A composition for ceramic-to-metal welding and a method for preparing and using the same

Abstract

The application belongs to the technical field of welding, and particularly relates to a composition for welding ceramic and metal, a preparation method and application thereof. The composition comprises glass powder, tin oxide, diaphosphorus pentoxide, zinc oxide and lanthanum oxide, and the structural stability is enhanced. The composition is used as a welding agent to weld ceramic and metal, and has good welding strength, interface stability, acid and alkali resistance, small alkali metal dissolution and small thermal expansion coefficient deviation.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, specifically relating to a ceramic-metal welding composition, its preparation method, and its application. Background Technology

[0002] Medical micro-feedthrough devices encompass a wide variety of categories, including feedthroughs for electrophysiological monitoring, ultrasound imaging, and implantable device signals, and are used in many critical medical scenarios such as cardiovascular interventional therapy, neurosurgical monitoring, and data transmission for wearable medical devices. The feedthrough connector is formed by welding a ceramic insulator and a metal conductor together at high temperatures through the melting of the metal.

[0003] For example, CN102824692A discloses a feedthrough connector for implantable medical devices, including a flange ring, an insulator, at least one signal probe, and a glass seal body that is fixed and hermetically sealed to the above structure. The glass seal body comprises SiO2 (approximately 60-80%), Al2O3 (approximately 5-15%), B2O3 (approximately 10-25%), Li2O (approximately 0-5%), Na2O (approximately 5-15%), and K2O (approximately 0-5%), all percentages being by mass. This type of process has the following drawbacks:

[0004] (1) The above-mentioned traditional glass seals contain a large amount of alkali metal oxides (such as Na2O, Li2O, K2O). Under some harsh chemical environments, alkali metal ions are easily dissolved by chemical reactions with external substances. For example, in the human physiological environment, acidic and alkaline substances in blood and tissue fluid may exchange with alkali metal ions, leading to the destruction of the glass structure;

[0005] (2) Although B2O3 can adjust the coefficient of thermal expansion to a certain extent, due to its many and complex components, it is difficult to accurately control the coefficient of thermal expansion to match different materials (such as ceramics and metals).

[0006] (3) In terms of mechanical strength, due to the complex composition of traditional glass sealants, microstructural defects may occur during the sealing process due to uneven distribution of components. For example, uneven distribution of alkali metal oxides may cause local structural loosening, affecting the sealing quality.

[0007] In summary, using this type of glass composition and formulation will greatly reduce its practical value, and further optimization of the composition and process is needed to develop feedthrough connectors with good biocompatibility. Summary of the Invention

[0008] This invention provides a ceramic-metal welding composition, its preparation method, and its application.

[0009] The technical solution of the present invention is as follows:

[0010] This invention provides a composition for welding ceramics and metals, the composition comprising glass powder and an organic carrier, wherein the glass powder comprises the following raw materials in weight percentages:

[0011] Tin oxide 30%-40%, phosphorus pentoxide 20%-30%, zinc oxide 20%-30%, lanthanum oxide 1%-5%;

[0012] The glass powder has a particle size of 30-50 μm.

[0013] The weight ratio of the glass powder to the organic carrier is 6-8:2-4.

[0014] The organic carrier is terpineol and ethyl cellulose, with a weight ratio of terpineol to ethyl cellulose of 8-9:1-1.5.

[0015] The present invention also provides a method for preparing the ceramic-metal welding composition described above, comprising the following steps:

[0016] (1) Tin oxide, phosphorus pentoxide, zinc oxide and lanthanum oxide are mixed and then successively melted, quenched in water and ground to obtain glass powder;

[0017] (2) Glass powder is mixed with an organic carrier composed of terpineol and ethyl cellulose and ground to obtain a composition.

[0018] In step (1), the melting temperature is 1000-1200℃ and the melting time is 2-3h.

[0019] In step (1), the particle size of the glass powder is 30-50 μm.

[0020] The present invention also provides the application of the ceramic-metal welding composition prepared by the above preparation method in a welding flux.

[0021] Furthermore, the ceramic-metal welding composition is used to improve the welding strength, interface stability, acid and alkali resistance of the welding flux, reduce alkali metal leaching, and reduce the deviation of the coefficient of thermal expansion.

