Zirconia ceramic and iron-based alloy air reaction brazing filler metal, preparation method and application thereof
By using a brazing filler metal composed of Ag, CuO, and TiO2 to regulate the interfacial reaction process, the problem of brittle oxide layer formation in air reactive brazing of zirconia ceramics and iron-based alloys was solved, achieving a high-strength, high-sealing joint connection suitable for medium and high temperature conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HARBIN INST OF TECH
- Filing Date
- 2026-05-08
- Publication Date
- 2026-06-30
Smart Images
Figure CN122299247A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of materials welding, and relates to a brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys, its preparation method and application. Background Technology
[0002] Zirconia ceramics, with their excellent thermal stability, chemical inertness, mechanical strength, and unique ionic conductivity, are widely used in aerospace, electronics, energy, and machinery manufacturing, making them a highly promising high-performance structural and functional integrated ceramic material. Yttrium doping modification can stabilize the zirconia lattice, improve its high-temperature performance, and expand its application scenarios in medium and high temperatures. Iron-based alloys possess excellent mechanical and high-temperature oxidation resistance properties, are electrically conductive, and are inexpensive, making them commonly used industrial structural metals. They are often paired with zirconia ceramics to leverage the performance advantages of both.
[0003] In engineering applications, reliable bonding between zirconia ceramics and iron-based alloys is crucial for achieving functional synergy and expanding applications. However, the significant differences in crystal structure and coefficient of thermal expansion between the two have made heterogeneous bonding a persistent industrial challenge. Traditional adhesive and mechanical bonding methods suffer from poor sealing, low strength, and insufficient temperature resistance, failing to meet the long-term service requirements under medium- and high-temperature and complex operating conditions. Zirconia ceramics have a high melting point, and conventional fusion welding easily leads to cracking and damage, making effective bonding impossible. Brazing, which eliminates the need to melt the base material and avoids damage, is a suitable solution for heterogeneous bonding. Other commonly used techniques, such as reactive metal brazing, tend to cause post-weld blackening and a decrease in resistivity in the ceramic, further limiting their applicability. Among these, air reactive brazing, due to its lack of the need for a vacuum or protective atmosphere, ease of operation, and low cost, has become the most widely used brazing technology for heterogeneous bonding of ceramics and metals.
[0004] However, existing air reaction brazing technology has significant drawbacks that severely restrict joint performance and applications. The welding process of air reaction brazing relies on oxygen to participate in the reaction. Although iron-based alloys have good high-temperature oxidation resistance, under air reaction brazing conditions, a brittle oxide layer is still easily formed on the surface, leading to uneven microstructure of the joint and easy fracture along the oxide layer, significantly reducing joint strength and service reliability. At the same time, some air reaction brazing processes also have problems such as loose joint bonding and insufficient temperature resistance, making them unsuitable for medium and high temperature operating conditions.
[0005] Therefore, in order to address the aforementioned shortcomings of existing air reaction brazing technology, it is urgent to optimize and improve the air reaction brazing process and brazing filler metal composition. By adjusting the brazing filler metal ratio and optimizing process parameters, the content of brittle oxide layer and intermetallic compounds in the joint can be reduced and their dispersion can be improved. This will reduce the adverse effects of brittleness on joint performance, achieve high-strength, high-sealing, and high-temperature resistant connections between zirconia ceramics and iron-based alloys, improve the service stability of the joint, and promote its widespread application in various industrial fields. Summary of the Invention
[0006] To address the problem of the continuous brittle composite oxide layer easily generated during the air reactive brazing process of zirconia ceramics and iron-based alloys, this invention provides a brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys, its preparation method, and its application.
[0007] The brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys of the present invention is composed of Ag, CuO and TiO2; the molar fraction of Ag in the brazing filler metal is 92-93%, the molar fraction of CuO is 4%, and TiO2 is the balance.
