A welding method for quartz glass

Abstract

This application relates to the field of brazing technology and provides a welding method for quartz glass, comprising: preparing a nano-silver paste; coating the nano-silver paste onto the bonding surface of the quartz glass and the material to be bonded; bringing the bonding surface of the quartz glass and the bonding surface of the material to be bonded into contact to melt the nano-silver paste, thereby forming a weld joint; and cooling the weld joint, the quartz glass, and the material to be bonded. The welding method for quartz glass provided by this application can improve the connection strength between the quartz glass and the material to be bonded, and reduce the occurrence of cracking in the quartz glass.

Description

Technical Field

[0001] This application relates to the field of brazing technology, and more particularly to a brazing method for quartz glass. Background Technology

[0002] Quartz glass is widely used in optics, electronics, and aerospace due to its excellent optical properties, high temperature resistance, and chemical stability. However, because of its low coefficient of thermal expansion and high hardness, quartz glass is prone to cracking when bonded to other materials, leading to reduced bond strength. Summary of the Invention

[0003] In view of this, embodiments of this application aim to provide a welding method for quartz glass with high connection strength.

[0004] To achieve the above objectives, the technical solution of this application embodiment is implemented as follows:

[0005] This application discloses a welding method for quartz glass, including:

[0006] Preparation of nano-silver paste;

[0007] The nano-silver paste is coated on the bonding surface between the quartz glass and the material to be joined.

[0008] The bonding surfaces of the quartz glass and the bonding surfaces of the materials to be joined are brought into contact and abutted, melting the nano-silver paste to form a welded joint;

[0009] Cool the weld joint, the quartz glass, and the materials to be joined.

[0010] In one embodiment, the preparation of the nano-silver paste includes:

[0011] The nano-silver particles are dispersed in an organic solvent, and a binder and dispersant are added, and then stirred evenly to form the nano-silver paste.

[0012] In one embodiment, the organic solvent is ethanol and / or isopropanol; and / or,

[0013] The adhesive is polyvinyl alcohol or polyethylene glycol.

[0014] In one embodiment, the particle size of the silver nanoparticles is between 10 nm and 100 nm; and / or,

[0015] The weight percentage of the silver nanoparticles in the silver nanoparticle paste is 10% to 50%.

[0016] In one embodiment, the thickness of the nano-silver paste on the bonding surface is between 40 μm and 50 μm.

[0017] In one embodiment, before coating the bonding surfaces of the quartz glass and the materials to be bonded with the nano-silver paste, the welding method includes:

[0018] The quartz glass and the material to be joined are sequentially cleaned with organic solvent, ultrasonically cleaned, and plasma cleaned.

[0019] In one embodiment, a set pressure is applied between the quartz glass and the material to be joined during the melting of the nano-silver paste.

[0020] In one embodiment, the set pressure is between 1 MPa and 5 MPa.

[0021] In one embodiment, a vacuum brazing apparatus is used to melt the nano-silver paste at a set temperature, wherein the vacuum degree within the vacuum brazing apparatus is 1×10⁻⁶. -3 Pa to 1×10 -5 The set temperature is between 200°C and 350°C.

[0022] In one embodiment, the cooling rate of the welding joint, the quartz glass, and the material to be joined is between 1°C / min and 10°C / min.

[0023] This application discloses a welding method for quartz glass. The method involves first preparing a nano-silver paste, then coating the nano-silver paste onto the bonding surface of the quartz glass and the material to be joined, then bringing the bonding surface of the quartz glass into contact with the bonding surface of the material to be joined, subsequently melting the nano-silver paste to form a weld joint, and finally cooling the weld joint, the quartz glass, and the material to be joined. On the one hand, by using nano-silver paste as a solder during welding, the low melting point of nano-silver allows for a strong bond between the quartz glass and the materials to be joined at a lower temperature. This reduces the likelihood of quartz glass cracking due to thermal stress caused by high temperatures, enhances the bond strength between the quartz glass and the materials to be joined, and improves the reliability and stability of the connection. On the other hand, the excellent wettability of the nano-silver paste ensures its uniform spread on the bonding surface of the quartz glass. After subsequent melting, it forms a strong weld joint, which significantly improves the mechanical strength and reliability of the weld joint. Furthermore, after the weld joint is formed, cooling the weld joint, quartz glass, and materials to be joined further reduces the likelihood of thermal stress concentration causing cracking of the quartz glass, thereby further improving the mechanical strength of the weld joint and the bond strength between the quartz glass and the materials to be joined. Attached Figure Description

