Liquid cold welding method and apparatus

Abstract

A method of liquid cold welding (LCW) is disclosed, comprising: (a) joining two or more porous conductive substrate layers between a plurality of perforated non-conductive frames such that the two or more porous conductive substrate layers are in contact with each other; (b) immersing the two or more porous conductive substrate layers in an electrolyte solution; and (c) applying an electric current and / or voltage and / or power to the electrolyte solution. Apparatuses suitable for performing some embodiments of the method are also disclosed.

Description

[0001] This application claims priority to IL 277589, which has the same title and inventors as this application and was filed on September 24, 2020, pursuant to section 119(a) of 35 U.S.SC; the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention belongs to the field of metal manufacturing. Background Technology

[0003] Porous 3D metallic objects can be fabricated from stacked 2D meshes and / or porous films. These substrates are stacked under pressure and placed in a high-temperature furnace under vacuum or inert gas conditions. The high temperature increases the thermal energy diffused to the metal atoms on the substrate. This results in the formation of 3D metallic objects with various porosities and pore shapes and sizes. The porosity can be open or closed. Prior art in US8715871B2 and US20050017055A1 discloses several embodiments of such methods for fabricating electrochemical reactors with porous metallic structures. One of the main drawbacks of this method is the requirement of high temperatures for actual layer bonding.

[0004] A combination of photoresist patterning and electrodeposition can also be used to form high-resolution porous 3D metal structures. To achieve the desired thickness and porosity, multiple repeatable steps are required, including patterning, electroplating, pattern dissolution, and partial metal dissolution. Examples of such fabrication processes are described in US20090239353A1, US20100147695A1, US20130029481A1, and US009244101B2. While these steps are frequently used in the microfabrication industry, making them cost-effective and scalable for substrates larger than typical silicon wafers is quite challenging. Summary of the Invention

[0005] One aspect of some embodiments of the present invention relates to the production of porous 3D metal structures using liquid cold welding (LCW) or welding. For the purposes of this specification and the appended claims, the term "liquid cold welding" or "LCW" refers to joining two or more metal or metal composite substrates immersed in a liquid electrolyte solution by depositing metal or metal composites from an electrolyte solution during a localized electrochemical reaction. According to various exemplary embodiments of the present invention, liquid cold welding is cost-effective and / or scalable.

[0006] It should be understood that the above aspects relate to solutions to technical problems related to the scalability of porous 3D metal structure production.

[0007] Alternatively or additionally, it should be understood that the foregoing aspects relate to solutions to technical issues concerning performance control during production.

[0008] In some exemplary embodiments of the present invention, a liquid cold welding (LCW) method is provided, comprising: (a) bonding two or more porous conductive substrate layers between a plurality of perforated nonconductive frames such that the two or more porous conductive substrate layers are in contact with each other; (b) immersing the substrate layers in an electrolyte solution; and (c) applying a current and / or voltage and / or power to the electrolyte solution. In some embodiments, the application includes applying a current from a working electrode (WE) flowing through the two or more porous metal substrate layers between the plurality of perforated nonconductive frames to a counter electrode (CE). Alternatively or additionally, in some embodiments, the application includes applying a constant voltage. Alternatively or additionally, the application includes applying a constant voltage using a reference electrode (RE). Alternatively or additionally, in some embodiments, the application includes applying a constant power. Alternatively or additionally, in some embodiments, the method includes folding a single porous conductive substrate layer to form two or more porous conductive substrate layers. In some embodiments, the method includes: simultaneously supplying two or more porous conductive substrate layers between the plurality of perforated non-conductive frames; and retracting the two or more porous conductive substrate layers as adhesive substrates after the liquid cold soldering. Alternatively or additionally, in some embodiments, the method includes increasing the distance between the plurality of perforated non-conductive frames to facilitate insertion and / or removal of the two or more porous conductive substrate layers. Alternatively or additionally, in some embodiments, the method includes decreasing the distance between the plurality of perforated non-conductive frames such that the two or more porous conductive substrate layers contact each other. Alternatively or additionally, in some embodiments, the method includes pumping the electrolyte solution through the plurality of perforated non-conductive frames and the two or more porous conductive substrate layers during the application.

[0009] In some exemplary embodiments of the present invention, a liquid cold welding (LCW) apparatus is provided, comprising: a container having two opposing electrodes within the container; and at least two perforated non-conductive frames adapted to join and hold a multilayer substrate such that the layers remain in contact with each other; the at least two perforated non-conductive frames being located between the opposing electrodes. In some embodiments, the contact is mechanical contact.

[0010] In some exemplary embodiments of the present invention, a liquid cold welding (LCW) apparatus is provided, comprising: a container in which an active electrode and a reference electrode are placed opposite each other; and at least two perforated non-conductive frames adapted to bond and hold a multilayer substrate such that the layers remain in contact with each other; the at least two perforated non-conductive frames being located between the active electrode and the reference electrode.

[0011] Regarding one or both of the above-mentioned devices:

[0012] In some embodiments, the apparatus includes two or more supply rollers adapted to simultaneously supply two or more porous conductive substrate layers between the plurality of perforated nonconductive frames; and a take-up roller adapted to roll up the two or more porous conductive substrate layers as an adhesive substrate after liquid cold soldering. Alternatively or additionally, in some embodiments, the apparatus includes a distance adjustment mechanism adapted to adjust a distance between the plurality of perforated nonconductive frames. In some embodiments, the distance adjustment mechanism increases the distance to facilitate the insertion and / or removal of the two or more porous conductive substrate layers. Alternatively or additionally, in some embodiments, the distance adjustment mechanism decreases the distance between the perforated nonconductive frames such that the substrate layers contact each other during soldering. Alternatively or additionally, in some embodiments, the apparatus includes a folding mechanism configured to fold a single porous conductive substrate layer to create a stack of porous conductive substrate layers. Alternatively or additionally, in some embodiments, the apparatus includes a pump positioned to pump the electrolyte solution through the plurality of perforated nonconductive frames and the two or more porous conductive substrate layers during operation.