[0008] The preparation method of the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys according to the present invention is carried out according to the following steps:
[0009] Step 1: Weigh Ag, CuO and TiO2 as raw materials. The molar fraction of Ag in the raw materials is 92-93%, the molar fraction of CuO is 4%, and TiO2 is the balance.
[0010] Step 2: Mix the raw materials weighed in Step 1 with anhydrous ethanol and then perform wet ball milling. After wet ball milling, dry the mixture to obtain the brazing filler metal.
[0011] The method for brazing zirconia ceramics and iron-based alloys using the above-mentioned brazing filler metal is carried out according to the following steps: the surfaces of the zirconia ceramics and iron-based alloys to be brazed are ground to remove surface oil and oxides; the brazing filler metal is mixed with a binder to form a paste-like brazing filler metal; the paste-like brazing filler metal is evenly applied between the surfaces of the zirconia ceramics and iron-based alloys to be brazed to obtain the workpiece to be brazed; the workpiece to be brazed is placed in a brazing furnace for air reaction brazing.
[0012] The air reaction brazing process is as follows: In an air atmosphere, the temperature is initially raised to 1000-1050℃ at a rate of 10℃ / min and held for 10-20min. Then, the workpiece is cooled to room temperature in the furnace, and the workpiece is removed to complete the brazing of zirconia ceramic and iron-based alloy.
[0013] The principle and beneficial effects of this invention are as follows:
[0014] 1. In the air reactive brazing filler metal for zirconia ceramics and iron-based alloys of this invention, Ag, as the main element, increases the fluidity of the filler metal on the base material surface. Simultaneously, its good plasticity helps regulate the thermal stress of the weld joint. CuO undergoes a eutectic reaction with Ag, meeting the low-temperature brazing requirements of zirconia ceramics and iron-based alloys. The synergistic effect of Ag-based filler metal and CuO significantly improves the wettability of the filler metal on the base material surface and effectively reduces the wetting angle of the filler metal on the base material, achieving a tight interfacial bond between the filler metal and the base material. Since CuO can undergo a eutectic reaction with Ag and TiO2, and TiO2 has a melting point above 1800℃, which is much higher than the brazing temperature, there will inevitably be residual TiO2 in the weld in solid form during the brazing process. During the cooling process, the TiO2 in solid form will act as a non-uniform nucleation site for oxides, causing oxides to grow around TiO2. Ultimately, the oxides in the brazing seam will change from a continuous distribution to a dispersed distribution. In addition, the brazing temperature of this brazing filler metal is lower than that of Ag-CuO, and the holding time is shortened. The shorter high-temperature dwell time also makes the oxide layer thickness on the iron-based alloy side significantly thinner. Therefore, since CuO can undergo a eutectic reaction with Ag and TiO2, it can control the morphology and distribution of interface products, avoid the formation of a continuous brittle oxide layer on the iron-based alloy side, improve the aggregation of brittle phases, and reduce the content of brittle phases to a dispersed distribution. It can also lower the melting point of the brazing filler metal, effectively reduce the corrosion of the base material and the deterioration of the interface, and make the brazing seam structure uniform and dense, greatly improving the joint strength. It is suitable for efficient and reliable brazing of zirconia ceramics and iron-based alloys.
[0015] Therefore, the brazing filler metal of the present invention for brazing zirconia ceramics and iron-based alloys relies on the synergistic effect of multiple components Ag, CuO and TiO2 to effectively regulate the interfacial reaction process and suppress the formation of a continuous brittle oxide layer on the iron-based alloy side.
[0016] 2. In existing active metal brazing processes, the presence of active elements such as Ti, coupled with the absence of oxygen, causes the zirconia ceramic to lose oxygen during brazing, resulting in non-stoichiometric zirconia and subsequent blackening of the ceramic surface after welding. This invention employs air reactive brazing, which avoids the problem of blackening on the ceramic side of the joint after active metal brazing, ensuring a good interface between the zirconia ceramic and the iron-based alloy, and yielding a high-quality brazed joint with excellent sealing performance and stable mechanical properties.
