Amalgamated preforms

Abstract

An amalgamated preform is provided. The amalgamation preform of the present invention includes a base metal and multiple types of solid particles dispersed in the base metal, the base metal including one liquid base metal and one solid base metal, the multiple types of solid particles including at least non-reactive magnetic particles responsive to a magnetic region to controllably disperse the multiple types of solid particles in the base metal, and reactive particles capable of reacting with the base metal under the magnetic region.

Description

[Technical Field]

[0001] This PCT application claims priority to U.S. Patent Application No. 17 / 365,811, filed July 1, 2021, which is a continuation-in-part of U.S. Patent Application No. 17 / 073,379, filed October 18, 2020, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to bonding and welding techniques, and more particularly to amalgamation preforms and methods of making / using said amalgamation preforms. Summary of the Invention [Problem to be solved by the invention]

[0003] Classical joining and welding techniques using soldering or brazing require the application of heat energy and flow. In both soldering and brazing, heat energy is required to melt the weld or filler material, making it flowable and allowing the surfaces to contact and join. Flow is required to remove oxides and contaminants from the joining surfaces and filler, and to protect the filler from environmental oxidation. Generally, oxidation of the filler material with an oxide layer on the filler material is detrimental to the formation of the joint and must be prevented. [Means for solving the problem]

[0004] BRIEF SUMMARY OF THE DISCLOSURE According to one aspect of the present disclosure, there is provided an amalgamation preform comprising a base metal and multiple types of solid particles dispersed in the base metal, the multiple types of solid particles including one liquid base metal and one solid base metal, the multiple types of solid particles including at least non-reactive magnetic particles reactive with a magnetic region for controllably dispersing the multiple types of solid particles in the base metal, and reactive particles capable of reacting with the base metal beneath the magnetic region.

[0005] Another aspect of the present disclosure provides a method for making an amalgamated preform. A particle-liquid mixture is provided, including multiple types of solid particles and a liquid base metal. The multiple types of solid particles include at least reactive particles capable of reacting with the base metal and non-reactive magnetic particles. A magnetic region is applied to the particle-liquid mixture to magnetically disperse the multiple types of solid particles in the liquid base metal, forming a particle-liquid dispersion without substantially inducing a reaction between the reactive particles and the liquid base metal. A playdough-like amalgamated preform is prepared based on the particle-liquid dispersion without solidifying the liquid base metal.

[0006] Another aspect of the present disclosure provides a method for making an amalgamation preform. A particle-liquid mixture is provided, comprising multiple types of solid particles and a liquid base metal. The multiple types of solid particles include at least reactive particles capable of reacting with the base metal and non-reactive magnetic particles. A magnetic region is applied to the particle-liquid mixture to magnetically disperse the multiple types of solid particles in the liquid base metal, forming a particle-liquid dispersion without substantially inducing a reaction between the reactive particles and the liquid base metal. The liquid base metal is solidified to disperse the multiple types of solid particles in the solidified base metal without substantially inducing a reaction between the reactive particles and the solid base metal. A solid amalgamation preform is prepared, comprising the multiple types of solid particles and the solidified base metal.

[0007] Another aspect of the present disclosure provides a method for using an amalgamation preform. Mating bonding surfaces are provided, and a particle-liquid mixture corresponding to the amalgamation preform is placed between the mating bonding surfaces. The particle-liquid mixture includes multiple types of solid particles and a liquid base metal, and the multiple types of solid particles include at least reactive particles and non-reactive magnetic particles. A first magnetic region is applied to the particle-liquid mixture to magnetically disperse the multiple types of solid particles in the liquid base metal to form a particle-liquid dispersion, and a second magnetic region is applied to cure the particle-liquid dispersion and enable reaction between the reactive particles and the base metal.

[0008] Another aspect of the present disclosure provides a method of using an amalgamation preform. Joining surfaces are provided, and the amalgamation preform is placed between the joining surfaces. The amalgamation preform includes multiple types of solid particles and a base metal, and the multiple types of solid particles include at least reactive particles and non-reactive magnetic particles. The amalgamation preform is heated to a temperature above the lower melting point of the base metal to provide a particle-liquid mixture including the multiple types of solid particles in the liquid base metal. During heating, a magnetic region is applied to magnetically disperse the multiple types of solid particles in the liquid base metal and enable a reaction between the reactive particles and the base metal.

[0009] Other aspects of the present disclosure can be understood by those skilled in the art in light of the specification, claims, and drawings of the present disclosure. [Brief explanation of the drawings]

[0010] The following figures are merely examples for illustrative purposes according to various aspects of the present disclosure and are not intended to limit the scope of the present disclosure.

[0011] FIG. 1A illustrates an example method of making an amalgamation preform according to various embodiments of the present disclosure.

[0012] FIG. 1B illustrates another example of a method for making an amalgamation preform according to various embodiments of the present disclosure.

[0013] FIG. 2 illustrates an example of a particle-liquid mixture in a container according to various embodiments of the present disclosure.

[0014] FIG. 3 illustrates an example of an apparatus including a magnetic processing device for processing a particle-liquid mixture according to various embodiments of the present disclosure.

[0015] 4-7 illustrate the controllable application of magnetic regions to a particle-liquid mixture in a vessel according to various embodiments of the present disclosure.

[0016] FIG. 8 illustrates an example of a solidified particle-liquid mixture in a container according to various embodiments of the present disclosure.

[0017] FIG. 9A illustrates an example of a method of using an amalgamation preform according to various embodiments of the present disclosure.

[0018] FIG. 9B illustrates another example of a method of using an amalgamation preform according to various embodiments of the present disclosure.

[0019] FIG. 10 illustrates an example of an apparatus including a magnetic processing device for processing a solid amalgamation preform according to various embodiments of the present disclosure.

[0020] 11-15 show an example of mixing and dispersion of a liquefied amalgamated preform under application of controlled magnetic domains according to various embodiments of the present disclosure.

[0021] FIG. 16 illustrates an example of a solid alloy corresponding to an amalgamated preform according to various embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0022] Reference will now be made in detail to the exemplary aspects of the present disclosure, which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0023] 1A-1B illustrate an example method of making an amalgamation preform according to various embodiments of the present disclosure.

[0024] At 102 in FIGS. 1A-1B, a particle-liquid mixture including multiple types of solid particles and a liquid base metal (ie, a base metal in a liquid state) is provided, for example, in a vessel.

[0025] In one embodiment, the multiple types of solid particles can be mixed with the base metal in a solid state (e.g., the base metal or base metal particles in solid particles) in a container to provide the particle-liquid mixture. The base metal particles and / or the multiple types of solid particles can be in the form of metal powder, pellets, wire, fiber, ingot, or a combination thereof. The base metal particles and the multiple types of solid particles can be mixed, for example, at room temperature. The base metal particles can then be melted into a liquid state with the mixed multiple types of solid particles, for example, by any suitable heat treatment to form the particle-liquid mixture. For example, the base metal particles can be melted by convective or inductive heating via application of a magnetic field. The magnetic field can be controlled / adjusted to heat the base metal without destroying the structure of other particles in the mixture.

[0026] Alternatively, to form the particle-liquid mixture, the base metal particles can be melted to form a liquid base metal in a container, followed by injecting the multiple types of solid particles into the liquid base metal to form the particle-liquid mixture.

[0027] The base metal can include a metal and / or metal alloy with a low melting point. For example, the base metal can have a melting point less than about 200° C. The base metal can include, for example, Ga, In, Sn, Bi, Pb, Cd, Hg, Rb, Zn, Bi, or any combination / alloy thereof. In certain embodiments, the base metal can include Ga, GaInSn, and / or InSnBi.

