Preparation method of environment-friendly welding glass slurry connecting ceramic

Abstract

The invention relates to the technical field of welding materials, in particular to a preparation method of environment-friendly welding glass slurry connecting ceramic, which comprises the following specific steps: cleaning: polishing a ceramic matrix, then placing the ceramic matrix in an alcohol container to enable the ceramic matrix to be completely immersed in a solution, mixing: fully mixing glass raw materials according to a mass ratio to obtain a mixture, and drying the mixture to obtain the environment-friendly welding glass slurry connecting ceramic. Melting: putting the mixed glass raw materials into a smelting furnace for high-temperature melting and water quenching: pouring the molten liquid into flowing deionized water, quickly cooling to room temperature, taking out, ball-milling: putting the prepared glass material into a ball mill for ball-milling and sieving, and preparing slurry: adding the prepared glass powder into a plasticizer, an organic solvent, a dispersing agent and a thixotropic agent, and uniformly stirring; the prepared slurry is evenly coated on a ceramic welding area, a core body is assembled and then placed in a vacuum furnace for high-temperature sintering, and compared with the prior art, the glass slurry is high in quality and high in sensor welding performance.

Description

Technical Field

[0001] The present invention relates to the technical field of welding materials, and in particular to a method for preparing an environmentally friendly welding glass slurry for connecting ceramics. Background Art

[0002] In recent years, the booming automotive and microelectronics industries have significantly driven market demand for highly sensitive, fast-response, and miniaturized electronic sensors. Against this backdrop, pressure sensors with high precision, adaptability to a wide range of operating environments, and long service life have become a focus of both scientific research and industry. To advance the development of new pressure sensors, researchers are exploring the optimization of their internal structures and efficient, rational packaging technologies. Ceramic capacitive pressure sensors, with their unique advantages, stand out. They utilize a combination of advanced ceramic wafer manufacturing processes, precise dimensional control techniques, sophisticated electrode layout and vacuum packaging methods, and complex electronic circuit design. Their construction involves numerous high-tech requirements. These sensors must meet extremely high standards in performance, particularly repeatability, stability, and reliability. However, current domestic technology is unable to fully meet these stringent requirements. The core welding process is a key factor in determining the performance of ceramic capacitive pressure sensors. Developing a detailed plan for this process not only holds profound scientific significance but also offers high practical application value.

[0003] In the welding process of ceramic sensors, suitable welding slurry can not only improve the performance of ceramic capacitors, but also extend the service life of the chip. Among the welding methods of various ceramic materials, glass solder has good chemical compatibility with ceramics, low manufacturing cost, is suitable for large-scale production, and is easy to form assembly line production. Therefore, glass welding is more suitable for the connection of ceramics themselves.

[0004] According to a method for sintering and preparing low-temperature glass solder sheets and its application disclosed in patent publication number CN111056744A, the method for sintering and preparing low-temperature glass solder sheets is specifically carried out in the following steps: a mold is designed according to the shape of the test piece to be welded, the mold is made of stainless steel, low-temperature glass powder is loaded into the mold cavity, and under the action of a constant pressure block, sintering is carried out at a temperature 20 to 40°C higher than the softening point of the low-temperature glass powder to obtain a glass solder sheet.

[0005] The above technical solution uses an original low-temperature glass solder sheet sintering technology to weld aluminum-based composite materials. According to different materials to be connected, low-temperature glass powder and process parameters with corresponding softening temperature and linear expansion coefficient are used, and special molds and tooling are used to achieve the connection between the aluminum-based composite material itself or the aluminum-based composite material and glass. This not only avoids the vacuum environment brazing of aluminum-based composite material metal solder, but also prevents the shortcomings of conventional paste solder such as uneven smearing, introduction of impurities, many pores, and poor strength. In addition, the glass powder of this process does not need to be granulated, which is simple and efficient, and can obtain dense, pore-free, high-strength low-temperature glass solder brazing seams. The airtightness of the sealing parts can meet the relevant standard requirements. However, for the glass solder sheets obtained by this process, a mold needs to be customized according to the shape of the sample to be welded each time it is used, which not only wastes time, but also causes a waste of resources and is not suitable for industrial production.

