US-12617016-B2 - Sub-micron particles of rare earth and transition metals and alloys, including rare earth magnet materials

Abstract

The present disclosure is directed to methods of preparing substantially spherical metallic alloyed particles, having micron and sub-micron (i.e., nanometer)-scaled dimensions, and the powders so prepared, as well as articles derived from these powders. In particular embodiments, these metallic alloyed particles, comprising rare earth metals, can be prepared in sizes as small 80 nm in diameter with size variances as low as 2-5%.

Inventors

• Miha Zakotnik
• Davide Prosperi
• Gojmir FURLAN
• Catalina O. TUDOR
• Alex Ivor BEVAN

Assignees

• URBAN MINING TECHNOLOGY COMPANY, INC.

Dates

Publication Date

20260505

Application Date

20211229

Claims (14)

1. 1 . A method comprising impinging at least one inert fluid stream having a velocity of 0.2-10.5 km/sec onto a stream of a molten or liquid metallic alloy under appropriate conditions so as to produce a dispersion of substantially spherical solid particles of the metallic alloy within the at least one inert fluid stream, the particles having a mean particle size in a range of 80 nm to 500 microns; and wherein the molten or liquid metallic alloy is represented by the formula Nd j Dy k Co m Cu n Fe p , wherein: j is atomic percent in a range from 1 to 20 atom %, relative to the entire composition; k is atomic percent in a range from 1 to 60 atom %, relative to the entire composition; m is atomic percent in a range from 1 to 60 atom %, relative to the entire composition; n is atomic percent in a range from 0.1 to 20 atom %, relative to the entire composition; p is atomic percent in a range from 1 to 20 atom %, relative to the entire composition; and j, k, m, n, and p are independently variable within their stated ranges provided that the sum of j+k+m+n+p is greater than 95 atom %.
2. 2 . The method of claim 1 , wherein the at least one inert fluid stream comprises nitrogen, argon, helium, hydrogen, or a mixture thereof.
3. 3 . The method of claim 1 , wherein the at least one inert fluid stream is a liquid.
4. 4 . The method of claim 1 , wherein the at least one inert fluid stream is a gas.
5. 5 . The method of claim 1 , wherein the at least one inert fluid stream comprises a plurality of inert fluid streams that are impinged onto the stream of a molten or liquid metallic alloy, at least one of the inert fluid streams has a velocity of 0.2-10.5 km/sec.
6. 6 . The method of claim 1 , wherein the at least one inert fluid stream impinges the stream of a molten or liquid metallic alloy at an oblique angle.
7. 7 . The method of claim 1 , wherein the molten or liquid metallic alloy is directed into the inert fluid stream.
8. 8 . The method of claim 1 , wherein the stream of molten or liquid metallic alloy is directed into a hot zone of a tangential reactor.
9. 9 . The method of claim 8 , wherein the hot zone is maintained at a temperature controlled to within ±10° C. variance or within ±5% of a set temperature.
10. 10 . The method of claim 1 , wherein the appropriate reaction conditions are such that the combined carbon and oxygen content of the particles is in a range of from 0 to 1700 ppm by weight relative to the entire weight of the particle.
11. 11 . The method of claim 1 , wherein the substantially spherical solid particles of the metallic alloy are separated from the inert fluid stream by gravity.
12. 12 . The method of claim 1 , wherein the alloy is present as: Nd 1-14 Dy 30-50 Co 25-45 Cu 1-10 Fe 1-10 atom % or Nd 8.5-12.5 Dy 35-45 Co 32-41 Cu 3-6.5 Fe 1.5-5 atom %.
13. 13 . The method of claim 1 , wherein the alloy is present as: Nd 1-14 Dy 30-50 Co 25-45 Cu 1-10 Fe 1-10 atom %.
14. 14 . The method of claim 1 , wherein the alloy is present as: Nd 8.5-12.5 Dy 35-45 Co 32-41 Cu 3-6.5 Fe 1.5-5 atom %.