[0028] In the particle-liquid mixture, the ratio of the liquid base metal to the multiple types of solid particles can be in the range of about 4:1 to about 1:4 by weight, e.g., 4:1 to 1:2, so that the multiple types of solid particles are easily handled in the liquid state while still having sufficient mechanical properties. The multiple types of solid particles can have an average size in the range of about 100 nm to about 100 μm.

[0029] Various types of solid particles can be mixed with the base metal, for example, the multiple types of solid particles can include reactive particles, non-reactive magnetic particles, and / or any suitable additives to impart desired characteristics to the particle-liquid mixture and / or the subsequently formed amalgamated preform.

[0030] As used in this disclosure, the terms "reactive" and "non-reactive" are relative terms that indicate the degree of reactivity or reactivity between the solid particles and the base metal. For example, under certain conditions, "reactive" particles can react with the base metal in a liquid state (i.e., liquid base metal) to bond / curing / alloy the solid particles with the base metal corresponding to an amalgamated preform. "Non-reactive" particles refer to solid particles that cannot bond / curing / alloy with the liquid base metal under the same certain conditions. For example, solid particles can be considered non-reactive if they "react" with the liquid base metal with significantly slower reaction kinetics, such that they cannot bond / curing / alloy, for example, after a predetermined time interval. As an extreme example, materials that are completely non-reactive with the liquid base metal can include ceramics or covalently bonded organic materials.

[0031] The reactive particles may be capable of reacting with the base metal. The reactive particles may include at least a reactive metal material. The reactive metal material may include Fe, Ni, Cu, Ag, Au, In, Cu, Sn, Bi, Zn, Ti, V, Cr, Mo, Nb, Zr, Hf, Pt, Ir, and / or any combination (e.g., alloy) thereof.

[0032] The reactive particles can have an average size ranging from about 100 nm to about 50 μm, for example, from about 100 nm to about 25 μm. For a desired reactivity, the reactive particles can be selected to be neither too large nor too small. The reactive particles that are too large can have a reaction time with the base metal that is too long, while the reactive particles that are too small can react too quickly. The inventors have discovered that when the reactive particles have a size less than 100 nm, the reaction between the reactive particles and the base metal is too rapid for the alloying to occur.

[0033] The reactive particles can be magnetic and / or non-magnetic. For example, reactive magnetic particles can include Fe, Ni, and / or alloys thereof. Reactive non-magnetic particles can include Cu, Ag, Au, In, Cu, Sn, Bi, Zn, Ti, V, Cr, Mo, Nb, Zr, Hf, Pt, Ir, or any combination (e.g., alloy) thereof. In addition to being capable of reacting with the base metals, in some embodiments, the reactive magnetic particles can also respond to magnetic signals.

[0034] The reactive particles, whether magnetic or non-magnetic, can include a core-shell structure. The core-shell structure can include a core material and a shell material that is different from the core material and at least partially encases the core material. The core material can have a higher reaction rate with the base metal than the shell material, or vice versa.

[0035] In some embodiments, the core-shell structure of the reactive particle may include an oxide shell material at least partially covering a reactive metal material as a core material. The oxide shell material may include an oxide of the reactive metal material. The oxide shell material may be a natural oxide material or may be intentionally generated by an oxidation reaction, such as thermal oxidation, with the reactive metal material. For example, if the reactive metal material is one or more of Fe and Ni as a core material, the shell material may be an oxide of the one or more of Fe and Ni. Unlike conventional preform materials, which require the removal of an oxide shell layer to form and use the amalgamation preform, the oxide shell layer is required to control the reaction kinetics / rate in forming and using the amalgamation preform.

[0036] In other embodiments, the core-shell structure of the reactive particle can comprise a non-oxide shell material. For example, the core-shell structure can comprise one or more core-shell structures, where one core-shell structure has the shell material comprising Cu, and the core material comprises Au; one core-shell structure has the shell material comprising steel, and the core material comprises Cu; one core-shell structure has the shell material comprising ZnO or TiO, and the core material comprises Cu, Ag, Ni, or a combination thereof; and / or one core-shell structure has the core material comprising Cu and a copper oxide at least partially covering Cu, and the core material comprises Co, AlN-containing ceramic material, SiC, SiO, TiO, ZrO, AlO, BeO, SiN, or BC.

[0037] In various embodiments, the core material can be multi-layered, for example, formed of at least one material reactive with the base metal and at least one other material that provides a desirable property (e.g., improved mechanical strength) to the subsequently formed amalgamated preform. Optionally and additionally, the shell material can also be multi-layered. For example, if the shell material includes copper, for example, to react with the base metal, the copper shell material can include an additional shell layer of copper oxide at least partially covering the copper shell material.

[0038] In various embodiments, the particle-liquid mixture is magnetically dispersed to form a particle-liquid dispersion (e.g., as shown in operation 104 in FIGS. 1A-1B). This can be a homogeneous dispersion that does not induce substantially any reaction (e.g., alloying reaction) between the reactive particles and the base metal. The particle-liquid dispersion can be used to form amalgamation preforms, including playdough-like amalgamation preforms (e.g., as shown in operation 106 in FIG. 1A) and solid amalgamation preforms (e.g., as shown in operations 108 and 109 in FIGS. 1A-1B), as disclosed herein.

[0039] As disclosed herein, in one embodiment, the shell material of a reactive particle can be used to control the equilibrium and dissolution kinetics and dissolution rates of the core material, and consequently, for example, the shelf life and / or reaction rate of the formed amalgamated preform.

[0040] The core-shell structure of the reactive particles can further extend the shelf life of at least the formed amalgamation preform. For example, the shell material can be thick enough to substantially prevent solid-state alloying between the reactive particles and the solid base metal, yet thin enough to stop the reaction from proceeding during reflow. The shell material can have a thickness ranging from an elemental layer thickness to about 100 nm thick. For example, the shell material can have a thickness of several elemental layers. The thickness of the shell material can be controlled depending on the selection of the base metal and the reactive particles and / or the desired shelf life of the formed amalgamation preform.

[0041] In one example of an amalgamation preform having reactive particles in which the core material is one or more Fe and Ni and the shell material is one or more Fe and Ni oxides, the dissociation or flux rate of the base metal Ga material through the shell material depends on the thickness of the shell material. In one example of forming a playhouse-like amalgamation preform for rapid use, the shell material can be relatively thin for rapid setting, and the thickness can be increased to extend the handling and setting time of the material. For the formation of a solid amalgamation preform, the shell material can be sufficiently thick, e.g., at least a few nanometers, so that there is no reaction during initial mixing and continued solidification (e.g., several minutes). The reaction and flux rate of the liquid base metal through the shell material increases with temperature, which can extend shelf life near room temperature while allowing rapid hardening at processing temperatures.

[0042] According to various embodiments, in addition to controlling shell thickness, other mechanisms can be applied to the core-shell structure of the reactive particles and thus to control the shelf life, reaction kinetics / rate of the formed amalgamated preform.

[0043] For example, an amalgamated preform can include reactive particles that include a shell material that reacts slower with the base metal than the core material to provide a longer preform processing time. For example, the shell material can be copper, the core material can be gold, and the base metal can be Ga liquid, which reacts faster with gold than copper.

