JP7571181B2 - High quality spherical powder for additive manufacturing processes and method for forming same - Google Patents

Description

PRIORITY INFORMATION This application claims priority to U.S. Provisional Patent Application No. 62/551,981, entitled "High Quality Spherical Powders for Additive Manufacturing Processes Along with Methods of Their Formation," filed August 30, 2017, which is incorporated herein by reference.

The present invention generally relates to a system and method for forming high quality spherical powder from a metal powder feedstock, the high quality spherical powder being particularly suitable for additive manufacturing of objects or parts.

Additive manufacturing processes, as opposed to subtractive manufacturing methods, generally involve the accumulation of one or more materials to create a net-shape or near-net-shape (NNS) object. "Additive manufacturing" is an industry standard term, but encompasses a variety of manufacturing and prototyping techniques known under various additive manufacturing terms, including freeform fabrication, 3D printing, rapid prototyping/tooling, etc. Additive manufacturing techniques allow the creation of complex components from a wide variety of materials. Generally, freestanding objects can be created from computer-aided design (CAD) models.

In a particular type of additive manufacturing process, an energy beam, e.g., electromagnetic radiation such as an electron beam or a laser beam, is used to sinter or melt powder materials to create solid three-dimensional objects in which the particles of the powder material are bonded together. Different material systems are used, e.g., engineering plastics, thermoplastic elastomers, metals, and ceramics. Laser sintering or melting is also a notable additive manufacturing process for the rapid creation of functional prototypes and tools. Applications include patterns for investment casting, metal molds for injection molding and die casting, and molds and cores for sand casting. The creation of prototype objects and proof of concept to facilitate communication in the design cycle are other common applications of additive manufacturing processes.

Laser sintering is a common industrial term used to refer to the production of three-dimensional (3D) objects by sintering or melting fine powder with a laser beam. More precisely, sintering is the fusing (agglomerating) of powder particles at temperatures below the melting point of the powder material, while melting is the complete melting of the powder particles to form a solid homogenous mass. The physical processes involved in laser sintering or laser melting include the transfer of heat to the powder material followed by sintering or melting of the powder material.

In this process, the physical and chemical properties of the powder material can affect the quality of the resulting object; that is, the properties of components built by additive manufacturing depend on the metal powder itself, and the higher the quality of the powder (e.g., denser, purer, more spherical), the more predictable the behavior and, consequently, the better the part. Therefore, components formed from additive manufacturing techniques require high-quality spherical powders, especially when used to manufacture components for gas turbines and/or medical implants or devices.

Powder fabrication methods from metal sources mainly include gas atomization and water atomization (although other techniques such as hydride/dihydride, ball milling, rotating electrode, and plasma atomization exist). In general, gas atomization produces more spherical and uniform particles, while water atomization produces irregularly shaped particles. Furthermore, due to the presence of oxygen in water, particles formed by water atomization may develop an oxide layer on the outside. Today, gas atomized powders are preferred for additive manufacturing over water atomized powders because gas atomized powders are more regular in shape (e.g., more spherical) and have a limited oxide layer on the powder.

However, powders formed from gas atomization are much more expensive to produce than water atomized powders. Thus, components formed from gas atomized powders are expensive. This creates a need to reduce the cost of high quality powders for diversification in additive manufacturing while maintaining control over the physical and chemical properties of the powder material.

Aspects and advantages are set forth in part in the description that follows, or may be obvious from the specification, or may be learned by practice of the invention.

A method is provided for forming a high quality powder from a feedstock powder, the feedstock particles generally having irregular shapes. In one embodiment, the method includes exposing the feedstock powder to a plasma field to form a treated powder of treated particles having a shape that is more nearly spherical than the feedstock particles. Prior to exposure to the plasma field, the feedstock particles have an oxide layer on the particles as a result of exposure to water. After exposure to the plasma field, the treated particles are substantially free of the oxide layer.

In some embodiments, the feedstock powder may be formed from water atomization, mechanical milling or grinding, gas atomization, and/or plasma atomization. For example, the oxide layer on the feedstock particles may be the result of exposure to water during the water atomization process that formed the feedstock particles, or exposure to water vapor in the air during mechanical grinding.

To expose the feedstock powder to the plasma field, the method may include introducing the feedstock powder into the plasma field such that the surfaces of the feedstock particles melt and/or vaporize to form a more spherical shape.