[0013] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although suitable methods and materials are described below, similar or equivalent methods and materials may be used to practice this invention. In case of conflict, the patent specification (including definitions) shall prevail. All materials, methods, and embodiments are illustrative only and not restrictive.

[0014] As used herein, the terms “comprising” and “including” or their grammatical variations should be considered as specifying that the stated feature, whole, action, or component is included, without excluding the addition of one or more additional features, wholes, actions, components, or groups thereof. The terms are broader than and include the terms “consisting of” and “substantially consisting of” as defined in the U.S. Patent and Trademark Office Patent Examination Procedure Manual. Therefore, any statement that an embodiment “comprising” or “including” a feature is a specific statement that a sub-embodiment is “substantially consisting of” and / or “consisting of” the stated features.

[0015] When used herein, the phrase “consistently of…” or its grammatical variations shall be regarded as specifying the stated feature, whole, step or component, but without excluding the addition of one or more additional features, wholes, steps, components or groups thereof, provided that the additional features, wholes, steps, components or groups do not materially alter the essential and novel features of the claimed composition, device or method.

[0016] The phrase “applies to” as used in this specification and the appended claims imposes additional structural limitations on the previously referenced components.

[0017] The term "method" refers to the manner, means, techniques, and procedures used to accomplish a given task, including but not limited to those known manner, means, techniques, and procedures, or those easily developed from known manner, means, techniques, and procedures by practitioners of architecture and / or computer science.

[0018] The implementation of the methods and systems according to one embodiment of the present invention involves manually, automatically, or in combination thereof, performing or completing selected tasks or steps. Furthermore, in practical instruments and devices according to exemplary embodiments of the methods, apparatus, and systems of the present invention, several selected steps can be implemented by hardware or by software on any operating system with any firmware, or a combination thereof. For example, as hardware, the selected steps of the present invention can be implemented as a chip or circuit. As software, the selected steps of the present invention can be implemented as a plurality of software instructions executed by a computer using any suitable operating system. In any case, the selected steps of the methods and systems of the present invention can be described as being executed by a data processor, such as a computing platform for executing multiple instructions.

[0019] Unless otherwise stated, the percentage (%) of chemicals is w / w (weight / weight). Attached Figure Description

[0020] To understand the invention and how to practice it, embodiments will now be described by way of non-limiting example only with reference to the accompanying drawings. In the drawings, identical or similar structures, components, or portions thereof appearing in more than one figure are generally labeled with the same or similar reference numerals in the figures in which they appear. The dimensions of the components and features shown in the figures are chosen primarily for ease of presentation and clarity, and are not necessarily drawn to scale. The drawings are listed below:

[0021] Figure 1 This is a cross-sectional schematic diagram of a liquid cold welding (LCW) apparatus according to some embodiments of the present invention;

[0022] Figure 2 This is a schematic diagram illustrating the shape of the working electrode (WE) and the non-conductive frame according to various embodiments of the present invention;

[0023] Figure 3This is a top perspective view of a liquid cold welding (LCW) apparatus according to some embodiments of the present invention.

[0024] Figure 4A This is a simplified schematic diagram of an apparatus according to some embodiments of the present invention, the apparatus being used for continuous production of 3D substrates from rolled or stacked porous membranes;

[0025] Figure 4B This is a simplified schematic diagram of an apparatus according to some embodiments of the present invention, the apparatus being used for the continuous production of folded 3D substrates from a rolled-up porous membrane;

[0026] Figure 4C Is it like this? Figure 4B The simplified schematic diagram shown is of an apparatus for continuous production of 3D substrates from a rolled-up porous membrane, illustrating the operation of an exemplary folding mechanism;

[0027] Figure 4D Is it like this? Figure 4B and 4C A simplified schematic diagram of an apparatus for the continuous production of folded 3D substrates from a rolled-up porous membrane is shown, illustrating the compression of the folded substrate stack.

[0028] Figure 4E Is it like this? Figure 4B , 4C A simplified schematic diagram of an apparatus for the continuous production of 3D substrates folded from rolled-up porous membranes, as shown in 4D, illustrates the fully compressed stacking of the folded substrates.

[0029] Figure 5A This is a simplified schematic diagram of an apparatus according to some embodiments of the present invention, the apparatus being used for continuous production of 3D substrates from rolled or stacked porous membranes;

[0030] Figure 5B This is a simplified schematic diagram of another apparatus according to some embodiments of the present invention, the apparatus being used for continuous production of 3D substrates from rolled or stacked porous membranes;

[0031] Figure 5C This is a simplified flowchart of a method according to some embodiments of the present invention;

[0032] Figure 6A This is a micrograph of a porous nickel film after liquid cold welding according to an embodiment of the present invention;

[0033] Figure 6B This is a micrograph of a porous nickel film after liquid cold welding according to another embodiment of the present invention;

[0034] Figure 7AThis is a micrograph of a porous nickel film after liquid cold welding according to an embodiment of the present invention;

[0035] Figure 7B This is a micrograph of a porous nickel film after liquid cold welding according to an embodiment of the present invention;

[0036] Figure 8A This is a top-view micrograph of a porous nickel foam being liquid-cold-welded between porous nickel films according to an embodiment of the present invention.