[0044] Another example of an amalgamated preform can include a reactive shell material (e.g., copper) and a non-reactive core material (e.g., Co, and / or ceramic materials including AlN, SiC, SiO2, TiO2, ZrO2, Al2O3, BeO, Si3n4, B4C, WC, and / or diamond). In some cases, the reactive shell material can include multiple layers with an oxide layer at least partially covering the reactive shell material. In one example, the shell material can be Cu and the core material can be Co, while the shell material can further include copper oxide covering the shell material. The magnetic properties of Co can be utilized for heating, mixing, and / or humidification, while the shell material allows for an adhesive interface and strong bonding with the bonding surface of the preform material. In another example, the shell material can be Cu and the core material can be a ceramic material such as AlN, while the shell material can further include copper oxide covering the copper shell material. Such reactive particles can provide a slow reaction rate and an extended shelf life of the formed amalgamated preform.

[0045] In various embodiments, the shell material can be selectively incorporated to support and strengthen the matrix / mass of the amalgamated preform.

[0046] In one example of an amalgamated preform, the shell material of the reactive particles can be non-reactive and / or partially cover the inner particles of the reactive core material (e.g., as a patchy shell). When the inner particles are dissolved by Ga liquid, the shell material remains in the preform, providing mechanical strength and forming a composite. Such shell materials can include ductile materials, including steel, and the core material can be Cu. In another example, the shell material can be a brittle oxide, such as ZnO and / or TiO, which can break due to thermal expansion mismatch with the Cu, Ag, and / or Ni metals used as core materials within the shell material. The hard, brittle shell material, when processed, can strengthen the matrix / mass of the amalgamated preform.

[0047] In various embodiments, the shell material can be broken down during pre-forming processing. For example, the shell material of the reactive particles can be overcome, for example, through dissolution of the base metal due to application of a magnetic domain. For example, under the control of a magnetic domain, the oxide shell material can be broken down, allowing the core material, Fe or Cu, to interact / react with the liquid base metal.

[0048] The multiple types of solid particles can further include non-reactive magnetic particles. The non-reactive magnetic particles may not be capable of reacting with the base metal, but may be responsive to a magnetic signal, for example, to facilitate / induce heating, mixing, and / or humidification of the particle-liquid mixture (e.g., as shown in operation 104 of FIGS. 1A-1B). For example, the non-reactive magnetic particles can include Co-containing particles, Nd-containing particles, and / or Cr-containing particles.

[0049] The non-reactive magnetic particles can have an average size ranging from about 1 micron to about 100 microns, e.g., from about 5 microns to about 100 microns. For example, the non-reactive magnetic particles can have at least one dimension greater than 5 μm. Such large-sized magnetic particles can include microwires, microfibers, or combinations thereof.

[0050] In some cases, large-sized magnetic particles, such as, for example, microwires and / or microfibers, can be added as solid particles to further enhance the heating, mixing, and / or humidifying properties of the particle-liquid mixture placed in a container or between bonding surfaces and / or to provide additional desirable characteristics. The large-sized magnetic particles can be reactive or non-reactive. For example, large-sized (e.g., larger than about 50 microns) reactive and magnetic Fe and / or Ni particles can be added to the particle-liquid mixture to provide desirable mixing and humidification for dispersion and to at least partially participate in the reaction for bonding / curing.

[0051] Optionally and additionally, the multiple types of solid particles can include any other particles to provide desired characteristics / properties to the continuously formed amalgamation preform. For example, semiconductor particles and / or metal-doped semiconductor particles (SiC, AlN, SiO, and / or diamond, with or without doping) can be added to provide improved thermal conductivity to the formed amalgamation preform while decreasing the electrical conductivity of the amalgamation preform. In some cases, the additive particles, whether reactive, non-reactive, magnetic, or non-magnetic, can be further added to the particle-liquid mixture to enhance heating, mixing, and / or humidification characteristics when forming or processing the amalgamation preform.

[0052] Figure 2 shows an example of a particle-liquid mixture in a container according to various embodiments of the present disclosure. As disclosed, the particles shown in Figure 2 can be modified and / or omitted, and more particles can be included in the example particle-liquid mixture.

[0053] As shown in FIG. 2, one example particle-liquid mixture 220 includes a liquid base metal 20A mixed with various particles disclosed herein, including, for example, reactive particles 201 / 203 (e.g., including at least reactive magnetic particles 201 and reactive non-magnetic particles 203), non-reactive magnetic particles 206, and / or any other suitable solid additives 208.

[0054] The particle-liquid mixture 220 is contained in the container 210. The container 210 can be used for mixing, dispersing, and / or solidification. The container 210 can be polymeric, with or without fillers, to minimize bonding forces between the contained mixture and the interior surface of the container. For example, the container 210 can be made of a material that includes at least a flexible surface for contacting the particle-liquid mixture and has a low surface energy to prevent wetting, including polytetrafluoroethylene (PTFE or Teflon), high-density polyethylene (HDPE), or low-density polyethylene (LDPE). Of course, the container can be made of any other suitable material, including metal, ceramic, or non-polymeric materials, with or without the flexible surface thereon.

[0055] 1A-1B, a magnetic region is applied to the particle-liquid mixture to magnetically disperse the multiple types of solid particles in the liquid base metal to form a particle-liquid dispersion. The magnetic region may be applied in a manner that does not substantially induce any reaction between the solid particles and the liquid base metal.

[0056] As disclosed herein, the particle-liquid dispersion can be referred to as a magnetically dispersed particle-liquid mixture, where the multiple types of solid particles can be controlled to be dispersed substantially uniformly in the liquid base metal, for example, by applying a magnetic region.

[0057] 3-7 illustrate the controllable application of magnetic regions to an example of the particle-liquid mixture 220 in the vessel 210 to magnetically disperse the multiple types of solid particles (e.g., particles 201, 203, 206, and / or 208) in the liquid base metal 20A to form a particle-liquid dispersion.

[0058] While the containers shown in Figures 2-7 are oriented with an opening on one side and a substantially horizontal length (as shown in Figure 3) on the open side, the containers can be positioned in any manner or at any angle desired according to various aspects of the present disclosure. Furthermore, the particle-liquid mixture contained in the container is positioned such that it has a thickness from the interior wall of the container, the thickness covering a partial width / diameter or the complete width / diameter of the container.

[0059] Referring to FIG. 3, the vessel 210 containing the particle-liquid mixture 220 can be placed in a magnetic field, for example, generated by a device 330 for magnetic processing.

[0060] In one embodiment, the magnetic processing device 330 can include a coil wound around the vessel 210. The shape and / or size of the wire used in the coil can be determined based on the particular application of the magnetic region. For example, the coil can have a uniform shape and size and can be wound evenly or non-uniformly along the length of the vessel 210.

[0061] The magnetic processing device 330 can be connected to and include a controller (not shown), such as a computer controller, to control the current and / or current changes in the wound coil, thereby controlling, for example, the polarity, strength, location, movement, direction, rotation, spinning, etc., of the magnetic region. For example, a specific length of the coil can be selected by the controller to selectively apply the magnetic region to a partial amount of the particle-liquid mixture to locally disperse solid particles in the particle-liquid mixture. In another example, the magnetic region can be controlled and changed in a specific direction, for example, along the length of the vessel. In yet another example, the controller can be controlled to cause the wound coil to repeatedly provide rotational and / or translational regions, for example, back and forth along a specific direction. In yet another example, the controller can control the wound coil to move the particle-liquid mixture between different positions, from one position to another along the interior wall of the vessel, or to physically wrap the material around the coil.

[0062] The magnetic region can be applied in any suitable manner. Other suitable magnetic processing devices include electromagnets and / or physical permanent magnets. For example, the magnetic region can be provided by electronically controlling an electromagnet and / or controlling the movement of a physical permanent magnet in close proximity to the particle-liquid mixture contained in the vessel.

[0063] In some embodiments, the vessels of Figures 3-7 can be placed in a device for magnetic processing.