[0022] Beneficial effects

[0023] The ceramic-metal welding composition provided by this invention includes glass powder comprising tin oxide, phosphorus pentoxide, zinc oxide, and lanthanum oxide, which enhances structural stability. When this composition is used as a welding agent to weld ceramics and metals, it exhibits good welding strength, interface stability, and acid and alkali resistance, with less alkali metal leaching and a small deviation in the coefficient of thermal expansion. Detailed Implementation

[0024] The following examples are intended to illustrate the present invention, and not to further limit the invention.

[0025] This invention provides a composition for welding ceramics and metals, the composition comprising glass powder and an organic carrier, wherein the glass powder comprises the following raw materials in weight percentages:

[0026] Tin oxide 30%-40%, phosphorus pentoxide 20%-30%, zinc oxide 20%-30%, lanthanum oxide 1%-5%;

[0027] The glass powder has a particle size of 30-50 μm. Glass powder within this particle size range can ensure good flowability and has sufficient specific surface area, which is beneficial for subsequent welding.

[0028] The weight ratio of glass powder to organic carrier is 6-8:2-4.

[0029] Furthermore, the organic carrier is terpineol and ethyl cellulose. Terpineol serves as the organic solvent, and ethyl cellulose as the coupling agent. The weight ratio of terpineol to ethyl cellulose is 8-9:1-1.5.

[0030] The present invention also provides a method for preparing the ceramic-metal welding composition described above, comprising the following steps:

[0031] (1) Tin oxide, phosphorus pentoxide, zinc oxide and lanthanum oxide are mixed and then melted, quenched in water and ground in sequence to obtain glass powder.

[0032] Specifically, by mass percentage, 30%-40% tin oxide, 20%-30% phosphorus pentoxide, 20%-30% zinc oxide, and 1%-5% lanthanum oxide are mixed and then melted.

[0033] It should be noted that, in addition to the above-mentioned raw materials, there may be small amounts of other impurities or trace amounts of additives.

[0034] Preferably, the melting temperature is 1000-1200℃ and the melting time is 2-3 hours.

[0035] During the melting process, the atoms work together and are "reshaped". After melting, water quenching is performed, for example with a cooling rate of over 100°C / s, to obtain glass slag. The glass slag is then ground and sieved to obtain glass powder of the target particle size.

[0036] Furthermore, the glass powder has a particle size of 30-50μm to ensure welding performance.

[0037] (2) Glass powder is mixed with an organic carrier composed of terpineol and ethyl cellulose and ground to obtain a composition.

[0038] Preferably, the weight ratio of glass powder to organic carrier is 6-8:2-4.

[0039] Furthermore, the weight ratio of terpineol to ethyl cellulose is 8-9:1-1.5.

[0040] By adjusting the amounts of glass powder, terpineol, and ethyl cellulose, operational flexibility is increased, allowing for better adaptation to different application scenarios and material property requirements. In practice, the ratio of glass powder to organic carrier can be adjusted within an appropriate range based on actual conditions (such as requirements for the composition's flowability, drying speed, and weld strength).

[0041] For example, when high welding strength is required or subsequent drying needs to be carried out at a lower drying rate, the proportion of glass powder should be increased appropriately; when high flowability of the composition is required or subsequent drying needs to be carried out at a higher drying rate, the proportion of organic carrier should be increased appropriately.

[0042] Specifically, the mixture is thoroughly ball-milled in a ball milling apparatus to obtain a homogeneous composition.

[0043] The present invention also provides the application of the ceramic-metal welding composition described above in a welding flux.

[0044] Specifically, the ceramic-metal welding composition is used to improve the welding strength, interface stability, and acid and alkali resistance of the welding flux.

[0045] The obtained composition was used as a welding flux for welding ceramics and metals. The specific welding process is as follows:

[0046] Step 1: Pre-treatment of ceramic insulators and platinum conductors

[0047] Select alumina ceramic insulators with an alumina content ≥95%. Based on actual application requirements, set the insulator's outer diameter within the range of 5-20mm and the length within the range of 10-50mm. Before use, place the ceramic insulators in an acetone solution and treat them with ultrasonic cleaning technology for 10-15 minutes. The ultrasonic cavitation effect powerfully removes surface oil and impurities. Afterward, dry them in an oven at 80-100℃ for 1-2 hours.