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application is a Divisional Application of U.S. patent application Ser. No. 16/325,865 filed Feb. 15, 2019, which is the National Stage Application filed under 35 US.C. 371 of International Patent Application No. PCT/US2017/047108 filed Aug. 16, 2017, which claims the benefit of priority to U.S. Provisional Application Nos. 62/375,947 and 62/375,943, both filed Aug. 17, 2016, the contents of which are both incorporated by reference in their entirety for all purposes. TECHNICAL FIELD The present disclosure is directed to micron and sub-micron sized metal and metallic alloy powders and methods of making the same. BACKGROUND Powder metallurgy describes processes in which metal powders are used to produce a wide range of materials or components. Such powder processes can avoid, or greatly reduce, the need to use post-forming metal removal processes, thereby drastically reducing yield losses in manufacture and can often result in lower manufacturing costs. Moreover, these powder processes provide means by which compositionally complex materials can be made homogeneously. Typically, in such applications, fine metal powders of individual metals are mixed with binders, such as lubricant wax or metallic grain boundary-forming metal, and compressed into a “green body” of the desired shape, and then the green body is heated in a controlled atmosphere to bond the material by sintering. Variations on this process includes powder forging, hot isostatic pressing (HIP), metal injection molding, electric current assisted sintering (ECAS), additive manufacturing (AM). Other processes include, selective laser sintering (SLS), selective laser melting (SLM), and electron beam melting (EBM). Alternatively, processed magnetic powders can be incorporated into bonded magnets. In their most basic form, bonded magnets may be seen as a polymer composite, comprising a hard magnetic powder and a non-magnetic polymer or rubber binder. Bonded magnets may be processed by any means used to prepare filled polymer composites, for example, calendering, injection molding, extrusion and compression bonding, and as such offer the advantages seen with processing such composites, for example near final shape forming. The chemical and physical homogeneity of the precursor powders is, in either case, critical to the formation and ultimate performance of materials made through a powder metallurgical route. It is desirable, for example, to provide mixtures of metal powder particles with specific particle size ranges, preferably with one or more mono-dispersed size distributions, each having, narrow variances with respect to the mean particle size (e.g., bi-, tri-, or polymodal distributions of specific individually monodispersed particles) for efficiency of packing or mixing. In other applications, mixtures of compositionally different powders, each having different particle size distributions, provide attractive options for blending, for example, discrete larger-sized grain and smaller-sized grain boundary materials. Likewise, compositional homogeneity within an individual powder particle, especially for complex alloys, ultimately provides sintered bodies having superior-compositional consistency throughout the sintered body, and so improved performance of that body It is also desirable that such powder particles are processed in the absence of oxidizing or carbon-containing conditions to minimize the presence of these contaminants in the final sintered bodies. For example, such powder forming methods are useful in the preparation of Neodymium, Iron, Boron (NdFeB), and other compositionally complex, magnets. The performance of such magnetic materials have been shown to depend quite significantly on the homogeneity of the sintered magnetic body, and this homogeneity can, at least in part, be attributed to the size and compositional homogeneity of the precursor powder particles. Further, the supply of rare earth elements, in particular dysprosium (Dy) and terbium (Tb), which are required for increased magnetic performance, is scarce, and the ability to provide intimate and homogeneous mixtures of particles of different sizes and compositions allows for the less use of these scarcer materials. Presently, typical processes for preparing powders for such applications include melt processing of the desired alloys, followed by pulverizing and, in some cases, decrepitation steps, and sieving to achieve particles within a desired size window. Pulverizing is typically done using tumble mixers, optionally in the presence of pulverizing media. Decrepitation involves the treatment of the pulverized metallic alloy particles with hydrogen under conditions and for a time to allow absorption of the hydrogen into the alloy, followed by an outgassing treatment. Combinations of pulverizing and decrepitation steps, followed by sieving is an effective, albeit time-consuming, method of provide powders. But even in these ca