Systems and methods for deagglomerating powders by subjecting them to strong shear

Abstract

A system for high-velocity deposition of particles onto a substrate may include a source of pressurized aerosol and a deagglomerator. The deagglomerator may include a static body, an inlet formed in the static body and fluidically coupled to the source of pressurized aerosol, and a plurality of parallel rotating discs housed within a volume formed within the static body and rotationally coupled to the static body, such that rotation of the plurality of parallel rotating discs relative to the static body imparts a shearing force to shear apart agglomerates suspended in the pressurized aerosol.

Description

[0001] ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 1 SYSTEMS AND METHODS FOR DEAGGLOMERATING POWDERS BY SUBJECTING THEM TO STRONG SHEAR GOVERNMENT SUPPORT CLAUSE This invention was made with government support under Grant no. W911NF- 17-2-0180 awarded by Army Research Office. The government has certain rights in the invention. RELATED APPLICATION The present disclosure claims priority to United States Provisional Application Serial No. 63 / 589,558 filed October 11, 2023, which is incorporated by reference herein in its entirety. FIELD OF DISCLOSURE The present disclosure relates in general to methods and systems for the high- velocity deposition of particles, including micro-scale and nano-scale particles of metal, ceramic, or other material, and in particular the deagglomeration of powders to generate such particles. 42093209v.1 ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 2 BACKGROUND Cold spray and micro-cold spray are techniques that may be used to produce thick (e.g., 1–100 µm), nearly full density metal and ceramic films using a feedstock of dry particles, typically 200 nm to 5 µm in diameter in micro-cold spray and typically 1 µm to 75 µm in diameter for cold spray, using known approaches. Micro-cold spray techniques may also be referred to as aerosol deposition, low pressure cold spray, vacuum cold spray, or vacuum kinetic spraying. In micro-cold spray, particles may be aerosolized in a low pressure carrier gas and then accelerated through a nozzle into a vacuum chamber. In cold spray, particles may be aerosolized in a high pressure carrier gas and then accelerated through a nozzle into an ambient pressure chamber. For both micro-cold spray and cold spray, the particles may impact onto a substrate at a high enough velocity where particles may deform and adhere to the substrate. In cold-spray and micro-cold spray applications, it may be desirable that small particles be used for deposition, rather than agglomerates of material. If agglomerates of material are sprayed onto a substrate, such agglomerates may absorb significant impact energy through fracture and particle rearrangement and such absorbed energy may not be available to deform and cause adhesion of particles to the substrate. Further, agglomerates may reduce film quality when they are present during aerosol- based film deposition processes such as cold spray and micro-cold spray. Current approaches to avoiding deposition of agglomerates are to: (1) perform heat treatments on powders of materials that result in strongly-bonded aggregates or granules or (2) segregate the powder such that only the fraction of the powder that is not agglomerated is used. However, such approaches are not ideal. For example, for ceramic powders, larger aggregates may be detrimental to film deposition efficiency and may limit film thickness that can be produced. Further, segregating powders may be costly and inefficient because only a small fraction of fine powders are typically not agglomerated and the remaining agglomerated powder may be disposed of. ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 3 SUMMARY In accordance with the teachings of the present disclosure, the disadvantages and problems associated with existing approaches for depositing particles using cold spray and micro-cold spray techniques may be reduced or eliminated. In accordance with embodiments of the present disclosure, a system for high- velocity deposition of particles onto a substrate may include a source of pressurized aerosol and a deagglomerator. The deagglomerator may include a static body, an inlet formed in the static body and fluidically coupled to the source of pressurized aerosol, and a plurality of parallel rotating discs housed within a volume formed within the static body and rotationally coupled to the static body, such that rotation of the plurality of parallel rotating discs relative to the static body imparts a shearing force to shear apart agglomerates suspended in the pressurized aerosol. In accordance with these and other embodiments of the present disclosure, a method may include forming an inlet in a static body of a deagglomerator, wherein the inlet is configured to couple to a source of pressurized aerosol and rotationally coupling a plurality of parallel rotating discs to the static body within a volume formed within the static body, such that rotation of the plurality of parallel rotating discs relative to the static body imparts a shearing force to shear apart agglomerates suspended in the pressurized aerosol. In accordance with these and other embodiments of the present disclosure, a deagglomerator for use in a system for high-velocity deposition of particles onto a substrate may include a static body, an inlet formed in the static body and configured to fluidically couple to a source of pressurized aerosol, and a plurality of parallel rotating discs housed within a volume formed within the static body and rotationally coupled to the static body, such that rotation of the plurality of parallel rotating discs relative to the static body imparts a shearing force to shear apart agglomerates suspended in the pressurized aerosol. In accordance with these and other embodiments of the present disclosure, a method for high-velocity deposition of particles onto a substrate may include fluidically coupling an inlet formed in a static body of a deagglomerator to a source of ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 4 pressurized aerosol and causing rotation of a plurality of parallel rotating discs rotationally coupled to the static body within a volume formed within the static body, such that rotation of the plurality of parallel rotating discs relative to the static body imparts a shearing force to shear apart agglomerates suspended in the pressurized aerosol. Technical advantages of the present disclosure may be readily apparent to one having ordinary skill in the art from the figures, description and claims included herein. The objects and advantages of the embodiments will be realized and achieved at least by the elements, features, and combinations particularly pointed out in the claims. It is to be understood that both the foregoing general description and the following detailed description are examples and explanatory and are not restrictive of the claims set forth in this disclosure.