In certain embodiments, the plasma field includes a reducing component, such as hydrogen, carbon monoxide, or a mixture thereof, that reacts with the oxide layer on the feedstock particles.

In such a manner, the treated particles may have an average particle size that is less than the average particle size of the feedstock particles. For example, the treated particles may have an average particle size that is about 10% to about 90% of the average particle size of the feedstock particles.

The feedstock particles may be formed from metallic materials such as pure metals, iron alloys, aluminum alloys, nickel alloys, chromium alloys, nickel-based superalloys, iron-based superalloys, cobalt-based superalloys, or mixtures thereof. In some embodiments, particles an alloying element such as carbon may be mixed with the feedstock particles in the plasma field.

In some embodiments, a method of forming a high quality powder may include: forming a feedstock powder by water atomization, where the feedstock powder includes feedstock particles having an irregular shape, the feedstock particles having an oxide layer thereon; and then exposing the feedstock powder to a plasma field to melt and/or vaporize the surfaces of the feedstock particles, thereby forming a treated powder of treated particles having a shape that is more spherical than the feedstock particles. The plasma field may include a reducing component (e.g., hydrogen, carbon monoxide, or a mixture thereof) that reacts with the oxide layer on the feedstock particles such that the treated particles are substantially free of the oxide layer. In some embodiments, the treated particles have an average particle size that is less than the average particle size of the feedstock particles.

A treated powder comprising the treated particles is also generally provided herein, along with a method for additively manufacturing a component from the treated powder.

These and other features, aspects, and advantages will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain certain principles of the invention.

A full and enabling disclosure of the present invention, including the best mode thereof, to one of ordinary skill in the art is set forth below with reference to the accompanying drawings.

FIG. 1 illustrates an exemplary powder material plasma spheronization apparatus that can improve the properties of the powder material and make it more suitable for additive manufacturing processes.

FIG. 2A is a scanning electron microscope (SEM) image of an exemplary feedstock powder according to an embodiment.

FIG. 2B is a magnified SEM image of the exemplary feedstock powder of FIG. 2A.

FIG. 3A is a SEM image of an exemplary spheroidized powder formed from the pre-washed feedstock powder shown in FIGS. 2A and 2B, according to an embodiment.

FIG. 3B is a magnified SEM image of the exemplary spheroidized powder of FIG. 3A.

FIG. 4A is a SEM image of the exemplary spheroidized powder shown in FIGS. 3A and 3B after washing, in accordance with an embodiment.

FIG. 4B is a magnified SEM image of the exemplary washed spheroidized powder of FIG. 4A.

Repeated use of reference numbers in the present specification and drawings is intended to represent like or similar features or elements of the present invention.

Hereinafter, the embodiments of the present invention will be described in more detail. One or more examples of the present invention will be illustrated in the drawings, each of which is presented as a means of explaining the present invention, and is not intended to limit the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations of the present invention can be made without departing from the scope or spirit of the present invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to obtain yet a further embodiment. It is therefore intended that the present invention encompass such modifications and variations as fall within the scope of the appended claims and their equivalents.

The terms "first," "second," and "third" used herein are interchangeable terms that may be used to distinguish one component from another and are not intended to denote the location or importance of the individual components.

The terms "upstream" and "downstream" refer to directions relative to fluid flow in a fluid pathway. For example, "upstream" refers to the direction from which the fluid flow is coming, and "downstream" refers to the direction to which the fluid flow is going.

Methods for producing high quality powder material (i.e., treated powder) from a low quality powder source (i.e., feedstock powder) are generally provided, along with an apparatus for carrying out the method and the resulting particles. In some embodiments, powders formed from water atomization and having irregular shapes (such as those formed from water atomization) result in higher quality powders. In some embodiments, treated particles of treated powder can have a shape closer to a sphere than feedstock particles of feedstock powder, which can have irregular, non-spherical shapes. Additionally, any oxide layer present on the feedstock powder can be removed (e.g., by chemical reduction). In some embodiments, the treated powder can be substantially free of any oxide layer on its surface. As used herein, the term "substantially absent" means present in negligible amounts, including complete absence (e.g., 0 mol % to 0.01 mol %).

In one embodiment, the treatment powder is plasma spheronized (e.g., exposed) to produce a high quality powder. A schematic diagram of a plasma spheronization apparatus 10 is shown in FIG. 1. Feedstock powder 12 (comprised of a plurality of feedstock particles 13) is typically introduced into a plasma chamber 14 along with a treatment gas 16 (also referred to as a plasma gas, regardless of the state of matter). A plasma field 18 may be formed within the plasma chamber 14 by heating the plasma gas 16 to a temperature sufficient to change it from a gaseous state to a plasma state. A heating element 20, such as, for example, an induction coil, may be included within the plasma chamber 14.

