A low-temperature connection method for ultrasonic-assisted brazing of ceramics and metals by using Sn / AlSi / Sn filler metal
The ultrasonic-assisted brazing method using Sn/AlSi/Sn solder solves the problems of residual stress and poor wettability caused by high-temperature ceramic-metal bonding, achieving high-strength ceramic-metal bonding at low temperatures. It is applicable to a variety of materials and reduces process costs and operational difficulty.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HARBIN INST OF TECH AT WEIHAI
- Filing Date
- 2026-06-12
- Publication Date
- 2026-08-04
AI Technical Summary
In existing technologies, the connection between ceramics and metals suffers from residual stress caused by high-temperature brazing, and conventional Sn-based brazing filler metals are difficult to form effective metallurgical connections, especially with poor wettability during low-temperature brazing.
An ultrasonic-assisted brazing method using Sn/AlSi/Sn solder is employed. By applying ultrasonic vibration at 250~350℃, the dissolution and diffusion of the AlSi layer in liquid Sn are utilized to achieve low-temperature bonding between ceramics and metals. Ultrasonic cavitation and acoustic flow effects are used to remove the oxide film and promote metallurgical reactions.
It achieves high-strength bonding between ceramics and metals at low temperatures, reduces thermal expansion mismatch, lowers process costs and operational difficulty, is applicable to a variety of ceramic and metal materials, and requires no complex pretreatment.
Smart Images
Figure CN122500296A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of dissimilar material joining technology, specifically relating to a low-temperature joining method for ceramics and metals using Sn / AlSi / Sn solder with ultrasonic-assisted brazing. Background Technology
[0002] Ceramics possess excellent properties such as high hardness, high insulation, high temperature resistance, and corrosion resistance, but they are brittle and difficult to process. Metals, on the other hand, have good plasticity, high thermal conductivity, and machinability, but their corrosion resistance and high-temperature stability are relatively insufficient. Joining ceramics and metals can fully leverage the advantages of both, and has broad application prospects in fields such as electronic packaging. Therefore, achieving a reliable connection between ceramics and metals has significant engineering implications.
[0003] Brazing is a common method for joining ceramics and metals. However, there is a significant difference in the coefficients of thermal expansion between ceramics and metals (ceramics have a coefficient of 1~10×10⁻⁶). -6 / K, for metals, is 16~23×10 -6 The high temperature (e.g., 800-1000℃ for Ag-based brazing filler metals and 600-650℃ for Al-based brazing filler metals) leads to significant residual stress during the cooling process of the welded joint. Traditional brazing requires high temperatures, and the residual thermal stress generated at these high temperatures greatly reduces the joint strength and can even cause ceramic cracking. Therefore, it is necessary to develop a low-temperature joining method to reduce the brazing temperature between ceramics and metals and decrease the thermal stress of the brazed joint.
[0004] Ultrasonic-assisted brazing technology utilizes the cavitation and acoustic flow effects generated by ultrasound in liquid brazing filler metals to effectively remove oxide films from the base material surface, improve the spreading and wetting behavior of the filler metal, and achieve low-temperature bonding between ceramics and metals. However, conventional Sn-based filler metals have limited chemical affinity for ceramics, making it difficult to form effective metallurgical bonds even under ultrasonic fields. Furthermore, the coefficient of thermal expansion of Sn-based filler metals is significantly higher than that of ceramic materials, easily leading to significant interfacial residual stress during the cooling process from high brazing temperatures to room temperature. Based on this background, this invention proposes a method for low-temperature bonding of ceramics and metals using Sn / AlSi / Sn filler metal with ultrasonic assistance. Summary of the Invention
[0005] The present invention aims to solve the problems of high temperature in existing ceramic / metal brazing, significant residual stress due to the large difference in the thermal expansion coefficients between the two, poor connection strength, and poor wettability of the brazing filler metal to ceramic during low-temperature brazing, which makes it difficult to form a metallurgical connection. The present invention provides a low-temperature connection method for ceramic and metal using Sn / AlSi / Sn brazing filler metal with ultrasonic assistance.
[0006] This invention employs a low-temperature brazing method for ceramic-metal bonding using Sn / AlSi / Sn solder with ultrasonic assistance, implemented according to the following steps:
[0007] 1. An AlSi solder foil is sandwiched between two Sn foils to form a "Sn / AlSi / Sn" three-layer foil structure, resulting in a composite sandwich solder.