[0002] ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 5 BRIEF DESCRIPTION OF THE DRAWINGS A more complete understanding of the present embodiments and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features, and wherein: FIGURE 1 illustrates a block diagram of an example system for high-velocity deposition of particles using micro-cold spray, in accordance with embodiments of the present disclosure; and FIGURE 2 illustrates a side elevation cross-sectional view of an example feeder and example deagglomerator which may be used in the system of FIGURE 1, in accordance with embodiments of the present disclosure.

[0003] ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 6 DETAILED DESCRIPTION The description below sets forth example embodiments according to this disclosure. Further example embodiments and implementations will be apparent to those having ordinary skill in the art. Further, those having ordinary skill in the art will recognize that various equivalent techniques may be applied in lieu of, or in conjunction with, the embodiments discussed below, and all such equivalents should be deemed as being encompassed by the present disclosure. FIGURE 1 illustrates a block diagram of an example system 100 for high- velocity deposition of particles using micro-cold spray, in accordance with embodiments of the present disclosure. As shown in FIGURE 1, system 100 may include a carrier gas supply 102, a particle supply 104, a feeder 106, a deagglomerator 108, a vacuum chamber 110, a nozzle 112 within vacuum chamber 110, a vacuum pump 114 fluidically coupled to vacuum chamber 110, and a stage 116 within vacuum chamber 110 for positioning a substrate 118 relative to nozzle 112 within vacuum chamber 110. A similar system may be used for cold spray deposition of particles. For example, for cold spray deposition, the upstream pressure may be elevated to tens or hundreds of atmospheres and the pressure downstream of the nozzle may be at atmospheric pressure, and thus a vacuum chamber (e.g., vacuum chamber 110) may not be present. Carrier gas supply 102 may include any suitable container or housing for a carrier gas (e.g., air, helium, argon, or nitrogen), and may comprise pressurized storage for such carrier gas. In some embodiments, the pressure of the gas may be near atmospheric pressure. In other embodiments, the pressure may be elevated to as high as several hundred atmospheres. Particle supply 104 may include any suitable container or housing for solid particles (e.g., metal, metallic alloy, semi-conductor, polymer, ceramic, composites of any combination of the foregoing, etc.). In some embodiments, such particles may be in the form of a fine powder (e.g., a powder of particles 10 nm to 5 µm in diameter for ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 7 micro-cold spray applications or 1 μm to 75 µm in diameter for cold spray applications). Feeder 106 may be fluidically coupled to carrier gas supply 102 and may comprise any suitable system, device, or apparatus for controlling a rate of particles from particle supply 104. For example, in some embodiments, feeder 106 may comprise a screw feeder, as discussed below with respect to FIGURE 2. Accordingly, feeder 106 may output an aerosol of solid particles to deagglomerator 108. Deagglomerator 108 may comprise any suitable system, device, or apparatus configured to deagglomerate solid particles from each other in the aerosol. Deagglomeration of particles may be useful in micro-cold spray applications so that individual particles impact substrate 118 rather than agglomerates. Because agglomerates may absorb significant impact energy through fracture and particle rearrangement, this absorbed energy may not then be available to deform and stick the particles to substrate 118. Thus, deagglomerator 108 may enhance the uniformity of the sprayed aerosol density because there is a range of residence times before the powder is fed into nozzle 112. In some embodiments, deagglomerator 108 may be implemented with a motor configured to cause rotation of discs at a high angular velocity, such that as the aerosol of solid particles passes through deagglomerator 108, such spinning discs shear apart agglomerates of particles, as discussed below with respect to FIGURE 2. Due to pressure differentials between carrier gas supply 102 and vacuum chamber 110, the aerosolized particles may be accelerated through nozzle 112, and onto substrate 118, in order to deposit a film of the particles onto substrate 118. Example embodiments of nozzle 112 are described in Patent Cooperation Treaty International Application PCT / US24 / 34816, filed June 20, 