Ceramic-metal brazed joint with nanocrystalline interface reaction layer as well as preparation method and application of ceramic-metal brazed joint
By forming a nanocrystalline interface reaction layer in the ceramic-metal brazed joint, the anisotropy and weak grain boundary bonding problems caused by the traditional coarse-grained structure are solved, improving the overall performance of the joint, especially its airtightness and durability under high temperature and high vacuum environments.
Patent Information
- Application Number
- CN202511869235.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-11
- Publication Date
- 2026-02-24
AI Technical Summary
In traditional ceramic-metal brazed joints, the interfacial reaction layer has a coarse-grained structure, which leads to anisotropy, weak grain boundary bonding, and intrinsic brittleness. This results in reduced thermal shock resistance and fatigue life of the joint, and the airtightness is difficult to meet the requirements of high-end equipment.
By adjusting the brazing conditions, a continuous and dense nanocrystalline interface reaction layer is formed at the connection between the ceramic substrate and the active brazing filler metal. The average grain size is 5-50 nm and the thickness is 0.01-5 μm, which improves the interfacial bonding strength and uniformly alleviates thermal mismatch stress.
It significantly improves the thermal shock resistance and thermal fatigue life of the joint, reduces the leakage rate to 10-10 Pa·m3/s, and meets the sealing reliability requirements in high temperature and high vacuum environments.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to a ceramic-metal brazing joint with a nanocrystalline interface reaction layer, its preparation method and application, belonging to the field of heterogeneous material joining technology. Background Technology
[0002] Highly reliable bonding between ceramics and metals is a core component in the manufacturing of high-end equipment such as aerospace thermal protection systems, high-power electronic device packaging, and high-temperature, high-pressure sensors. Active metal brazing (AMB) technology, which utilizes reactive elements such as Ti, Zr, and Hf to react with ceramics at the interface and form a metallurgical bond, has become one of the key methods for achieving this type of bonding. Joints prepared using this method must possess excellent mechanical properties, high-temperature stability, and long-term airtightness.
[0003] However, the interfacial reaction layer in joints currently prepared using this technology is mostly composed of submicron or micron-scale equiaxed or columnar crystal structures. The anisotropic nature of this structure makes it a source of stress concentration under thermomechanical cyclic loading, ultimately reducing the joint's thermal shock resistance and fatigue life. Furthermore, this coarse-grained structure exhibits low grain boundary bonding strength and easily accumulates impurities and microscopic defects. Under the coupled environment of high temperature and complex stress, these weak areas readily become preferred pathways for microcrack initiation and propagation, leading to early joint fracture. Simultaneously, the non-uniform spatial distribution of grain boundary diffusion channels formed by the coarse-grained structure further exacerbates gas permeation, resulting in a significant decrease in joint sealing performance, with a typical leakage rate remaining at approximately 10%. -9 Pa·m 3 The / s level is insufficient to meet the requirements of high airtightness applications. Summary of the Invention
[0004] To address the structural mismatch and performance degradation caused by the coarse-grained interfacial reaction layer in traditional ceramic-metal brazed joints due to its anisotropy, weak grain boundary bonding, and intrinsic brittleness, this invention provides a ceramic-metal brazed joint with a nanocrystalline interfacial reaction layer, its preparation method, and its applications. This invention significantly improves the overall performance of the joint by adjusting brazing conditions to form a continuous and dense nanocrystalline interfacial reaction layer at the junction of the ceramic matrix and the active brazing filler metal.
[0005] A ceramic-metal brazing joint with a nanocrystalline interface reaction layer, the ceramic-metal brazing joint comprising a ceramic substrate, a metal substrate, an active solder layer connecting the ceramic substrate and the metal substrate, and a nanocrystalline structure layer grown in situ between the active solder layer and the ceramic substrate.
[0006] The nanocrystalline structure layer of the present invention is composed of one or more nanocrystalline phases selected from nitrides, oxides, silicides, borides, or carbides formed after the reaction between the ceramic matrix and the active solder layer.