As discussed above, the feedstock particles 13 may have an irregular shape (e.g., non-spherical) when introduced into the plasma chamber 14. In some embodiments, the feedstock particles 13 have a maximum size of about 150 micrometers (μm). For example, the feedstock particles 13 may have an average size of about 10 μm to about 150 μm (e.g., about 50 μm to about 100 μm).

In general, the feedstock powder 12 may be any metallic material. In certain embodiments, the metallic material may include, but is not limited to, a pure metal, an iron alloy, an aluminum alloy, a nickel alloy, a chromium alloy, a nickel-based superalloy, a cobalt-based superalloy, an iron-based superalloy, or mixtures thereof. In certain embodiments, alloying elements may be mixed with the feedstock powder 12 prior to or during exposure to the plasma gas 16. In this manner, the chemical composition of the resulting treated powder may be adjusted. For example, in certain embodiments, carbon particles may be mixed with the feedstock particles within the plasma field.

As the feedstock powder 12 travels through the plasma field 18, which contains the plasma gas 16 in a plasma state, the surfaces of the feedstock particles 13 melt or vaporize within the melting zone 22, which contains the plasma field 18. However, it is believed that the feedstock particles 13 do not completely melt and/or vaporize, but rather that the surfaces of the feedstock particles 13 melt/soften and change into smaller and more regular shapes (e.g., more spherical shapes); without wishing to be bound by any particular theory, it is believed that the surfaces of the feedstock particles 13 thus melt/soften at least partially within the melting zone 22.

In certain embodiments, the treatment gas 16 (i.e., plasma gas) comprises a reducing gas, such as hydrogen, carbon monoxide, or a mixture thereof. The reducing gas can react with any oxide layer, which may be in the form of chromium oxide, iron oxide, etc., on the surface of the feedstock particles 13. The reducing gas can react with and remove the oxide from the particle surface, such that substantially no oxide layer is present on the particles of the resulting treated powder 24 (in the form of a plurality of treated particles 25). Thus, in certain embodiments, the reducing component reduces any oxide layer on the surface of the feedstock particles, such that substantially no oxide layer is present on the resulting treated particles.

The plasma spheronization process can reduce the size of the feedstock particles 13 such that the resulting treated particles 25 have an average particle size that is less than the average particle size of the feedstock particles 13. In some embodiments, the resulting treated particles 25 have an average particle size that is about 10% to about 90% of the average particle size of the feedstock particles 13. In some particular embodiments, the treated particles 25 have a maximum size of about 150 μm (e.g., an average size of about 10 μm to about 150 μm). In some particular embodiments, the treated particles 25 have a maximum size of about 50 μm (e.g., an average size of about 10 μm to about 50 μm).

Such techniques can also be used to recondition powders.

As described above, plasma spheroidization of the feedstock powder 12 improves the properties of the feedstock powder 12, and the improved powder material (i.e., treated powder 24) may be more suitable for additive manufacturing. As used herein, the term "additively manufactured" or "additive manufacturing technique or process" generally refers to the layer-by-layer "additive manufacturing" of a three-dimensional component, in which layers of material are provided successively on top of each other. Successive layers typically fuse together to form a monolithic component that may have various integral subcomponents. Although additive manufacturing techniques have been described herein as enabling the manufacture of complex objects by building objects point-by-point or layer-by-layer, typically in a vertical direction, other manufacturing methods are possible and are within the scope of the present subject matter. For example, while the discussion herein relates to the formation of successive layers by the addition of material, one of ordinary skill in the art will understand that any additive manufacturing method or technique may be used to implement the methods and structures disclosed herein. For example, embodiments of the present invention may use a layer-additive process, a layer-removal process, or a hybrid process.

Suitable additive manufacturing methods according to the present disclosure include, for example, fused deposition modeling (FDM), selective laser sintering (SLS), 3D printing such as inkjet, laser jet, and binder jet, stereolithography (SLA), direct selective laser sintering (DSLS), electron beam sintering (EBS), electron beam melting (EBM), laser engineered net shaping (LENS), laser net shape manufacturing (LNSM), direct metal deposition (DMD), digital light process (DLP), direct selective laser melting (DSLM), selective laser melting (SLM), direct metal laser melting (DMLM), and other known processes.

