Process for diffusion bonding with an interlayer

Abstract

The application provides a diffusion welding process method of an intermediate layer, comprising the following steps: preparing a slurry by mixing metal particles and an organic solvent; cleaning the surfaces of two metal plates to be diffused; coating or spraying the slurry on the diffusion interface; after coating or spraying, air-drying or oven-drying; bonding the diffusion interfaces of the two metal plates to be diffused, sealing the four edges, and welding an air pipe at a preset position to form a blank; loading the blank into an oven, heating to the evaporation temperature of the organic solvent, and performing vacuum evaporation; after the vacuum evaporation is completed, loading the blank into a diffusion welding device, heating to the diffusion welding temperature, and pressurizing, and then performing vacuum diffusion welding; after the vacuum diffusion welding is completed, cooling, and taking out the part. The process is simple and flexible, is not limited by size and shape, can realize accurate preparation of a large-area and special-shaped intermediate layer, and has the advantages of high efficiency, low cost, high reliability, and environmental protection.

Description

Technical Field

[0001] This invention relates to the field of metal joining technology, and more specifically, to a diffusion bonding process with an intermediate layer. Background Technology

[0002] For lightweight alloys such as aluminum alloys, magnesium alloys, and aluminum-lithium alloys, their reactive chemical properties make them prone to oxide film formation when exposed to air, which can negatively impact diffusion welding quality. To address this issue, an intermediate layer is typically added to the diffusion interface to promote diffusion bonding. This intermediate layer is usually a single metal such as Cu, Ni, Al, or Ag, or a composite intermediate layer such as Al / Cu. In practical applications, metal foil is generally used to cover the diffusion interface, or a metal intermediate layer is deposited at the diffusion interface using electroless plating. However, both methods have inherent drawbacks. Using metal foil is limited by foil size and placement methods, hindering large-area, efficient fabrication. Electroless plating typically uses single-element metals, making it difficult to achieve composite intermediate layer plating, resulting in inconsistent quality across large areas and environmental restrictions. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] The technical problem that this invention aims to solve is that existing intermediate layer metals cannot be prepared efficiently over a large area, or the quality of large-area coatings is difficult to guarantee, and there are environmental restrictions.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] This invention provides a diffusion bonding process with an intermediate layer, comprising the following steps:

[0008] Metal particles are mixed with organic solvents to prepare a slurry;

[0009] Clean the surfaces of the two metal plates to be diffused;

[0010] The slurry is coated or sprayed onto the interface to be diffused, and then air-dried or oven-dried after coating or spraying.

[0011] The interfaces of the two metal plates to be diffused are bonded together, the four sides are sealed and welded, and the gas pipe is welded at the preset position to form a blank.

[0012] The blank is placed in a baking oven and heated to the evaporation temperature of the organic solvent for vacuum evaporation.

[0013] After vacuum evaporation is completed, the blank is loaded into the diffusion welding equipment, heated to the diffusion welding temperature and pressurized to perform vacuum diffusion welding.

[0014] After vacuum diffusion welding is completed, the parts are cooled down and removed.

[0015] Preferably, the method further includes the following steps:

[0016] The diffusion welding quality of the parts was inspected.

[0017] Preferably, the metal particles are elemental metal particles or alloy metal particles.

[0018] Preferably, the size of the metal particles is between the nanometer and micrometer scales.

[0019] Preferably, when the interface to be diffused has a diffusion connection interface of a specific shape, the step of coating or spraying the slurry onto the interface to be diffused specifically includes the following steps:

[0020] A template is made based on the shape of the diffusion connection interface, so that the shape of the hollow area of ​​the template is consistent with the shape of the diffusion connection interface.

[0021] The template is placed over the diffusion interface of the metal plate;

[0022] The slurry is coated or sprayed onto the diffusion bonding interface;

[0023] Remove the template.

[0024] Preferably, when the interface to be diffused has a diffusion connection interface of a specific shape, the step of coating or spraying the slurry onto the interface to be diffused specifically includes the following steps:

[0025] A coating pattern is applied to the diffusion interface of the metal plate so that the shape of the patterned area matches the shape of the diffusion connection interface.

[0026] The slurry is coated or sprayed onto the diffusion bonding interface;

[0027] Remove the coating.

[0028] Preferably, the metal plate is made of aluminum alloy, magnesium alloy, or aluminum-lithium alloy.

[0029] Preferably, after the blank is made, the air pipe of the blank is connected to a vacuum pump, a vacuum is drawn to conduct an airtightness test, and after the test is qualified, it is put into the baking oven.