[0024] Figure 1 A schematic flowchart of a welding method for quartz glass provided in an embodiment of this application;

[0025] Figure 2 This is a microstructure diagram of the welded joint;

[0026] Figure 3 for Figure 2 A 10x magnified image. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and technical features in the embodiments of this application can be combined with each other, and the detailed descriptions in the specific embodiments should be understood as explanations of the purpose of this application and should not be regarded as undue limitations on this application.

[0028] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. The terms "first," "second," etc., used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly including at least one feature. In the description of the embodiments of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0029] This application provides a welding method for quartz glass. Please refer to [link to relevant documentation]. Figure 1 Welding methods include:

[0030] S1. Preparation of nano-silver paste;

[0031] S2. Coat the bonding surface of the quartz glass and the material to be joined with the nano-silver paste;

[0032] S3. The bonding surface of the quartz glass and the bonding surface of the material to be joined are brought into contact and abutted, and the nano-silver paste is melted to form a welded joint;

[0033] S4. Cool the welding joint, the quartz glass, and the materials to be joined.

[0034] This application provides a welding method for quartz glass, which involves first preparing a nano-silver paste, then coating the nano-silver paste onto the bonding surface of the quartz glass and the material to be joined, then bringing the bonding surface of the quartz glass into contact with the bonding surface of the material to be joined, subsequently melting the nano-silver paste to form a weld joint, and finally cooling the weld joint, the quartz glass, and the material to be joined. On the one hand, by using nano-silver paste as a solder during welding, the low melting point of nano-silver allows for a strong bond between the quartz glass and the materials to be joined at a lower temperature. This reduces the likelihood of quartz glass cracking due to thermal stress caused by high temperatures, enhances the bond strength between the quartz glass and the materials to be joined, and improves the reliability and stability of the connection. On the other hand, the excellent wettability of the nano-silver paste ensures its uniform spread on the bonding surface of the quartz glass. After subsequent melting, it forms a strong weld joint, which significantly improves the mechanical strength and reliability of the weld joint. Furthermore, after the weld joint is formed, cooling the weld joint, quartz glass, and materials to be joined further reduces the likelihood of thermal stress concentration causing cracking of the quartz glass, thereby further improving the mechanical strength of the weld joint and the bond strength between the quartz glass and the materials to be joined.

[0035] It should be noted that the cracking temperature of quartz glass is around 1200℃, while the melting point of nano silver is much lower than that of quartz glass.

[0036] For example, in one embodiment, the material to be joined can be a metal or a non-metal. Thus, the welding method provided in this application can effectively solve problems such as poor wettability, low mechanical strength of the weld joint, and easy cracking of the quartz glass due to thermal stress during the joining process between quartz glass and the material to be joined.

[0037] In one embodiment, S1, preparing the nano-silver paste includes:

[0038] S11. Disperse the silver nanoparticles in an organic solvent, add a binder and a dispersant, and then stir until homogeneous to form the silver nanoparticle paste.

