Active solders and their applications

Abstract

This application relates to the field of brazing technology, and more particularly to active solders and their applications. The active solder comprises the following components in the following proportions: copper, 45wt%–85wt%; indium, 15wt%–50wt%; titanium, 1wt%–5wt%; and tin, 0.5wt%–2wt%. The active solder of this application is suitable for welding ceramics to low-melting-point metals or alloys (≤600℃). The technical solution of this application uses a copper-indium system as the main component of the active solder. By adding an appropriate amount of titanium to the copper-indium system, the welding strength between ceramics and low-melting-point metals or alloys is improved. During the welding process, the titanium in the active solder migrates to its surface and combines with carbon atoms, nitrogen atoms, and other atoms in the ceramic to form an interfacial phase, making the solder joint between the ceramic and the low-melting-point metal or alloy less prone to detachment. Furthermore, by adding an appropriate amount of tin, the hardness of the weld joint can be reduced, its toughness enhanced, and the welding strength between the ceramic and the low-melting-point metal or alloy further improved.

Description

Technical Field

[0001] This invention relates to the field of brazing technology, and more particularly to active solders and their applications. Background Technology

[0002] Joining ceramics with metals or alloys is a major challenge in ceramic applications. Traditionally, this is achieved through high-temperature active brazing in a high-vacuum environment. However, when the metal or alloy is low-melting-point (≤600℃) metal or alloy, such as aluminum, the melting point of commercially available active solders is higher than that of these low-melting-point metals or alloys, causing the base material to melt first during the welding process. To address this issue, several solutions have been proposed in this field. For example, Chinese patent document CN105418132A proposes using physical vapor deposition to deposit an aluminum film followed by brazing to prepare an aluminum-coated ceramic backing plate; CN101538166A proposes using a special mold for aluminizing; and CN113511915A proposes printing an aluminum alloy paste onto the ceramic surface, sintering it to obtain an aluminum film layer, and then fusing it with aluminum.

[0003] In the process of realizing this invention, the inventors discovered that the prior art has at least one of the following problems:

[0004] (1) The preparation process is complicated, costly, and yields low results;

[0005] (2) The bonding strength between ceramics and metals or alloys needs to be further improved, resulting in poor performance of finished products.

[0006] Therefore, how to solve the bonding problem between ceramics and low-melting-point metals or alloys remains an urgent technical problem to be solved in ceramic applications. Summary of the Invention

[0007] This application proposes an active solder and its application, aiming to solve the technical problems mentioned in the background art.

[0008] In a first aspect, embodiments of this application provide an active solder, the active solder comprising the following components in the following amounts:

[0009] Copper, 45wt%~85wt%;

[0010] Indium, 15wt% to 50wt%;

[0011] Titanium, 1wt% to 5wt%;

[0012] Tin, 0.5wt% to 2wt%.

[0013] In some embodiments, the active solder further contains 1 wt% to 5 wt% silver; and / or,

[0014] The active solder also contains less than 0.1 wt% of rare earth elements.

[0015] In some embodiments, the rare earth element includes at least one of rhenium, scandium, and lanthanum.

[0016] In some embodiments, the melting point of the active solder is 350°C to 550°C.

[0017] In some embodiments, the active solder is in the form of blocks, rods, flakes, powder, foil, filaments, or granules.

[0018] In some embodiments, the active solder is a solder sheet with a thickness of 0.01 mm to 0.5 mm; and / or,

[0019] The length or width of the welding sheet is 1mm to 500mm.

[0020] Secondly, embodiments of this application also propose the application of the active solder described in the first aspect in the fabrication of ceramic-metal composite components, wherein the ceramic-metal composite components include a ceramic substrate and a metal substrate, and the ceramic substrate and the metal substrate are welded together by the active solder.

[0021] In some embodiments, the metal matrix includes one or more of aluminum-based metals and magnesium-based metals.

[0022] In some embodiments, the melting point of the metal matrix is ​​450°C to 600°C.