[0037] Figure 8B yes Figure 8A Micrographs (cross-sectional views) of the material.

[0038] Figure 9A This is a micrograph of a porous copper film after liquid cold soldering according to an embodiment of the present invention;

[0039] Figure 9B This is a micrograph of a porous copper film after liquid cold soldering according to an embodiment of the present invention;

[0040] Figure 10A This is a top-view micrograph of a porous aluminum film after liquid cold welding treatment according to an embodiment of the present invention.

[0041] Figure 10B This is a micrograph (cross-sectional view) of a porous aluminum film after liquid cold welding treatment according to an embodiment of the present invention.

[0042] Figure 11A This is a micrograph of a porous copper film after liquid cold soldering according to an embodiment of the present invention;

[0043] Figure 11B yes Figure 11A A close-up of the sample.

[0044] Figure 12A This is a micrograph of a porous copper film after liquid cold soldering using copper electrolyte, according to an embodiment of the present invention.

[0045] Figure 12B This is a micrograph of a porous copper film after liquid cold soldering using copper electrolyte, according to an embodiment of the present invention.

[0046] Figure 12C This is a micrograph of a porous copper film after liquid cold soldering using copper electrolyte, according to an embodiment of the present invention.

[0047] Figure 12D This is a micrograph of a porous copper film subjected to liquid cold welding using a copper electrolyte, according to an embodiment of the present invention.

[0048] Figure 12E These are micrographs of a porous copper film after liquid cold soldering using a copper electrolyte, according to an embodiment of the present invention.

[0049] Figure 12F This is a micrograph of a porous copper film after liquid cold soldering using copper electrolyte, according to an embodiment of the present invention. Detailed Implementation

[0050] Embodiments of the present invention relate to electrochemical bonding methods and apparatus.

[0051] Specifically, some embodiments of the present invention can be used to produce porous 3D metal structures. According to various exemplary embodiments of the present invention, these porous 3D metal structures are designed for a variety of electrochemical and non-electrochemical applications. Electrochemical applications include, but are not limited to, batteries, fuel cells, and electrolyzers. Non-electrochemical applications include, but are not limited to, small heat exchangers, catalyst supports, etc.

[0052] The principles and operation of the methods and / or apparatus according to exemplary embodiments of the present invention can be better understood by referring to the accompanying drawings and description.

[0053] Before explaining at least one embodiment of the invention in detail, it should be understood that the application of the invention is not limited to the details set forth in the following description or illustrated by examples. The invention can have other embodiments or can be practiced or performed in various ways. Furthermore, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered limiting.

[0054] Overview

[0055] Figure 1 This is a simplified schematic diagram of equipment used in the liquid cold welding (LCW) process. Figure 1 The device stacks multiple porous conductive layers 4 between non-conductive frames 3A and 3B. Frames 3A and 3B apply pressure to the layers 4 to ensure good multiple mechanical and electrical contact between the stacked layers 4 themselves and with the working electrode (WE) 5. In some embodiments, two or more working electrodes are employed. Items 3A, 3B, 4, and 5 include a working electrode assembly (WEA). The working electrode assembly (WEA) is placed in a liquid aqueous or non-aqueous electrolyte 2 between two counter electrodes (CE) 1A and 1B. In some embodiments, there is only one counter electrode. In other embodiments, there are more than two counter electrodes.

[0056] According to various exemplary embodiments of the present invention, the working electrode is fully or partially immersed in the electrolyte 2. In some embodiments, the contact between the working electrode 5 and the electrolyte 2 is minimized, but good contact between it and the substrates in the working electrode assembly is ensured. By applying a negative current, voltage, or power to the working electrode and a positive current, voltage, or power to the opposite electrode, metal ions in the electrolyte 2 begin to deposit on each substrate in electrical contact with the working electrode.

[0057] As metal or metal alloy layers grow on different substrates 4, the metal or metal alloy forms a bonding layer between the substrates 4.

[0058] According to various exemplary embodiments of the present invention, the thickness and morphology of the bonding layer are varied by changing the electrolyte composition (optionally including one or more different additives) and / or the type and / or concentration of metal ions and / or pH and / or the temperature and / or flow rate and / or the stirring of the electrolyte and / or the current density and / or voltage and / or power. According to various exemplary embodiments of the present invention, the electrolyte is aqueous or non-aqueous and contains dissolved metal ions, such as copper, nickel, zinc, etc.

[0059] In the illustrated embodiment, the reference electrode 6 controls the voltage between the working electrode 5 and the reference electrode 6 by adjusting the current between the relative electrodes 1A and 1B and the working electrode 5. Examples of aqueous reference electrodes include, but are not limited to, Ag / AgCl, Hg / Hg2Cl2, and Hg / HgO.

[0060] Example materials

[0061] According to various exemplary embodiments of the present invention, the working electrode 5 may be made of any conductive material, as long as it is stable in the electrolyte and the bonded 3D electrode can be easily separated therefrom. For example, stainless steel, titanium, niobium, carbon, and composite carbon-polymer conductive materials are suitable in the context of various embodiments of the present invention.

[0062] There are two types of relative electrodes (e.g.) Figure 1 1A and 1B in the above can be used for liquid cold welding.

