10 to 53 μm, with a flow rate of less than 32 seconds as measured according to ASTM B213.

[0043] For example, the particle size distribution can range from approximately 10 to approximately 53 μm, with a flow rate of less than 30 seconds as measured according to ASTM B213.

[0044] For example, the particle size distribution can range from approximately 10 to approximately 53 μm, with a flow rate of less than 28 seconds as measured according to ASTM B213.

[0045] For example, the particle size distribution may be approximately 10 to 45 μm, with a flow rate of less than 36 seconds as measured according to ASTM B213.

[0046] For example, the particle size distribution may be approximately 10 to 45 μm, with a flow rate of less than 32 seconds as measured according to ASTM B213.

[0047] For example, the particle size distribution may be approximately 10 to 45 μm, with a flow rate of less than 30 seconds as measured according to ASTM B213.

[0048] For example, the particle size distribution may be approximately 10 to 45 μm, with a flow rate of less than 28 seconds as measured according to ASTM B213.

[0049] For example, the particle size distribution may be approximately 15 to 45 μm, with a flow rate of less than 36 seconds as measured according to ASTM B213.

[0050] For example, the particle size distribution may be approximately 15 to 45 μm, with a flow rate of less than 32 seconds as measured according to ASTM B213.

[0051] For example, the particle size distribution may be approximately 15 to 45 μm, with a flow rate of less than 30 seconds as measured according to ASTM B213.

[0052] For example, the particle size distribution may be approximately 15 to 45 μm, with a flow rate of less than 28 seconds as measured according to ASTM B213.

[0053] For example, the particle size distribution may be approximately 15 to 53 μm, with a flow rate of less than 36 seconds as measured according to ASTM B213.

[0054] For example, the particle size distribution may be approximately 15 to 53 μm, with a flow rate of less than 32 seconds as measured according to ASTM B213.

[0055] For example, the particle size distribution may be approximately 15 to 53 μm, with a flow rate of less than 30 seconds as measured according to ASTM B213.

[0056] For example, the particle size distribution may be approximately 15 to 53 μm, with a flow rate of less than 28 seconds as measured according to ASTM B213.

[0057] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 25 to 45 μm with a flow rate of less than 36 seconds, as measured according to ASTM B213.

[0058] For example, the reactive metal powder raw material includes a reactive metal powder raw material consisting of a particle size distribution of approximately 25 to approximately 45 μm, with a flowability of less than 32 seconds as measured according to ASTM B213.

[0059] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 25 to 45 μm, comprising reactive metal powder raw materials with a flowability of less than 30 seconds as measured according to ASTM B213.

[0060] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 25 to 45 μm with a flow rate of less than 25 seconds, as measured according to ASTM B213.

[0061] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 25 to 53 μm with a flow rate of less than 36 seconds, as measured according to ASTM B213.

[0062] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 25 to 53 μm with a flow rate of less than 32 seconds, as measured according to ASTM B213.

[0063] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 25 to 53 μm with a flow rate of less than 30 seconds, as measured according to ASTM B213.

[0064] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 25 to 53 μm with a flow rate of less than 25 seconds, as measured according to ASTM B213.

[0065] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 75 μm with a flow rate of less than 26 seconds, as measured according to ASTM B213.

[0066] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 75 μm with a flow rate of less than 25 seconds, as measured according to ASTM B213.

[0067] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 75 μm with a flow rate of less than 24 seconds, as measured according to ASTM B213.

[0068] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 75 μm with a flow rate of less than 23 seconds, as measured according to ASTM B213.

[0069] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 106 μm with a flow rate of less than 26 seconds, as measured according to ASTM B213.

[0070] For example, a reactive metal powder raw material has a fluidity of 25 as measured according to ASTM B213. It consists of a particle size distribution of approximately 45 to 106 μm, measured in less than a second.

[0071] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 106 μm with a flow rate of less than 24 seconds, as measured according to ASTM B213.

[0072] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 106 μm with a flow rate of less than 23 seconds, as measured according to ASTM B213.

[0073] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 150 μm with a flow rate of less than 26 seconds, as measured according to ASTM B213.

[0074] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 150 μm with a flow rate of less than 25 seconds, as measured according to ASTM B213.

[0075] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 150 μm with a flow rate of less than 24 seconds, as measured according to ASTM B213.

[0076] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 150 μm with a flow rate of less than 23 seconds, as measured according to ASTM B213.

[0077] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 180 μm with a flow rate of less than 26 seconds, as measured according to ASTM B213.