[0023] In some embodiments, an interface phase is formed on the surface of the ceramic substrate, the interface phase including at least one of titanium nitride and titanium carbide, the interface phase being generated by the reaction of the active solder with the ceramic substrate.

[0024] Compared with the prior art, this technical solution has at least the following technical advantages:

[0025] The active solder of this application is suitable for welding ceramics to low-melting-point metals or alloys (≤600℃). The technical solution of this application uses a copper-indium system as the main component of the active solder. Copper has excellent thermal conductivity, which is beneficial for rapid heat transfer and uniform heating of the welding area, reducing thermal stress during welding and lowering the risk of welding deformation. Indium has a low melting point, which helps to lower the melting point of the active solder, reduce the brazing temperature, and improve the strength of the weld joint. Furthermore, by adding an appropriate amount of titanium to the copper-indium system, the welding strength between ceramics and low-melting-point metals or alloys is improved. During welding, titanium in the active solder migrates to its surface and combines with carbon and nitrogen atoms in the ceramic to form an interface phase. This interface phase enhances the bonding strength between the active solder and the ceramic, making the solder joint less prone to detachment. In addition, by adding an appropriate amount of tin to the copper-indium system, the hardness of the weld joint can be reduced, its toughness enhanced, and the welding strength between the ceramic and the low-melting-point metal or alloy further improved. In summary, the active solder of this application has the advantages of excellent thermal conductivity, low welding melting point, high welding strength and simple welding process. Detailed Implementation

[0026] To better understand the technical solution of the present invention, the embodiments of the present invention will be described in detail below.

[0027] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0028] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0029] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0030] Joining ceramics with metals or alloys is a major challenge in ceramic applications. Traditionally, this is achieved through high-temperature active brazing in a high-vacuum environment. However, when the metal or alloy is a low-melting-point metal or alloy such as aluminum, the melting point of commercially available active solders is higher than that of these low-melting-point metals or alloys, causing the base material to melt first during the welding process.

[0031] To address the aforementioned technical problems, in a first aspect, this application proposes an active solder that can be used for welding ceramics to low-melting-point metals or alloys, and features a simple welding process and high welding strength.

[0032] In this embodiment of the application, the active solder comprises the following components in the following proportions: copper, 45wt% to 85wt%; indium, 15wt% to 50wt%; titanium, 1wt% to 5wt%; and tin, 0.5wt% to 2wt%.

[0033] The active solder of this application is suitable for welding ceramics to low-melting-point metals or alloys (≤600℃). The technical solution of this application uses a copper-indium system as the main component of the active solder. Copper has excellent thermal conductivity, which is conducive to rapid heat transfer and uniform heating of the welding part, reducing thermal stress during the welding process and reducing the risk of welding deformation. Indium has a low melting point, which is conducive to lowering the melting point of the active solder, lowering the brazing temperature, and improving the strength of the weld joint. Furthermore, adding an appropriate amount of titanium to the copper-indium system is beneficial for improving the welding strength between ceramics and low-melting-point metals or alloys. During the welding process, titanium in the active solder migrates to its surface and combines with carbon and nitrogen atoms in the ceramic to form an interface phase. This interface phase enhances the bonding strength between the active solder and the ceramic, making the solder joint less prone to detachment. In addition, adding an appropriate amount of tin to the copper-indium system can reduce the hardness of the weld joint, enhance its toughness, and lower the melting point. During solder preparation, Ti and Sn form a TiSn phase, avoiding the formation of CuTi defect phase, further improving the welding strength between ceramics and low-melting-point metals or alloys. In summary, the active solder of this application has advantages such as excellent thermal conductivity, low welding melting point, high welding strength, and simple welding process.

[0034] In this embodiment of the application, the copper content in the active solder is 45wt% to 85wt%, specifically 45wt%, 55wt%, 65wt%, 75wt%, 85wt%, or any value between them.