[0017] 3. The brazing filler metal of this invention for brazing zirconia ceramics and iron-based alloys has a uniform composition, is easy to assemble, and can precisely control the brazing seam width, thus having good prospects for engineering applications. Attached Figure Description
[0018] Figure 1 Micrograph of the weld microstructure obtained by air reactive brazing with conventional Ag-CuO filler metal for Comparative Example 1;
[0019] Figure 2 Micrograph of the weld microstructure obtained by air reactive brazing with Ag-CuO-TiO2 filler metal in Example 1; Detailed Implementation
[0020] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any reasonable combination of the specific embodiments.
[0021] Specific Implementation Method 1: The brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys in this implementation method is composed of Ag, CuO and TiO2; the molar fraction of Ag in the brazing filler metal is 92-93%, the molar fraction of CuO is 4%, and TiO2 is the balance.
[0022] This embodiment has the following beneficial effects:
[0023] 1. In this embodiment, the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys uses Ag as the main element, which increases the fluidity of the filler metal on the base material surface. Its good plasticity also helps regulate the thermal stress of the weld joint. CuO undergoes a eutectic reaction with Ag, meeting the low-temperature brazing requirements of zirconia ceramics and iron-based alloys. The synergistic effect of Ag-based filler metal and CuO significantly improves the wettability of the filler metal on the base material surface and effectively reduces the wetting angle of the filler metal on the base material, achieving a tight interfacial bond between the filler metal and the base material. Since CuO can undergo a eutectic reaction with Ag and TiO2, and TiO2 has a melting point above 1800℃, which is much higher than the brazing temperature, there will inevitably be residual TiO2 in the weld in solid form during the brazing process. During the cooling process, the TiO2 in solid form will act as a non-uniform nucleation site for oxides, causing oxides to grow around TiO2. Ultimately, the oxides in the brazing seam will change from a continuous distribution to a dispersed distribution. In addition, the brazing temperature of this brazing filler metal is lower than that of Ag-CuO, and the holding time is shortened. The shorter high-temperature dwell time also makes the oxide layer thickness on the iron-based alloy side significantly thinner. Therefore, since CuO can undergo a eutectic reaction with Ag and TiO2, it can control the morphology and distribution of interface products, avoid the formation of a continuous brittle oxide layer on the iron-based alloy side, improve the aggregation of brittle phases, and reduce the content of brittle phases to a dispersed distribution. It can also lower the melting point of the brazing filler metal, effectively reduce the corrosion of the base material and the deterioration of the interface, and make the brazing seam structure uniform and dense, greatly improving the joint strength. It is suitable for efficient and reliable brazing of zirconia ceramics and iron-based alloys.
[0024] Therefore, the brazing filler metal used in this embodiment for brazing zirconia ceramics and iron-based alloys relies on the synergistic effect of multiple components, including Ag, CuO, and TiO2, to effectively regulate the interfacial reaction process and suppress the formation of a continuous brittle oxide layer on the iron-based alloy side.
[0025] 2. In existing active metal brazing processes, the presence of active elements such as Ti, coupled with the absence of oxygen, causes the zirconia ceramic to lose oxygen during brazing, resulting in non-stoichiometric zirconia and subsequent blackening of the ceramic surface after welding. This embodiment utilizes air reactive brazing, which avoids the problem of blackening on the ceramic side of the joint after active metal brazing, ensuring a good interface between the zirconia ceramic and the iron-based alloy, and yielding a high-quality brazed joint with excellent sealing performance and stable mechanical properties.
[0026] 3. The brazing filler metal used in this embodiment for brazing zirconia ceramics and iron-based alloys has a uniform composition, is easy to assemble, and allows for precise control of the brazing seam width, thus possessing good prospects for engineering applications.
[0027] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys is composed of Ag, CuO and TiO2; the molar fraction of Ag in the brazing filler metal is 92%, the molar fraction of CuO is 4%, and TiO2 is the balance.