[0063] The first type is a consumable metal counter electrode that dissolves during liquid cold welding. As a result of dissolution, the chemical composition of the bonding layer will also include the metal dissolved from the counter electrode. According to various exemplary embodiments of the invention, the consumable metal counter electrode is made of metal, including but not limited to Zn, Ni, Co, Fe, Pb, Cu, Sn, Cr, Mn, and alloys thereof.

[0064] The second type of counter electrode is made of or coated with a material that does not dissolve during liquid cold welding but catalyzes the oxidation reaction of the electrolyte. Examples of such materials include, but are not limited to, a layer of noble metals (TI, Nb, W, Mo, and V, or water or any other solvent) several micrometers thick coated with Au, Pt, Ir, Ru, or any other metal capable of electrocatalyzing the oxidation of the solvent in electrolyte 2. For the second type of counter electrode, the process associated with metal deposition is sensitive to changes in the pH of the electrolyte (in the case of aqueous electrolyte 2). In some embodiments, sufficient amounts of reduced metal ions are required to form a binding layer between the porous substrates. Alternatively or additionally, pH adjustment is required in some embodiments.

[0065] Exemplary working electrode (WE) and conductive framework

[0066] Figure 2 This is a schematic diagram illustrating the shape of the working electrode (5) and the non-conductive frame (3) according to various embodiments of the present invention. The aperture size in the non-conductive frame (3) can range from tens of micrometers to tens of centimeters, depending on the overall electrode size. Alternatively or additionally, according to various exemplary embodiments of the present invention, the apertures have different shapes, including but not limited to circular (3A), square (3B), and triangular (3C). According to various exemplary embodiments of the present invention, the number of apertures varies from one to tens, hundreds, or more.

[0067] Figure 2 This is illustrative only and does not cover all possible shapes and sizes, but it provides guidance for the fabrication of frame 3 and electrode 5. The number and size of the holes in each plate will determine the electroplating rate in these areas. For example, to reduce the weight of the deposited material, the number and / or size of the holes can be reduced.

[0068] According to various exemplary embodiments of the present invention, the holes in the frame 3 are configured to: produce uniform adhesion on the porous substrate; or only in specific areas, such that the substrate will only be attached at predefined locations.

[0069] Alternatively or additionally, in some embodiments, the shape of the frame 3 is customized according to the shape of the substrate. Alternatively or additionally, in some embodiments, the number of holes per unit area in the frame 3 is adjusted to change the bonding force. Alternatively or additionally, in some embodiments, the frame 3 is made of a machined dielectric material or of a metal coated with a dielectric material in some way.

[0070] Exemplary electrolyte flow considerations

[0071] In some embodiments, in order to improve the stacked porous layers ( Figure 1 In step 4), the electrolyte 2 permeates through the orifice by applied pressure (e.g., from a pump).

[0072] First exemplary device

[0073] Figure 3 This is a perspective view of an exemplary device seen from above, the device providing porous layers through stacks ( Figure 1 Forced flow of the electrolyte in 4) of the above. In the depicted embodiment, the electrolyte is pumped through inlet 7 into a closed compartment 10 containing... Figure 1 Sections 3, 4, and 5. The working electrode (5; invisible) within compartment 10 is in electrical contact with the external negative terminal 11, while the opposing electrode (1; invisible) is connected to the external positive terminal 9. Compartment 10 is located within electrolytic cell 8. Electrolyte exiting compartment 10 fills electrolytic cell 8 and is pumped out through electrolyte outlet 12. This apparatus enables liquid cold soldering of manually loaded porous samples to fabricate porous 3D substrates.

[0074] Second exemplary device

[0075] Figure 4A An apparatus for the continuous production of 3D substrates from rolled or stacked porous membranes is schematically presented. In the depicted embodiment, a single-layer porous membrane 17A is folded to form a layer and then supplied between two CEs 15A and 15B. A counter electrode 15A is mounted within a compartment 13, which in some embodiments can be vertically and / or horizontally moved to accommodate the folded porous membrane 17A. The counter electrodes 15A and 15B are porous, allowing electrolyte flow. During liquid cold soldering, the compartment 13 applies pressure to the folded layer 17A, which acts as the working electrode, to ensure mechanical and electrical contact between the folded layers. The compartment 13 has an inlet 14A and a flow distributor 14B to ensure uniform flow of pressurized electrolyte through the counter electrode 15A and a non-conductive plate 16A, through the folded substrate 17A and non-conductive plate 16B, and the counter electrode 15B, mounted in a bottom compartment 18. The flow rate and / or pressure of the electrolyte are controlled by a pump (not depicted). The electrolyte is then collected from outlet 19 and circulated back through inlet 14A. Some embodiments are equipped with an electrolyte reservoir (not depicted) in which the collected electrolyte is first pumped back before being pumped back through inlet 14A. After liquid cold soldering is completed, the adhesive layer (20) is removed and a new folded layer 17A is fed into compartments 13 and 18, thereby providing a continuous process for forming a 3D porous substrate. In the depicted embodiment, 17A is supplied from roll 17B. According to various exemplary embodiments of the invention, the folding process is performed manually, semi-automatically, or using a fully automated dedicated robotic device mounted to perform folding of substrates of a certain length.

[0076] Figure 4BThis is a simplified schematic diagram of an apparatus for the continuous production of 3D substrates folded from a rolled-up porous membrane, according to some embodiments of the present invention. The apparatus depicted is... Figure 4A The device includes a retractable clamp 20B that closes to hold substrate 17A in place. The folding mechanism comprises two rows of retractable rods 20C and 20D. The folding mechanism first moves the lowest rod from 20C to the right so that it engages and pushes substrate 17A to the right. Simultaneously, the lowest rod moves from 20D to the left, engaging substrate 17B and pushing it to the left. The process is repeated using the next lowest rod from 20C and the next lowest rod from 20D.