[0048] For platinum wires, select high-quality products with a purity of ≥99.9% and a wire diameter of 0.3-1.5mm. First, carefully wipe with alcohol to remove surface stains, then place in a hydrogen atmosphere and anneal at 400-500℃ for 30-60 minutes. Utilizing the synergistic effect of hydrogen reduction and thermal annealing, internal stress is eliminated and its flexibility is significantly improved, laying a solid foundation for subsequent welding.

[0049] Step 2: Coating

[0050] The composition obtained in this invention is coated onto the welding area of ​​the ceramic insulator with a coating thickness of 0.2-0.3 mm. For the welding end of the platinum conductor, the coating thickness is 0.1-0.2 mm over a length of 2-5 mm, ensuring sufficient and uniform interface material during welding. The coating operation can be achieved using screen printing technology (with the screen mesh count precisely controlled at 200-300 mesh).

[0051] The coating thickness refers to the thickness measured after the coating composition has been coated and dried. Preferably, the drying temperature is 80-120℃ and the drying time is 30-90 minutes.

[0052] Within this drying temperature range, the terpineol in the organic carrier can gradually volatilize without causing adverse changes to components such as glass powder due to excessively high temperatures. For example, if the temperature is too high, the glass powder may soften prematurely or the components in the organic carrier may decompose, affecting the quality of the coating.

[0053] Regarding drying time, generally, thicker coatings require longer drying times to ensure sufficient evaporation of the organic solvents. Environmental factors such as humidity also affect drying time. If the ambient humidity is high, the drying time may need to be extended to ensure the coating is completely dry. In practice, the degree of dryness can be initially judged by observing the appearance of the coating. When the surface changes from wet to dry and no longer has noticeable stickiness, drying can be preliminarily considered complete. However, the final determination should be based on whether the thickness measurement meets the requirements.

[0054] Step 3: Pre-assembly

[0055] The ceramic insulator coated with the composition and the platinum conductor are precisely connected to ensure that the welded parts are tightly aligned. They are then fixed with a professional clamp, and the clamp pressure is precisely controlled at 0.4-0.6MPa to ensure that the gap between the ceramic insulator and the platinum conductor is maintained stably at 0.05-0.1mm, creating ideal conditions for subsequent high-quality welding.

[0056] Step 4: Welding

[0057] Place the pre-assembled weldment smoothly into the heating furnace and steadily raise the temperature from room temperature to 350-400℃ at a heating rate of 5-8℃ / min, and hold for 20-30 minutes. After holding, lower the temperature to 200℃ at a cooling rate of 3-5℃ / min, and then let it cool naturally to room temperature.

[0058] The heating parameters must be strictly controlled during the welding process. First, the heating rate must match the heat conduction and melting kinetics between the weldments to avoid internal defects. Second, the holding temperature and holding time must meet the energy required for atomic migration and chemical reactions to achieve atomic bonding between interfaces. Third, the cooling rate must be appropriate to control the gradual release of thermal stress and avoid uneven shrinkage due to sudden cooling, which can lead to cracks. Finally, natural cooling should be combined to slowly eliminate residual stress and stabilize the welded structure.

[0059] Example 1

[0060] (1) By mass percentage, 40% tin oxide, 30% phosphorus pentoxide, 25% zinc oxide and 5% lanthanum oxide are mixed and melted at 1100℃ for 2.5h;

[0061] After melting is complete, the glass is quenched in water to obtain glass slag. The glass slag is then ground and sieved to obtain glass powder with a particle size of 30-50μm.

[0062] (2) Glass powder and an organic carrier composed of terpineol and ethyl cellulose in a weight ratio of 9:1 are mixed in a weight ratio of 7:3 and ball-milled thoroughly to obtain a composition.