[0006] According to a method for infiltrating and connecting zirconia ceramics using glass solder disclosed in patent publication number CN113666766A, the method is to use glass solder to infiltrate and connect zirconia ceramic base material, and the raw materials of the glass solder are composed of the following components in weight percentage: CaO: 30% to 38%, TiO2: 20% to 26%, REO: 5% to 10%, B2O3: 1-5%, SiO2: 34% to 44%. The method for infiltrating and connecting zirconia ceramics using glass solder specifically includes the following steps: (1) material preparation: grinding and polishing the surface of the zirconia ceramic to be welded, ultrasonically cleaning it with acetone as the medium for 5-20 minutes, and blowing it dry for use; (2) glass solder preparation: preparing the glass solder according to the following formula: Weigh each oxide raw material, mix them evenly, and then use the melting-water quenching method to prepare glass solder powder; 3) Solder pre-sintering: Add polyvinyl alcohol to the glass powder and stir evenly, then put it into a tablet pressing mold to press it into a sheet structure with a certain thickness, and then put it into a muffle furnace for pre-sintering to obtain a glass solder sheet; (4) Joint assembly: Cut the pre-sintered glass solder sheet into a shape with the same size as the surface of the ceramic to be welded, and then place it between two polished zirconia ceramics to form a "sandwich" assembly structure. No pressure is used during the connection process; (5) Joint connection: Place the joint assembled in step (4) into an air atmosphere muffle furnace and quickly heat it to the welding temperature. The purpose of rapid heating is to prevent the glass solder from excessively penetrating before holding. Heat to the welding temperature and hold it for a long enough time to ensure that the glass solder and the ceramic grains are evenly mixed; after the holding period is completed, the joint is cooled to room temperature with the furnace.

[0007] The main method of the above technical solution is to grind and polish the surfaces of two zirconia ceramics to be welded to make them smooth, prepare glass solder powder according to the route of ball milling-drying-melting-water quenching-ball milling-drying-screening, press the glass solder powder into sheets, and pre-sinter and densify it. The glass solder sheet is placed between the two ceramics to be welded for assembly, and the assembled sample is placed in a muffle furnace and heated to the welding temperature. After keeping warm for a certain period of time, it is cooled with the furnace. However, this process is to press the glass powder into sheets and then sinter them into shape. The density of the glass cannot be guaranteed, and the welding effect is seriously affected. At the same time, this method is highly targeted and only applicable to zirconia ceramics.

[0008] According to the glass solder and its preparation method disclosed in patent publication number CN107021635A, the following steps are included: a) ball milling: ball milling the encapsulated glass sheet into glass powder; b) molding: pressing the glass powder into a solder blank; c) sintering: sintering the solder blank to obtain the glass solder.

[0009] The above technical solution mainly presses the glass powder obtained after ball milling into a shape directly, avoiding the use of organic substances such as adhesives. Therefore, it avoids the problem of changes in the performance of the glass powder due to the addition of adhesives, and avoids environmental pollution and harm to the human body caused by the volatilization of adhesives during use. However, this method is to prepare the glass fragments into the shape of solder by a certain method. The raw materials and components cannot be controlled, and it is not suitable for application in sensor welding.

[0010] Therefore, we provide a preparation method for environmentally friendly welding glass paste to connect ceramics to solve this problem. Summary of the Invention

[0011] The purpose of the present invention is to solve the shortcomings of the prior art and to propose an environmentally friendly method for preparing a glass slurry for joining ceramics to solve this problem.