2024, which is incorporated by reference herein in its entirety. Vacuum chamber 110 may comprise any sealed container or housing from which air and other gases may be removed (e.g., via vacuum pump 114) to create a low-pressure environment within such container. Vacuum pump 114 may include any ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 8 system, device, or apparatus configured to remove gas molecules from the sealed volume of vacuum chamber 110 to create a vacuum within vacuum chamber 110. Stage 116 may comprise any suitable system, device, or apparatus configured to carry or otherwise hold and position substrate 118. In some embodiments, stage 116 may comprise or may be coupled to a motor or other device configured to vertically or horizontally translate stage 116 relative to nozzle 112, in order to enable a stream of aerosolized particles sprayed from nozzle 112 to impinge upon desired locations upon the surface of substrate 118. In cold spray deposition, substrate 118 may be fixed and nozzle 112 may be placed on a movable stage or robotic arm. Substrate 118 may comprise any suitable substrate of material upon which particles within the aerosolized particles sprayed from nozzle 112 may be deposited using cold spray or micro-cold spray techniques. For example, substrate 118 may include any solid material (e.g., metal, metallic alloy, semi-conductor, polymer, ceramic, a composite of any combination of foregoing, etc.). FIGURE 2 illustrates a side elevation cross-sectional view of an example feeder 106 and example deagglomerator 108 which may be used in system 100, in accordance with embodiments of the present disclosure. As shown in FIGURE 2, feeder 106 may be implemented as a screw feeder having an inlet for receiving particles or a powder of material from particle supply 104. Feeder 106 may include a main body 202, which may be machined out of stainless steel or other suitable material. A long butt flange 204 may be welded or otherwise mechanically coupled to main body 202. Together, main body 202 and long butt flange 204 may form a cylindrical volume that may function as a reservoir 206 or “hopper” where particles / powder may reside before being dispensed from feeder 106 to deagglomerator 108. The bottom of such reservoir 206 may include a conical section 208 that tapers into a screw channel 210, such that the particles / powder may be gravimetrically fed to screw channel 210. Feeder 106 may also include a vertical channel 212 fluidically coupled between carrier gas supply 102 and deagglomerator 108. Feeder 106 may also include a screw 214 that, when actuated, may convey particles / powder from the bottom of conical section 208, into screw channel 210, and through screw channel 210, similar to an auger, such ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 9 that pressurized gas from carrier gas supply 102 may drive such particle / powder into deagglomerator 108. Although not shown in FIGURE 2, a stepper motor or other actuator may drive rotation of screw 214. Further, although not shown in FIGURE 2, screw channel 210, vertical channel 212, and long butt flange 204 may include seals configured to prevent undesirable material from entering feeder 106. In operation, feeder 106 may meter particles / powder into the inert gas stream from carrier gas supply 102, such that particles / powder may be dispensed consistently such that the density of the aerosol passing through nozzle 112 and impacting substrate 118 during a deposition process is approximately constant, to ensure uniform deposition onto substrate 118. While feeder 106 is depicted in FIGURE 2 as comprising a screw feeder, it is understood that feeder 106 may be implemented using any suitable system, device, or apparatus configured to convey particles to deagglomerator 108. For example, in some embodiments, feeder 106 may comprise a vibratory feeder. As its name implies, deagglomerator 108 may deagglomerate particles so that individual particles may impact substrate 118 rather than agglomerates. Accordingly, deagglomerator 108 may be configured to break apart “soft” agglomerates, which are aerosolized particles which may be more loosely bound by van der Waals attraction or joined by very small necks. Within system 100, deagglomerator 108 may serve at least two functional purposes: (1) to prepare the aerosol for deposition by breaking apart soft agglomerates; and (2) to serve in a “residence” or “capacitive” function as a provider of powder for the aerosol. Regarding this second purpose, feeder 106 may feed powder at inconsistent rates, for reasons beyond the scope of this disclosure. To combat such inconsistency, a