[0007] In the above technical solution, the average grain size of the nanocrystalline structure layer is 5-50 nm.
[0008] Preferably, the average grain size of the nanocrystalline structure layer is 5-40 nm.
[0009] More preferably, the average grain size of the nanocrystalline structure layer is 5-30 nm.
[0010] In the above technical solution, the thickness of the nanocrystalline structure layer is 0.01-5 μm.
[0011] Preferably, the thickness of the nanocrystalline structure layer is 0.01-3 μm.
[0012] More preferably, the thickness of the nanocrystalline structure layer is 0.01-1.2 μm.
[0013] In the above technical solution, the ceramic matrix is selected from one of oxide ceramics, nitride ceramics, carbide ceramics or boride ceramics.
[0014] Preferably, the ceramic matrix is selected from one of silicon nitride ceramics, alumina ceramics, silicon carbide ceramics, aluminum nitride ceramics, zirconium boride ceramics, or yttrium oxide-stabilized zirconium oxide ceramics.
[0015] In the above technical solution, the active element in the active solder layer is selected from one or more of Ti, Zr, Hf, V, Nb or Ta.
[0016] Furthermore, the active solder described in this invention refers to solder formed by adding active elements to traditional solder.
[0017] Preferably, the conventional brazing filler metal is one of Ag-Cu-In, Ag-Cu, Cu-Si, Ni-Cr, or Au-Ni.
[0018] Furthermore, the active element content in the active solder layer is 0.1-10 wt.%.
[0019] Preferably, the active element content in the active solder layer is 0.1-5 wt.%.
[0020] More preferably, the active element content in the active solder layer is 0.1-2 wt.%.
[0021] In the above technical solution, the metal matrix is composed of metal or metal alloy.
[0022] Preferably, the metal is copper.
[0023] Preferably, the metal alloy is a nickel-based alloy, an iron-based alloy, a titanium-based alloy, or a molybdenum alloy.
[0024] More preferably, the metal alloy is Invar alloy 4J36, Hastelloy C-276, Kovar alloy 4J29, TC4 alloy, or TZM alloy.
[0025] Another object of the present invention is to provide a method for preparing the above-mentioned ceramic-metal brazed joint with a nanocrystalline interface reaction layer, comprising the following steps: placing an active brazing filler metal between the surfaces to be brazed of a ceramic substrate and a metal substrate, and applying an axial pressure of 0.1~100 kPa to form an assembly; placing the assembly in a vacuum brazing furnace, and brazing at a vacuum degree ≤5×10 -3 Under Pa conditions, the material is heated to the brazing temperature at a heating rate of 5-30 ℃ / min and held at that temperature for 5-120 min. Then, the brazed assembly is cooled to 200-300 ℃ at a cooling rate of 1-50 ℃ / min and then cooled to room temperature in the furnace to obtain the ceramic-metal brazed joint. The brazing temperature is 10-100 ℃ higher than the liquidus temperature of the selected active brazing filler metal.
[0026] Furthermore, before adding the active solder, the surfaces of the ceramic substrate and the metal substrate to be brazed are cleaned and activated.
[0027] Preferably, before adding the active solder, the surfaces of the ceramic substrate and the metal substrate to be brazed are immersed in alcohol for ultrasonic cleaning.
[0028] Preferably, after cleaning, the material undergoes low-temperature plasma activation treatment under an argon atmosphere.
[0029] Furthermore, the active solder is in the form of foil strip or paste.
[0030] Preferably, the axial pressure is 0.1-50 kPa, more preferably 0.1-10 kPa.
[0031] Preferably, the heating rate is 5-20 °C / min, more preferably 5-10 °C / min.
[0032] Preferably, the brazing temperature is 10-50 °C higher than the liquidus temperature of the selected active brazing filler metal, and more preferably 10-30 °C.
[0033] Preferably, the heat preservation time is 5-60 min, more preferably 5-20 min.
[0034] Preferably, the cooling rate is 1-20 °C / min, more preferably 1-5 °C / min.