The additive manufacturing processes described herein can be used to form components using any suitable material. For example, the material may be plastic, metal, concrete, ceramic, polymer, epoxy, photopolymer resin, or any other suitable material that may be in a solid, liquid, powder, sheet material, wire, or any other suitable form, or combinations thereof. More specifically, according to exemplary embodiments of the present subject matter, the additively manufactured components described herein may be formed partially or entirely from materials including, but not limited to, pure metals, iron alloys, aluminum alloys, nickel alloys, chromium alloys, and nickel-, iron-, or cobalt-based superalloys (e.g., available under the trade name Inconel® from Special Metals Corporation), or in any combination thereof. These materials are examples of materials suitable for use in the additive manufacturing processes described herein and may be generally referred to as "additive materials."

Those skilled in the art will also appreciate that a variety of materials and methods of joining these materials may be used and are considered within the scope of the present disclosure. As used herein, "fusing" may refer to any suitable process for creating a bonded layer of any of the above materials. For example, if the object is made of a polymer, fusing may refer to forming a thermosetting bond between the polymeric materials. If the object is an epoxy, the bond may be created by a crosslinking process. If the material is a ceramic, the bond may be created by a sintering process. If the material is a powder metal, the bond may be created by a melting or sintering process. Those skilled in the art will appreciate that other methods of fusing materials are possible for creating components by additive manufacturing and the subject matter of the present disclosure may be practiced by these methods.

Additionally, the additive manufacturing processes described herein allow for the formation of a single component from multiple materials. Thus, the components described herein may be formed from any suitable mixture of the above materials. For example, a component may include multiple layers, segments, or parts formed using different materials, processes, and/or different additive manufacturing equipment. In this manner, components may be constructed having different materials and material properties to meet the needs of any particular application. Additionally, while the components described herein are constructed entirely by additive manufacturing processes, it should be understood that in alternative embodiments, the components may be formed in whole or in part by casting, machining, and/or any other suitable manufacturing process. Indeed, components may be formed from any suitable combination of materials and manufacturing methods.

An exemplary additive manufacturing process is now described. In an additive manufacturing process, a component is manufactured using three-dimensional (3D) information of the component, for example a three-dimensional computer model. Thus, a three-dimensional design model of the component may be defined prior to manufacturing. In this regard, a model or prototype of the component may be scanned to determine the three-dimensional information of the component. As another example, a model of the component may be constructed using a suitable computer-aided design (CAD) program to define the three-dimensional design model of the component.

The design model may include 3D numerical coordinates of the overall configuration of the component, including both the exterior and interior surfaces of the component. For example, the design model may define the body, surfaces, and/or internal pathways of openings, support structures, etc. In an example embodiment, the three-dimensional design model is converted into multiple slices or segments, for example along a central axis (e.g., vertical axis) of the component or any other suitable axis. Each slice may define a thin cross-section of the component for a slice at a given height. Successive cross-sectional slices collectively form the 3D component. The component is then "additively built" slice by slice or layer by layer until completed.

In this manner, the components described herein are manufactured using additive processes, more specifically, each layer is successively formed, for example, by fusing or polymerizing plastics with laser energy or heat, or sintering or melting metal powders. For example, certain types of additive manufacturing processes may sinter or melt powdered materials using an energy beam, for example, electromagnetic radiation, for example, an electron beam or laser beam. Any suitable laser and laser parameters may be used, taking into consideration considerations related to power, laser beam spot size, and scanning speed. The build material may be formed from any suitable powder or material selected for its strength, durability, and useful life, especially at elevated temperatures.

Each successive layer may be, for example, about 10 μm to 200 μm, although the thickness may be selected based on various parameters and may be any suitable size according to alternative embodiments. Thus, using the additive forming methods described herein, the components described herein may have a cross-section that is as thin as one layer thickness of the associated powder layer utilized during the additive forming process, for example, on the order of 10 μm.

Additionally, additive processes can be used to vary the surface finish and features of a component according to application needs. For example, the surface finish can be adjusted (e.g., made smoother or rougher) during the additive process by selecting appropriate laser scanning parameters (e.g., laser power, scanning speed, laser focal spot size, etc.), particularly at the outer surface of the cross-sectional layer corresponding to the part surface. For example, a rougher finish can be achieved by increasing the laser scanning speed or decreasing the size of the melt pool formed, and a smoother finish can be achieved by decreasing the laser scanning speed or increasing the size of the melt pool formed. Additionally, the scan pattern and/or laser power can be altered to change the surface finish of selected areas.