[0028] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 in that the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys is composed of Ag, CuO and TiO2; the molar fraction of Ag in the brazing filler metal is 93%, the molar fraction of CuO is 4%, and TiO2 is the balance.
[0029] Specific Implementation Method Four: The preparation method of the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys in this implementation method is carried out according to the following steps:
[0030] Step 1: Weigh Ag, CuO and TiO2 as raw materials. The molar fraction of Ag in the raw materials is 92-93%, the molar fraction of CuO is 4%, and TiO2 is the balance.
[0031] Step 2: Mix the raw materials weighed in Step 1 with anhydrous ethanol and then perform wet ball milling. After wet ball milling, dry the mixture to obtain the brazing filler metal.
[0032] 1. In this embodiment, the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys uses Ag as the main element, which increases the fluidity of the filler metal on the base material surface. Its good plasticity also helps regulate the thermal stress of the weld joint. CuO undergoes a eutectic reaction with Ag, meeting the low-temperature brazing requirements of zirconia ceramics and iron-based alloys. The synergistic effect of Ag-based filler metal and CuO significantly improves the wettability of the filler metal on the base material surface and effectively reduces the wetting angle of the filler metal on the base material, achieving a tight interfacial bond between the filler metal and the base material. Since CuO can undergo a eutectic reaction with Ag and TiO2, and TiO2 has a melting point above 1800℃, which is much higher than the brazing temperature, there will inevitably be residual TiO2 in the weld in solid form during the brazing process. During the cooling process, the TiO2 in solid form will act as a non-uniform nucleation site for oxides, causing oxides to grow around TiO2. Ultimately, the oxides in the brazing seam will change from a continuous distribution to a dispersed distribution. In addition, the brazing temperature of this brazing filler metal is lower than that of Ag-CuO, and the holding time is shortened. The shorter high-temperature dwell time also makes the oxide layer thickness on the iron-based alloy side significantly thinner. Therefore, since CuO can undergo a eutectic reaction with Ag and TiO2, it can control the morphology and distribution of interface products, avoid the formation of a continuous brittle oxide layer on the iron-based alloy side, improve the aggregation of brittle phases, and reduce the content of brittle phases to a dispersed distribution. It can also lower the melting point of the brazing filler metal, effectively reduce the corrosion of the base material and the deterioration of the interface, and make the brazing seam structure uniform and dense, greatly improving the joint strength. It is suitable for efficient and reliable brazing of zirconia ceramics and iron-based alloys.
[0033] Therefore, the brazing filler metal used in this embodiment for brazing zirconia ceramics and iron-based alloys relies on the synergistic effect of multiple components, including Ag, CuO, and TiO2, to effectively regulate the interfacial reaction process and suppress the formation of a continuous brittle oxide layer on the iron-based alloy side.
[0034] 2. In existing active metal brazing processes, the presence of active elements such as Ti, coupled with the absence of oxygen, causes the zirconia ceramic to lose oxygen during brazing, resulting in non-stoichiometric zirconia and subsequent blackening of the ceramic surface after welding. This embodiment utilizes air reactive brazing, which avoids the problem of blackening on the ceramic side of the joint after active metal brazing, ensuring a good interface between the zirconia ceramic and the iron-based alloy, and yielding a high-quality brazed joint with excellent sealing performance and stable mechanical properties.
[0035] 3. The brazing filler metal used in this embodiment for brazing zirconia ceramics and iron-based alloys has a uniform composition, is easy to assemble, and allows for precise control of the brazing seam width, thus possessing good prospects for engineering applications.
[0036] Specific Implementation Method 5: This implementation method differs from Specific Implementation Method 4 in that: the Ag, CuO and TiO2 in the raw materials mentioned in step one are powders, and the particle size should not be less than 325.
[0037] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Four in that the purity of Ag, CuO, and TiO2 in the raw materials mentioned in Step One is not less than 99.9%.