[0078] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 180 μm with a flow rate of less than 25 seconds, as measured according to ASTM B213.

[0079] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 180 μm with a flow rate of less than 24 seconds, as measured according to ASTM B213.

[0080] For example, the reactive metal powder raw material consists of a particle size distribution of approximately 45 to 180 μm with a flow rate of less than 23 seconds, as measured according to ASTM B213.

[0081] For example, a heated metal source comes into contact with the at least one additive gas in the spray area of ​​the atomizer.

[0082] For example, the heated metal source comes into contact with the at least one additive gas within the heating region of the atomizer.

[0083] For example, the heated metal source comes into contact with the at least one additive gas substantially simultaneously with contact with the spray gas.

[0084] For example, aerosol gases are inert gases.

[0085] For example, the atomizing gas and additive gases are mixed before contact with the heated metal source.

[0086] For example, contact with an additive gas results in the formation of a first layer and a second layer on the surface of the metal particle raw material, the first layer containing atoms of the heated metal together with atoms and / or molecules of the additive gas, the first layer being a depletion layer deeper and thicker than the native oxide film, and the second layer being the native oxide film.

[0087] For example, the first layer has a substantially positive charge, and the second layer has a substantially negative charge, where the first and second layers have a substantially neutral combined charge.

[0088] For example, the method is, The process further includes sieving the reactive metal powder raw material after atomizing the heated metal source, and separating the reactive metal powder raw material according to its particle size distribution.

[0089] For example, the method is, The process further includes stirring the separated powdered raw materials individually in water after sieving.

[0090] For example, the water is either distilled water or desalinated water.

[0091] For example, the fluidity of reactive metal powders is measured for sieved, dried metal powders after stirring.

[0092] For example, the reactive metal powder contains electronegative atoms and / or electronegative molecules derived from the added gas at an added content of less than 1000 ppm each.

[0093] For example, the reactive metal powder contains the electronegative atoms and / or electronegative molecules derived from the added gas at an added content of less than 500 ppm each.

[0094] For example, the reactive metal powder contains the electronegative atoms and / or electronegative molecules derived from the added gas at an added content of less than 250 ppm each.

[0095] For example, the reactive metal powder contains the electronegative atoms and / or electronegative molecules derived from the added gas at an added content of less than 200 ppm each.

[0096] For example, the reactive metal powder contains the electronegative atoms and / or electronegative molecules derived from the added gas at an added content of less than 150 ppm each.

[0097] For example, the reactive metal powder contains the electronegative atoms and / or electronegative molecules derived from the added gas at an added content of less than 100 ppm each.

[0098] For example, a given particle size consists of a particle size distribution of approximately 10-53 μm, such as 10-45 μm, 15-45 μm, 10-53 μm, 15-53 μm, and / or 25-45 μm.

[0099] For example, at least one of the added gases is an oxygen-containing gas.

[0100] For example, at least one additive gas is an oxygen-containing gas selected from O2, CO2, CO, NO2, air, water vapor, and mixtures thereof.

[0101] For example, at least one of the additive gases is a halogen-containing gas.

[0102] For example, halogens are F, Cl, Br, or I.

[0103] For example, at least one of the added gases is a hydrogen-containing gas.

[0104] For example, at least one of the added gases is a sulfur-containing gas.

[0105] For example, at least one of the added gases is a nitrogen-containing gas.

[0106] For example, at least one additive gas is selected from O2, H2O, CO, CO2, NO2, N2, NO3, Cl2, SO2, SO3, and mixtures thereof.

[0107] For example, the reactive metal powder includes at least one of titanium, zirconium, magnesium, and aluminum.

[0108] For example, the reactive metal powder is a metal powder containing at least one selected from titanium, titanium alloys, zirconium, zirconium alloys, magnesium, magnesium alloys, aluminum, and aluminum alloys.

[0109] For example, reactive metal powders include titanium.

[0110] For example, reactive metal powders include titanium alloys.

[0111] For example, reactive metal powders include zirconium.

[0112] For example, reactive metal powders include zirconium alloys.

[0113] For example, the reactive metal powder is a metal powder containing at least one selected from titanium and titanium alloys.

[0114] For example, the method is carried out using at least one plasma torch.

[0115] For example, the method is carried out using at least one plasma torch.

[0116] For example, at least one of the plasma torches is a radio frequency (RF) plasma torch.

[0117] For example, at least one plasma torch is a direct current (DC) plasma torch.

[0118] For example, at least one of the plasma torches is a microwave (MW) plasma torch.