[0035] Another object of the present invention is to provide the application of the above-mentioned ceramic-metal brazing joint with nanocrystalline interface reaction layer in aerospace thermal protection systems, high-power electronic device packaging, or high-temperature and high-pressure sensor sealing components.
[0036] The beneficial effects of this invention are as follows: By forming a continuous and dense nanocrystalline interface reaction layer with an average grain size of 5-50 nm in the ceramic-metal brazed joint, this invention fundamentally solves the structural mismatch and performance degradation problems caused by the anisotropy, weak grain boundary bonding, and intrinsic brittleness of traditional coarse-grained interface reaction layers, thereby significantly improving the overall performance of the joint. The nanocrystalline grains generated by the method provided by this invention, through a fine-grain strengthening and toughening mechanism, combined with their isotropic structure, effectively enhance the interface bonding strength and inhibit the initiation and propagation of microcracks. The uniform and fine nanocrystalline structure helps to alleviate the thermal mismatch stress between the ceramic and the metal brazing filler metal, thereby improving the thermal shock resistance and thermal fatigue life of the joint. In addition, the reaction layer composed of nanoscale grains can more effectively block gas permeation, ensuring that the joint still has excellent sealing reliability under harsh conditions such as high temperature and high vacuum, with a leakage rate of less than 10%. -10 Pa·m 3 This invention provides an innovative ceramic-metal bonding solution for high-end equipment fields such as aerospace thermal protection systems, high-power electronic device packaging, and high-temperature and high-pressure sensors. Attached Figure Description
[0037] Figure 1 This is a STEM-DF image of the nanocrystalline interface reaction layer in Example 1.
[0038] Figure 2 This is the selected area electron diffraction pattern of the nanocrystalline interface reaction layer in Example 1.
[0039] Figure 3 These are TEM-BF and TEM-DF images of the nanocrystalline interface reaction layer in Example 1. Detailed Implementation
[0040] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way.
[0041] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents and materials described are commercially available unless otherwise specified.
[0042] The method for testing the mechanical properties of ceramic-metal brazed joints is GB / T 11363-2008 Test Method for Strength of Brazed Joints.
[0043] The method for thermal fatigue cycle testing of ceramic-metal brazed joints is GB / T 33812-2017.
[0044] The following leakage rate test was performed using a helium mass spectrometer leak detector.
[0045] Example 1 Silicon nitride ceramic (Si3N4, with a thermal expansion coefficient of 3.2 × 10⁻⁶) was selected. -6 The ceramic matrix is selected as oxygen-free copper (Cu, with a thermal expansion coefficient of 16.6 × 10⁻⁶ °C). -6 Using Ag-23Cu-14.7In-2Ti (wt.%) foil as the metal substrate and Ag-23Cu-14.7In-2Ti (wt.%) foil with a thickness of 150 μm as the active solder, the method for preparing a ceramic-metal brazed joint with a nanocrystalline interface reaction layer is implemented according to the following steps: (1) The silicon nitride ceramic and oxygen-free copper surfaces to be brazed were immersed in alcohol for ultrasonic cleaning for 15 min, and then low-temperature plasma activation treatment was performed under argon atmosphere. (2) Place the foil brazing filler metal between the ceramic substrate and the metal substrate to be brazed, and apply an axial pressure of 5 kPa to form an assembly; (3) Place the assembly in a high-vacuum brazing furnace and evacuate the vacuum to 3.0 × 10⁻⁶. -3 After Pa, heat to 740 ℃ (30 ℃ above the liquidus) at a heating rate of 15 ℃ / min, hold for 30 min, and slowly cool to 250 ℃ at a rate of 8 ℃ / min. Then, cool to room temperature in the furnace to obtain the final product.
[0046] TEM samples were prepared using focused ion beam (FIB) technology for testing, and the results are shown in [Figure number missing]. Figures 1-3 .from Figure 1 and Figure 2 As can be seen, a continuous, dense nanocrystalline TiN reaction layer with a thickness of approximately 200 nm is formed at the solder / ceramic interface. Figure 3 As can be seen, the average grain size of the nanocrystalline reaction layer is 15 nm.