[0039] Here, by first dispersing the silver nanoparticles in an organic solvent, the organic solvent effectively disperses the silver nanoparticles in the solution, forming a uniform dispersion system. This helps the silver nanoparticles to be evenly distributed on the bonding surface during subsequent fusion welding, thereby improving the mechanical strength of the weld joint. A binder and dispersant are added. The binder reduces the sedimentation and aggregation of silver nanoparticles at the bottom, while the dispersant enhances the stability of the silver nanoparticles in the solvent, reducing sedimentation and agglomeration. Finally, the mixture is stirred to ensure uniform mixing of all components, thus obtaining a silver nanoparticle slurry with good flowability and stability.

[0040] In one embodiment, a magnetic stirrer can be used for stirring. For example, the magnetic stirrer can be placed in the container and stirred at 500 rpm for 30 minutes. This can ensure that all components are mixed evenly, improve the fluidity and stability of the prepared nano-silver paste, and use a magnetic stirrer makes it easy to control the stirring speed and stirring time, with precise control and stable speed adjustment.

[0041] In one embodiment, the organic solvent is ethanol and / or isopropanol. That is, the organic solvent can be ethanol, isopropanol, or a mixture of ethanol and isopropanol. Here, by selecting ethanol and / or isopropanol as the organic solvent, on the one hand, the nano-silver particles can be effectively dispersed in the solution to form a uniform dispersion system; on the other hand, the viscosity of the nano-silver paste can be well adjusted, thereby controlling the flowability of the nano-silver paste to meet the subsequent welding requirements; furthermore, ethanol and isopropanol are non-reactive diluents, which can maintain the stable dispersion of nano-silver particles in the solution and reduce the aggregation and precipitation between nano-silver particles.

[0042] In one embodiment, the particle size of the silver nanoparticles is between 10 nm and 100 nm. For example, the silver nanoparticles can be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm, etc. By setting the appropriate particle size of the silver nanoparticles, on the one hand, after subsequent melting, a tight and uniform weld joint can be formed, improving its thermal conductivity to effectively transfer heat; on the other hand, the melting temperature of the silver nanoparticle slurry can be reduced, decreasing the likelihood of cracking in the quartz glass; furthermore, after subsequent melting, the bond strength between the silver nanoparticles and the quartz glass and the materials to be joined is improved, exhibiting good adhesion and enhancing the stability and reliability of the weld joint; and finally, the silver nanoparticles possess broad-spectrum antibacterial properties, inhibiting the growth and reproduction of various pathogenic microorganisms to meet the needs of conductive and antibacterial applications.

[0043] In one embodiment, the adhesive can be polyvinyl alcohol (PVA). On the one hand, the hydroxyl groups of the PVA molecular chain can interact with the functional groups on the surface of the silver nanoparticles, thereby effectively dispersing the silver nanoparticles and preventing their aggregation. Good dispersibility helps to form a uniform slurry, thereby improving the coating effect and sintering quality. On the other hand, the hydroxyl groups of the PVA molecular chain can form hydrogen bonds or chemical bonds with the functional groups on the surface of quartz glass and / or the materials to be bonded, thereby enhancing the bonding strength between the silver nanoparticle slurry and the quartz glass and the materials to be bonded. Higher bonding strength can improve the stability and reliability of the welded joint. Furthermore, the addition of PVA can adjust the fluidity and viscosity of the silver nanoparticle slurry, thereby helping to obtain a uniform coating layer on the bonding surface and improving the subsequent welding effect. Moreover, the hydroxyl groups of the PVA molecular chain help to form a better conductive path for electron transport, thereby improving the conductivity of the silver nanoparticle slurry.

[0044] In one embodiment, the adhesive can be polyethylene glycol (PEG). On one hand, PEG has good solubility and can dissolve in various solvents, thereby forming a uniform slurry with the silver nanoparticles, which helps to obtain good coating effect and sintering quality. On the other hand, PEG can reduce the surface tension between the silver nanoparticle slurry and the quartz glass and the materials to be bonded, thereby enhancing its wettability. Good wettability helps the silver nanoparticles adhere better to the surfaces of the quartz glass and the materials to be bonded, improving sintering quality. Furthermore, the addition of PEG can adjust the viscosity and flowability of the silver nanoparticle slurry, and appropriate viscosity and flowability help to obtain a uniform coating layer, improving the sintering effect. Finally, the addition of PEG can promote the sintering reaction between the silver nanoparticles, thereby increasing the sintering density and strength, thus improving the mechanical strength of the welded joint, and consequently improving the stability and reliability of the welded joint.