[0038] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Four in that the wet ball milling described in step two uses a planetary ball mill.
[0039] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Four in that the wet ball milling process described in step two is as follows: the ball milling speed is 250 r / min, and the ball milling time is 3-5 hours.
[0040] Specific Implementation Method Nine: This implementation method utilizes a brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys to braze zirconia ceramics and iron-based alloys, and follows these steps: the surfaces to be brazed, namely the zirconia ceramics and iron-based alloys, are ground to remove surface oil and oxides; the filler metal is mixed with a binder to form a paste-like filler metal; the paste-like filler metal is evenly applied between the surfaces to be brazed, namely the zirconia ceramics and iron-based alloys, to obtain the workpiece to be brazed; the workpiece to be brazed is placed in a brazing furnace for air reactive brazing.
[0041] The air reaction brazing process is as follows: In an air atmosphere, the temperature is initially raised to 1000-1050℃ at a rate of 10℃ / min and held for 10-20min. Then, the workpiece is cooled to room temperature in the furnace, and the workpiece is removed to complete the brazing of zirconia ceramic and iron-based alloy.
[0042] 1. In this embodiment, the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys uses Ag as the main element, which increases the fluidity of the filler metal on the base material surface. Its good plasticity also helps regulate the thermal stress of the weld joint. CuO undergoes a eutectic reaction with Ag, meeting the low-temperature brazing requirements of zirconia ceramics and iron-based alloys. The synergistic effect of Ag-based filler metal and CuO significantly improves the wettability of the filler metal on the base material surface and effectively reduces the wetting angle of the filler metal on the base material, achieving a tight interfacial bond between the filler metal and the base material. Since CuO can undergo a eutectic reaction with Ag and TiO2, and TiO2 has a melting point above 1800℃, which is much higher than the brazing temperature, there will inevitably be residual TiO2 in the weld in solid form during the brazing process. During the cooling process, the TiO2 in solid form will act as a non-uniform nucleation site for oxides, causing oxides to grow around TiO2. Ultimately, the oxides in the brazing seam will change from a continuous distribution to a dispersed distribution. In addition, the brazing temperature of this brazing filler metal is lower than that of Ag-CuO, and the holding time is shortened. The shorter high-temperature dwell time also makes the oxide layer thickness on the iron-based alloy side significantly thinner. Therefore, since CuO can undergo a eutectic reaction with Ag and TiO2, it can control the morphology and distribution of interface products, avoid the formation of a continuous brittle oxide layer on the iron-based alloy side, improve the aggregation of brittle phases, and reduce the content of brittle phases to a dispersed distribution. It can also lower the melting point of the brazing filler metal, effectively reduce the corrosion of the base material and the deterioration of the interface, and make the brazing seam structure uniform and dense, greatly improving the joint strength. It is suitable for efficient and reliable brazing of zirconia ceramics and iron-based alloys.
[0043] Therefore, the brazing filler metal used in this embodiment for brazing zirconia ceramics and iron-based alloys relies on the synergistic effect of multiple components, including Ag, CuO, and TiO2, to effectively regulate the interfacial reaction process and suppress the formation of a continuous brittle oxide layer on the iron-based alloy side.
[0044] 2. In existing active metal brazing processes, the presence of active elements such as Ti, coupled with the absence of oxygen, causes the zirconia ceramic to lose oxygen during brazing, resulting in non-stoichiometric zirconia and subsequent blackening of the ceramic surface after welding. This embodiment utilizes air reactive brazing, which avoids the problem of blackening on the ceramic side of the joint after active metal brazing, ensuring a good interface between the zirconia ceramic and the iron-based alloy, and yielding a high-quality brazed joint with excellent sealing performance and stable mechanical properties.
[0045] 3. The brazing filler metal used in this embodiment for brazing zirconia ceramics and iron-based alloys has a uniform composition, is easy to assemble, and allows for precise control of the brazing seam width, thus possessing good prospects for engineering applications.