[0063] (3) Select alumina ceramic insulators with an outer diameter of 10 mm and a length of 30 mm (alumina content ≥95%), ultrasonically clean them in acetone solution for 12 min, dry them in an oven at 90℃ for 1.5 h, and then set them aside for use.

[0064] Platinum wires with a purity of 99.95% and a diameter of 0.5 mm were selected, wiped with alcohol, and then annealed at 450°C for 45 minutes in a hydrogen atmosphere before use.

[0065] (4) The composite material is applied to the welding area of ​​the ceramic insulator using a 250-mesh screen printing machine. After drying, the thickness is 0.25 mm.

[0066] The platinum wire is coated with the composition along a 3mm length of the solder end, and after drying, the thickness is 0.15mm.

[0067] (5) Pre-assemble the ceramic insulator and the platinum conductor, and fix them with a clamp at 0.5MPa so that the gap between the ceramic insulator and the platinum conductor is 0.08mm.

[0068] (6) Place the pre-assembled weldment smoothly into the heating furnace and steadily raise the temperature from room temperature to 380°C at a heating rate of 6°C / min, and hold for 25 minutes. After the holding period, lower the temperature to 200°C at a cooling rate of 4°C / min, and then let it cool naturally to room temperature.

[0069] Example 2

[0070] (1) By mass percentage, 35% tin oxide, 30% phosphorus pentoxide, 30% zinc oxide and 5% lanthanum oxide are mixed and melted at 1100℃ for 2.5h;

[0071] After melting is complete, the glass is quenched in water to obtain glass slag. The glass slag is then ground and sieved to obtain glass powder with a particle size of 30-50μm.

[0072] (2) Glass powder and an organic carrier composed of terpineol and ethyl cellulose in a weight ratio of 9:1 are mixed in a weight ratio of 7:3 and ball-milled thoroughly to obtain a composition.

[0073] (3) Select alumina ceramic insulators with an outer diameter of 5 mm and a length of 10 mm (alumina content ≥95%), ultrasonically clean them in acetone solution for 12 min, dry them in an oven at 90℃ for 1.5 h, and then set them aside for use.

[0074] Platinum wires with a purity of 99.9% and a diameter of 0.3 mm were selected, wiped with alcohol, and then annealed at 450°C for 45 minutes in a hydrogen atmosphere before use.

[0075] (4) The composite material is applied to the welding area of ​​the ceramic insulator using a 250-mesh screen printing machine. After drying, the thickness is 0.25 mm.

[0076] The platinum wire is coated with the composition along a 3mm length of the solder end, and after drying, the thickness is 0.15mm.

[0077] (5) Pre-assemble the ceramic insulator and the platinum conductor, and fix them with a clamp at 0.5MPa so that the gap between the ceramic insulator and the platinum conductor is 0.08mm.

[0078] (6) Place the pre-assembled weldment smoothly into the heating furnace and steadily raise the temperature from room temperature to 380°C at a heating rate of 6°C / min, and hold for 25 minutes. After the holding period, lower the temperature to 200°C at a cooling rate of 4°C / min, and then let it cool naturally to room temperature.

[0079] Example 3

[0080] (1) By mass percentage, 40% tin oxide, 25% phosphorus pentoxide, 30% zinc oxide and 5% lanthanum oxide are mixed and melted at 1100℃ for 2.5h;

[0081] After melting is complete, the glass is quenched in water to obtain glass slag. The glass slag is then ground and sieved to obtain glass powder with a particle size of 30-50μm.

[0082] (2) Glass powder and an organic carrier composed of terpineol and ethyl cellulose in a weight ratio of 9:1 are mixed in a weight ratio of 7:3 and ball-milled thoroughly to obtain a composition.

[0083] (3) Select alumina ceramic insulators with an outer diameter of 10 mm and a length of 30 mm (alumina content ≥95%), ultrasonically clean them in acetone solution for 12 min, dry them in an oven at 90℃ for 1.5 h, and then set them aside for use.

[0084] Platinum wires with a purity of 99.95% and a diameter of 0.5 mm were selected, wiped with alcohol, and then annealed at 450°C for 45 minutes in a hydrogen atmosphere before use.

[0085] (4) The composite material is applied to the welding area of ​​the ceramic insulator using a 250-mesh screen printing machine. After drying, the thickness is 0.25 mm.