large volume of deagglomerator 108 may serve to store and dispense particles at rates that are more consistent than the rate at which they enter deagglomerator 108 from feeder 106. As shown in FIGURE 2, deagglomerator 108 may comprise a static body 222, an inlet 220 formed with static body 222 and fluidically coupled to vertical channel 212, rotating discs 224 housed within static body 222 and configured to rotate relative to static body 222, and a motor 226 or other actuator mechanically coupled to rotating ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 10 discs 224 via a drive shaft 228 and configured to drive rotation of rotating discs 224 relative to static body. Although not necessarily shown to scale in FIGURE 2, small gaps on the order of between approximately (e.g., within design tolerances) 100 nm to approximately (e.g., within design tolerances) 10 mm may exist between adjacent rotating discs 224. In operation, motor 226 may cause rotation of a plurality of parallel rotating discs 224, which may impart a shearing force that shears apart loosely-bound particles suspended in the aerosol driven by carrier gas supply 102 through vertical channel 212 and into an inlet channel 228 formed in static body 222. In some embodiments, motor 226 may drive rotating discs 224 at rotational velocities between approximately (e.g., within design tolerances) 1,000 and approximately (e.g., within design tolerances) 30,000 revolutions per minute, wherein higher rotational velocities may be applied to stronger agglomerates. Deagglomerator 108 may include seals configured to prevent undesirable material from entering feeder 106 and particles from undesirably exiting feeder 106. As used herein, when two or more elements are referred to as “coupled” to one another, such term indicates that such two or more elements are in mechanical communication, whether connected indirectly or directly, with or without intervening elements. This disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments herein that a person having ordinary skill in the art would comprehend. Similarly, where appropriate, the appended claims encompass all changes, substitutions, variations, alterations, and modifications to the example embodiments herein that a person having ordinary skill in the art would comprehend. Moreover, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, or component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative. Accordingly, modifications, additions, or omissions may be made to the ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 11 systems, apparatuses, and methods described herein without departing from the scope of the disclosure. For example, the components of the systems and apparatuses may be integrated or separated. Moreover, the operations of the systems and apparatuses disclosed herein may be performed by more, fewer, or other components and the methods described may include more, fewer, or other steps. Additionally, steps may be performed in any suitable order. As used in this document, “each” refers to each member of a set or each member of a subset of a set. Although exemplary embodiments are illustrated in the figures and described below, the principles of the present disclosure may be implemented using any number of techniques, whether currently known or not. The present disclosure should in no way be limited to the exemplary implementations and techniques illustrated in the drawings and described above. Unless otherwise specifically noted, articles depicted in the drawings are not necessarily drawn to scale. All examples and conditional language recited herein are intended for pedagogical objects to aid the reader in understanding the disclosure and the concepts contributed by the inventor to furthering the art, and are construed as being without limitation to such specifically recited examples and conditions. Although embodiments of the present disclosure have been described in detail, it should be understood that various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the disclosure. Although specific advantages have been enumerated above, various embodiments may include some, none, or all of the enumerated advantages. Additionally, other technical advantages may become readily apparent to one of ordinary skill in the art after review of the foregoing figures and description. To aid the Patent Office and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants wish to note that they do not intend any of the appended claims or claim elements to invoke 35 U.S.C. § 112(f) unless the words “means for” or “step for” are explicitly used in the particular claim.