[0030] (III) Beneficial Effects

[0031] The above-described technical solution of the present invention has at least the following advantages:

[0032] 1. This invention prepares the intermediate metal layer into nano- to micro-sized metal particles, prepares a slurry with the metal particles using an organic solvent, and covers the diffusion connection interface by coating or spraying. Before diffusion connection, the organic solvent is evaporated by heating and vacuuming, leaving the metal particle layer to participate in the diffusion connection process. The process is simple and flexible, not limited by size and shape, and can achieve precise preparation of large-area and special-shaped intermediate layers.

[0033] 2. It can realize the preparation of intermediate layers of single metals or multiple metals and alloys;

[0034] 3. By preparing a slurry and coating or spraying it onto the diffusion bonding interface, compared with the method of laying metal foil and electroplating metal layers, it is more efficient, less costly, more reliable, and more environmentally friendly.

[0035] 4. Metal particles can be used as fillers to fill the gap between two metal plates, allowing them to fully contact at the diffusion interface, thereby facilitating atomic diffusion between the two plates. Furthermore, compared to diffusion bonding processes using metal foil or plating as an intermediate layer, the intermediate layer formed by metal particles in this invention effectively increases the contact area between the metal particles and the metal plates, resulting in more complete atomic diffusion and thus improving the connection strength of the structure. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the assembly state of the template and the first metal plate provided in an embodiment of the present invention.

[0038] Figure 2 This is a schematic diagram of the location of the diffusion connection interface provided in an embodiment of the present invention.

[0039] Figure 3 This is an exploded view of the structure of the blank provided in an embodiment of the present invention.

[0040] Figure 4 This is a structural diagram of the blank provided in an embodiment of the present invention.

[0041] Figure 5 This is a state diagram of diffusion welding of the blank provided in the embodiment of the present invention.

[0042] The labels for the attached figures are as follows:

[0043] 1. First metal plate; 2. Template; 3. Second metal plate; 4. Preset position; 5. Air tube; 10. Diffusion connection interface. Detailed Implementation

[0044] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0045] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be located directly on or indirectly on the other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to the other component.

[0046] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate that the device or element must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0047] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or the number of technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. The specific implementation of this invention will be described in more detail below with reference to specific embodiments:

[0048] like Figures 1 to 5 As shown, this embodiment of the invention provides a diffusion bonding process with an intermediate layer, comprising the following steps:

[0049] A slurry is prepared by combining metal particles with an organic solvent. The organic solvent should be able to evaporate completely at a certain temperature without reacting with the metal particles. Simultaneously, the slurry should ensure uniform distribution of the metal particles and exhibit a certain bonding strength with the metal to be diffused and welded at room temperature after coating, making it suitable for coating or spraying processes. Specifically, the organic solvent includes, but is not limited to, ethyl acetate and acetone. The specific metal particles are determined based on the material of the metal plate and the process requirements, and include, but are not limited to, elemental metals such as Cu, Ni, Al, and Ag, as well as copper-aluminum alloys.

[0050] Clean the surfaces of the two metal plates to be diffused (including the first metal plate 1 and the second metal plate 3); specifically, the cleaning method can be physical or chemical.

[0051] Apply or spray the slurry onto the interface to be diffused, and then let it air dry or bake it.

[0052] The interfaces of the two metal plates to be diffused are bonded together, the four sides are sealed and welded, and the gas pipe 5 is welded at the preset position 4 to form a blank.

[0053] The blank is placed in a baking oven and heated to the evaporation temperature of the organic solvent, then vacuumed for evaporation. The organic solvent is heated and evaporated into a gaseous state, and then vacuumed away.

[0054] After vacuum evaporation is completed, the blank is loaded into the diffusion welding equipment, heated to the diffusion welding temperature and pressurized (pressure value is P) to perform vacuum diffusion welding.

[0055] After vacuum diffusion welding is completed, the parts are cooled down and removed.

[0056] In one embodiment, the following steps are also included:

[0057] Perform diffusion welding quality inspection on the parts.

[0058] In one embodiment, the metal particles are elemental metal particles or alloy metal particles. Specifically, the metal particles can be a homogeneous metal material of the same type as the metal plate material, or a dissimilar metal material different from the metal plate material. When the metal particles are a dissimilar metal material different from the metal plate material, they achieve effective bonding by forming intermetallic compounds through a chemical reaction with the metal plate.