[0045] In one embodiment, the weight percentage of silver nanoparticles in the silver nanoparticle paste is 10% to 50%. For example, the weight percentage of silver nanoparticles in the silver nanoparticle paste can be 10%, 20%, 30%, 40%, or 50%, etc. Here, by setting an appropriate weight percentage of silver nanoparticles, on the one hand, the conductivity of the weld joint can be improved; on the other hand, the large specific surface area and high surface activity of silver nanoparticles enable them to form a stronger bond with the quartz glass and the materials to be joined. This strong bond helps to improve the shear strength and tensile strength of the weld joint, thereby improving the stability and reliability of the weld joint.

[0046] In one embodiment, S2, before coating the bonding surface of the quartz glass and the material to be bonded with the nano-silver paste, the welding method includes:

[0047] S5. The quartz glass and the material to be joined are sequentially cleaned with organic solvent, ultrasonically cleaned, and plasma cleaned.

[0048] For example, the quartz glass and the material to be joined can be placed in an ethanol solution to remove surface oil and particulate impurities.

[0049] The quartz glass and the material to be joined can then be placed in an ultrasonic cleaning device. For example, ultrasonic cleaning can be performed at a frequency of 20kHz to 40kHz for 10 to 30 minutes to further remove fine contaminants from the surface.

[0050] Finally, the quartz glass and the material to be joined can be placed in a plasma cleaning device. For example, a 10-minute surface treatment with low-pressure plasma can be used to remove residual oxide layers or other organic contaminants, enhance the surface activity of the quartz glass and the material to be joined, and improve the wettability of the nano-silver paste.

[0051] Here, by cleaning the quartz glass and the materials to be joined with organic solvents, ultrasonic cleaning, and plasma cleaning, impurities can be removed from the surfaces of the quartz glass and the materials to be joined. This not only improves the welding quality but also reduces welding defects and lowers the risk of thermal deformation.

[0052] In one exemplary embodiment, during the process of coating the bonding surface of the quartz glass and the material to be bonded with nano-silver paste, a doctor blade or a coating machine can be used to uniformly coat the prepared nano-silver paste onto the bonding surface of the quartz glass and the material to be bonded, ensuring that the thickness of the nano-silver paste is controlled within the set thickness. Then, a microscope can be used to check the uniformity of the nano-silver paste coating to reduce the occurrence of voids or uneven thickness. Finally, the coated bonding surface is placed at room temperature to wait for the solvent in the nano-silver paste to evaporate, which takes about 10 to 15 minutes, to ensure that the flowability of the nano-silver paste is moderate during the welding process.

[0053] In one embodiment, the thickness of the nano-silver paste on the bonding surface is between 40 μm and 50 μm. For example, the thickness of the nano-silver paste on the bonding surface can be 40 μm, 41 μm, 42 μm, 43 μm, 44 μm, 45 μm, 46 μm, 47 μm, 48 μm, 49 μm, or 50 μm, etc. Thus, by coating with a nano-silver paste of a suitable thickness, on the one hand, the contact area between the nano-silver particles and the quartz glass and the materials to be bonded can be increased, thereby improving conductivity; on the other hand, the bonding between the nano-silver particles and the quartz glass and the materials to be bonded can be made stronger, thereby improving the mechanical strength and durability of the welded joint.

[0054] In one embodiment, a vacuum brazing apparatus is used to melt the nano-silver paste at a set temperature. Here, because the vacuum brazing apparatus has a certain degree of vacuum, on the one hand, the influence of air on the welding process, such as oxidation and contamination, can be reduced, thereby improving the quality and reliability of the weld joint; on the other hand, the nano-silver paste can melt more uniformly in vacuum brazing to form a dense weld joint and improve the weld strength.