[0047] The ceramic-metal brazed joint obtained in Example 1 was tested and found to have a shear strength of 211 MPa at room temperature and 135 MPa at high temperature (600 ℃), with a thermal fatigue cycle of 1200 cycles.
[0048] Example 2 Alumina ceramic (Al2O3, with a coefficient of thermal expansion of 7.5 × 10⁻⁶) was selected. -6 The ceramic matrix is selected as TC4 alloy (with a thermal expansion coefficient of 8.6 × 10⁻⁶ °C). -6The metal substrate is Ag-34.25Cu-1.75Ti (wt.%) foil with a thickness of 100 μm, and the active solder is used. The preparation method of the ceramic-metal brazed joint with a nanocrystalline interface reaction layer is carried out according to the following steps: (1) The surfaces of alumina ceramic and TC4 alloy to be brazed were immersed in alcohol for ultrasonic cleaning for 15 min, and then subjected to low-temperature plasma activation treatment under argon atmosphere. (2) Place the foil brazing filler metal between the ceramic substrate and the metal substrate surfaces to be brazed, and apply 2 kPa axial pressure to form an assembly; (3) Place the assembly in a high-vacuum brazing furnace and evacuate the vacuum to 2.5 × 10⁻⁶. -3 Pa is heated to 800 ℃ (25 ℃ above the liquidus) at a heating rate of 20 ℃ / min, held at that temperature for 20 min, and then slowly cooled to 300 ℃ at a rate of 18 ℃ / min. The mixture is then cooled to room temperature in the furnace to obtain the final product.
[0049] TEM analysis showed that a continuous, dense nanocrystalline reaction layer with a thickness of about 900 nm was formed at the solder / ceramic interface, with an average grain size of 45 nm, and was composed of Ti3Cu3O nanocrystalline phase.
[0050] Testing showed that the ceramic-metal brazed joint obtained in Example 2 had a shear strength of 158 MPa at room temperature and a leakage rate of 3.0 × 10⁻⁶. -11 Pa·m 3 / s, 1200 thermal fatigue cycles.
[0051] Example 3 Silicon carbide ceramic (SiC, with a thermal expansion coefficient of 4.0 × 10⁻⁶) was selected. -6 The ceramic matrix is selected as Invar alloy 4J36 (with a thermal expansion coefficient of 1.5 × 10⁻⁶ °C). -6 Using Ag-32Cu-4.2Zr (wt.%) as the metal substrate and Ag-32Cu-4.2Zr (wt.%) as the active solder, the ceramic-metal brazed joint with a nanocrystalline interface reaction layer is prepared according to the following steps: (1) The surfaces of silicon carbide ceramic and Invar alloy 4J36 to be brazed were immersed in alcohol for ultrasonic cleaning for 15 min, followed by low-temperature plasma activation treatment under argon atmosphere. (2) Apply active solder paste evenly to the ceramic surface to be brazed, then place the metal substrate surface to be brazed on it, apply 4 kPa axial pressure to form an assembly; (3) Place the assembly in a high-vacuum brazing furnace and evacuate the vacuum to 3.5 × 10⁻⁶. -3Pa is heated to 840 ℃ (20 ℃ above the liquidus) at 10 ℃ / min, held at that temperature for 40 min, and then slowly cooled to 280 ℃ at 5 ℃ / min. The mixture is then cooled to room temperature in the furnace to obtain the final product.
[0052] TEM analysis showed that a continuous, dense nanocrystalline reaction layer with a thickness of about 800 nm was formed at the solder / ceramic interface, with an average grain size of 60 nm, and composed of ZrC nanocrystalline phase.
[0053] The ceramic-metal welded joint obtained in Example 3 was tested and found to have a shear strength of 195 MPa at room temperature and 135 MPa at high temperature (600 ℃), with a thermal fatigue cycle of 1100 cycles.