[0077] Figure 4C The appearance of substrate 17A is shown after all the rods in 20C have been moved to the right and all the rods in 20D have been moved to the left.

[0078] Figure 4D The illustration shows how to compress the folded substrate 17A by reducing the distance between 15A and 15B.

[0079] Figure 4E The fully compressed folded substrate 17A is shown, with rods 20C and 20D retracted. This configuration is similar to... Figure 4A The configuration described in the text.

[0080] Third Exemplary Device

[0081] Figure 5A An apparatus for the continuous production of 3D substrates from multiple layers from different sources (e.g., roller 21, or stacks) is schematically presented. In the depicted embodiment, layers from roller 21 are fed into apparatus for liquid cold soldering, as indicated. After liquid cold soldering is completed, the bonded 3D porous substrates exit compartments (14 and 18) and allow bonding of the next multilayer substrate, thus providing a continuous manufacturing process. In the depicted embodiment, take-up roller 22 winds the manufactured 3D substrate after liquid cold soldering. Figure 5A Other reference figures are as described above. Figure 4A As described in the context.

[0082] In the depicted embodiment, the device includes two or more supply rollers 21 adapted to simultaneously supply two or more porous conductive substrate layers between perforated non-conductive frames 16A; and a winding roller 22 adapted to wind the two or more porous conductive substrate layers into an adhesive substrate after liquid cold welding.

[0083] In the depicted embodiment, the device includes a distance adjustment mechanism (not depicted) adapted to adjust the distance between the perforated non-conductive frames 16A.

[0084] In some embodiments, increasing the distance between the frames 16A facilitates the insertion and / or removal of two or more porous conductive substrate layers. Alternatively or additionally, in some embodiments, reducing the distance between the perforated non-conductive frames 16A causes the substrate layers to contact each other during soldering.

[0085] Fourth exemplary device

[0086] Figure 5B An apparatus for the continuous production of 3D substrates from multiple layers from different sources (e.g., roller 21, or stacks) is schematically illustrated. In the described embodiment, feed roller 21 supplies multiple porous 2D samples to a deposition roller comprising at least three sections, as shown.

[0087] In the depicted embodiment, the deposition roller includes a counter electrode 24 within a porous, non-conductive cylinder 23 surrounded by a cover 25. The size of the holes in the cylinder 23 varies between 50 μm and 10 cm depending on the size of the cylinder 23.

[0088] During use, the electrolyte solution is pumped into cylinder 23 and discharged through a hole. Current / voltage / power is applied between electrode 24 and the 2D substrate to induce metal deposition in the area between 24 and the substrate. Cover 25 prevents electrolyte spillage. As rollers 21 and / or 22 rotate, the next portion of the 2D substrate electrochemically bonds with the 3D thin film finally wound onto receiving roller 22. Liquid cold bonding of the substrate layers is regulated by the electrolyte composition and / or current / voltage / power and / or temperature, and / or the aperture and / or the number of pores in cylinder 23 and / or the pumping rate of the electrolyte and / or the rotational speed of cylinder 23. In some embodiments, the device operates continuously rather than discretely incrementally. In some exemplary embodiments, more than two rollers with features 23, 24, and 25 are installed.

[0089] Example Method

[0090] Figure 5C This is a simplified flowchart of a method for electrochemical bonding, typically denoted as ㄩ, and usually represented as 500.

[0091] In the described embodiments, method 500 includes step 510 of bonding two or more porous conductive substrate layers between perforated non-conductive frames such that the substrate layers are in contact with each other. In some embodiments, such as Figure 4A A single layer is folded in the middle. Alternatively or additionally, in some embodiments, layers from different sources are introduced, such as... Figure 1 and 2 5A and 5B.

[0092] According to various exemplary embodiments of the present invention, the substrate layers have the same or different materials. Alternatively or additionally, the substrate layers have the same or different thicknesses.

[0093] The described method 500 further includes step 520 of immersing the substrate layer in an electrolyte solution and step 530 of applying current and / or voltage and / or electricity to the electrolyte solution. According to various exemplary embodiments of the present invention, method 500 uses, for example... Figure 1 , Figure 4A , 5A Or it may be performed by the device described in 5B.

[0094] In some embodiments, applying 530 includes applying a current flowing from one opposing electrode (e.g., 15A) to the porous metal substrate layer 17A, which serves as a working electrode between the perforated non-conductive frames.

[0095] According to various exemplary embodiments of the present invention, the current is constant or pulsed. According to various exemplary embodiments of the present invention, different pulse sequences are employed, including but not limited to pulse inversion.

[0096] In some embodiments, applying 530 includes applying a voltage using a reference electrode (e.g., 6). In some embodiments, the applied voltage is constant.

[0097] In some embodiments, applying 530 includes applying power. In some embodiments, the applied power is constant.

[0098] In some embodiments, method 500 includes simultaneously supplying two or more porous conductive substrate layers between perforated non-conductive frames; such as Figure 5A As shown in 5B, after the liquid cold soldering, the two or more porous conductive substrate layers are withdrawn as adhesive substrates. Alternatively or additionally, in some embodiments, method 500 includes increasing the distance between the perforated non-conductive frames 16A to facilitate the insertion and / or removal of the two or more porous conductive substrate layers. Alternatively or additionally, in some embodiments, method 500 includes decreasing the distance between the perforated non-conductive frames 16A such that the substrate layers contact each other. Alternatively or additionally, in some embodiments, method 500 includes pumping an electrolyte solution through the perforated non-conductive frames and the two or more porous conductive substrate layers during application 530.