[0008] 2. Grind the surface of the ceramic to be welded with a diamond grinding wheel and the surface of the metal to be welded with sandpaper. Then, perform ultrasonic cleaning on the ceramic and metal to be welded to obtain pre-treated ceramic and metal to be welded.
[0009] 3. The composite brazing filler metal is sandwiched between the pretreated ceramic and metal surfaces to be welded to form a “ceramic / Sn / AlSi / Sn / metal” assembly structure to obtain the workpiece to be welded;
[0010] 4. Place the workpiece to be welded on the heating platform and heat it to a brazing temperature of 250~350℃. Keep it at the temperature to completely melt the Sn foil. Place the ultrasonic probe on the surface of the ceramic or metal to be welded and apply ultrasonic vibration.
[0011] V. After the ultrasonic vibration stops, the temperature is lowered to complete the low-temperature connection method of ultrasonic-assisted brazing of ceramics and metals.
[0012] This invention proposes a high-strength, low-temperature brazing method for ceramics and metals using Sn / AlSi / Sn solder with ultrasonic assistance. AlSi solder is used as an intermediate layer, forming a solid-liquid contact system with a low-melting-point Sn foil. Under ultrasonic assistance, AlSi dissolves into Sn. Utilizing the cavitation and acoustic flow effects of ultrasound, the oxide film on the surface of the metal substrate and solder is effectively removed, creating conditions for sufficient liquid-solid interface contact. Furthermore, ultrasound accelerates the dissolution of the AlSi layer into liquid Sn, allowing Al elements to diffuse to the ceramic interface and undergo a metallurgical reaction, thus achieving a low-temperature connection between ceramics and metals.
[0013] This invention employs a low-temperature brazing method for ceramics to metals using Sn / AlSi / Sn solder with ultrasonic assistance, which mainly offers the following advantages:
[0014] 1. This invention adopts a low-temperature brazing strategy with a brazing temperature of only 250~350℃, which is much lower than that of traditional Ag-based or Al-based brazing fillers. This significantly reduces the degree of thermal expansion mismatch between ceramics and metals and reduces the generation of residual thermal stress.
[0015] 2. This invention dissolves the AlSi interlayer under ultrasonic action, allowing Al elements to be released in situ and react with the ceramic surface to form a metallurgical bond. This eliminates the need to add additional active elements to the brazing filler metal and avoids complex pre-metallization treatment of the ceramic surface, significantly reducing process costs and operational difficulty.
[0016] 3. This invention adopts a three-layer structure design of Sn / AlSi / Sn. The outer layer of low-melting-point Sn foil melts at low temperature to form a liquid medium, and the inner layer of high-melting-point AlSi serves as the source of Al. The dissolution behavior of AlSi is controlled by ultrasonic action. The structure is simple and easy to implement.
[0017] 4. The method of the present invention is applicable to the low-temperature bonding of various ceramics such as alumina, zirconium oxide, and silicon nitride with various metals such as aluminum alloys, copper alloys, and stainless steel. It has wide material applicability, requires no flux, and the ultrasonic-assisted process does not produce harmful emissions. The process is simple and low-cost, and has good application and promotion value. Attached Figure Description
[0018] Figure 1 This is a backscattered image of the microstructure of the 6061Al alloy and ZrO2 ceramic joint ultrasonically assisted brazing using Sn / Al12Si / Sn solder in Example 1.
[0019] Figure 2 This is a backscattered image of the ZrO2 ceramic interface microstructure in the ultrasonic-assisted brazing joint between 6061Al alloy and ZrO2 ceramic using Sn / Al12Si / Sn solder in Example 1.
[0020] Figure 3 This is a backscattered image of the interface microstructure of the 6061Al alloy in the ultrasonic-assisted brazing joint between the Sn / Al12Si / Sn alloy and the ZrO2 ceramic joint in Example 1. Detailed Implementation
[0021] Specific Implementation Method 1: This implementation method uses a low-temperature connection method for ultrasonic-assisted brazing of Sn / AlSi / Sn solder between ceramics and metals, and is carried out according to the following steps:
[0022] 1. An AlSi solder foil is sandwiched between two Sn foils to form a "Sn / AlSi / Sn" three-layer foil structure, resulting in a composite sandwich solder.