[0119] The following shows a cross-section of an example of a spray system 2', referencing Figure 1. The spray system 2' includes a receptacle 8 that receives a supply of a metal source 16 from an upstream system. For example, the supply of the metal source 16 is as a molten flow, but it may also be supplied as a metal rod or metal wire. The metal source can be heated according to various techniques.

[0120] The heated metal source 16 is supplied to the spraying area 32 through the outlet 24 and immediately comes into contact with the spray fluid from the spray source 40. The contact of the spray fluid with the heated metal source 16 results in the formation of reactive metal powder material 64, which is then discharged from the spraying area 32. For example, the spray fluid may be a spray gas. For example, the spray gas may be an inert gas.

[0121] For example, the inert gas can be selected from Ar and / or He.

[0122] The spraying system 2' has a spraying plasma torch 40, but the method and apparatus for forming reactive metal powders having improved fluidity as described herein is skull dissolution gas It is understood that this method can be applied to other types of spherical powder production systems, such as atomization methods, electrode-induced melting gas atomization methods (EIGA method), plasma rotating electrode methods, and plasma (RF, DC, MW) spheroidization methods.

[0123] In the example shown, the plasma source 40 includes at least one plasma torch. The focus of at least one individual nozzle 48 of the at least one plasma torch 40 is aligned with the metal source supply. For example, the cross section of the nozzle 48 tapers toward the metal source supply so as to focus on the plasma that contacts the metal source supply. As described in other parts of this specification, the nozzle 48 may be positioned so that the tip of the plasma jet contacts the metal source supplied from the receptacle 8. The metal source is atomized by the contact of the plasma originating from the at least one plasma source 40 with the metal source supply.

[0124] When multiple plasma torches are provided, the nozzles of the torches are individual nozzles 48 of the plasma torches directed toward the metal source from the receptacle 8. For example, the individual nozzles 48 are positioned so that the tip of the plasma jet emanating from them comes into contact with the metal source from the receptacle 8.

[0125] According to various exemplary embodiments for preparing spherical powder, a heated metal source comes into contact with at least one additive gas during the implementation of the atomization method.

[0126] The additive gas may be any gas containing electronegative atoms or molecules. The additive gas may also include fluorine, chlorine, iodine, bromide, hydrogen compounds, nitrogen compounds, and carbon compounds.

[0127] The additive gas may be an oxygen-containing gas. The term "oxygen-containing gas" as used here means a gas containing at least one oxygen atom. For example, such gases may be O2, CO2, CO, NO2, air, water vapor, ozone, etc.

[0128] According to various exemplary embodiments, the additive gas comes into contact with a heated metal source 16 within the spraying area 32 of the sprayer. This spraying area 32 is the high-temperature area of ​​the sprayer. Therefore, the heated metal source 16 can come into contact with the spraying gas and the additive gas substantially simultaneously within the spraying area 32.

[0129] If the metal particles are hot enough to diffuse electronegative atoms and / or electronegative molecules into the surface layer by tens of nanometers, a reaction can occur between the metal particles produced by the atomization of the heated metal source and the added gas.

[0130] According to the various exemplary embodiments described herein, in addition to the contact between the heated metal source and the atomizing fluid, the additive gas is understood to come into contact with the heated metal source during the atomization process.

[0131] It is further understood that, according to existing atomization methods, some of the additive gas can be introduced into the atomized fluid in an inherent way, for example, through contamination, potential impurities, or leaks. For example, the introduced additive gas may include air or oxygen.

[0132] However, according to various exemplary embodiments for producing spherical powder described herein, in addition to any additive gases that can be essentially introduced during the atomization process, an additive gas is intentionally supplied for contact with a heated metal source.

[0133] According to various exemplary embodiments, a first series of nozzles introduces a spray fluid into the spray area 32 and brings it into contact with a heated metal source 16, and a second series of nozzles introduces an additive gas into the spray area 32 and brings it into contact with the heated metal source 16. In other alternatives, the second series of nozzles Before being introduced into the spray area 32, the additive gas in an affinity fluid may be mixed with the spray fluid. For example, the spray fluid and the additive gas come into contact with the heated metal source 16 substantially simultaneously or with a slight delay. For example, it is possible to dilute such additive gas by mixing, thereby avoiding excessively high local concentrations that may lead to side reactions or undesirable reactions.