[0054] Example 4 Aluminum nitride ceramic (AlN, with a thermal expansion coefficient of 4.5 × 10⁻⁶) was selected. -6 The ceramic matrix is selected as oxygen-free copper (Cu, with a thermal expansion coefficient of 16.6 × 10⁻⁶ °C). -6 The metal substrate is Cu-3.0Si-2.5Ti (wt.%) foil with a thickness of 50 μm, and the active solder is used. The preparation method of the ceramic-metal brazed joint with a nanocrystalline interface reaction layer is carried out according to the following steps: (1) The surfaces of aluminum nitride ceramic and oxygen-free copper to be brazed were immersed in alcohol for ultrasonic cleaning for 15 minutes, and then low-temperature plasma activation treatment was performed under argon atmosphere. (2) Place the foil brazing filler metal between the ceramic substrate and the metal substrate to be brazed, and apply an axial pressure of 4.2 kPa to form an assembly; (3) Place the assembly in a high-vacuum brazing furnace and evacuate the vacuum to 4.0 × 10⁻⁶. -3 Pa is heated to 980 ℃ (30 ℃ above the liquidus) at 12 ℃ / min, held for 15 min, and then slowly cooled to 300 ℃ at 20 ℃ / min. It is then cooled to room temperature in the furnace to obtain the product.
[0055] TEM analysis showed that a continuous, dense nanocrystalline reaction layer with a thickness of about 1200 nm was formed at the solder / ceramic interface, with an average grain size of 80 nm, and was composed of TiN nanocrystalline phase.
[0056] The ceramic-metal brazed joint obtained in Example 4 was tested and found to have a room temperature shear strength of 165 MPa and a thermal fatigue cycle of 1000 cycles.
[0057] Example 5 Zirconium boride ceramic (ZrB2, with a thermal expansion coefficient of 5.9 × 10⁻⁶) was selected. -6The ceramic matrix is selected as TZM molybdenum alloy (with a thermal expansion coefficient of 5.3 × 10⁻⁶ °C). -6 / ℃) as the metal matrix. Ni-7.2Cr-8.5Hf (wt.%) active solder paste was used as the active brazing filler metal. The preparation method of the ceramic-metal brazed joint with nanocrystalline interface reaction layer is carried out according to the following steps: (1) The surfaces of zirconium boride ceramic and TZM alloy to be brazed were immersed in alcohol for ultrasonic cleaning for 15 min, and then subjected to low-temperature plasma activation treatment under argon atmosphere. (2) Apply active solder paste evenly to the ceramic surface, then place the metal substrate to be brazed on it, apply 3.5 kPa axial pressure to form an assembly; (3) Place the assembly in a high-vacuum brazing furnace and evacuate the vacuum to 5.0 × 10⁻⁶. -3 Pa is heated to 1250 ℃ (25 ℃ above the liquidus) at 8 ℃ / min, held for 25 min, and then slowly cooled to 300 ℃ at 16 ℃ / min. It is then cooled to room temperature in the furnace to obtain the product.
[0058] TEM analysis showed that a continuous, dense nanocrystalline reaction layer with a thickness of about 1600 nm was formed at the solder / ceramic interface, with an average grain size of 85 nm, and composed of HfB2 nanocrystalline phase.
[0059] The ceramic-metal brazed joint obtained in Example 5 was tested and found to have a room temperature shear strength of 185 MPa, a high temperature (800℃) shear strength of 112 MPa, and a thermal fatigue cycle of 1000 cycles.