[0035] In this embodiment, the indium content in the active solder is 15wt% to 50wt%, specifically 15wt%, 20wt%, 30wt%, 40wt%, 50wt%, or any value between them. Too low an indium content will result in an inability to effectively lower the melting point of the active solder, while too high an indium content will affect the welding strength of the weld joint and the thermal conductivity of the active solder.

[0036] In this embodiment, the titanium content in the active solder is 1wt% to 5wt%, specifically 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, or any value between them. Excessive titanium content will lead to an overly brittle weld joint, while insufficient titanium content will affect the bonding strength between the active solder and the ceramic, and reduce the welding stability of the ceramic with low-melting-point metals or alloys.

[0037] In this embodiment, the tin content in the active solder is 0.5wt% to 2wt%, specifically 0.5wt%, 1wt%, 1.5wt%, 2wt%, or any value between them. Excessive tin content can lead to the formation of other alloy phases, introducing more defects; conversely, insufficient tin content will prevent the effective formation of the TiSn phase, reducing the hardness of the weld joint and affecting its weld strength.

[0038] In this embodiment, the melting point of the active solder is 350℃ to 550℃, specifically 350℃, 370℃, 400℃, 420℃, 450℃, 470℃, 500℃, 520℃, 550℃, or any value between them. Those skilled in the art can adjust the melting point of the active solder to below the highest preset welding temperature by appropriately adjusting the content of each component in the active solder.

[0039] In the embodiments of this application, it can be understood that the total content of the components contained in the active solder is 100wt%. When the effective components contained in the active solder are copper, indium, titanium and tin, the total content of copper, indium, titanium and tin in the active solder is ≥99.99wt%, and the balance is impurities.

[0040] In some embodiments, the active solder further contains 1 wt% to 5 wt% silver. Specifically, the silver content can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, or any value between them. Adding an appropriate amount of silver is beneficial to improving the thermal conductivity of the active solder, while excessive silver content is detrimental to lowering the melting point of the active solder.

[0041] In some embodiments, the active solder further contains less than 0.1 wt% of rare earth elements. By adding a small amount of rare earth elements to the active solder, the thermal conductivity of the active solder can be improved, thereby further enhancing the processing performance of the active solder.

[0042] Based on the above embodiments, in some embodiments, the rare earth element includes at least one of rhenium, scandium, and lanthanum.

[0043] In this embodiment, the active solder can be any shape, such as block, rod, sheet, powder, foil, filament or granules, and those skilled in the art can choose according to the specific application scenario.

[0044] In some embodiments, the active solder is in the form of a sheet, that is, the active solder is a solder sheet, and the size of the solder sheet can be designed according to the actual application scenario.

[0045] In some embodiments, the thickness of the welding sheet is 0.01mm to 0.5mm, specifically 0.01mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, or any value between them. If the thickness of the welding sheet is too small, it will affect the welding strength and increase the welding difficulty; if the thickness of the welding sheet is too large, it will result in waste and is not conducive to cost savings.

[0046] The length or width of the welding piece is 1mm to 500mm, specifically 1mm, 100mm, 200mm, 300mm, 400mm, 500mm, or any value between them. Similarly, if the length or width of the welding piece is too small, it will affect the welding strength and increase the welding difficulty; if the length or width of the welding piece is too large, it will cause waste and is not conducive to cost saving.

[0047] In some embodiments, the method for preparing the solder pad is as follows:

[0048] S1. Weigh 45-95 parts copper powder, 5-50 parts indium powder, 1-5 parts titanium powder and 0.5-2 parts tin powder according to the mass fraction. The purity of copper powder, indium powder, titanium powder and tin powder is ≥99.99%. Then, vacuum melt and mix the weighed copper powder, indium powder, titanium powder and tin powder to prepare ingots or plates.

[0049] S2. Using processes such as cold forging, rolling, stamping, and laser cutting, ingots or plates are prepared into welding sheets of specific sizes.