[0134] According to various alternative exemplary embodiments, the atomizing fluid is an atomizing gas, which is mixed with at least one additive gas to form an atomizing mixture. For example, the atomizing gas and the additive gas are mixed before contact with a heated metal source. The atomizing gas and the additive gas may be mixed in a gas storage tank or pipe upstream of contact with the heated metal source. For example, the additive gas may be introduced into a tank of atomizing gas. The introduced additive gas is added to any additive gas that is essentially present in the atomizing gas.

[0135] The amount of additive gas that comes into contact with the heated metal source can be controlled based on the desired final properties of the reactive metal powder formed by the atomization method.

[0136] For example, additive gases contained within the formed reactive metal powder can be considered contaminants in the metal powder. Therefore, the amount of additive gas that comes into contact with the heated metal source is controlled so that the amount of atoms and / or molecules of the additive gas contained within the reactive metal powder is maintained within a certain limit.

[0137] For example, the limits on the chemical composition in reactive metal powders can be specified by appropriate standards, such as the compositions in Table 1 of AMS4998, ASTM F3001, ASTM F2924, ASTM B348, ASTM B350, and Table 3 of ASTM B550. Therefore, the amount of additive gas in contact with the heated metal source is controlled based on one or more limits specified by standards relating to the composition of the additive gas and to one or more atoms and / or molecules constituting the additive gas.

[0138] For example, if the additive gas contains oxygen and the reactive metal powder formed is titanium alloy powder, the amount of additive gas in contact with the heated metal source is controlled so that the amount of oxygen in the formed reactive metal powder is less than 1800 ppm according to AMS4998 and less than 1300 ppm according to ASTM F3001.

[0139] For example, if the additive gas contains carbon and the reactive metal powder formed is titanium alloy powder, the amount of additive gas in contact with the heated metal source is controlled so that the amount of carbon in the formed reactive metal powder is less than 1000 ppm according to AMS4998 standard and less than 800 ppm according to ASTM F3001.

[0140] For example, if the additive gas contains hydrogen and the reactive metal powder formed is titanium alloy powder, the amount of additive gas in contact with the heated metal source is controlled so that the amount of hydrogen in the formed reactive metal powder is less than 120 ppm, in accordance with AMS4998 and ASTM F3001.

[0141] For example, if the additive gas contains nitrogen and the reactive metal powder formed is titanium alloy powder, the amount of additive gas in contact with the heated metal source is controlled so that the amount of nitrogen in the formed reactive metal powder is less than approximately 400 ppm according to AMS4998 standards and less than 500 ppm according to ASTM F3001 standards.

[0142] For example, if the additive gas contains chlorine and the reactive metal powder formed is titanium metal powder, the amount of additive gas that comes into contact with the heated metal source is controlled so that the amount of chlorine in the formed reactive metal powder is less than approximately 1000 ppm, in accordance with the ASTM F3001 standard.

[0143] For example, the amount of additive gas that comes into contact with the heated metal source can be controlled by controlling the amount of additive gas introduced into the spray gas when forming the spray mixture. For example, the amount of additive gas introduced can be controlled so that the ratio of spray gas to additive gas in the formed spray mixture achieves one or more desired ranges.

[0144] In the case of reactive metal powders formed without the addition of additive gases, it was found that reactive metal powders with various different particle size distributions did not necessarily flow sufficiently after the sieving and blending processes to allow their fluidity to be measured using a whole flow meter (see Figure 1 in ASTM B213). For example, reactive metal powders with a particle size distribution in the range of 10 to 53 μm did not flow through a whole flow meter according to ASTM B213.

[0145] While not bound by any particular theory, one important factor contributing to the poor fluidity of reactive metal powders is their susceptibility to static electricity. Sieving, blending, and handling processes can cause the particles of reactive metal powder to form colloids with each other, thereby increasing the level of static electricity. This static electricity further generates cohesive forces between particles, causing the reactive metal powder to not flow properly.

[0146] The reactive metal powder raw material, formed by atomizing the heated metal source by contacting it with a spray gas and an additive gas, is further recovered. The recovered reactive metal powder raw material contains a mixture of metal particles of various sizes. The reactive metal powder raw material is further sieved to separate it into different size distributions such as 10-45 μm, 15-45 μm, 10-53 μm, 15-53 μm, and / or 25-45 μm.

[0147] After sieving, each particle size distribution of metal powder is individually stirred in distilled water or demineralized water. Stirring helps to remove any static charge accumulated on the surface of the metal powder particles.