[0046] Specific Implementation Method 10: This implementation method differs from Specific Implementation Method 9 in that the binder is terpineol; the mass fraction of the binder in the paste-like brazing filler metal is 4-6%.
[0047] Example 1
[0048] The preparation method of the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys according to the present invention is carried out according to the following steps:
[0049] Step 1: Weigh Ag, CuO and TiO2 as raw materials. The molar fraction of Ag in the raw materials is 92%, the molar fraction of CuO is 4%, and TiO2 is the balance.
[0050] The raw materials contain Ag, CuO, and TiO2 in powder form with a particle size of 325 mesh.
[0051] The purity of Ag, CuO, and TiO2 in the raw materials is 99.9%;
[0052] Step 2: Mix the raw materials weighed in Step 1 with anhydrous ethanol and then perform wet ball milling. After wet ball milling, dry the mixture to obtain the brazing filler metal.
[0053] The wet ball milling process is as follows: the ball milling speed is 250 r / min, and the ball milling time is 3 hours.
[0054] The wet ball milling process employs a planetary ball mill.
[0055] The method for brazing zirconia ceramics and iron-based alloys using the above-mentioned brazing filler metal is carried out according to the following steps: the surfaces of the YSZ ceramics and iron-based alloys (Crofer 22H) to be brazed are ground to remove surface oil and oxides; the brazing filler metal is mixed with terpineol to prepare a paste-like brazing filler metal, wherein the mass fraction of terpineol in the paste-like brazing filler metal is 5%; the paste-like brazing filler metal is evenly applied between the surfaces of the YSZ ceramics and iron-based alloys to be brazed to obtain the workpiece to be brazed; the workpiece to be brazed is placed in a brazing furnace for air reaction brazing;
[0056] The air reaction brazing process is as follows: under an air atmosphere, the temperature is initially raised to 1000°C at a rate of 10°C / min and held for 10 minutes. Then, the temperature is cooled to room temperature with the furnace, the workpiece is removed, and the brazing of YSZ ceramic and iron-based alloy is completed.
[0057] Comparative Example 1:
[0058] Unlike Example 1, Comparative Example 1 used Ag-4CuO brazing filler metal, and the brazing temperature was 1050°C for 30 minutes. Other processes and parameters were the same as in Example 1.
[0059] Figure 1 The image shows a micrograph of the weld microstructure obtained by air reactive brazing with conventional Ag-4CuO filler metal for Comparative Example 1. The shear strength of the brazed joint in Comparative Example 1 is 40 MPa. A relatively thick, continuously distributed oxide band can be found on the iron-based alloy side of the weld, which has a significant impact on the mechanical properties of the joint.
[0060] Figure 2 The image shows a micrograph of the weld microstructure obtained by air reactive brazing with Ag-CuO-TiO2 filler metal in Example 1. The YSZ / Ag-CuO-TiO2 / Crofer 22H brazed joint obtained in this example exhibits good metallurgical bonding. The shear strength of the brazed joint in Example 1 is 93 MPa. The weld microstructure is uniform, effectively suppressing the formation of brittle oxide bands on the iron-based alloy side, and the joint performance is excellent.
[0061] Example 2
[0062] The preparation method of the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys in this embodiment is carried out according to the following steps:
[0063] Step 1: Weigh Ag, CuO and TiO2 as raw materials. The molar fraction of Ag in the raw materials is 92%, the molar fraction of CuO is 4%, and TiO2 is the balance.
[0064] The raw materials contain Ag, CuO, and TiO2 in powder form with a particle size of 325 mesh.
[0065] The purity of Ag, CuO, and TiO2 in the raw materials is 99.9%;
[0066] Step 2: Mix the raw materials weighed in Step 1 with anhydrous ethanol and then perform wet ball milling. After wet ball milling, dry the mixture to obtain the brazing filler metal.
[0067] The wet ball milling process is as follows: the ball milling speed is 250 r / min, and the ball milling time is 3 hours.