[0086] The platinum wire is coated with the composition along a 3mm length of the solder end, and after drying, the thickness is 0.15mm.

[0087] (5) Pre-assemble the ceramic insulator and the platinum conductor, and fix them with a clamp at 0.5MPa so that the gap between the ceramic insulator and the platinum conductor is 0.08mm.

[0088] (6) Place the pre-assembled weldment smoothly into the heating furnace and steadily raise the temperature from room temperature to 380°C at a heating rate of 6°C / min, and hold for 25 minutes. After the holding period, lower the temperature to 200°C at a cooling rate of 4°C / min, and then let it cool naturally to room temperature.

[0089] Comparative Example 1

[0090] Compared with Example 1, step (1) does not involve the addition of lanthanum oxide, while the remaining operations, raw material types, and amounts are consistent with those in Example 1.

[0091] Comparative Example 2

[0092] The preparation was carried out using raw materials published under CN102824692A, specifically as follows:

[0093] (1) By mass percentage, 70% SiO2, 10% Al2O3, 10% B2O3, 3% Li2O, 5% Na2O and 2% K2O are mixed and melted at 1100℃ for 2.5h.

[0094] After melting is complete, the glass is quenched in water to obtain glass slag. The glass slag is then ground and sieved to obtain glass powder with a particle size of 30-50μm.

[0095] (2) Glass powder and an organic carrier composed of terpineol and ethyl cellulose in a weight ratio of 9:1 are mixed in a weight ratio of 7:3 and ball-milled thoroughly to obtain a composition.

[0096] (3) Select alumina ceramic insulators with an outer diameter of 10 mm and a length of 30 mm (alumina content ≥95%), ultrasonically clean them in acetone solution for 12 min, dry them in an oven at 90℃ for 1.5 h, and then set them aside for use.

[0097] Platinum wires with a purity of 99.95% and a diameter of 0.5 mm were selected, wiped with alcohol, and then annealed at 450°C for 45 minutes in a hydrogen atmosphere before use.

[0098] (4) The composite material is applied to the welding area of ​​the ceramic insulator using a 250-mesh screen printing machine. After drying, the thickness is 0.25 mm.

[0099] The platinum wire is coated with the composition along a 3mm length of the solder end, and after drying, the thickness is 0.15mm.

[0100] (5) Pre-assemble the ceramic insulator and the platinum conductor, and fix them with a clamp at 0.5MPa so that the gap between the ceramic insulator and the platinum conductor is 0.08mm.

[0101] (6) Place the pre-assembled weldment smoothly into the heating furnace and steadily raise the temperature from room temperature to 380°C at a heating rate of 6°C / min, and hold for 25 minutes. After the holding period, lower the temperature to 200°C at a cooling rate of 4°C / min, and then let it cool naturally to room temperature.

[0102] Performance testing

[0103] 1. Welding strength test

[0104] According to GB / T 2651-2008 "Tension Test Method for Welded Joints", the welding strength of the weldments in Examples 1-3 and Comparative Examples 1-2 was tested.

[0105] 2. Interface stability test

[0106] The test was conducted according to GB / T 2654-2008 "Test Method for Hardness of Welded Joints" and combined with a custom-designed electrical load and temperature cycling test procedure. First, before conducting the electrical load and temperature cycling tests, multiple test points were selected at different locations on the welded joint (including the ceramic-glass interface, glass-metal interface, and the base material area far from the interface) using appropriate hardness testing equipment (such as a Vickers hardness tester or Rockwell hardness tester), according to the methods specified in GB / T 2654-2008. The initial hardness values ​​were measured, and the hardness distribution was recorded. Then, the weldment was placed in a specially designed testing device for a simulated 500-hour electrical load and -30℃ to 150℃ temperature cycling test. During the test, the electrical load parameters (such as current, voltage, and frequency) were controlled within a specific range to simulate the electrical signal transmission under actual working conditions. A precise temperature control system was used for the temperature cycling to ensure that the temperature change rate, low-temperature holding time, and high-temperature holding time met the set requirements. After the test, the hardness value was measured again at the same test point according to the GB / T 2654-2008 standard, and the change in hardness value before and after the test was compared. If the change in hardness value is within the allowable error range, and the hardness distribution is still uniform, and no obvious cracks, weld failures or other defects are found when the weld interface is observed under a microscope, and the signal transmission is stable during the electrical load test (monitored in real time by a signal detection device connected to the weldment), then the interface stability is judged to be good.