[0148] After sieving, the metal powders of each particle size distribution are dried individually. It has been observed that reactive metal powders formed according to various exemplary atomization methods described herein, in which a heated metal source comes into contact with an additive gas, exhibit substantially higher fluidity than reactive metal powders formed by atomization methods that do not involve contact with an additive gas. The differences in fluidity among metal powders formed by different methods can be largely distinguished by metal powders having size distributions of 10–45 μm, 15–45 μm, 10–53 μm, 15–53 μm, and / or 25–45 μm or similar particle size distributions. However, it is understood that metal powders with other size distributions may also show a slight increase in fluidity when formed according to methods involving contact between a heated metal source and an additive gas.

[0149] It is well known that titanium, once exposed to air, forms a native surface oxide film. This film is typically about 3-5 nm thick and is essentially composed of titanium oxide (S. Axelsson, 2012, p. 37). The native oxide acts as a passivation layer, reducing reactivity. This native film has a high affinity (hydrophilicity) for water vapor and possesses hydroxyl groups on its surface (Tanaka et al., 2008, p. 1; Lu et al., 2000, p. 1).

[0150] Although not bound by any theory, contact between the heated metal source and the additive gas during atomization causes atoms and / or molecules of the additive gas to react with the reactive metal powder particles as these particles are formed. Therefore, a first layer, formed of compounds of the heated metal and additive gas and depleted throughout its thickness, forms on the outer surface of the reactive metal particles. This layer is thicker, deeper from the surface, and located below the native oxide film. For example, the compounds of the heated metal and additive gas in the depletion layer are metal oxides, nitrides, carbides, or halides. The atoms of the added gas are consumed through the thickness of the surface layer, forming non-stoichiometric compounds with the metal. Such compounds result in a substantially positive charge on this first layer.

[0151] Since electronegative atoms and / or electronegative molecules need to have enough energy to diffuse further from the native oxide film into the surface layer, this first layer can only be formed at high temperatures.

[0152] A second layer, which is a native oxide film, is further formed on the surface of the reactive metal powder particles. The hydroxyl groups formed on the surface give the second layer a substantially negative charge.

[0153] A first layer having a substantially positive charge and a second layer having a substantially negative charge together form an electrical double layer. The combined charge of the double layer has a substantially neutral charge (i.e., a net charge toward zero). This neutral charge on the surface of the reactive metal powder particles can contribute to improved fluidity of the reactive metal powder formed according to the exemplary methods and apparatus described herein. For example, while a net charge on particles formed by conventional atomization methods tends to polarize the particles and increase their interaction with other particles, weakly charged particles have little to no electrical interaction with other particles. This reduced interaction can result in excellent fluidity.

[0154] Figure 2 shows a schematic diagram of particles 100 of reactive metal powder formed according to an atomization method in which the heated metal source 16 is not in contact with the additive gas. The formed particles 100 generally consist of particulate matter 108 (e.g., Ti-6Al-4V particles) and a surface native oxide film 116. The surface native oxide film 116 has a negative charge as a whole, and the formed particles 100 have a non-zero net charge (i.e., Q with respect to particle 108). net It gives a negative charge (≠0). Such a negative charge gives a higher polarization ability. Particle 108 also contains hydroxyl groups on its surface 116.

[0155] Figure 3 shows a schematic diagram of particles 104 of reactive metal powder formed according to the exemplary atomization method described herein, in which a heated metal source 16 is brought into contact with an additive gas. A first layer 148 (or layer 1) is formed on the outer surface of the particle body 156 (e.g., Ti-6Al-4V particles). This is produced by the combination of the heated metal and electronegative atoms and / or electronegative molecules that are consumed through the thickness. A second layer 164 (or layer 2), which is a native oxide film, is further formed on the surface of the particle body 156. As described elsewhere herein, the first layer 148 and the second layer 164 have a substantially neutral bond charge, and the particles 140 formed thereby have a substantially zero net charge (Q net To provide a polarization capability of approximately 0, and even lower.

[0156] Based on the theory that electronegative atoms and / or electronegative molecules derived from the added gas act as surface additives to the formed metal powder raw material particles, the amount of added gas introduced with the spray gas to form the spray mixture can be controlled to vary quasi-linearly with respect to the production rate of metal powder having a predetermined particle size distribution. The amount of added gas required to form layer 1 is related to the total surface area of ​​the metal particles, which is determined by the production rate and particle size distribution (see Figure 4). The concentration of the added gas and the thermal conditions of the metal particles determine the depth of the depletion layer of layer 1.