[0068] The wet ball milling process employs a planetary ball mill.
[0069] The method for brazing zirconia ceramics and iron-based alloys using the above-mentioned brazing filler metal is carried out according to the following steps: the surfaces of the YSZ ceramics and iron-based alloys (Crofer 22H) to be brazed are ground to remove surface oil and oxides; the brazing filler metal is mixed with terpineol to prepare a paste-like brazing filler metal, wherein the mass fraction of terpineol in the paste-like brazing filler metal is 5%; the paste-like brazing filler metal is evenly applied between the surfaces of the YSZ ceramics and iron-based alloys to be brazed to obtain the workpiece to be brazed; the workpiece to be brazed is placed in a brazing furnace for air reaction brazing;
[0070] The air reaction brazing process is as follows: Under an air atmosphere, the temperature is initially raised to 1000°C at a rate of 10°C / min and held for 20 minutes. Then, the workpiece is cooled to room temperature in the furnace, and the workpiece is removed, completing the brazing of the YSZ ceramic and the iron-based alloy. The shear strength of the brazed joint obtained in this embodiment is 84 MPa.
[0071] Example 3
[0072] The preparation method of the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys in this embodiment is carried out according to the following steps:
[0073] Step 1: Weigh Ag, CuO and TiO2 as raw materials. The molar fraction of Ag in the raw materials is 92%, the molar fraction of CuO is 4%, and TiO2 is the balance.
[0074] The raw materials contain Ag, CuO, and TiO2 in powder form with a particle size of 325 mesh.
[0075] The purity of Ag, CuO, and TiO2 in the raw materials is 99.9%;
[0076] Step 2: Mix the raw materials weighed in Step 1 with anhydrous ethanol and then perform wet ball milling. After wet ball milling, dry the mixture to obtain the brazing filler metal.
[0077] The wet ball milling process is as follows: the ball milling speed is 250 r / min, and the ball milling time is 3 hours.
[0078] The wet ball milling process employs a planetary ball mill.
[0079] The method for brazing zirconia ceramics and iron-based alloys using the above-mentioned brazing filler metal is carried out according to the following steps: the surfaces of the YSZ ceramics and iron-based alloys (Crofer 22H) to be brazed are ground to remove surface oil and oxides; the brazing filler metal is mixed with terpineol to prepare a paste-like brazing filler metal, wherein the mass fraction of terpineol in the paste-like brazing filler metal is 5%; the paste-like brazing filler metal is evenly applied between the surfaces of the YSZ ceramics and iron-based alloys to be brazed to obtain the workpiece to be brazed; the workpiece to be brazed is placed in a brazing furnace for air reaction brazing;
[0080] The air reaction brazing process is as follows: Under an air atmosphere, the temperature is initially raised to 1050°C at a rate of 10°C / min and held for 20 minutes. Then, the workpiece is cooled to room temperature in the furnace, and the workpiece is removed, completing the brazing of the YSZ ceramic and the iron-based alloy. The shear strength of the brazed joint obtained in this embodiment is 64 MPa.
[0081] Example 4
[0082] The preparation method of the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys in this embodiment is carried out according to the following steps:
[0083] Step 1: Weigh Ag, CuO and TiO2 as raw materials. The molar fraction of Ag in the raw materials is 93%, the molar fraction of CuO is 4%, and TiO2 is the balance.
[0084] The raw materials contain Ag, CuO, and TiO2 in powder form with a particle size of 325 mesh.
[0085] The purity of Ag, CuO, and TiO2 in the raw materials is 99.9%;
[0086] Step 2: Mix the raw materials weighed in Step 1 with anhydrous ethanol and then perform wet ball milling. After wet ball milling, dry the mixture to obtain the brazing filler metal.
[0087] The wet ball milling process is as follows: the ball milling speed is 250 r / min, and the ball milling time is 3 hours.
[0088] The wet ball milling process employs a planetary ball mill.