[0064] In one embodiment, the magnetic region can be applied and aligned such that solid particles in the liquid base metal can be attracted and moved toward the boundary surface of the container, for example, as shown in Figure 4. Alternatively, the magnetic region can be used to heat and maintain the base metal in the liquid state without further application of heat of reaction.

[0065] The magnetic region can move at various angles to pull the solid particles across the surface of the container. For example, it can move in any shape or motion path through the cross section of the particle-liquid mixture, for example, as shown in FIG. 5 . Solid particles dragging across the container surface scrape, remove, and / or disrupt the native oxide layer that forms on the outermost 505 of the particle-liquid mixture at the mixture-container interface, allowing for wetting. In some embodiments, larger sized particles allow for greater forces compared to the viscous forces experienced in the particle-liquid mixture and may have a better chance of moving the solid particles to the mixture-container interface, for example, as shown in FIG. 6 . In this way, the movement of magnetic particles can be controlled to improve surface wetting and reduce defects and gaps that commonly occur in conventional solder materials.

[0066] The application of the magnetic domains can enable the movement and dispersion of all solid particles in the particle-liquid mixture. Instead of mechanical force, which often compresses the particles and expels the liquid portion, the disclosed particle-liquid mixture / dispersion can move as a slug from one location to another without expelling the liquid portion. Additionally, the magnetic domains can also be used to lubricate the particle-liquid mixture after it has been dispensed as a large "slug," as shown in FIG. 7.

[0067] Thus, the non-reactive solid particles can be used to drive, diffuse, mix, and / or heat the particle-liquid mixture to form a uniform particle-liquid dispersion and, as a result, to form a high quality amalgamated preform. When the amalgamated preform is processed, the non-reactive solid particles can be used to drive hardening and strengthen the corresponding bonding particle mixture / dispersion.

[0068] In one embodiment, gradient magnetic domains can be used to allocate magnetic fibers or wires within the particle-liquid mixture to provide preferential, anisotropic properties, as shown, for example, in Figure 6. For example, large-sized magnetic particles of Fe, Ni, Co, Cr, Nb, and / or their alloys can be incorporated into the particle-liquid mixture to form the amalgamated preform or for bonding / hardening / alloying when processing the amalgamated preform. The magnetic alignment can be varied to produce different properties, such as anisotropic thermal conductivity and / or mechanical strength.

[0069] Instead of having traditional mechanical mixing, the disclosed magnetic mixing / dispersion can be pre-formed under magnetic regions such that various particles can be oriented, moved, and / or positioned along the entire cross section of the particle-liquid mixture.

[0070] For example, in dynamic or spiral magnetic regions, the movement of the solid magnetic particles (large or small, reactive or non-reactive) can be driven through the liquid base metal. The mixing geometry can be designed, for example, to mimic the desired amalgamation preform. The disclosed magnetic mixing / dispersion can be in a random or ordered fashion and can be performed simultaneously with magnetic heating.

[0071] The disclosed magnetic mixing / dispersing can enable the continuously formed amalgamation preform to have well-separated reactive materials / particles to dramatically extend the shelf life of the formed amalgamation preform. When the amalgamation preform is prepared for bonding, the separated materials in the amalgamation preform can be reflowed and redispersed either before being placed on the bonding surface or after contacting the bonding surfaces. In some cases, the materials in the amalgamation preform can be coarsely mixed as clumps of particles, or can include layers of the different materials.

[0072] In some embodiments, the particle-liquid mixture / dispersion can be spread and flattened onto a surface, as shown in Figure 7. The flattened particle-liquid mixture / dispersion can have a thickness of, for example, about 1 mm or less.

[0073] 1A, operation 106, the particle-liquid dispersion is then processed, e.g., rolled, compressed, extruded, poured, etc., to form a playhouse-like amalgamated preform without solidifying the liquid base metal. The playhouse-like amalgamated preform can be formed into any suitable shape, including rods, sheets, ingots, and wires. For example, the playhouse-like amalgamated preform can be rolled to a thickness ranging from about 5 microns to about 500 microns.

[0074] The plaything-like amalgamation preform can then be used directly or solidified to form a solid amalgamation preform at 108 in Figure 1A, which can have a shape / size corresponding to the plaything-like amalgamation preform.

[0075] 1A, the plaything amalgamation preform can be cooled, for example, by liquid cooling, Peltier cooling, or submersion in a cooling liquid such as water or LN2. The cooling process can quench the plaything amalgamation preform without inducing any substantial reaction to provide a corresponding solid amalgamation preform.

[0076] Alternatively, as shown in FIG. 1B, after forming the particle-liquid dispersion in operation 104, a solidification process in 107 can be carried out to uniformly disperse the solid particles in the solidified base metal without substantially inducing reaction therebetween, as shown in FIG. 8.

[0077] To solidify the particle-liquid dispersion, for example, the entire assembly, including the container and the particle-liquid dispersion contained therein, can be cooled, for example, by liquid cooling, Peltier cooling, or immersion in a cooling liquid such as water. The cooling process can quench the particle-liquid dispersion without inducing any substantial reaction, for example, without destroying the shell material of a reactive core material.

[0078] 1B at 109, the solidified particle-liquid dispersion can be processed by rolling, pulling, forging, compressing, grinding, whirling, etc. to form a solid amalgamation preform. For example, the solidified particle-liquid dispersion can be rolled to a thickness of about 25 microns to about 10 mm, and in some cases pulled into a wire. In other cases, the solidified particle-liquid dispersion can be ground at room temperature or freeze-ground into a powder formulation to form the solid amalgamation preform.

[0079] In this manner, the plaything-like amalgamation preform prepared in operation 106 of FIG. 1A or the solid amalgamation preform prepared in 108 of FIG. 1A can be configured for application and ready to use.

[0080] 1A-1B, it should be noted that substantially no reaction is induced between the base metal and the reactive particles. For example, the formed playhouse-like amalgamation preform can include various types of solid particles magnetically dispersed in the liquid base metal, and substantially no reaction occurs between the reactive particles and the liquid base metal at about room temperature (e.g., about 25°C) or below. The formed solid amalgamation preform can include various types of solid particles magnetically dispersed in the solid base metal, and substantially no reaction occurs between the reactive particles and the solid base metal at about room temperature (e.g., about 25°C) or below.

[0081] 9A-9B illustrate examples of methods of using amalgamation preforms according to various aspects of the present disclosure.

[0082] At 902 in Figures 9A-9B, an interface bonding surface is provided.

[0083] As used herein, the terms "mating surface," "bonding surface," and "mating bonding surface" may be used interchangeably in this disclosure. Thus, the term "bonding material" may refer to any material that is placed and processed between mating bonding surfaces for, for example, reflow, redistribution, and bonding / hardening / alloying.

[0084] Thus, the bonding material can include, for example, a particle-liquid mixture (e.g., as shown at 102 in FIGS. 1A-1B), a particle-liquid dispersion (e.g., as shown at 104 in FIGS. 1A-1B), and / or any amalgamation preform, including a playhouse-like amalgamation preform (e.g., as shown at 106 in FIG. 1A), and / or a solid amalgamation preform (e.g., as shown at 108 in FIGS. 1A and 109 in FIG. 1B).

[0085] The bonding surfaces can be provided by two bonding materials. In some cases, the bonding surfaces can be opposite surfaces of a single substrate. The bonding surfaces can be provided for placing a particle-liquid mixture / dispersion and / or an amalgamation preform (e.g., a playhouse amalgamation preform and / or a solid amalgamation preform) therebetween for bonding / hardening / alloying of the particle-liquid mixture in correspondence with the amalgamation preform.