[0157] Furthermore, based on the theory that electronegative atoms and / or electronegative molecules derived from the added gas become surface additives to the formed metal powder raw material particles, the amount of added gas introduced together with the spray gas to form the spray mixture can be controlled to vary with the total surface area of ​​the formed metal powder particles, as shown in Figure 4.

[0158] Furthermore, based on the theory that electronegative atoms and / or electronegative molecules derived from the added gas become surface additives to the formed metal powder raw material particles, they are introduced together with the spray gas and sprayed together. The amount of additive gas used to form the compound can be controlled to vary with the temperature of the surface of the metal powder raw material particles being formed. The reaction rate Φ of such a chemical reaction, with an activation energy E, is generally given by the Arrhenius relation at temperature T:

[0159]

number

[0160] Figure 4 shows a schematic diagram of particle 180 with radius R and depletion depth δ at particle surface 188. The total surface area of ​​the particle is S1 = 4πR 2 That is the case.

[0161] Figure 4 further illustrates a schematic diagram of multiple particles (n particles) 200 of the same size, with a total mass equal to the mass of particle 180. The size of particle 200 is smaller than that of particle 180, but the total surface area of ​​particle 200 is larger than that of particle 180. Each particle 200 has a radius r, and the total number of particles is n = R. 3 / r 3 Therefore, the surface area of ​​the combined particle 200 is

[0162]

number

[0163] Therefore, since the volume being processed is the product of the total surface area and the depletion depth, the amount of surface additive added is a function of the total surface area.

[0164] For example, the resulting metal powder may contain approximately 100, 150, 200, 300, 500, 1000, or less than 1500 ppm of electronegative atoms and / or electronegative molecules (e.g., electronegative atoms and / or electronegative molecular elements contained in the additive gas used in the production of the powder). [Examples]

[0165] Using plasma spraying, four different batches of powder were produced under identical experimental conditions, except for the composition of the spray mixture in contact with the heated metal source.

[0166] The spray gas is high-purity argon (>99.997%).

[0167] In Tests 1 and 2, only the atomizing gas was used in contact with the heated metal source during the atomization process.

[0168] In Test 3, air was introduced into high-purity argon to form a spray mixture of argon and air containing 80 ppm. The heated metal came into contact with the spray mixture during the atomization process.

[0169] In Test 4, O2 was added to high-purity argon to form a spray mixture of argon and O2 containing 50 ppm. The heated metal came into contact with this second spray mixture during the atomization process.

[0170] After contact with spray gas (Tests 1 and 2) or spray mixture (Tests 3 and 4) The formed reactive metal powder raw material is then sieved to isolate a particle size distribution of 15-45 μm.

[0171] The sieved powder is then mixed to ensure uniformity.

[0172] To remove any static electricity accumulated during the previous process, the powder was further stirred in distilled water or demineralized water.

[0173] The powder was dried in air at 80°C for 12 hours.

[0174] Figure 5 is a graph showing a comparison of oxygen profiles between different samples using TOF-SIMS. TOF-SIMS properties of particles are obtained for tests 1-4. As seen in Table 1, the presence of a depletion layer may be associated with highly fluid powders.

[0175] The TOF-SIMS properties of the processed fine powder are clearly visible in Figure 5. The oxygen content extends deeper into the surface layer. To obtain improved fluidity behavior, it is important to obtain this depletion layer with a certain critical depth. The TOF-SIMS results suggest that the depth of the depletion layer is on the order of 100 nm. The depth can be estimated by using a profilometer and calibrating the sputtering rate of the ion beam obtained for the Ti-6Al-4V bulk portion. The sputtering rate depends on the ion beam intensity and the type of material. Calibration is performed before measurement, and the ion beam energy is very stable.

[0176] [Table 1]

[0177] [Table 2]

[0178] [Table 3]

[0179] Statistical data analysis from multiple batches revealed that introducing air (Test 3) added approximately 100-150 ppm of nitrogen and approximately 50 ppm of oxygen to the powder. The introduction of air improved the fluidity of the resulting reactive metal powder.

[0180] Furthermore, statistical data analysis revealed that by adding only O2 (Test 4), approximately 150-200 ppm of oxygen was added to the powder, while nitrogen was not added.

[0181] By introducing steam, we successfully conducted additional tests on the fluidity of particles with a particle size distribution of 15-45 μm. An improvement in fluidity for particles with a particle size distribution of 15-45 μm was similarly observed.

[0182] The processes performed conform to the compositions of ASTM B348, ASTM F2924, and ASTM F3001 standards, maintaining a sufficient chemical composition. This would also conform to the composition of AMS4998 if the raw materials had a slightly higher oxygen content.