Claims

ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 12 WHAT IS CLAIMED IS:

1. A system for high-velocity deposition of particles onto a substrate, comprising: a source of pressurized aerosol; and a deagglomerator comprising: a static body; an inlet formed in the static body and fluidically coupled to the source of pressurized aerosol; and a plurality of parallel rotating discs housed within a volume formed within the static body and rotationally coupled to the static body, such that rotation of the plurality of parallel rotating discs relative to the static body imparts a shearing force to shear apart agglomerates suspended in the pressurized aerosol.

2. The system of Claim 1, further comprising a nozzle fluidically coupled to the deagglomerator and configured to spray the pressurized aerosol.

3. The system of Claim 1, further comprising a feeder fluidically coupled to the inlet and configured to meter particles into an inert gas stream from a carrier gas supply in order provide the source of pressurized aerosol.

4. The system of Claim 1, wherein at least two adjacent rotating discs of the plurality of parallel rotating discs are separated by a gap of between approximately 100 nm and approximately 10 mm.

5. The system of Claim 1, wherein the plurality of rotating discs are configured to rotate relative to the static body at rotational velocities between approximately 1,000 revolutions per minute and 30,000 revolutions per minute.ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 13 6. A method comprising: forming an inlet in a static body of a deagglomerator, wherein the inlet is configured to couple to a source of pressurized aerosol; and rotationally coupling a plurality of parallel rotating discs to the static body within a volume formed within the static body, such that rotation of the plurality of parallel rotating discs relative to the static body imparts a shearing force to shear apart agglomerates suspended in the pressurized aerosol.

7. The method of Claim 6, further comprising fluidically coupling a nozzle to the deagglomerator to enable the nozzle to spray the pressurized aerosol.

8. The method of Claim 6, further comprising fluidically coupling a feeder to the inlet configured to meter particles into an inert gas stream from a carrier gas supply in order provide the source of pressurized aerosol.

9. The method of Claim 6, wherein at least two adjacent rotating discs of the plurality of parallel rotating discs are separated by a gap of approximately 100 nm and approximately 10 mm.

10. The method of Claim 6, wherein the plurality of rotating discs are configured to rotate relative to the static body at rotational velocities between approximately 1,000 revolutions per minute and 30,000 revolutions per minute.ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 14 11. A deagglomerator for use in a system for high-velocity deposition of particles onto a substrate, comprising: a static body; an inlet formed in the static body and configured to fluidically couple to a source of pressurized aerosol; and a plurality of parallel rotating discs housed within a volume formed within the static body and rotationally coupled to the static body, such that rotation of the plurality of parallel rotating discs relative to the static body imparts a shearing force to shear apart agglomerates suspended in the pressurized aerosol.

12. The deagglomerator of Claim 11, wherein the deagglomerator is further configured to couple to a nozzle configured to spray the pressurized aerosol.

13. The deagglomerator of Claim 11, wherein the deagglomerator is further configured to couple via its inlet to a feeder configured to meter particles into an inert gas stream from a carrier gas supply in order provide the source of pressurized aerosol.

14. The deagglomerator of Claim 11, wherein at least two adjacent rotating discs of the plurality of parallel rotating discs are separated by a gap of approximately 100 nm and approximately 10 mm.

15. The deagglomerator of Claim 11, wherein the plurality of rotating discs are configured to rotate relative to the static body at rotational velocities between approximately 1,000 revolutions per minute and 30,000 revolutions per minute.ATTORNEY’S DOCKET PCT PATENT APPLICATION 215595.00239 (8249 KOV PCT) 15 16. A method for high-velocity deposition of particles onto a substrate, comprising: fluidically coupling an inlet formed in a static body of a deagglomerator to a source of pressurized aerosol; and causing rotation of a plurality of parallel rotating discs rotationally coupled to the static body within a volume formed within the static body, such that rotation of the plurality of parallel rotating discs relative to the static body imparts a shearing force to shear apart agglomerates suspended in the pressurized aerosol.

17. The method of Claim 16, further comprising fluidically coupling a nozzle to the deagglomerator to enable the nozzle to spray the pressurized aerosol.

18. The method of Claim 16, further comprising fluidically coupling a feeder to the inlet configured to meter particles into an inert gas stream from a carrier gas supply in order provide the source of pressurized aerosol.

19. The method of Claim 16, wherein at least two adjacent rotating discs of the plurality of parallel rotating discs are separated by a gap of approximately 1 mm.

20. The method of Claim 16, further comprising causing the plurality of rotating discs to rotate relative to the static body at rotational velocities between approximately 1,000 revolutions per minute and 30,000 revolutions per minute.

Images