[0086] For purposes of explanation, examples of methods of use of the amalgamated preforms are described using a pair of bonding surfaces as an example, although the bonding surfaces may be disposed between a single bonding surface or bonding surfaces of the same substrate, according to various aspects of the present disclosure.

[0087] The bonding surfaces can include engineering metals such as steel with gold coatings, e.g., FCC (face-centered cubic) metals in loose or plated form, ceramics such as silicon carbide, silicon dioxide, and / or aluminum nitride, and / or insulators including glass, quartz, and / or sapphire. The insulators may or may not be metallized prior to bonding. The two bonding surfaces can be made of the same or different materials.

[0088] In various embodiments, optionally, the bonding surfaces can be pretreated to provide bonding surfaces that are thoroughly cleaned and / or free of any excess oxides.

[0089] For example, the bonding surface can be solvent cleaned by immersion in a solvent containing acetone, alcohol, and / or deionized water at a temperature below 20° C. In some cases, the bonding surface can be first cleaned in acetone and alcohol, and then the surface can be rinsed with deionized water.

[0090] In another example, if the bonding surface is made of a metal, such as Cu or Ag, excess copper or silver oxides may form on the bonding surface. The bonding surface can be pretreated to remove such excess oxides, for example, by etching (including plasma etching, acid etching, and / or base etching) and / or mechanical polishing (e.g., blasting, peening, etc.). In an exemplary embodiment, the bonding surface can be pretreated by mechanical polishing with P2000 or 0000 steel and / or polished by chemical etching with NaOH with successive deionized water rinses.

[0091] On the other hand, it should be appreciated that some (or a small amount) of native oxide may be retained on the joining surface without being completely removed, thereby avoiding the possibility of alloying between the joining material and the joining surface.

[0092] In various embodiments, the treated bonding surface can have a surface roughness ranging from 1 nm to 100 microns. Such roughness is desirable for providing adhesion to the bonding material during the subsequent reflow, redistribution, and / or curing process. In contrast, a surface that is too smooth for the bonding / curing process may be undesirable for the bonding material to undergo remixing and curing.

[0093] 9A-9B, a particle-liquid mixture, which may correspond to an amalgamation preform, for example, is placed between the joining surfaces at 904. The particle-liquid mixture may include various types of solid particles and base metals similar to, the same as, or different from those shown in FIGS.

[0094] In some embodiments, the particle-liquid mixture for bonding / hardening / alloying can be obtained by operation 102 of Figures 1A-1B. In other embodiments, the particle-liquid mixture for bonding / hardening / alloying can be obtained from a plaything amalgamation preform (e.g., obtained at 106 of Figure 1A) and / or a solid amalgamation preform (e.g., obtained at 108 of Figure 1A and 109 of Figure 1B) by a heating process, for example, by convection / induction heating generated by controlled magnetic fields and / or by any other suitable heating process.

[0095] At 906 in FIG. 9, a first magnetic region is applied to disperse the particle-liquid mixture to form a particle-liquid dispersion.

[0096] In various embodiments, the application of the first magnetic region in operation 906 of FIG. 9 can be similar or the same as the application of the magnetic region in operation 104 of FIGS. 1A-1B so that various types of solid particles in the particle-liquid mixture can be uniformly or otherwise controllably dispersed to form the particle-liquid dispersion.

[0097] FIG. 10 illustrates an example configuration with a solid amalgamation preform positioned between bonding surfaces for bonding / hardening / alloying according to various aspects of the present disclosure.

[0098] In Figure 10, an example solid amalgamation preform 1040 is placed between bonding surfaces 1055 of joining materials 1050. The bonding surfaces 1055 can have the disclosed surface roughness to facilitate manipulation of the bonding materials at the interface therebetween. The solid amalgamation preform is then heated, for example, using a magnetic machining device / mechanism 1030 (or any other suitable heating means) to liquefy the solid base metal 1020B to form a corresponding particle-liquid mixture with liquid base metal 1020A, as shown in Figure 11. Under magnetic control at 1070 in Figure 11, the solid particles in the particle-liquid mixture can be uniformly dispersed to form the particle-liquid dispersion.

[0099] As shown in Figures 10-11, the various particles disclosed herein can include, for example, reactive particles 1001 / 1003 and 1101 / 1103 (e.g., including at least reactive magnetic particles 1001 / 1101 and reactive non-magnetic particles 1003 / 1103), non-reactive magnetic particles 1006 / 1106, and / or any other possible solid additives 1008 / 1108.

[0100] Returning to FIG. 10 , each bonding surface 1055 can be configured to have a gap 1060 with the solid amalgamation preform 1040. The gap 1060 can have an initial thickness between the bonding surface 1055 and the solid amalgamation preform 1040. Such an initial thickness can allow the solid amalgamation preform 1040 to contact each bonding surface 1055 without pressure or little pressure (<1 MPa) being applied to the solid amalgamation preform 1040. In the undesirable case where large pressures are applied, the bonding surfaces can tend to compress toward each other, and the components of the solid amalgamation preform can separate, resulting in an undesirable hardening effect of the bonding material.

[0101] The initial thickness of the gap 1060 can be maintained throughout the bonding / curing / alloying process, for example, using physical spacers or space constraints on both bonding surfaces 1050. For example, jigs or robotic holdings can be used to maintain the initial thickness of the gap 1060. In various embodiments, the spacers can be removed after the bonding / curing / alloying process of the solid amalgamated preform 1040 is complete, or can remain in place after the bonding / curing / alloying process is complete and become an inactive portion of the joining material of the bonded structure.

[0102] In various embodiments, the spacer can be made of a material selected to add toughness or strength to the bond formed with the solid amalgamation preform, providing hermeticity and conductivity to the bond formed. For example, the spacer can include a solid core material and a low-melting adhesive material formed over the solid core material. In this case, the polymer can strengthen the bond formed and cushion pressure from the solid amalgamation preform.

[0103] In various embodiments, the solid core material used for the spacer can be a metallic or organic polymer. The solid core material is relatively ductile and can deform to fill the gaps in the bond. The solid core material can have a melting point greater than the processing temperature for the bond so that the spacer remains solid. One example of the solid core material can include a ductile metal, such as copper, gold, silver, or aluminum, that does not form harmful oxides that couple with the material or the amalgam. Another example of the solid core material can include a polymer, such as nylon (polyamide).

[0104] The low melt adhesive material formed over the solid core material can include a polymer having a melting point below the amalgam set temperature, and includes, for example, thermoplastic polyurethane, styrene block copolymer, ethylene vinyl acetate, polyolefin, and / or polylactic acid.

[0105] 11-14 illustrate the controllable application of the first magnetic region to the example particle-liquid mixture 1120 between the binding surfaces 1055 to magnetically disperse the multiple types of solid particles (e.g., particles 1101, 1103, 1106, and / or 1108) in the liquid base metal 1020 to form a particle-liquid dispersion. During this process, the reactive particles 1101 / 1103 may or may not react with the liquid base metal 1020A. For example, the first magnetic region may be applied in a manner that does not destroy the shell material to cause a reaction.

[0106] In one embodiment, a magnetic processing device, such as device 1030 of FIG. 10, can be used to apply the first magnetic region. The magnetic processing device can include a coil winding around the binding material 1050. The shape and size of the wire used in the coil winding can be determined based on the particular application of the first magnetic region. For example, the coil winding can have a uniform shape and size, and can be wound evenly or non-uniformly along the length of the binding material.