[0183] Figure 6 is a photograph of a batch of metal powder weighing approximately 100 kg, formed according to an atomization method that does not involve contact with an additive gas. Due to aggregates, the recovery bucket is 90% full, and the visual compressibility is poor.

[0184] Figure 7 is a photograph of a batch of metal powder approximately 100 kg in size, formed according to an atomization method in which the metal source is brought into contact with an additive gas. Due to improved fluidity and smaller interparticle surface interactions, the same amount of material used in the experiment in Figure 6 filled 20% of the recovery bucket, and the visual compressibility was good.

[0185] The same tests as in Tests 3 and 4 were conducted by intermittently introducing the additive gas. It was found that the treatment was still effective while having the advantage of adding fewer impurities to the final product.

[0186] Similarly, we were able to blend a mixture consisting of up to 30% of well-flowing powder with 70% of powder that did not flow in a whole flow meter, and we showed that the resulting powder still flowed, though not as well as the starting powder. [Examples]

[0187] A pre-formed metal powder, created by a method without the use of additive gases, was subjected to a subsequent heat treatment.

[0188] More specifically, the already formed metal powder was heated in an atmospheric environment at approximately 250°C for 12 hours. This heating was expected to add oxygen to the particle surface of the metal powder raw material, thereby increasing the thickness of the native oxide film.

[0189] Subsequent oxidation / nitriding did not yield the same results as those obtained with the atomization method in which the additive gas was brought into contact with the atomized material in the spray region. No improvement in the fluidity of the metal powder was observed.

[0190] Post-heating of already formed metal powders only thickens the native oxide film and does not appear to have the ability to create a sufficiently deep depletion oxide / nitride layer on the particles. Even thicker oxide films cannot maintain a quasi-stoichiometric ratio and cannot produce a positively charged layer 1 arising from the depletion layer.

[0191] While not bound by any particular theory, the high temperatures and low concentrations of additive gases during atomization allow for oxidation / nitridation reactions that form a depletion oxide / nitride layer when the metal source comes into contact with the additive gases.

[0192] The embodiments described in paragraphs

[0027] to

[0191] of this disclosure are shown in this disclosure in such a way that, where appropriate, any combination of embodiments is possible. Accordingly, these embodiments are shown in the specification in such a way that it is equivalent to creating dependent claims for all embodiments that depend on any of the prior claims (including the embodiments shown earlier), thereby indicating that these embodiments are combinatorial in any possible way. For example, where appropriate, all possible combinations between the embodiments in paragraphs

[0027] to

[0191] and the methods in paragraphs

[0006] to

[0026] are all incorporated herein by reference.

[0193] For the purpose of making the description concise and clear, reference numbers are understood to be shared and repeated between drawings to indicate corresponding or similar elements or processes, where deemed appropriate. Various specific details are described to provide a full understanding of the exemplary embodiments described herein. However, those skilled in the art will understand that the embodiments described herein can be carried out without these specific details. In other instances, well-known methods, procedures, and components are not described in detail so as not to obscure the embodiments described herein. Furthermore, this specification should not be considered to limit the scope of the embodiments described herein in any way, but rather to be understood as simply describing the various embodiments described herein. [Explanation of Symbols]

[0194] 2' Spray System 8 Receptacles 16 Metal sources 24 Exit 32 Spray area 40 Spray source 48 nozzles 64 Reactive metal powder raw materials 100 particles 10⁸ particle bodies 116 Surface 140 particles 148 The first layer 156 particle bodies 164 The second layer 180 particles 188 Scarcity 200 particles

Claims

1. A method for producing reactive metal powders by atomization, A process for producing a reactive metal powder raw material by atomizing a heated reactive metal source, comprising the steps of contacting the heated reactive metal source with an atomized mixture containing a spray gas and an additive gas, A method comprising forming a depletion layer containing components from the additive gas with the additive gas, wherein the depletion layer is a layer in which the concentration of the components decreases from the surface inward of the reactive metal powder raw material, and has a concentration profile in which the concentration of the components decreases to 50 percent of the maximum concentration at a second depth deeper than the first depth, from a first depth in which the concentration of the components is maximum, and the second depth is such that the fluidity measurement of the reactive metal powder raw material measured according to ASTM B213 is less than 40 seconds.