[0050] Secondly, this application also proposes the application of the active solder described in the first aspect in the fabrication of ceramic-metal composite components.

[0051] In this embodiment of the application, the ceramic-metal composite component includes a ceramic substrate and a metal substrate, wherein the ceramic substrate and the metal substrate are welded together using the active solder described in the first aspect.

[0052] In this embodiment, the ceramic substrate is made of ceramic material, the metal substrate is a metal or alloy, the melting point of the metal substrate is >350°C, and the melting point of the metal substrate is higher than the melting point of the active solder.

[0053] In some embodiments, the melting point of the metal matrix is ​​450°C to 600°C, specifically 450°C, 500°C, 550°C, 600°C or any value between them.

[0054] In some embodiments, the metal matrix includes one or more of aluminum-based metals and magnesium-based metals, the magnesium-based metals include at least one of magnesium metal and magnesium alloys, and the aluminum-based metals include at least one of aluminum metal and aluminum alloys.

[0055] It should be noted that the metal matrix can also be a high-melting-point metal, with a melting point greater than 600°C. The embodiments of this application do not specifically limit the maximum melting point of the metal matrix.

[0056] In this embodiment, an interface phase is formed on the surface of the ceramic substrate. This interface phase is generated by the reaction of titanium in the active solder with the ceramic substrate. During the soldering process, titanium in the active solder migrates to the surface and combines with non-metallic atoms in the ceramic substrate to form the interface phase. This interface phase enhances the bonding strength between the ceramic substrate and the active solder, thereby improving the bonding stability between the ceramic substrate and the metal substrate.

[0057] In some embodiments, the ceramic matrix includes at least one of silicon nitride, aluminum nitride, boron nitride, boron carbide, and silicon carbide, and the interface phase includes at least one of titanium nitride and titanium carbide.

[0058] The present application will be further described below through specific embodiments and comparative examples, but the present application is not limited to these specific examples.

[0059] 1. Preparation of active solder:

[0060] At least a portion of the metal powders from copper powder, indium powder, titanium powder, tin powder, silver powder, and rhenium powder with a purity ≥ 99.99% are added to a melting furnace and melted at high temperature. The mixture is stirred evenly, and then the metal in the furnace is cast into ingots or plates and processed into solder sheets with a thickness of 0.5 mm, a length of 500 mm, and a width of 250 mm.

[0061] 2. Performance Testing:

[0062] The thermal conductivity of the above-mentioned welding sheet was measured, and the above-mentioned welding sheet was used to braze ceramics and aluminum alloys. The welding temperature was recorded, and the shear strength of the welded joint was tested (which can reflect the welding strength of the welding sheet).

[0063] The content of each component in the solder sheets prepared in each embodiment and comparative example is shown in Table 1 below, and the performance test results of the solder sheets prepared in each embodiment and comparative example are shown in Table 2 below.

[0064] Table 1. Component content of the solder sheets prepared in each embodiment and comparative example

[0065] sample Copper (wt%) Indium (wt%) Titanium (wt%) Tin (wt%) Silver (wt%) Rare earth elements (wt%) Example 1 73 23 3 1 / / Example 2 70 23 5 2 / / Example 3 48 48 3 1 / / Example 4 83.5 15 1 0.5 / / Example 5 68 23 3 1 5 / Example 6 72.95 23 3 1 / 0.05 Comparative Example 1 74 23 3 / / / Comparative Example 2 64 23 3 10 / / Comparative Example 3 61 23 15 1 / / Comparative Example 4 76 23 / 1 / / Comparative Example 5 95 1 3 1 / / Comparative Example 6 33 63 3 1 / /

[0066] Table 2. Performance tests of the solder sheets prepared in each embodiment and comparative example