[0023] 2. Grind the surface of the ceramic to be welded with a diamond grinding wheel and the surface of the metal to be welded with sandpaper. Then, perform ultrasonic cleaning on the ceramic and metal to be welded to obtain pre-treated ceramic and metal to be welded.
[0024] 3. The composite brazing filler metal is sandwiched between the pretreated ceramic and metal surfaces to be welded to form a “ceramic / Sn / AlSi / Sn / metal” assembly structure to obtain the workpiece to be welded;
[0025] 4. Place the workpiece to be welded on the heating platform and heat it to a brazing temperature of 250~350℃. Keep it at the temperature to completely melt the Sn foil. Place the ultrasonic probe on the surface of the ceramic or metal to be welded and apply ultrasonic vibration.
[0026] V. After the ultrasonic vibration stops, the temperature is lowered to complete the low-temperature connection method of ultrasonic-assisted brazing of ceramics and metals.
[0027] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the AlSi solder foil in step one is an Al-Si eutectic alloy or a hypereutectic Al-Si alloy, with a Si content of 12wt.%~30wt.%.
[0028] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the thickness of the AlSi solder foil in step 1 is 0.05~1mm, and the thickness of the Sn foil is 0.01~0.5mm.
[0029] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the ceramic to be welded in step two is ZrO2 ceramic, Al2O3 ceramic, ZTA ceramic, SiO2 ceramic, SiC ceramic, Si3N4 ceramic, or AlN ceramic.
[0030] Specific Implementation Method 5: This implementation method differs from Specific Implementation Methods 1 to 4 in that the metal to be welded in step 2 is an Al alloy, Mg alloy, Cu alloy, Ti alloy, or stainless steel.
[0031] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the heat preservation time in step four is 1 to 10 minutes.
[0032] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the brazing temperature in step four is 250~300℃.
[0033] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that a pressure of 20~100kPa is applied to the workpiece to be welded in step four.
[0034] In this embodiment, pressure is applied to clamp the workpiece to be welded.
[0035] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the frequency of ultrasonic vibration applied in step four is 20~60kHz.
[0036] Specific Implementation Method 10: This implementation method differs from Specific Implementation Methods 1 to 9 in that the ultrasonic vibration time in step 4 is 5 to 80 seconds.
[0037] Specific Implementation Method Eleven: This implementation method differs from Specific Implementation Methods One through Ten in that the cooling rate in step five is 2 to 15°C / min.
[0038] Example 1: This example uses an ultrasonic-assisted low-temperature joining method with Sn / AlSi / Sn solder to connect 6061Al alloy and ZrO2 ceramic, implemented according to the following steps:
[0039] 1. A 0.1 mm thick Al-12 wt.% Si solder foil is sandwiched between two pure Sn foils to form a "Sn / AlSi / Sn" three-layer foil structure. The thickness of the pure Sn foil is 0.05 mm, thus preparing a composite sandwich solder with a "Sn / AlSi / Sn" three-layer structure.
[0040] 2. Grind the ZrO2 ceramic surface to be welded with 800# and 1200# diamond grinding discs in sequence, and grind the 6061Al alloy surface to be welded with 1000# and 1200# sandpaper in sequence. Then, immerse them in anhydrous ethanol for ultrasonic cleaning for 5 minutes. After cleaning 3 times, blow dry to obtain the pretreated ZrO2 ceramic and 6061Al alloy to be welded.
[0041] 3. Stack the pretreated 6061Al alloy to be soldered, the composite brazing filler metal, and the ZrO2 ceramic to be soldered in sequence, so that the composite brazing filler metal is placed between the ceramic and the metal to be soldered surfaces, forming an assembly structure of "ceramic / Sn / AlSi / Sn / metal" to obtain the part to be soldered.
[0042] 4. Place the assembled workpiece obtained in step 3 on a heating platform and heat it to 280°C. Keep it at this temperature to completely melt the Sn foil. Then place the ultrasonic probe on the upper surface of the 6061Al alloy base material, apply a pressure of 80 kPa, apply ultrasonic vibration for 10 seconds, and control the vibration frequency at 35 kHz.
[0043] 5. After the ultrasonic treatment stops, the workpiece is cooled to room temperature at a rate of 10℃ / min, thus completing the low-temperature connection method of ultrasonic-assisted brazing of 6061Al alloy and ZrO2 ceramic using Sn / AlSi / Sn solder.