[0089] The method for brazing zirconia ceramics and iron-based alloys using the above-mentioned brazing filler metal is carried out according to the following steps: the surfaces of the YSZ ceramics and iron-based alloys (Crofer 22H) to be brazed are ground to remove surface oil and oxides; the brazing filler metal is mixed with terpineol to prepare a paste-like brazing filler metal, wherein the mass fraction of terpineol in the paste-like brazing filler metal is 5%; the paste-like brazing filler metal is evenly applied between the surfaces of the YSZ ceramics and iron-based alloys to be brazed to obtain the workpiece to be brazed; the workpiece to be brazed is placed in a brazing furnace for air reaction brazing;
[0090] The air reaction brazing process is as follows: Under an air atmosphere, the temperature is initially raised to 1050°C at a rate of 10°C / min and held for 20 minutes. Then, the workpiece is cooled to room temperature in the furnace, and the workpiece is removed, completing the brazing of the YSZ ceramic and the iron-based alloy. The shear strength of the brazed joint obtained in this embodiment is 58 MPa.
Claims
1. A brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys, characterized in that: The brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys is composed of Ag, CuO and TiO2; the molar fraction of Ag in the brazing filler metal is 92-93%, the molar fraction of CuO is 4%, and TiO2 is the balance.
2. The brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys according to claim 1, characterized in that: The brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys is composed of Ag, CuO and TiO2; the molar fraction of Ag in the filler metal is 92%, the molar fraction of CuO is 4%, and TiO2 is the balance.
3. The brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys according to claim 1, characterized in that: The brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys is composed of Ag, CuO and TiO2; the molar fraction of Ag in the filler metal is 93%, the molar fraction of CuO is 4%, and TiO2 is the balance.
4. The method for preparing the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys as described in claim 1, characterized in that: The preparation method of the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys is carried out according to the following steps: Step 1: Weigh Ag, CuO and TiO2 as raw materials. The molar fraction of Ag in the raw materials is 92-93%, the molar fraction of CuO is 4%, and TiO2 is the balance. Step 2: Mix the raw materials weighed in Step 1 with anhydrous ethanol and then perform wet ball milling. After wet ball milling, dry the mixture to obtain the brazing filler metal.
5. The method for preparing the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys according to claim 4, characterized in that: In step one, the raw materials Ag, CuO and TiO2 are in powder form and the particle size should be no less than 325.
6. The method for preparing the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys according to claim 4, characterized in that: The purity of Ag, CuO and TiO2 in the raw materials mentioned in step one is not less than 99.9%.
7. The method for preparing the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys according to claim 4, characterized in that: Step two describes a wet ball milling process using a planetary ball mill.
8. The method for preparing the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys according to claim 4, characterized in that: The wet ball milling process described in step two is as follows: the ball milling speed is 250 r / min, and the ball milling time is 3-5 hours.
9. The application of the brazing filler metal for air reactive brazing of zirconia ceramics and iron-based alloys as described in claim 1, characterized in that: The method of brazing zirconia ceramics and iron-based alloys using this brazing filler metal is carried out according to the following steps: the surfaces of the zirconia ceramics and iron-based alloys to be brazed are ground to remove surface oil and oxides; the brazing filler metal is mixed with a binder to form a paste-like brazing filler metal; the paste-like brazing filler metal is evenly applied between the surfaces of the zirconia ceramics and iron-based alloys to be brazed to obtain the workpiece to be brazed; the workpiece to be brazed is placed in a brazing furnace for air reaction brazing. The air reaction brazing process is as follows: In an air atmosphere, the temperature is initially raised to 1000-1050℃ at a rate of 10℃ / min and held for 10-20min. Then, the workpiece is cooled to room temperature in the furnace, and the workpiece is removed to complete the brazing of zirconia ceramic and iron-based alloy.
10. The application according to claim 9, characterized in that: The binder is terpineol; the mass fraction of the binder in the paste-like solder is 4-6%.