[0107] The magnetic processing device can be connected to or include a controller (not shown), such as a computer controller, to control the current and / or current variations in the wound coil, and thus, for example, to control, for example, the polarity, strength, location, movement, rotation, spin, etc., of the first magnetic region. For example, a particular length of the coil can be selected by the controller to selectively apply the first magnetic region to a partial amount of the particle-liquid mixture. In another example, the first magnetic region can be controlled to vary along a particular direction, for example, along the length of the binding material. In yet another example, the controller can control the wound coil to provide repeated rotational and / or translational regions, for example, back and forth along a particular direction. In yet another example, the controller can control the wound coil to move the particle-liquid mixture between different positions along the binding surface of the binding material or to move the particle-liquid material out of the particle-liquid mixture in the binding material.

[0108] The first magnetic region can be applied in any suitable manner. Other suitable magnetic processing devices include electromagnets and / or physical permanent magnets that can be controlled to heat, mix, disperse, etc. For example, electrical control of electromagnets and / or control of moving physical permanent magnets can be implemented to provide the first magnetic region.

[0109] In one embodiment, the first magnetic region can be applied and aligned to attract and move solid particles in the liquid base metal toward the interface with the bonding surface, as shown in Figure 12. Alternatively, the first magnetic region can be used to heat and maintain the base metal in the liquid state.

[0110] The first magnetic region can move through the cross section of the bonding material in any suitable shape or motion path, moving at various angles to pull the solid particles across two bonding surfaces, as shown, for example, in FIG. 13 . Solid particles pulled across the bonding surfaces can scratch, remove, and / or disrupt the native oxide layer that forms on the outermost layer 1305 of the bonding material (e.g., particle-liquid mixture) at the interface, allowing for dispersion and wetting. In some embodiments, as shown, for example, in FIG. 14 , larger-sized particles can allow for greater forces compared to the viscous forces experienced by the bonding material and have a better chance of moving the solid particles to the bonding material-bonding surface interface. In this way, the motion of magnetic particles can be controlled to eliminate the need for fluxing agents and improve surface wetting to reduce chipping and gaps that often occur with conventional solders.

[0111] The application of the first magnetic region can enable the movement and dispersion of all solid particles in the binder. Instead of being driven by mechanical forces that often compress the solids and expel the liquid components, the disclosed particle-liquid mixture / dispersion can move as a slug from one location to another without expelling the liquid components. Additionally, the first magnetic region can also be used to lubricate the particle-liquid mixture after dispersion as a large "slug," as shown in FIG. 14.

[0112] The non-reactive solid particles can be used to drive, spread, mix, and / or heat the particle-liquid mixture to form a uniform particle-liquid dispersion that can cause a uniform reaction for curing and further strengthen the bonding material.

[0113] In one embodiment, gradient static magnetic regions can be used to align magnetic fibers or wires within the bonding material to provide preferential and anisotropic properties, e.g., see Figure 15. For example, large-sized magnetic particles of Fe, Ni, Co, Cr, Nb, and / or their alloys can be incorporated into the particle-liquid mixture for bonding. The magnetic alignment can be varied to produce various properties, e.g., anisotropic thermal conductivity and / or mechanical strength.

[0114] Instead of traditional mechanical mixing, the disclosed magnetic mixing can be achieved, for example, by a dynamic magnetic domain or a spiral magnetic domain, which induces the movement of the solid magnetic particles (reactive or non-reactive, with or without large size) through the binding material. For example, under a dynamic magnetic domain, multiple types of solid particles as disclosed above can be drawn toward the interface between the binding material and the binding surface. Once at the interface, the solid particles can move in-plane to mix the native oxide of the base metal into the binding material at the outer surface (e.g., at the boundary) of the solid material, creating interfacial scratching or rubbing. By removing or disturbing the oxide layer, metal alloying can induce and enhance interfacial strengthening.

[0115] The shape of the binding material can be designed, for example, according to the practical application. The disclosed magnetic mixing / dispersing can be in a random or ordered manner and can be performed with simultaneous magnetic heating.

[0116] In 908 of Figure 9A, a second magnetic region is applied to bond / cure / alloy the particle-liquid dispersion, allowing for reaction or hardening between the reactive particles and the base metal. During this hardening operation, the temperature can be controlled by the second magnetic region in combination with the controllable composition of the particle-liquid dispersion. For example, use of the second magnetic region allows for a hardening temperature of a particular particle-liquid dispersion that differs from the conventional hardening temperature of the corresponding material in the particle-liquid system.

[0117] In various embodiments, the curing temperature can be about 250° C. or less, e.g., about 150° C. or less, or about 50° C. or less (e.g., at room temperature). More specifically, the use of the second magnetic region, in combination with a specific / controlled composition of the particle-liquid dispersion, allows for much lower curing temperatures, e.g., 150° C. or less, and in some embodiments, 100° C. or less, and in some embodiments, 50° C. or less. Of course, by controlling the composition of the second magnetic region and / or the particle-liquid dispersion, higher curing temperatures, e.g., about 250° C., can also be controlled and used.

[0118] The second magnetic region can be applied in a manner different from the first magnetic region, such as in strength, polarity, time, etc. The second magnetic region can be provided by the same magnetic treatment as the first magnetic region, but with different adjustments.

[0119] Under the second magnetic region, the bonding material can be heated to a temperature that activates a chemical reaction between the hardening / alloying reactive particles and the base metal, for example, a temperature above the melting point of the liquid component of the reaction (the bonding material resulting from operation 904 in FIG. 9A). During these hardening / bonding / alloying processes, the temperature is 150°C or less, and in some embodiments, 100°C or less, and in some embodiments, 50°C or less.

[0120] In one embodiment, the first magnetic region can be dynamic in nature to induce particle movement and disperse the particle-liquid mixture to form a particle-liquid dispersion. For example, a fixed-pole magnet can move within the space surrounding the entire configuration, as shown in FIG. 10. The generated first magnetic region is controlled / adapted to not induce significant hardening or heating, preventing premature hardening. The second magnetic region is controlled to have an effect similar to induction heating, limiting particle movement, and generating heating of the amalgamation pre-product to induce the hardening.

[0121] As disclosed herein, the reactive particles can include a core-shell structure with a shell material at least partially covering a core material. In one embodiment, the shell material of the reactive particles can be used to control the kinetics and dissociation rate of the core material, and consequently, the reaction rate between the reactive particles and the hardening base metal.

[0122] The shell material can have a thickness ranging from an atomic layer thick to about 100 nm thick, such as several atomic layers. The shell material can be thick enough to largely prevent solid-state alloying between the reactive particles and solid base metal for the amalgamation pre-product, and thin enough not to undergo such reaction during hardening. The thickness of the shell material can be controlled by the selection of the base metal and the reactive particles.

[0123] In one example embodiment in which the core material is one or more of Fe and Ni and the shell material is an oxide of the one or more of Fe and Ni, the rate of dissociation or penetration of the example base metal Ga material through the shell material depends on the thickness of the shell material.

[0124] According to various embodiments, in addition to controlling shell thickness, other mechanisms can be applied to the core-shell structure of the reactive particles to consequently control the reaction kinetics / rate for hardening / alloying.

[0125] For example, the reactive particles can include a shell material that reacts slower with the base metal than the core material to provide a longer cure time. For example, the shell material can be copper, the core material can be gold, and the base metal can be Ga liquid, which reacts faster with gold than copper.