[0044] from Figure 1 It can be seen that, under the action of an ultrasonic energy field, an effective interfacial connection between 6061Al alloy and ZrO2 ceramic was achieved using Sn / AlSi / Sn brazing filler metal. The main body of the brazing seam is an AlSi layer, with a thinner Sn layer retained on both sides. From Figure 2 As can be seen, the bonding interface between the ZrO2 ceramic and the solder is tight, and no defects such as cracks or pores are observed. Figure 3As can be seen, a reliable connection was formed between the 6061Al alloy and the brazing filler metal. Shear test results show that the maximum room temperature shear strength of the joint obtained in this embodiment reaches 27 MPa. This indicates that high-strength ultrasonic-assisted brazing of 6061Al alloy and ZrO2 ceramic was successfully achieved at low temperatures using Sn / AlSi / Sn brazing filler metal.
[0045] Example 2: This example uses an ultrasonic-assisted low-temperature joining method with Sn / AlSi / Sn solder to connect AZ31Mg alloy and ZrO2 ceramic, implemented according to the following steps:
[0046] 1. A 0.1 mm thick Al-7.5 wt.% Si solder foil is sandwiched between two pure Sn foils to form a "Sn / AlSi / Sn" three-layer foil structure. The thickness of the pure Sn foil is 0.05 mm, thus preparing a composite sandwich solder with a "Sn / AlSi / Sn" three-layer structure.
[0047] 2. Grind the ZrO2 ceramic surface to be welded with 800# and 1200# diamond grinding discs in sequence, and grind the AZ31Mg alloy surface to be welded with 1000# and 1200# sandpaper in sequence. Then, immerse them in anhydrous ethanol for ultrasonic cleaning for 5 minutes. After cleaning 3 times, blow dry to obtain the pretreated ZrO2 ceramic and AZ31Mg alloy to be welded.
[0048] 3. Stack the pretreated AZ31Mg alloy to be welded, the composite brazing filler metal, and the ZrO2 ceramic to be welded in sequence, so that the brazing filler metal is placed between the ceramic and the metal to be welded surfaces, forming an assembly structure of "ceramic / Sn / AlSi / Sn / metal" to obtain the assembled part to be welded.
[0049] 4. Place the assembled workpiece obtained in step 3 on a heating platform and heat it to 300°C. Keep it at this temperature to completely melt the Sn foil. Then place the ultrasonic probe on the upper surface of the ZrO2 ceramic, apply a pressure of 50 kPa, apply ultrasonic vibration for 20 seconds, and control the vibration frequency at 35 kHz.
[0050] 5. After the ultrasonic treatment stops, the workpiece is cooled to room temperature at a rate of 5℃ / min, thus completing the low-temperature connection method of ultrasonic-assisted brazing of AZ31Mg alloy and ZrO2 ceramic using Sn / AlSi / Sn solder.
[0051] Example 3: This example uses an ultrasonic-assisted low-temperature joining method between Sn / AlSi / Sn solder and TC4 alloy and Al2O3 ceramic, implemented according to the following steps:
[0052] 1. A 0.15mm thick Al-10wt.%Si solder foil is sandwiched between two pure Sn foils to form a "Sn / AlSi / Sn" three-layer foil structure. The thickness of the pure Sn foil is 0.2mm, thus preparing a composite sandwich solder with a "Sn / AlSi / Sn" three-layer structure.
[0053] 2. Grind the Al2O3 ceramic surface to be welded with 800# and 1200# diamond grinding discs in sequence, and grind the TC4 alloy surface to be welded with 1000# and 1200# sandpaper in sequence. Then, immerse them in anhydrous ethanol for ultrasonic cleaning for 5 minutes. After cleaning 3 times, blow dry to obtain the pretreated Al2O3 ceramic and TC4 alloy to be welded.
[0054] 3. Stack the pretreated TC4 alloy to be soldered, the composite brazing filler metal, and the Al2O3 ceramic to be soldered in sequence, so that the composite brazing filler metal is placed between the ceramic and the metal to be soldered surfaces, forming an assembly structure of "ceramic / Sn / AlSi / Sn / metal" to obtain the assembled part to be soldered.