[0059] In one embodiment, the size of the metal particles is between the nanometer and micrometer scales.

[0060] In one embodiment, when the interface to be diffused has a diffusion connection interface 10 of a specific shape, the slurry is coated or sprayed onto the interface to be diffused, specifically including the following steps:

[0061] Template 2 is made according to the shape of diffusion connection interface 10, so that the shape of the hollow area of ​​template 2 is consistent with the shape of diffusion connection interface 10; template 2 is mainly used to block the corresponding part on the metal plate to form a non-diffusion area.

[0062] Cover the diffusion interface of the first metal plate 1 (or the second metal plate 3) with the template 2;

[0063] The slurry is coated or sprayed onto the diffusion bonding interface;

[0064] Remove template 2.

[0065] In one embodiment, when the interface to be diffused 10 has a diffusion connection interface of a specific shape, the slurry is coated or sprayed onto the interface to be diffused, specifically including the following steps:

[0066] A coating pattern is applied to the diffusion interface of a metal plate (on a first or second metal plate) so that the shape of the etched area matches the shape of the diffusion connection interface. The thin film layer formed by the coating is mainly used to block the corresponding part of the metal plate from forming a non-diffusion area.

[0067] The slurry is coated or sprayed onto the diffusion bonding interface;

[0068] Remove the coating.

[0069] In one embodiment, the metal plates (including the first metal plate and the second metal plate) are made of aluminum alloy, magnesium alloy, or aluminum-lithium alloy.

[0070] In one embodiment, after the blank is made, the air pipe 5 of the blank is connected to a vacuum pump, and a vacuum is drawn to test the air tightness. After the test is qualified, it is put into the baking oven.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A diffusion bonding process with an intermediate layer, characterized in that, Includes the following steps: Metal particles are mixed with an organic solvent to form a slurry. The organic solvent should be able to evaporate completely at a certain temperature and not react with the metal particles. The slurry should allow the metal particles to be evenly distributed and have a certain bonding force with the metal to be diffused and welded at room temperature after coating or spraying, making it suitable for coating or spraying processes. Clean the surfaces of the two metal plates to be diffused; The slurry is coated or sprayed onto the interface to be diffused, and then air-dried or oven-dried after coating or spraying. The interfaces of the two metal plates to be diffused are bonded together, the four sides are sealed and welded, and the gas pipe is welded at the preset position to form a blank. The blank is placed in a baking oven and heated to the evaporation temperature of the organic solvent for vacuum evaporation. After vacuum evaporation is completed, the blank is loaded into the diffusion welding equipment, heated to the diffusion welding temperature and pressurized to perform vacuum diffusion welding. After vacuum diffusion welding is completed, the parts are cooled down and removed.

2. The diffusion bonding process with an intermediate layer as described in claim 1, characterized in that, It also includes the following steps: The diffusion welding quality of the parts was inspected.

3. The diffusion bonding process with an intermediate layer as described in claim 1, characterized in that, The metal particles are elemental metal particles or alloy metal particles.

4. The diffusion bonding process with an intermediate layer as described in claim 1, characterized in that, The size of the metal particles is between nanometer and micrometer scale.

5. The diffusion bonding process with an intermediate layer as described in claim 1, characterized in that, When the interface to be diffused has a diffusion connection interface of a specific shape, the process of coating or spraying the slurry onto the interface to be diffused specifically includes the following steps: A template is made based on the shape of the diffusion connection interface, so that the shape of the hollow area of ​​the template is consistent with the shape of the diffusion connection interface. The template is placed over the diffusion interface of the metal plate; The slurry is coated or sprayed onto the diffusion bonding interface; Remove the template.

6. The diffusion bonding process with an intermediate layer as described in claim 1, characterized in that, When the interface to be diffused has a diffusion connection interface of a specific shape, the process of coating or spraying the slurry onto the interface to be diffused specifically includes the following steps: A coating pattern is applied to the diffusion interface of the metal plate so that the shape of the patterned area matches the shape of the diffusion connection interface. The slurry is coated or sprayed onto the diffusion bonding interface; Remove the coating.

7. The diffusion bonding process with an intermediate layer as described in claim 1, characterized in that, The metal plate is made of aluminum alloy, magnesium alloy, or aluminum-lithium alloy.

8. The diffusion bonding process with an intermediate layer as described in claim 1, characterized in that, After the blank is made, the air pipe of the blank is connected to a vacuum pump, and a vacuum is drawn to test the air tightness. After the test is qualified, it is put into the baking oven.

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