[0107] In Example 1, the hardness values ​​at each test point of the welded joint fluctuated between 60-70 HV before testing. After 500 hours of testing, the hardness values ​​fluctuated between 58-72 HV, with deviations of 58-72 HV or 60-70 HV within ±2 HV. Microscopic observation revealed no obvious defects at the interface, and signal transmission was stable, indicating interface stability. In Example 2, the hardness values ​​ranged from 53-67 HV, with a deviation of ±2 HV. Although the composition changed, the overall interface stability still ensured that the hardness fluctuated within a reasonable range. In Example 3, the hardness values ​​ranged from 53-67 HV, with a deviation of ±2 HV. Although the composition changed, the overall interface stability still ensured that the hardness fluctuated within a reasonable range. In Comparative Example 1, the hardness values ​​ranged from 45-65 HV, with a deviation of ±5 HV. After testing, due to the lack of lanthanum oxide to optimize the structure, the hardness changed relatively significantly, and sudden hardness changes may occur in local areas, reflecting poor interface stability. Comparative Example 2 shows a hardness range of 30-60 HV, with a deviation range of ±10 HV. During the simulation test, due to structural instability caused by factors such as alkali metal oxides, the hardness changes significantly under thermal and electrical stress, and local softening or hardening may occur. At the same time, microscopic observation reveals obvious cracks and signs of weld detachment at the weld interface, and the signal transmission is also unstable, indicating poor interface stability.

[0108] 3. Alkali metal leaching test

[0109] Alkali metal leaching tests were conducted according to the principles outlined in GB / T 1549-2008 "Chemical Analysis Methods for Fiberglass". First, a precise immersion solution simulating the human body environment was prepared, controlling parameters such as the solution's composition (e.g., simulating the main ionic components in blood and tissue fluid), pH value, and osmotic pressure to approximate the real physiological environment of the human body. The welded components were completely immersed in the immersion solution at a specific temperature (e.g., 37°C, simulating human body temperature) for 30 days. After immersion, atomic absorption spectrometry (AAS) was used to determine the alkali metal leaching amount. The specific procedure was as follows: Using an AAS instrument, the immersion solution was appropriately diluted and pretreated to eliminate interference from other components on the detection of alkali metal elements. Then, based on the characteristic absorption wavelengths of different alkali metal elements (e.g., Na, K), detection was performed separately. By comparing the absorbance with that of a standard solution, the concentration of alkali metal ions in the immersion solution was calculated, thus yielding the alkali metal leaching amount (ppm). For example, in Comparative Example 2, the Na in the immersion solution was detected... + The concentration is 30 ppm, K + The concentration was 25 ppm, and the total alkali metal leaching exceeded 50 ppm, while in Examples 1-3, Na... + The concentrations were all below 0.5 ppm, K + The concentration is less than 0.5 ppm, and the total alkali metal leaching is less than 1 ppm.

[0110] 4. Thermal expansion coefficient deviation test

[0111] The deviation of the coefficient of thermal expansion of the weldments in Examples 1-3 and Comparative Examples 1-2 was tested in the range of -50℃ to 200℃.

[0112] 5. Acid and alkali resistance test

[0113] For the simulated human physiological environment acid-base test (immersion in pH 2-12 solution for 7 days), firstly, an acidic solution with a pH of 2 and an alkaline solution with a pH of 12 were precisely prepared according to standard requirements. A precision pH meter was used for calibration and measurement to ensure the accuracy of the solution pH values. The weldment was then immersed in the acidic and alkaline solutions respectively, under constant temperature (e.g., 25℃) for 7 days. After immersion, the weldment was removed, and the surface was gently rinsed with deionized water to remove residual solution. It was then dried in a drying oven at an appropriate temperature (e.g., 60℃) until constant weight. The weight loss rate was calculated by measuring the change in mass of the weldment before and after immersion, using the formula: Weight loss rate = [(mass before immersion - mass after immersion) / mass before immersion] × 100%. Simultaneously, the surface corrosion of the weldment was observed using a microscope, and any pitting, cracks, changes in gloss, etc., were recorded.