[0055] In one embodiment, the vacuum degree inside the vacuum brazing equipment is 1×10⁻⁶. -3 Pa to 1×10 -5 Between Pa. For example, the vacuum level inside a vacuum brazing apparatus can be 1 × 10⁻⁶. -3 Pa, 1×10 -4 Pa or 1×10 -5 Pa, etc. By setting an appropriate vacuum level, the production of oxides during the brazing process can be reduced, thereby improving the brazing quality.

[0056] In one embodiment, the set temperature is between 200°C and 350°C. Exemplarily, the set temperature can be 200°C, 220°C, 250°C, 280°C, 300°C, 320°C, or 350°C, etc. Thus, by setting a suitable set temperature, the nano-silver paste can be melted at a lower temperature, reducing the thermal stress on the quartz glass and the materials to be joined, reducing the likelihood of cracking in the quartz glass, and thereby improving the connection strength between the quartz glass and the materials to be joined.

[0057] In one embodiment, a set pressure is applied to the quartz glass and the material to be joined during the melting of the nano-silver paste.

[0058] In this way, by applying a set pressure, on the one hand, the contact and diffusion between the nano-silver particles in the nano-silver paste and the quartz glass and the materials to be joined can be promoted, so as to more effectively fill the tiny gaps in the welding interface and form a denser sintered structure, which helps to improve the mechanical strength and electrical conductivity of the weld joint. On the other hand, the pressure can ensure that the nano-silver paste is evenly distributed during the melting process, reducing the occurrence of local unmelted or uneven melting. The uniform melting distribution helps to form a uniform weld joint, reducing welding defects such as porosity and slag inclusions, thereby improving the welding quality. Furthermore, during the melting process, some organic matter in the nano-silver paste will decompose and generate gas. Applying a set pressure helps to expel these gases, reducing the porosity in the weld joint, thereby improving the density and strength of the weld joint.

[0059] In one embodiment, the pressure is set between 1 MPa and 5 MPa. For example, the set pressure can be 1 MPa, 2 MPa, 3 MPa, 4 MPa, or 5 MPa, etc. Thus, by setting an appropriate set pressure, the mechanical strength and welding quality of the welded joint can be improved.

[0060] In one embodiment, the cooling rate of the weld joint, quartz glass, and materials to be joined is between 1°C / min and 10°C / min.

[0061] For example, the cooling rates of the weld joint, quartz glass, and materials to be joined can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, or 10℃ / min, etc. By setting an appropriate cooling rate, the concentration of thermal stress caused by excessively rapid cooling can be reduced, and the occurrence of cracks in the quartz glass leading to a decrease in mechanical strength can be minimized.

[0062] For example, in one embodiment, taking the connection between quartz glass and stainless steel as an example, a quartz glass sheet with a length of 20mm, a width of 20mm, and a thickness of 2mm is selected.

[0063] Preparation of nano silver paste:

[0064] First, take 50nm silver nanoparticles and prepare isopropanol organic solvent, polyvinyl alcohol binder and dispersant.

[0065] The silver nanoparticles were dispersed in isopropanol solvent at a weight percentage of 20% to ensure uniform distribution of the silver nanoparticles.

[0066] Add 1% by weight of polyvinyl alcohol to the nano silver solution, and then add 0.5% by weight of dispersant.

[0067] Use a magnetic stirrer to stir at 500 rpm for 30 minutes to ensure all components are evenly mixed.

[0068] Surface impurity removal:

[0069] Place quartz glass and stainless steel in an ethanol solution;

[0070] Place the quartz glass and stainless steel into an ultrasonic cleaning device and perform ultrasonic cleaning at a frequency of 30kHz for 20 minutes.

[0071] The cleaned quartz glass and stainless steel were placed in a plasma cleaning device and cleaned with low-pressure plasma for 10 minutes.