[0060] Example 6 Yttrium oxide-stabilized zirconia ceramic (YSZ, 8 mol% Y₂O₃ stabilized, with a thermal expansion coefficient of 10.5 × 10⁻⁶) was selected. -6 The ceramic matrix was selected as Hastelloy C-276 (with a coefficient of thermal expansion of 11.2 × 10⁻⁶ °C) at 10 °C. -6 Using a metal substrate of (°C), a 120 μm thick Au-18Ni-5V (wt.%) foil solder was used as the active solder. The preparation method of the ceramic-metal brazed joint with a nanocrystalline interface reaction layer was carried out according to the following steps: (1) The surfaces of YSZ ceramic and C-276 alloy to be brazed were immersed in alcohol for ultrasonic cleaning for 15 min, and then low-temperature plasma activation treatment was performed under argon atmosphere. (2) Place the foil solder between the ceramic substrate and the metal substrate, apply an axial pressure of 3.8 kPa, and form an assembly; (3) Place the assembly in a high-vacuum brazing furnace and evacuate the vacuum to 3.0 × 10⁻⁶.-3 Pa is heated to 1050 ℃ (20 ℃ above the liquidus) at 15 ℃ / min, held at that temperature for 25 min, and then slowly cooled to 280 ℃ at 25 ℃ / min. It is then cooled to room temperature in the furnace to obtain the product.
[0061] TEM analysis showed that a continuous, dense nanocrystalline reaction layer with a thickness of about 700 nm was formed at the solder / ceramic interface, with an average grain size of 30 nm, and composed of ZrV2O7 nanocrystalline phase.
[0062] The ceramic-metal brazed joint obtained in Example 6 was tested and found to have a room temperature shear strength of 201 MPa and a thermal fatigue cycle of 1100 cycles.
[0063] Example 7 Silicon nitride ceramic (Si3N4, with a thermal expansion coefficient of 3.2 × 10⁻⁶) was selected. -6 The ceramic matrix was selected using Kovar alloy 4J29 (with a thermal expansion coefficient of 5.1 × 10⁻⁶ °C) at 10 °C. -6 The metal substrate is Ag-32Cu-1.2Ti-2.0Zr foil strip with a thickness of 80 μm is used as the active solder. The preparation method of the ceramic-metal brazed joint with a nanocrystalline interface reaction layer is carried out according to the following steps: (1) The surfaces of silicon nitride ceramic and 4J29 alloy to be brazed were immersed in alcohol for ultrasonic cleaning for 15 minutes, followed by argon low-temperature plasma activation treatment. (2) Place the foil solder between the ceramic substrate and the metal substrate, apply an axial pressure of 1.5 kPa, and form an assembly; (3) Place it in a high-vacuum brazing furnace and evacuate the vacuum to 2.8 × 10⁻⁶. -3 Pa is heated to 840 ℃ (20 ℃ above the liquidus) at 12 ℃ / min, held at that temperature for 35 min, and then slowly cooled to 280 ℃ at 10 ℃ / min. The mixture is then cooled to room temperature in the furnace to obtain the final product.
[0064] TEM analysis showed that a continuous and dense nanocrystalline reaction layer with a thickness of about 1500 nm was formed at the solder / ceramic interface. This layer was a composite reaction layer of TiN and ZrSi2, with average grain sizes of 28 nm (TiN) and 32 nm (ZrSi2), respectively.
[0065] The ceramic-metal brazed joint obtained in Example 7 was tested and found to have a room temperature shear strength of 190 MPa and a leakage rate of 2.0 × 10⁻⁶ MPa. -11 Pa·m 3 / s, 1000 thermal fatigue cycles.
[0066] Example 8 Silicon carbide ceramic (SiC, with a thermal expansion coefficient of 4.0 × 10⁻⁶) was selected. -6 The ceramic matrix is selected as TZM molybdenum alloy (with a thermal expansion coefficient of 5.3 × 10⁻⁶ °C). -6 Using a metal matrix of ( / ℃) and Ni-10Cr-5Nb (wt.%) active solder paste as the active filler metal, the preparation method of the ceramic-metal brazed joint with a nanocrystalline interface reaction layer is carried out according to the following steps: (1) The surfaces of silicon carbide ceramics and TZM alloys to be brazed were immersed in alcohol for ultrasonic cleaning for 15 minutes, and then subjected to low-temperature plasma activation treatment under argon atmosphere. (2) Apply active solder paste to the ceramic surface, then place the metal substrate to be brazed on it, apply 3 kPa axial pressure to form an assembly; (3) Place the assembly in a high-vacuum furnace and evacuate the vacuum to 4.5 × 10⁻⁶. -3 Pa is heated to 1150 ℃ (20 ℃ above the liquidus) at 10 ℃ / min, held for 20 min, and then slowly cooled to 300 ℃ at 5 ℃ / min. It is then cooled to room temperature in the furnace to obtain the product.