[0126] Another example of a reactive particle can include a reactive shell material (e.g., Cu) and a non-reactive core material (e.g., Co and / or AlN, SiC, SiO2, TiO2, ZrO2, Al2O3, BeO, Si3N4, B4C, ceramic materials including WC, and / or diamond). In some cases, the reactive shell material can include multiple layers with an oxide layer at least partially covering the reactive shell material. In one example, the shell material can be copper and the core material can be Co, while the shell material can further include copper oxide covering the copper shell material. The magnetic properties of Co can be utilized for heating, mixing, or humidification, while the shell material can enable a tight interface and strong bonding of the bonding material with the bonding surface. In another example, the shell material can be Cu and the core material can be AlN, while the shell material can further include copper oxide covering the copper shell material.

[0127] In various embodiments, the shell material can be selected to be incorporated to support and strengthen the solid alloy. In one example, the shell material of the reactive particle can be non-reactive and / or can partially cover the inner particle of the core material (e.g., as a patchy shell). When the inner particle dissolves in the Ga liquid, the shell material can remain in the preform to provide mechanical strength and form a composite. Such shell materials can include ductile materials, including steel, and the core material can be Cu. In another example, the shell material can be a brittle oxide, such as ZnO or TiO, which can fracture due to a thermal expansion mismatch with the Cu, Ag, or Ni metal used as the inner core material. The hard, brittle shell material can strengthen the solid alloy.

[0128] In various embodiments, the shell material can be broken down during processing of the preform, e.g., curing / bonding / alloying. For example, the shell material of the reactive particles can be overcome by dissociation of the base metal, e.g., due to application of a second magnetic region. For example, under the control of the second magnetic region, the oxide shell material can break down, allowing its core material, Fe or Cu, to interact / react with the liquid base metal.

[0129] In various embodiments, the hardened material, i.e., the bond or solid alloy, can be an all-metallic solid. FIG. 16 shows an example of a solid alloy doped with at least non-reactive magnetic particles according to various embodiments of the present disclosure. The solid alloy can have temperature stability above the hardening temperature. As shown in FIG. 16, non-reactive magnetic particles can be retained in the solid alloy and uniformly dispersed therein to provide desirable properties such as mechanical strength, high temperature, and electrical conductivity.

[0130] FIG. 9B illustrates an example method for using an amalgamation preform according to various embodiments of the present disclosure.

[0131] After operation 904 in FIG. 9B for placing the particle-liquid mixture corresponding to the amalgamated preform between the mating surfaces, the particle-liquid mixture can be heated to a temperature above the low melting point of the base metal to reflow the particle-liquid mixture, as shown in operation 907 in FIG. 9B.

[0132] The heating process in operation 907 of Figure 9B can include any heating means, such as by conduction, convection, or radiation. For example, a pulsed laser can be used to heat the particle-liquid mixture. The heating process can be performed while a magnetic region is applied to the particle-liquid mixture. During this heating process in operation 907 of Figure 9B, the temperature is 150°C or less, and in some embodiments, 100°C or less, and in some embodiments, 50°C or less.

[0133] 9B, a magnetic region is applied to the particle-liquid mixture while heating to allow a reaction to occur between the reactive particles and the base metal, 909. During this reaction operation 909, the temperature is 150° C. or less, in some embodiments 100° C. or less, and in some embodiments 50° C. or less.

[0134] Under the magnetic field, the bonding material is dispersed and can be further heated to a temperature that activates a chemical reaction between the reactive particles and the base metal for hardening, for example, a temperature that is above the melting point of the liquid component (bonding material resulting from operation 904 in Figure 9A) for the reaction to occur.

[0135] For example, a magnetic processing device (e.g., as shown in FIG. 10) can be used and controlled to adjust the magnetic region. For example, the magnetic processing device can include a coil wound around the bonded material. The shape and size of the wire used in the coil can be determined based on the specific application of the magnetic region.

[0136] The magnetic processing device can be connected to or include a controller, such as a computer controller, to control the current and / or current variations in the wound coil to thereby control, for example, the polarity, strength, location, movement, rotation, spin, etc., of the first magnetic region. For example, a specific length of the coil can be selected by the controller to selectively apply the magnetic region to a partial amount of the particle-liquid mixture to locally disperse solid particles in the particle-liquid mixture. In another example, the magnetic region can be controlled or varied along a specific direction, such as the length of the binding material. In yet another example, the controller can control the wound coil to repeatedly provide regions of rotation and / or translation of the particle-liquid mixture / dispersion back and forth along a specific direction. In yet another example, the controller can control the wound coil to move the particle-liquid mixture / dispersion between different positions along the binding surface of the binding material or to expel the particle-liquid material from the binding material.

[0137] Other suitable magnetic processing devices may include electromagnets and / or physical permanent magnets that can be controlled for heating, mixing, dispersing, etc. For example, electronic control of an electromagnet and / or movement control of a physical permanent magnet can be used to provide the first magnetic region.

[0138] The magnetic particles in the particle-liquid mixture can align, move, and disperse during heating. The magnetic regions can be adjusted to change the direction of the particles and to provide mixing / dispersion within the cross-section of the particle-liquid mixture. The magnetic movement can be rotational, translational, or a combination of rotational and translational, as the particles move within the cross-section of the particle-liquid mixture. During this process, the bonding surface can come into contact with some moving liquid, which can then break down and disperse the outermost native oxide layer of the particle-liquid mixture, creating a fresh interface.

[0139] In addition to more uniformly dispersing particles in the particle-liquid mixture, the magnetic domains can be adjusted to allow the reaction between the reactive particles and the base metal to form a solid alloy.

[0140] Thus, under the magnetic region, various types of solid particles can be oriented, moved, and / or aligned along the entire cross-section of the binding material containing the particles. Under a dynamic magnetic region, particles align and move along the movement of the magnetic region. Various particle movements can be introduced under the application of the magnetic region. For example, under a spin magnetic region, radial particle movement can occur, which can substantially break down and mix the binding material at the interface between the binding material and the binding surface. Particle movement can cause agitation at the interface. Dynamically controlling / adjusting the magnetic region can control the concentration at different locations. Particle movement can fill gaps in the binding material and redistribute the particles throughout the cross-section of the binding material. Such distribution can provide a uniform chemical composition. In addition, the surface bonds at the interface can be broken down and changed due to the particle movement, providing humidification on the contact material, thereby homogenizing the composition with uniform distribution. Furthermore, the fluctuation of the magnetic region and heating throughout the cross-section can provide localized distribution of heat and concentration.

[0141] Traditionally, flow is necessary for adhesion of solder / joint materials that form a natural oxide layer. Typically, the flow is applied and used to clean and moisten the joining surfaces prior to the joining process. However, flow has several drawbacks. For example, it can introduce corrosiveness and contamination to the joint, and there are adverse health effects caused by fumes and outgassing during joining and processing. Fluid materials are also often mixed with the metal powder in preforms to aid in interfacial bonding with the joining surfaces. For example, the surface or exterior of the joining material can have fluid mixed within it while the joining material cannot flow. However, agitation at the joining interface is required to break up the natural oxide layer floating on the exterior surface of the joining material; otherwise, adhesion at the interface is undesirably poor. Traditional preforms cannot adequately adhere to most joining surfaces.

[0142] The conditioned magnetic region can allow the various types of disclosed solid particles to migrate toward the interface between the bonding material and the bonding surface and further create scratches or abrasions at such interface, destroying the native oxides of the base metal on the outer surface of the bonding material (e.g., at 1305 in FIG. 13) and mixing the destroyed native oxides from the outer surface of the bonding material (e.g., at the interface) to the inner surface of the bonding material. The native oxides of the base metal fragmented inward from the outer surface of the bonding material can mechanically strengthen the resulting bonding material and can allow the base metal to react directly with the bonding surface to moisten the bonding surface.