[0072] Nano silver paste coating:

[0073] The prepared nano-silver paste was uniformly coated onto the bonding surface of quartz glass and stainless steel using a doctor blade or coating machine, with the thickness controlled at 40 μm.

[0074] The uniformity of the nano-silver paste coating was examined using a microscope.

[0075] Place the coated bonding surface at room temperature and wait for the solvent in the nano silver paste to evaporate, which takes about 10 to 15 minutes.

[0076] Molten nano silver paste:

[0077] Quartz glass and stainless steel coated with nano-silver paste are stacked in a vacuum brazing apparatus, ensuring that the bonding surfaces are aligned and appropriate pressure is applied.

[0078] Start the vacuum brazing equipment and control the vacuum level at 1×10⁻⁶. -4 Pa;

[0079] Set the temperature to 300℃ and apply a pressure of 2MPa. After the heating temperature reaches the set temperature, maintain the set temperature and pressure for 20 minutes.

[0080] Cooling process:

[0081] After brazing is completed, gradually reduce the temperature inside the vacuum brazing equipment, with the cooling rate controlled at 5℃ / min;

[0082] After the temperature drops to room temperature, remove the brazed quartz glass and stainless steel and check the integrity and surface quality of the weld joint.

[0083] The prepared welded joint was subjected to quality inspection: the welded joint has high mechanical strength, shear strength of 85MPa, and excellent electrical and thermal conductivity. Figure 2 and Figure 3 The image shows the microstructure of the welded joint. Figure 3 for Figure 2 The 10x magnified image shows that the connection between the quartz glass and the material to be joined is quite tight, and the quartz glass does not show any cracking.

[0084] The above description is merely a preferred embodiment of this application and is not intended to limit the application. Various modifications and variations can be made to this application by those skilled in the art. All modifications, equivalent substitutions, improvements, etc., within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A welding method for quartz glass, characterized in that, include: Preparation of nano-silver paste; The nano-silver paste is coated on the bonding surface between the quartz glass and the material to be joined. The bonding surfaces of the quartz glass and the bonding surfaces of the materials to be joined are brought into contact, and the nano-silver paste is melted at a set temperature using a vacuum brazing device to form a welded joint, wherein the set temperature is 200°C to 350°C. The welding joint, the quartz glass, and the materials to be joined are cooled, wherein the cooling rate is between 1°C / min and 10°C / min.

2. The welding method according to claim 1, characterized in that, The preparation of the nano-silver paste includes: The nano-silver particles are dispersed in an organic solvent, and a binder and dispersant are added, and then stirred evenly to form the nano-silver paste.

3. The welding method according to claim 2, characterized in that, The organic solvent is ethanol and / or isopropanol; and / or, The adhesive is polyvinyl alcohol or polyethylene glycol.

4. The welding method according to claim 2, characterized in that, The particle size of the silver nanoparticles is between 10 nm and 100 nm; and / or, The weight percentage of the silver nanoparticles in the silver nanoparticle paste is 10% to 50%.

5. The welding method according to claim 1, characterized in that, The thickness of the nano-silver paste on the bonding surface is between 40 μm and 50 μm.

6. The welding method according to claim 1, characterized in that, Before coating the bonding surfaces of the quartz glass and the materials to be bonded with the nano-silver paste, the welding method includes: The quartz glass and the material to be joined are sequentially cleaned with organic solvent, ultrasonically cleaned, and plasma cleaned.

7. The welding method according to claim 1, characterized in that, During the melting of the nano-silver paste, a set pressure is applied between the quartz glass and the material to be joined.

8. The welding method according to claim 7, characterized in that, The set pressure is between 1 MPa and 5 MPa.

9. The welding method according to claim 1, characterized in that, The vacuum degree inside the vacuum brazing equipment is 1×10⁻⁶. -3 Pa to 1×10 -5 Between Pa.

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