[0067] TEM analysis showed that a nanocrystalline NbC reaction layer with a thickness of about 1000 nm was formed at the solder / ceramic interface, with an average grain size of 40 nm.
[0068] Testing showed that the ceramic-metal brazed joint obtained in Example 8 had a room temperature shear strength of 180 MPa and a high temperature (1000 °C) shear strength of 110 MPa, with a leakage rate of 2.5 × 10⁻⁶. -11 Pa·m 3 / s, 1000 thermal fatigue cycles.
[0069] Comparative Example 1 The difference between this comparative example and Example 1 is that in step (3), the heating rate is 50 ℃ / min, the holding time is 150 min, the cooling rate is 100 ℃ / min, and the rest of the operations are the same as in Example 1.
[0070] TEM analysis showed that a reaction layer with a thickness of about 2500 nm and an average grain size of 550 nm was formed at the solder / ceramic interface.
[0071] Testing showed that the ceramic-metal brazed joint obtained in Comparative Example 1 had a room temperature shear strength of 120 MPa and a leakage rate of 3.0 × 10⁻⁶ MPa. -9 Pa·m 3 / s, 600 thermal fatigue cycles.
Claims
1. A ceramic-metal brazing joint with a nanocrystalline interface reaction layer, characterized in that: The ceramic-metal brazing joint includes a ceramic substrate, a metal substrate, an active solder layer connecting the ceramic substrate and the metal substrate, and a nanocrystalline structure layer grown in situ between the active solder layer and the ceramic substrate.
2. The ceramic-metal brazing joint according to claim 1, characterized in that: The average grain size of the nanocrystalline reaction layer is 5-50 nm, and the thickness is 0.01-5 μm.
3. The ceramic-metal brazing joint according to claim 1, characterized in that: The ceramic matrix is selected from one of oxide ceramics, nitride ceramics, carbide ceramics or boride ceramics.
4. The ceramic-metal brazing joint according to claim 1, characterized in that: The active element in the active solder layer is selected from one or more of Ti, Zr, Hf, V, Nb, or Ta.
5. The ceramic-metal brazing joint according to claim 4, characterized in that: The active element content in the active solder layer is 0.1-10 wt.%.
6. The method for preparing the ceramic-metal brazed joint according to any one of claims 1-5, characterized in that: An active brazing filler metal is placed between the ceramic substrate and the metal substrate surfaces to be brazed, and an axial pressure of 0.1~100 kPa is applied to form an assembly. The assembly is then placed in a vacuum brazing furnace at a vacuum level ≤ 5 × 10⁻⁶. -3 Under Pa conditions, the material is heated to the brazing temperature at a heating rate of 5-30 °C / min and held for 5-120 min. The brazed assembly is then cooled to 200-300 °C at a cooling rate of 1-50 °C / min and then cooled to room temperature in the furnace to obtain the ceramic-metal brazed joint. The brazing temperature is 10-100 °C higher than the liquidus temperature of the selected active brazing filler metal.
7. The preparation method according to claim 6, characterized in that: Before adding the active solder, the surfaces of the ceramic and metal substrates to be brazed are cleaned and activated.
8. The preparation method according to claim 6, characterized in that: The active solder is in the form of foil strip or paste.
9. The application of the ceramic-metal brazing joint with a nanocrystalline interface reaction layer as described in any one of claims 1-8 in aerospace thermal protection systems, high-power electronic device packaging, or high-temperature and high-pressure sensor sealing components.