[0055] 4. Place the assembled workpiece obtained in step 3 on a heating platform and heat it to 250°C. Keep it at this temperature to completely melt the Sn foil. Then place the ultrasonic probe on the surface of the Al2O3 ceramic, apply a pressure of 150 kPa, apply ultrasonic vibration for 15 seconds, and control the vibration frequency to 50 kHz.
[0056] 5. After the ultrasonic treatment stops, the workpiece is cooled to room temperature at a rate of 2℃ / min, thus completing the low-temperature connection method of ultrasonic-assisted brazing of TC4 alloy and Al2O3 ceramic using Sn / AlSi / Sn solder.
Claims
1. A low-temperature connection method for ultrasonic-assisted brazing of ceramics and metals using Sn / AlSi / Sn solder, characterized in that... The method for low-temperature bonding of ceramics and metals using ultrasonic-assisted brazing with Sn / AlSi / Sn solder is implemented according to the following steps:
1. An AlSi solder foil is sandwiched between two Sn foils to form a "Sn / AlSi / Sn" three-layer foil structure, resulting in a composite sandwich solder.
2. Grind the surface of the ceramic to be welded with a diamond grinding wheel and the surface of the metal to be welded with sandpaper. Then, perform ultrasonic cleaning on the ceramic and metal to be welded to obtain pre-treated ceramic and metal to be welded.
3. The composite brazing filler metal is sandwiched between the pretreated ceramic and metal surfaces to be welded to form a "ceramic / Sn / AlSi / Sn / metal" assembly structure to obtain the workpiece to be welded; 4. Place the workpiece to be welded on the heating platform and heat it to a brazing temperature of 250~350℃. Keep it at the temperature to completely melt the Sn foil. Place the ultrasonic probe on the surface of the ceramic or metal to be welded and apply ultrasonic vibration. V. After the ultrasonic vibration stops, the temperature is lowered to complete the low-temperature connection method of ultrasonic-assisted brazing of ceramics and metals.
2. The method for low-temperature bonding of ceramics and metals using ultrasonic-assisted brazing with Sn / AlSi / Sn solder according to claim 1, characterized in that... In step one, the AlSi solder foil is an Al-Si eutectic alloy or a hypereutectic Al-Si alloy with a Si content of 12wt.%~30wt.%.
3. The method for low-temperature bonding of ceramics and metals using ultrasonic-assisted brazing with Sn / AlSi / Sn solder according to claim 1, characterized in that... In step one, the thickness of the AlSi solder foil is 0.05~1mm, and the thickness of the Sn foil is 0.01~0.5mm.
4. The method for low-temperature bonding of ceramics and metals using ultrasonic-assisted brazing with Sn / AlSi / Sn solder according to claim 1, characterized in that... In step two, the ceramic to be welded is ZrO2 ceramic, Al2O3 ceramic, ZTA ceramic, SiO2 ceramic, SiC ceramic, Si3N4 ceramic, or AlN ceramic.
5. The method for low-temperature bonding of ceramics and metals using ultrasonic-assisted brazing with Sn / AlSi / Sn solder according to claim 1, characterized in that... In step two, the metal to be welded is an Al alloy, Mg alloy, Cu alloy, Ti alloy, or stainless steel.
6. The method for low-temperature bonding of ceramics and metals using ultrasonic-assisted brazing with Sn / AlSi / Sn solder according to claim 1, characterized in that... The heat preservation time in step four is 1~10 minutes.
7. The method for low-temperature bonding of ceramics and metals using ultrasonic-assisted brazing with Sn / AlSi / Sn solder according to claim 1, characterized in that... In step four, heat to a brazing temperature of 250~300℃.
8. The method for low-temperature bonding of ceramics and metals using ultrasonic-assisted brazing with Sn / AlSi / Sn solder according to claim 1, characterized in that... In step four, apply a pressure of 20~100kPa to the workpiece to be welded.
9. The method for low-temperature bonding of ceramics and metals using ultrasonic-assisted brazing with Sn / AlSi / Sn solder according to claim 1, characterized in that... In step four, the frequency of ultrasonic vibration applied is 20~60kHz.
10. The method for low-temperature bonding of ceramics and metals using ultrasonic-assisted brazing with Sn / AlSi / Sn solder according to claim 1, characterized in that... The duration of ultrasonic vibration in step four is 5-80 seconds.