In particular, in exemplary embodiments, some features of the components described herein were not previously feasible due to manufacturing constraints. However, the inventors have advantageously leveraged current advances in additive manufacturing technology to develop exemplary embodiments of components generally consistent with the present disclosure. Although the present disclosure is not limited to the use of additive manufacturing to form components generally, additive manufacturing offers a variety of manufacturing advantages, including ease of manufacture, reduced cost, improved accuracy, and the like.

In this regard, by utilizing additive manufacturing techniques, even multi-part components may be formed as a single continuous metal piece, resulting in fewer subcomponents and/or joints than known designs. Forming multi-part components integrally through additive manufacturing may advantageously improve the overall assembly process. For example, integral formation may reduce the number of individual parts that require assembly, reducing the associated time and overall assembly costs. It may also advantageously reduce existing issues related to leakage, joint quality between individual parts, and overall performance, for example.

The additive manufacturing methods described above also allow for much more complex and intricate shapes and contours for the components described herein. For example, a component may include additively manufactured thin layers and unique fluid pathways with integral attachment features. Furthermore, additive manufacturing processes also allow for the production of a single component having different materials such that different portions of the component exhibit different performance characteristics. The manufacturing process is continuous, additive in nature, allowing for the construction of these new features. As a result, the components described herein may have improved functionality and reliability.

As an example, the water atomized powder was purchased as 316 powder with a size of -325 mesh/15 microns. The water atomized powder is an iron-based alloy. The water atomized powder was found to have an apparent density of 2.75 (g/cm ³ ) and an oxygen content of 0.164% (by weight), a nitrogen content of 0.047% (by weight), and a hydrogen content of 0.001% (by weight). The water atomized powder, prior to any processing, was found to have the particle size distribution shown in Table 1.

Figures 2A and 2B show SEM images of the water atomized powder before any processing. As can be seen, the water atomized powder contains particles of various sizes and shapes.

The water atomized powder was then spheronized using argon as the primary gas and hydrogen as the secondary gas. Other experiments were also conducted using argon as the primary gas and helium and nitrogen as the secondary gases. It was found that spheronization resulted in more uniformly sized and shaped particles in the powder.

Figures 3A and 3B show images of the spheroidized powder after spheroidization using argon as the primary gas and hydrogen as the secondary gas.

The spheronized powder was then washed using an industrial washing unit. Figures 4A and 4B show images of the spheronized powder. As can be seen, after the spheronization and washing process, the powder is composed of relatively clean and uniform particles.

The spheroidized powder was found to have an oxygen content of 0.057% (wt%), a nitrogen content of 0.009% (wt%), and a hydrogen content of 0.0007% (wt%). Thus, the oxygen, nitrogen, and hydrogen contents of the spheroidized powder were significantly reduced.

Table 2 shows the particle size distribution after spheronization and washing.