2. The method according to claim 1, wherein the second depth is at least 40 nm and 100 nm or less.

3. The method according to claim 1, wherein the second depth is such that the particle size distribution of the reactive metal powder raw material, ranging from 10 to 53 micrometers, has a flowability measurement of less than 40 seconds, as measured according to ASTM B213.

4. The method according to claim 1, wherein the additive gas includes oxygen or air as one of its components.

5. A method for producing reactive metal powders by atomization, A process for producing a reactive metal powder raw material by atomizing a heated reactive metal source, the process comprising contacting the heated reactive metal source with a spray gas. A step of forming a depletion layer containing added components, Includes, The depletion layer is a layer in which the concentration of the additive decreases from the surface of the reactive metal powder raw material toward the interior, and has a concentration profile in which the concentration of the additive decreases to 50 percent of the maximum concentration at a second depth deeper than the first depth, from a first depth in which the concentration of the additive is maximum, wherein the second depth is such that the reactive metal powder raw material has a fluidity measurement of less than 40 seconds as measured according to ASTM B213.

6. A method for producing reactive metal powders by atomization, A process for producing a reactive metal powder raw material by atomizing a heated reactive metal source, comprising the steps of contacting the heated reactive metal source with an atomized mixture containing an atomizing gas and an additive gas, The process of forming a depletion layer containing components from the aforementioned additive gas, Includes, The depletion layer is a layer in which the concentration of the component decreases from the surface of the reactive metal powder raw material toward the interior, and the normalized concentration of at least 50% of the added gas atoms extends to a depth in which the fluidity measurement value of the reactive metal powder raw material, as measured according to ASTM B213, is less than 40 seconds.

7. The method according to claim 6, wherein the depth is at least 40 nm.

8. A method for producing reactive metal powders by atomization, A process for producing a reactive metal powder raw material by atomizing a heated reactive metal source, comprising contacting the heated reactive metal source with a spray gas and an additive gas, wherein the spray gas is supplied from a plasma source. During the atomization of the heat-reactive metal source, a step is taken to control the amount of additive gas that comes into contact with the heat-reactive metal source. A step of forming a depletion layer containing components from the aforementioned additive gas, Includes, A method comprising the step of controlling the amount of the additive gas that comes into contact with the heat-reactive metal source during the atomization of the heat-reactive metal source, wherein the step of controlling the amount of the additive gas that comes into contact with the heat-reactive metal source during the atomization of the heat-reactive metal source controls the depth of the depletion layer, the depletion layer being a layer in which the concentration of the components decreases from the surface to the interior of the reactive metal powder raw material.

9. A spraying system, A material holder including a heating device for supplying a heat-reactive metal source, A plasma source comprising a nozzle directed from a material holder toward the heated reactive metal source in order to atomize the heated reactive metal source to form a reactive metal powder raw material, wherein the atomized mixture comprises a spray gas and an additive gas, Includes, The atomizing system is configured to control the atomizing gas in the atomizing mixture in order to control the formation of a depletion layer in the reactive metal powder raw material, wherein the depletion layer contains the components of the additive gas and is a layer in which the concentration of the components decreases from the surface to the interior of the reactive metal powder raw material.

10. The atomization system according to claim 9, configured to control the depth of the depletion layer in the reactive metal powder raw material by controlling the amount of the additive gas in the atomization mixture.

11. A spraying system, A material holder including a heating device for supplying a heat-reactive metal source, A plasma source comprising a nozzle directed from a material holder toward the heated reactive metal source in order to atomize the heated reactive metal source to form a reactive metal powder raw material, wherein the atomized mixture comprises a spray gas and an additive gas, the plasma source and Includes, The atomization system is configured to control the atomizing gas in the atomized mixture in order to control the formation of a depletion layer in the reactive metal powder raw material and to control the fluidity of the reactive metal powder raw material, wherein the depletion layer contains the components of the added gas and is a layer in which the concentration of the components decreases from the surface to the interior of the reactive metal powder raw material. Atomization system.

12. A method for producing reactive metal powders by atomization, A process of supplying a heated reactive metal source to the atomization zone, A step of generating a reactive metal powder raw material by bringing the heated reactive metal source into contact with a spray gas and an additive gas in the atomization zone to atomize the heated reactive metal source, wherein bringing the heated reactive metal source into contact with the spray gas and the additive gas in the atomization zone includes forming a depletion layer in the reactive metal powder raw material containing the components of the additive gas, which is a layer in which the concentration of the components decreases from the surface to the interior of the reactive metal powder raw material, and the spray gas is supplied from a plasma source. A method that includes this.

Images