[0143] As such, the need for humidifying the binding material or any fluid reagents in the binding material is eliminated by applying the disclosed particle-liquid mixture in combination with the tuned magnetic regions according to various aspects of the present disclosure.

[0144] The resulting hardened bond, being a completely new and fairly stable alloy state, can sustain the fairly high temperatures experienced by the bonded surfaces (and portions thereof). In one embodiment, the resulting hardened bond can sustain temperatures higher than the hardening temperature, e.g., about 200°C or higher, such as about 260°C or higher.

[0145] Although the present disclosure has been disclosed as above, the present disclosure is not limited to the disclosed embodiments. Various changes and modifications can be made by those skilled in the art without departing from the essence and scope of the present disclosure. Therefore, the scope of the present invention should be limited to the scope defined by the claims. [Explanation of symbols]

[0146] 102 Particle-liquid mixture provision operation 104 Particle-liquid dispersion formation process 106 Forming Procedure of Children's Clay-Like Amalgamated Preforms 107 Particle-liquid dispersion formation process 108 Solid Amalgamation Preform Forming Operation 109 Solid Amalgamation Preform Forming Operation 201 One of several types of solid particles 203 One of several types of solid particles 206 One of several types of solid particles 208 One of several types of solid particles 210 Container 220 Particle-Liquid Mixture 330 Devices for magnetic processing 505 Outermost layer of particle-liquid mixture 902 Providing a joint surface 904 Installation of particle-liquid mixture between bonding surfaces 906 Application of the first magnetic region to particle-liquid mixture 907 Reflow operation of particle-liquid mixture 908 Application of the second magnetic region to particle-liquid mixtures 909 Reaction control of reactive particles with base metals 1001 Reactive Magnetic Particles 1003 Reactive Magnetic Particles 1006 Non-reactive magnetic particles 1008 Solid additives 1020 Liquid base metal 1020A Liquid Base Metal 1020B Solid base metal 1030 Magnetic machining devices / mechanisms 1040 Solid amalgamated preforms 1050 Bonding material 1055 Bonding surface 1060 gap 1070 Particle-liquid dispersion formation process 1101 Reactive non-magnetic particles 1103 Reactive non-magnetic particles 1106 Non-reactive magnetic particles 1108 Solid additives 1120 particle-liquid mixture between bonding surfaces 1055 1305 outermost layer of binding material 1580 Magnet

Claims

1. A base metal, and a plurality of types of solid particles dispersed in said substrate metal, wherein said substrate metal includes a liquid state or a solid state; A mixed preform comprising: wherein the plurality of types of solid particles comprises at least: non-reactive magnetic particles responsive to a magnetic field for controllably dispersing multiple types of solid particles in the substrate metal; and reactive particles capable of reacting with the substrate metal under a magnetic field for mixing; and the plurality of types of solid particles are localized together only in one or more regions near the outermost surface of the mixed preform; Mixed preform.

2. the substrate metal comprises Ga, In, Sn, Bi, Pb, Cd, Hg, Rb, Zn, Bi, or a combination thereof; the reactive particles include at least a reactive metal material, wherein the reactive metal material includes Fe, Ni, Cu, Ag, Au, In, Cu, Sn, Bi, Zn, Ti, V, Cr, Mo, Nb, Zr, Hf, Pt, Ir, or a combination thereof; The mixed preform of claim 1.

3. one of the reactive particles comprises one core-shell structure; wherein the core-shell structure comprises one core material and one shell material that is different from the core material and at least partially surrounds the core material; and 10. The mixed preform of claim 1, wherein said core material has a different reaction rate with said substrate metal than said shell material.

4. The shell material has a thickness ranging from an atomic diameter to 100 nm. the core material comprises a reactive metal material, and the shell material comprises an oxide layer of the reactive metal material; The mixed preform of claim 3.

5. The core-shell structure is a core-shell structure having the shell material comprising an oxide of one or more elements selected from Fe and Ni, and the core material comprising one or more elements selected from Fe and Ni; a core-shell structure having the shell material comprising Cu and the core material comprising Au; a core-shell structure with the shell material comprising steel and the core material comprising Cu; ZnO or TiO ２ and the core material comprises Cu, Ag, Ni, or a combination thereof; and The shell material includes Cu and copper oxide that at least partially covers Cu, and Co, BeO, Si ３ N ４ , B ４ C, WC, diamond, AlN, SiC, SiO ２ , TiO ２ , ZrO ２ , Al ２ O ３ or a core-shell structure having the core material comprising a combination thereof; 4. The mixed preform of claim 3, comprising one or more types of core-shell structures selected from the group consisting of:

6. The mixed preform of claim 1 , wherein the reactive particles comprise reactive magnetic particles, reactive non-magnetic particles, or a combination thereof.

7. the reactive magnetic particles comprise one or more elements selected from Fe and Ni; the reactive magnetic particles have an average particle size greater than 50 microns; and the reactive non-magnetic particles comprise Cu, Ag, Au, In, Cu, Sn, Bi, Zn, Ti, V, Cr, Mo, Nb, Zr, Hf, Pt, Ir, or a combination thereof; The mixed preform of claim 6.

8. 2. The mixed preform of claim 1, wherein the ratio of said substrate metal to said plurality of types of solid particles ranges from 4:1 to 1:4 by weight.

9. the plurality of types of solid particles have an average particle size in the range of 100 nm to 100 μm; the reactive particles have an average particle size in the range of 100 nm to 50 μm; and the non-reactive magnetic particles have an average particle size in the range of 5 microns to 100 microns; The mixed preform of claim 1.

10. The mixed preform of claim 1 , wherein the non-reactive magnetic particles comprise Co-containing particles, Nd-containing particles, Cr-containing particles, or a combination thereof.

11. the non-reactive magnetic particles being large size magnetic particles having at least one dimension greater than 5 μm; and the large-sized magnetic particles comprise microwires, microfibers, or a combination thereof, and the length directions of the microwires and microfibers are aligned parallel to a direction along the outermost surface of the amalgamation preform; The mixed preform of claim 1.

12. the plurality of types of solid particles further comprises an additive comprising semiconductor particles, metal-doped semiconductor particles, or a combination thereof; The semiconductor particles are SiC particles, AlN particles, SiO ２ particles, or combinations thereof, The mixed preform of claim 1.

13. liquid base metal, and a plurality of types of solid particles magnetically dispersed in said liquid substrate metal without solidifying said liquid substrate metal, The multiple types of solid particles include at least non-reactive magnetic particles responsive to a magnetic field for controllably dispersing the plurality of types of solid particles in the liquid substrate metal; and comprising reactive particles, wherein the plurality of types of solid particles are localized together only in one or more regions near the outermost surface of the mixed preform; the reactive particles are capable of reacting with the liquid substrate metal under the magnetic field for mixing; and No reaction occurs between the reactive particles and the liquid substrate metal at temperatures below 25°C. Mixed preform.

14. 14. A method for producing a mixed preform according to claim 1 or 13, comprising: providing a particle-liquid mixture comprising said plurality of types of solid particles and said liquid substrate metal; where: the plurality of types of solid particles includes at least the reactive particles and the non-reactive magnetic particles; applying a magnetic field to the particle-liquid mixture to magnetically disperse the plurality of types of solid particles in the liquid substrate metal to form a particle-liquid dispersion without inducing substantial reaction between the reactive particles and the liquid substrate metal; and preparing the mixed preform comprising the plurality of types of solid particles and the substrate metal; method.

15. 14. A method for producing a mixed preform according to claim 1 or 13, comprising: Provides a mating interface. placing a particle-liquid mixture corresponding to the preformed mixture between the mating bonding surfaces; and applying a magnetic region to the particle-liquid mixture; method.

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