[0114] For example, in Example 1, the weight loss rate after soaking in the pH 2 solution was 0.03%, and the weight loss rate after soaking in the pH 12 solution was 0.05%, with a total weight loss rate of less than 0.1%. Moreover, no obvious pits or erosion marks were observed on the surface, and the surface was smooth. In contrast, in Comparative Example 2, the weight loss rate after soaking in the pH 2 solution was 0.2%, and the weight loss rate after soaking in the pH 12 solution was 0.4%, with a total weight loss rate of more than 0.5%. The surface had obvious erosion pits, and the gloss was significantly reduced.

[0115] The test results above are summarized in a table, as shown in Table 1.

[0116] Table 1 Test Comparison

[0117]

[0118] As shown in Table 1, compared with Comparative Example 1 and Comparative Example 2, the compositions obtained by using the raw materials and preparation methods of this application in Examples 1-3, when coated onto ceramics and platinum wires, have good welding strength, interface stability, acid and alkali resistance, and less alkali metal leaching and smaller deviation in thermal expansion coefficient.

[0119] In addition, the coating thickness and the operating parameters of the heating furnace during welding were compared.

[0120] When the coating thickness is changed, specifically, compared with Example 1, in step (4), the composition is coated on the welding part of the ceramic insulator, and after drying, the thickness is 0.35 mm; the composition is coated on a 3 mm length of the welding end of the platinum wire, and after drying, the thickness is 0.25 mm. The remaining operations, raw material types, and addition amounts are consistent with Example 1.

[0121] The weld strength of this weldment is 16 N / mm². 2 A few tiny cracks appeared at the welding interface, and the signal transmission fluctuated slightly, resulting in performance inferior to Example 1.

[0122] When heating and welding, the operating parameters of the heating furnace are changed. Specifically, compared with Example 1, in step (6), the pre-assembled weldment is placed smoothly into the heating furnace and heated steadily from room temperature to 380°C at a heating rate of 10°C / min, and held for 15 minutes. After the holding period, the temperature is reduced to 200°C at a cooling rate of 6°C / min, and then naturally cooled to room temperature.

[0123] The weld strength of this component is 15 N / mm². 2 The weld interface showed localized detachment, and its performance was not as good as in Example 1.

Claims

1. The application of a ceramic-metal welding composition in the welding flux for the feedthrough connector of a medical micro-feedthrough device, characterized in that, The composition comprises glass powder and an organic carrier, wherein the glass powder comprises the following raw materials in weight percentages: Tin oxide 30%-40%, phosphorus pentoxide 20%-30%, zinc oxide 20%-30%, lanthanum oxide 1%-5%; The glass powder has a particle size of 30-50 μm.

2. The application according to claim 1, characterized in that, The weight ratio of the glass powder to the organic carrier is 6-8:2-4.

3. The application according to claim 1, characterized in that, The organic carrier is terpineol and ethyl cellulose, with a weight ratio of terpineol to ethyl cellulose of 8-9:1-1.

5.

4. The application according to claim 1, characterized in that, The composition is prepared by the following steps: (1) Tin oxide, phosphorus pentoxide, zinc oxide and lanthanum oxide are mixed and then melted, quenched in water and ground in sequence to obtain glass powder; (2) Glass powder is mixed with an organic carrier composed of terpineol and ethyl cellulose and ground to obtain a composition.

5. The application according to claim 4, characterized in that, In step (1), the melting temperature is 1000-1200℃ and the melting time is 2-3h.

6. The application according to claim 1, characterized in that, The ceramic-metal welding composition is used in the preparation of welding fluxes that improve the welding strength, interface stability, acid and alkali resistance of feedthrough connectors for medical micro feedthrough devices, as well as to reduce alkali metal leaching and reduce deviations in the coefficient of thermal expansion.

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