[0067] sample Welding temperature / ℃ Shear strength / MPa Thermal conductivity / W / (m·K) Example 1 450 62 71 Example 2 450 50 64 Example 3 370 56 42 Example 4 480 40 90 Example 5 450 70 79 Example 6 450 82 78 Comparative Example 1 450 45 73 Comparative Example 2 420 32 45 Comparative Example 3 470 25 39 Comparative Example 4 460 Unable to connect 70 Comparative Example 5 Aluminum alloys cannot be welded if their melting point is exceeded. Unable to test 182 Comparative Example 6 360 34 40 Test Standards / GB / T 31541-2015 GB / T 22588-2008

[0068] analyze:

[0069] By comparing Examples 1-6 with Comparative Examples 1-6, it can be demonstrated that when the copper content in the active solder is 45wt% to 85wt%, the indium content is 15wt% to 50wt%, the titanium content is 1wt% to 5wt%, and the tin content is 0.5wt% to 2wt%, the active solder has a low melting point, is suitable for welding ceramics and low-melting-point metals, and the thermal conductivity of the active solder meets the processing requirements, resulting in high shear strength and high welding strength of the welded joint.

[0070] By comparing Example 5 with Example 1, and Example 6 with Example 1, it can be concluded that the addition of appropriate amounts of silver and rare earth elements is beneficial to improving the thermal conductivity of the active solder and the shear performance of the welded joint.

[0071] By comparing Example 1 with Comparative Examples 1 and 2, it can be concluded that both excessively high and low tin content will affect the thermal conductivity of the active solder and the shear properties of the welded joint.

[0072] By comparing Example 1 with Comparative Example 3, it can be concluded that excessive titanium content will affect the thermal conductivity of the active solder and the shear properties of the weld joint; by comparing Example 1 with Comparative Example 4, it can be concluded that excessive titanium content will affect the bonding strength between the active solder and the ceramic, and reduce the welding stability of the ceramic with low melting point metals or alloys.

[0073] By comparing Example 1 with Comparative Example 5, it can be concluded that excessive indium content will result in an excessively low melting point of the active solder, which will not meet the welding requirements of ceramics and low-melting-point metals. By comparing Example 1 with Comparative Example 6, it can be concluded that excessive indium content will affect the thermal conductivity of the active solder and the shear properties of the weld joint.

[0074] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An active solder, characterized by, It includes the following components in the following amounts: Copper, 45wt%~85wt%; Indium, 15wt% to 50wt%; Titanium, 1wt% to 5wt%; Tin, 0.5wt% to 2wt%.

2. The active solder of claim 1, wherein, The active solder also contains 1 wt% to 5 wt% silver; and / or, The active solder also contains less than 0.1 wt% of rare earth elements.

3. The active solder of claim 2, wherein, The rare earth elements include at least one of rhenium, scandium, and lanthanum.

4. The active solder of any one of claims 1 to 3, wherein the active solder is characterized by, The melting point of the active solder is 350℃~550℃.

5. The active solder of claim 1, wherein, The active solder can be in the form of blocks, rods, flakes, powder, foil, filaments, or granules.

6. The active solder of claim 5, wherein, The active solder is a solder sheet with a thickness of 0.01 mm to 0.5 mm; and / or, The length or width of the welding sheet is 1mm to 500mm.

7. Use of the active solder according to any one of claims 1 to 6 for the production of ceramic-metal composite components, characterized in that The ceramic-metal composite component includes a ceramic substrate and a metal substrate, wherein the ceramic substrate and the metal substrate are welded together by the active solder.

8. Use according to claim 7, wherein the compound is ###0002### The metal matrix includes one or more of aluminum-based metals and magnesium-based metals.

9. The use according to claim 7, wherein the compound is ###00003### 8 or ###00004### 9. The melting point of the metal matrix is ​​450℃~600℃.

10. The use according to claim 7, wherein the compound is ###00003### 7 An interface phase is formed on the surface of the ceramic substrate, the interface phase including at least one of titanium nitride and titanium carbide, the interface phase being generated by the reaction of the active solder with the ceramic substrate.