[0099] Alternatively or additionally, in some embodiments, method 500 further includes step 540 of folding a single porous conductive substrate layer to form two or more porous conductive substrate layers. In some embodiments, a perforated isolator is inserted between the folded layers. In some embodiments, the perforated isolator facilitates the ability to separate the layers from the folded stack after liquid cold soldering.

[0100] It is anticipated that many new electrode types and / or electrolyte solutions will be developed during the term of this patent, and the scope of this invention is intended to include all of these prior technologies.

[0101] As used in this article, the term “about” means ±10%.

[0102] Although the invention has been described in conjunction with specific embodiments thereof, it will be apparent to those skilled in the art that many alternatives, modifications, and variations will be readily apparent. Therefore, it is intended to cover all such alternatives, modifications, and variations falling within the spirit and broad scope of the appended claims.

[0103] Specifically, various numerical indicators have been used. It should be understood that these numerical indicators can be further varied based on various engineering principles, materials, intended uses, and designs incorporated into the various embodiments of the invention. Furthermore, components and / or actions that pertain to exemplary embodiments of the invention and are described as single units can be divided into sub-units. Conversely, components and / or actions that pertain to exemplary embodiments of the invention and are depicted as sub-units / individual actions can be combined into a single unit / action having the described / depicted function.

[0104] Alternatively or additionally, the features used to describe the method can be used to characterize the device, and the features used to describe the device can be used to characterize the method.

[0105] It should also be understood that the various features described above can be combined in all possible combinations and sub-combinations to produce additional embodiments of the invention. The embodiments given above are exemplary in nature and are not intended to limit the scope of the invention as defined solely by the appended claims.

[0106] Each description of an embodiment of the invention, including a specific feature, part, component, module, or process, is an explicit statement of the existence of additional embodiments of the invention that do not include the described features, parts, components, modules, or processes.

[0107] Alternatively or additionally, various exemplary embodiments of the present invention exclude any particular feature, part, component, module, process, or component not specifically disclosed herein.

[0108] Specifically, the present invention has been described in the context of manufacturing 3D porous substrates, but it can also be used to prepare jewelry or other decorative items.

[0109] All publications, references, patents, and patent applications mentioned in this specification are incorporated herein by reference in their entirety as if each individual publication, patent, or patent application were specifically and individually indicated to be incorporated herein by reference. Furthermore, any reference or identification in this application should not be construed as an admission that such reference is used as prior art in this invention.

[0110] The terms “including” and “having” and their variations, as used in this document, mean “including but not limited to”.

[0111] Those skilled in the art will understand the additional objects, advantages, and novel features of the various embodiments of the present invention upon review of the following examples, which are not intended to be limiting. Furthermore, each of the various embodiments and aspects of the invention as described above and claimed in the following claims section finds experimental support in the following examples.

[0112] Example

[0113] The invention is now illustrated in a non-limiting manner by referring to the following embodiments, which, together with the description above, illustrate the invention.

[0114] Example 1:

[0115] The Influence of Current on Porosity in Liquid Cold Welding Manufacturing

[0116] To examine the effect of the applied current on the porosity of the porous 3D metal structures produced according to various embodiments of the present invention, in such cases... Figure 1 In the apparatus shown in Figure 5, three porous nickel films, each 50 micrometers thick, were liquid cold-welded. The electrolyte was a standard Watt electrolyte commonly used for nickel plating.

[0117] In one case, 300 mA / cm is applied. 2 A constant current density was applied for 2 hours. The final porosity was 70%. Figure 6A ).

[0118] In another case, 600 mA / cm is applied. 2 A constant current density was applied for 2 hours. The final porosity was 46%. Figure 6B The adhesive layers have different morphologies, and the layers appear to have a higher surface area.

[0119] The porosity percentage is estimated based on the weight and volume of the sample before and after deposition.

[0120] The embodiments illustrate that increasing the applied current helps reduce the porosity of the resulting product. Alternatively or additionally, the embodiments illustrate that 3D substrates with a thickness of at least 150 μm and unique morphology can be produced by liquid cold soldering, and that porosity and morphology can be controlled by current.

[0121] Example 2:

[0122] Exemplary use of reference electrodes in liquid cold welding manufacturing

[0123] To evaluate the possibility of using a reference electrode to control the porosity of porous 3D metal structures produced according to various embodiments of the present invention, in such cases... Figure 1 Five porous nickel films, each 50 micrometers thick, were liquid-cold-welded in the apparatus shown in Figure 5. The electrolyte was a standard Watt's solution commonly used for nickel plating.

[0124] In one case, 400 mA / cm is applied. 2 Under constant current density for 2 hours, the final porosity was 85%. Figure 7A ).

[0125] In another case, a constant voltage of -4V was applied to the Ag / AgCl reference electrode for 2 hours. Figure 7B ).

[0126] This embodiment illustrates that 3D structures formed by liquid cold soldering can also be created using a potential control mechanism with a reference electrode. Alternatively or additionally, the embodiment illustrates that 3D substrates with a thickness of at least 250 μm and unique morphologies can be produced, and their porosity and morphology can be controlled using a reference electrode.