In conclusion, the spheroidization of water-atomized powder was successful, resolving both of the major challenges of irregular shape and high oxygen content.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems, and performing any methods incorporated therein. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal words of the claims, or if they include equivalent structural elements that differ insignificantly from the literal words of the claims.
[Additional Notes]
＜1＞
1. A method for forming a high quality powder from a feedstock powder of feedstock particles having irregular shapes, comprising:
exposing the feedstock powder to a plasma field to form a treated powder of treated particles having a shape that is more nearly spherical than the feedstock particles;
the feedstock particles have an oxide layer thereon as a result of exposure to water, and the treated particles are substantially free of an oxide layer;
method.
＜2＞
The method according to claim 1, wherein the feedstock powder is formed by water atomization, mechanical grinding or pulverization, gas atomization, and/or plasma atomization.
＜3＞
2. The method of claim 1, wherein the oxide layer on the feedstock particles is the result of exposure to water during a water atomization process that formed the feedstock particles.
＜4＞
exposing the feedstock powder to the plasma field includes introducing the feedstock powder into the plasma field such that surfaces of the feedstock particles at least partially melt or vaporize to form a more spherical shape;
The method according to <1>, comprising:
＜5＞
The method according to claim 4, wherein the plasma field contains a reducing component that reacts with the oxide layer on the feedstock particles.
＜6＞
The method according to <5>, wherein the reducing component comprises hydrogen, carbon monoxide, or a mixture thereof.
＜７＞
The method according to <1>, wherein the feedstock particles have a maximum size of about 150 μm.
＜8＞
The method according to <7>, wherein the feedstock particles have an average size of about 10 μm to about 150 μm.
＜9＞
The method according to <8>, wherein the feedstock particles have an average size of about 50 μm to about 100 μm.
＜10＞
The method according to <1>, wherein the treated particles have an average particle size less than the average particle size of the feedstock particles.
<11>
The method according to <1>, wherein the treated particles have an average particle size that is about 10% to about 90% of the average particle size of the feedstock particles.
＜12＞
The method according to <1>, wherein the feedstock particles include a metal material.
＜13＞
The method according to <12>, wherein the metallic material comprises a pure metal, an iron alloy, an aluminum alloy, a nickel alloy, a chromium alloy, a nickel-based superalloy, an iron-based superalloy, a cobalt-based superalloy, or a mixture thereof.
＜14＞
The method according to claim 1, wherein carbon particles are mixed with the feedstock particles in the plasma field.
＜15＞
A treated powder comprising the treated particles formed by the method according to <1>.
＜16＞
A method for additively manufacturing a component from the processed powder according to <15>.
＜１７＞
1. A method of forming a high quality powder, comprising:
forming a feedstock powder by water atomization, wherein the feedstock powder comprises feedstock particles having irregular shapes, the feedstock particles having an oxide layer thereon; and
thereafter, exposing the feedstock powder to a plasma field to at least partially melt or vaporize surfaces of the feedstock particles, thereby forming a treated powder of treated particles having a shape that is more nearly spherical than the feedstock particles;
Including,
the plasma field includes a reducing component that reacts with the oxide layer on the feedstock particles such that the treated particles are substantially free of the oxide layer;
method.
＜18＞
The method according to <17>, wherein the reducing component comprises hydrogen, carbon monoxide, or a mixture thereof.
＜19＞
The method according to <17>, wherein the treated particles have an average particle size less than the average particle size of the feedstock particles.
＜20＞
The method according to claim 1, wherein the feedstock particles include a metal material, and carbon particles are mixed with the feedstock particles in the plasma field.

Claims (11)

1. A method for forming a high quality spheroidized powder from a feedstock powder of feedstock particles having irregular, non-spherical shapes and having an oxidized layer on the particles, comprising:
forming a plasma field within a plasma chamber using an induction coil;
passing the feedstock powder through the plasma field such that the feedstock particles are only partially melted and surfaces of the feedstock particles soften to form a treated powder of treated particles having a shape that is more spherical than the feedstock particles, wherein the plasma field includes a primary gas and a reducing gas that reacts with the oxide layer on the surfaces of the feedstock particles from exposure to water, passing the feedstock powder through the plasma field removes the oxide layer from the feedstock particles, and washing the treated powder of treated particles.
The treated particles are free of oxygen in negligible amounts, the treated particles having an average particle size that is 10% to 90% of the average particle size of the feedstock particles, and the treated particles are free of oxygen or have oxygen in an amount greater than 0 mole % but not greater than 0.01 mole %.
method. The method of claim 1, wherein the feedstock powder is formed by water atomization, mechanical grinding or pulverization, gas atomization, and/or plasma atomization. The method of claim 1 or claim 2, wherein the oxide layer on the feedstock particles is the result of exposure to water during a water atomization process that formed the feedstock particles. passing the feedstock powder through the plasma field includes introducing the feedstock powder into the plasma field such that surfaces of the feedstock particles are at least partially vaporized to form a more spherical shape;
The method according to any one of claims 1 to 3, comprising: The method according to any one of claims 1 to 4, wherein the reducing gas comprises hydrogen, carbon monoxide, or a mixture thereof. The method of any one of claims 1 to 5, wherein the feedstock particles have a maximum size of 150 μm. The method of claim 6, wherein the feedstock particles have an average size of 10 μm to 150 μm. The method according to any one of claims 1 to 7, wherein the feedstock particles include a metal material. The method of claim 8, wherein the metallic material comprises a pure metal, an iron alloy, an aluminum alloy, a nickel alloy, a chromium alloy, a nickel-based superalloy, an iron-based superalloy, a cobalt-based superalloy, or a mixture thereof. The method of any one of claims 1 to 9, wherein carbon particles are mixed with the feedstock particles in the plasma field. A method for additively manufacturing a component from the washed treated powder obtained by the method according to any one of claims 1 to 10 .