[0127] Example 3:

[0128] Examples of using layers with different properties in liquid cold welding manufacturing

[0129] To evaluate the effect of using layers with different properties on the resulting porous 3D metal structure according to an embodiment of the invention, a 500-micrometer-thick layer of foamed nickel was sandwiched between two 50-micrometer-thick porous nickel films and subjected to liquid cold welding in a device, such as... Figure 1 As shown in Figure 5. Using 400mA / cm 2 A constant current density was applied for 2 hours. The electrolyte was a standard Watt electrolyte commonly used in nickel plating.

[0130] Figure 8A It's a top view. Figure 8B This is a cross-sectional view of the resulting 3D substrate with a final porosity of 90%.

[0131] This embodiment illustrates that a thick (at least 600 μm) 3D substrate can be formed using a liquid cold soldering method. Alternatively or further, the embodiment illustrates that 2D and 3D porous metal films can be combined to produce a porous 3D substrate with a unique morphology.

[0132] Example 4:

[0133] Impact of current application duration on the resulting product

[0134] To evaluate the effect of varying the duration of current application on the resulting porous 3D metal structure according to an embodiment of the present invention, two porous copper films, each 50 μm thick, were used... Figure 1 Liquid cold welding is performed in the equipment shown in Figure 5. A current of 250 mA / cm² is used. 2 A constant current density for 20 minutes ( Figure 9A ) and 30 minutes ( Figure 9B The electrolytes are 1 M CuSO4 and 1 M H2SO4.

[0135] This example illustrates that increasing manufacturing time results in a thicker sample with fewer pores.

[0136] Alternatively or additionally, the embodiments illustrate that 3D substrates with a thickness of at least 100 μm and unique morphology can be produced, and their porosity and morphology can be controlled by deposition over a period of time.

[0137] Example 5:

[0138] Manufacturing of multi-metal nickel-aluminum substrates

[0139] To evaluate the possibility of producing porous 3D metal structures using porous aluminum films according to an embodiment of the present invention, Figure 1 In the apparatus shown in Figure 5, three porous aluminum films, each 50 micrometers thick, are liquid cold-welded. The electrolyte is a standard Watt's electrolyte commonly used for nickel plating.

[0140] Apply 200mA / cm 2 constant current density for 2 hours

[0141] Figure 10A It's a top view. Figure 10B This is a cross-sectional view of the novel 3D porous Ni-Al multimetallic structure, exhibiting unique morphology and physical properties. It can be fabricated via liquid cold soldering, demonstrating that the morphology and properties can be controlled through application. This embodiment illustrates the use of a nickel electrolyte solution for liquid cold soldering to fabricate a 3D aluminum substrate.

[0142] Alternatively or additionally, the embodiments illustrate that 3D porous Ni-Cu multimetallic structures with unique morphology and physical properties can be manufactured by liquid cold welding, and their morphology and properties can be controlled by electric current.

[0143] Example 6:

[0144] Manufacturing of multi-metal nickel-copper substrates

[0145] To evaluate the possibility of using porous copper films to produce porous 3D metal structures according to an embodiment of the present invention, in such cases... Figure 1 Five porous copper films, each 50 micrometers thick, were liquid-cold soldered in the apparatus shown in Figure 5. The electrolyte was a standard Watt's electrolyte commonly used for nickel plating. An application rate of 300 mA / cm² was used. 2 A constant current density for 2 hours.

[0146] Figure 11A A top view showing the active area with a diameter of 20×20mm. Figure 11B yes Figure 11A An enlarged view of the active region. This result confirms the possibility of combining two different metals with liquid cold welding, as shown in Example 5.

[0147] This embodiment illustrates that a 3D copper substrate can be fabricated in a nickel electrolyte and nickel can be used as a bonding material. This is another embodiment demonstrating that different metals can be bonded to different materials.

[0148] Example 7:

[0149] 3D substrate fabrication using localized / selective liquid cold welding

[0150] To investigate the effects of pore size, plate porosity, and current conditions on the quality and quantity of liquid cold soldering, a series of experiments were conducted using a porous copper substrate and a copper electrolyte solution, as in Example 4.

[0151] Figure 12A These are micrographs depicting localized liquid cold welding of copper and copper electrolyte. In this experiment, a non-conductive frame was used. Figure 2 The device has an inlet and outlet with 2 mm circular holes and an open area of ​​18%. The deposition current is 200 mA / cm². 2 The process lasted 30 minutes. Three porous substrates were bonded. The total weight after bonding increased by 12%. In this photograph and subsequent panels, the brighter areas represent deposited material, while the darker areas represent undeposited material.

[0152] Figure 12B These are micrographs depicting localized liquid cold welding of copper and copper electrolyte. In this experiment, a non-conductive frame was used. Figure 2The device has an inlet and outlet with a 1 mm circular aperture and a 4.5% open area. The deposition current is 100 mA / cm². 2 The bonding process lasted for 30 minutes. Three porous substrates were bonded. The total weight after bonding increased by 11%.

[0153] Figure 12C These are micrographs depicting localized liquid cold welding of copper and copper electrolyte. In this experiment, a non-conductive frame was used. Figure 2 The device has an inlet and outlet with 3 mm circular holes and a 40% open area. The deposition current is 100 mA / cm². 2 The bonding process lasted for 30 minutes. Three porous substrates were bonded. The total weight after bonding increased by 13%.

[0154] Figure 12D These are micrographs depicting localized liquid cold welding of copper and copper electrolyte. In this experiment, a non-conductive frame was used. Figure 2 The equipment has an inlet and outlet; the inlet orifice is 2 mm wide with an open area of ​​18%, and the outlet orifice is 1 mm wide with an open area of ​​4.5%. The deposition current is 200 mA / cm². 2 The bonding process lasted for 30 minutes. Three porous substrates were bonded. The total weight after bonding increased by 11.6%.

[0155] Figure 12E These are micrographs depicting localized liquid cold welding of copper and copper electrolyte. In this experiment, a non-conductive frame was used as... Figure 2 The device shown has an inlet and outlet. The inlet orifice is 1 mm in diameter with an opening area of ​​4.5%, and the outlet orifice is 1 mm in diameter with an opening area of ​​18%. The deposition current is 200 mA / cm². 2 The bonding process lasted for 30 minutes. Three porous substrates were bonded together. The total weight increased by 14% after bonding.

[0156] Figure 12F These are micrographs depicting localized liquid cold welding of copper and copper electrolyte. In this experiment, a non-conductive frame was used. Figure 2 The equipment has 3mm inlet and outlet holes (inlet and outlet), a plate porosity of 40%, and an outlet hole size of 1mm and 18% open area. The deposition current is 350mA / cm². 2 The signal was transmitted in 500-millisecond pulses, paused for 500 milliseconds (50% duty cycle), for 60 minutes. Three porous substrates were bonded together. The total weight increased by 24% after bonding.

[0157] This embodiment illustrates that liquid cold welding can be performed using a pulse deposition method and a constant current. Pulse parameters, such as amplitude, duration, rest step size, and even reversal of the pulse current / voltage / power direction, can be adjusted to produce various morphologies of metal deposits or to regulate the amount of deposited metal. Variations in pulse parameters are tailored for a wide range of applications, and the pulse parameters given above are not intended to limit the scope of the claimed invention.

Claims

1. A liquid cold welding method, comprising: (a) Joining two or more porous conductive substrate layers between multiple perforated non-conductive frames such that the two or more porous conductive substrate layers are in contact with each other. (b) Immersing the two or more porous conductive substrate layers in an electrolyte solution containing dissolved metal ions; as well as (c) Applying a negative current and / or voltage and / or power to the electrolyte solution to deposit the metal or metal complex from the metal ions in the electrolyte solution onto the two or more porous conductive substrate layers, thereby bonding the two or more porous conductive substrate layers and forming a bonding layer between the two or more porous substrate layers.

2. The liquid cold welding method according to claim 1, wherein the application includes applying a negative current, the negative current flowing from a plurality of opposing electrodes through the two or more porous conductive substrate layers between the plurality of perforated non-conductive frames to a plurality of working electrodes.

3. The liquid cold welding method according to claim 1, wherein the application includes applying a constant voltage using a reference electrode.

4. The liquid cold welding method according to claim 1, wherein the application includes applying a constant power.

5. The liquid cold welding method according to claim 1, further comprising: Fold a single porous conductive substrate layer to form two or more porous conductive substrate layers.

6. The liquid cold welding method according to claim 1, further comprising: Two or more porous conductive substrate layers are supplied simultaneously between the multiple perforated non-conductive frames. as well as After the bonding, the two or more porous conductive substrate layers are withdrawn as adhesive substrates.

7. The liquid cold welding method according to claim 5 or claim 6, further comprising: Increase the distance between the multiple perforated non-conductive frames to facilitate the insertion and / or removal of the two or more porous conductive substrate layers.

8. The liquid cold welding method according to any one of claims 5 to 6, further comprising: Reduce the distance between the multiple perforated non-conductive frames so that the two or more porous conductive substrate layers come into contact with each other.

9. The liquid cold welding method according to any one of claims 1 to 6, further comprising: During application, the electrolyte solution is pumped through the plurality of perforated non-conductive frames and the two or more porous conductive substrate layers.

10. A liquid cold welding apparatus for use in the liquid cold welding method according to any one of claims 1 to 9, the liquid cold welding apparatus comprising: (a) A container containing two opposing electrodes; as well as (b) A non-conductive frame with at least two perforations, suitable for: (i) joining and holding a multilayer substrate such that the layers remain in contact with each other; and (ii) allowing a forced electrolyte solution to flow through the non-conductive frame with at least two perforations and its perforations; The at least two perforated non-conductive frames are located between the opposing electrodes.

11. A liquid cold welding apparatus for use in the liquid cold welding method according to any one of claims 1 to 9, the liquid cold welding apparatus comprising: (a) A container in which an active electrode and a reference electrode are placed opposite each other; as well as (b) A non-conductive frame with at least two perforations, suitable for: (i) bonding and holding a multilayer substrate such that the layers remain in contact with each other; and (ii) allowing a forced electrolyte solution to flow through the non-conductive frame with at least two perforations and its perforations; The at least two perforated non-conductive frames are located between the active electrode and the reference electrode.

12. The liquid cold welding apparatus according to any one of claims 10 or 11, further comprising: Two or more supply rollers are adapted to simultaneously supply two or more porous conductive substrate layers between the plurality of perforated non-conductive frames; as well as A take-up roller is adapted to wind up the two or more porous conductive substrate layers as an adhesive substrate after bonding the two or more porous conductive substrate layers.

13. The liquid cold welding equipment according to any one of claims 10 or 11, further comprising: A distance adjustment mechanism is provided to adjust the distance between the plurality of perforated non-conductive frames.

14. The liquid cold welding apparatus according to any one of claims 10 or 11, comprising a folding mechanism for folding a single porous conductive substrate layer to produce a stack of a plurality of porous conductive substrate layers.

15. The liquid cold welding apparatus according to any one of claims 10 or 11, comprising: A pump is positioned to pump the electrolyte solution through the plurality of perforated non-conductive frames and the two or more porous conductive substrate layers during operation.

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