[0012] In order to achieve the above object, the present invention adopts the following technical solutions:

[0013] A method for preparing an environmentally friendly welding glass paste for joining ceramics was designed. The specific steps of the method are as follows: Step 1, cleaning: polish the ceramic substrate, then place the ceramic substrate in an alcohol container, immerse it completely in the solution, and vibrate it ultrasonically for 10-30 minutes at a temperature of 30-50°C, and then rinse it thoroughly with deionized water;

[0014] Step 2: Mixing: fully mix the glass raw materials according to the mass ratio;

[0015] Step 3: Melting: Put the glass raw materials mixed in the second step into the melting furnace and melt them at high temperature;

[0016] Step 4: Water quenching: Pour the melted liquid obtained in step 3 into flowing deionized water, quickly cool it to room temperature, and then take it out to obtain glass frit;

[0017] Step 5: Ball milling: Place the glass material prepared in step 4 in a ball mill for ball milling, then take out the ball milled material and sieve it to obtain glass powder;

[0018] Step 6: Slurry preparation: Add the glass powder prepared in step 5 to the plasticizer, organic solvent, dispersant, and thixotropic agent, and then fully stir at a speed of 30-60 rpm for 12-36 hours until the mixture is evenly mixed until it is molten; then, a slurry is obtained;

[0019] Step 7: Coating and welding: The slurry prepared in step 6 is evenly coated on the ceramic welding area. After the core is assembled, it is placed in a vacuum furnace and sintered at a high temperature of 460-660℃. After the program is completed, it is cooled in the furnace and taken out to complete the preparation of the environmentally friendly glass slurry welded ceramic pressure sensor.

[0020] As a further solution of the present invention: the components of the glass raw materials in the second step are as follows in percentage by weight: SiO2 10-20%, Bi2O3 10-60%, CaO 10-35%, TiO2 10-15%, Al2O3 1-3%, La2O3 3-7%, MnO2 0.5-2%, and B2O3 4-7%.

[0021] As a further solution of the present invention: the melting and holding time of the melting operation in the third step is 1-5 hours.

[0022] As a further solution of the present invention: the ball milling method in the fifth step adopts a step-type gradient ball milling scheme, specifically as follows: S1, the ball milling speed is 30-60 rpm, and the ball milling time is 1-3h; S2, the ball milling speed is 200-400 rpm, and the ball milling time is 1-3h; S3, the ball milling speed is 500-700 rpm, and the ball milling time is 0.5-2h.

[0023] As a further solution of the present invention: the average particle size of the sieved particles in the fifth step is 20-60 microns.

[0024] As a further solution of the present invention: in the sixth step, the glass powder accounts for 60-80% by mass, the plasticizer accounts for 0.1-5% by mass, the organic solvent accounts for 10-40% by mass, the dispersant accounts for 0.1-2% by mass, and the thixotropic agent accounts for 0.1-2% by mass.

[0025] As a further embodiment of the present invention: the plasticizer is selected from any one or two of PVB, ethyl phthalate, and ethyl acetate.

[0026] As a further embodiment of the present invention: the organic solvent is selected from any one or two of methanol, ethanol and toluene.

[0027] As a further solution of the present invention: the dispersant is selected from any one or two of sodium hexametaphosphate, Span 85, and triethanolamine.

[0028] As a further embodiment of the present invention: the thixotropic agent is selected from any one or two of silica, organic bentonite and polyamide wax.

[0029] The present invention proposes an environmentally friendly method for preparing a welding glass slurry for connecting ceramics. The beneficial effects are as follows: by fully mixing a plurality of glass raw materials according to an effective mass ratio and then melting them at a high temperature, agglomeration of glass powder and slurry is effectively avoided, the overall quality of the glass raw materials and slurry is increased, and the use effect is effectively improved; and by water quenching the high-temperature molten glass liquid fusion material, the molten liquid is poured into flowing deionized water for cooling, effectively avoiding agglomeration of glass powder and slurry, further increasing the quality of the glass raw materials and slurry, so that when the slurry is used for welding ceramic sensors, no bubbles are generated in the welding area, effectively improving the welding effect, thereby not only improving the performance of the ceramic capacitor, but also effectively extending the service life of the chip;

[0030] Compared with the existing technology, the environmentally friendly glass slurry product of the present invention is environmentally friendly, the preparation process is environmentally friendly, the economic cost is low, and it is convenient for rapid assembly line production and easy to mass produce. The slurry has strong welding performance for sensors and is easy to promote and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic flow chart of a method for preparing an environmentally friendly welding glass paste for connecting ceramics proposed by the present invention; DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0033] Example 1

[0034] Reference Figure 1 A method for preparing an environmentally friendly welding glass paste for connecting ceramics comprises the following steps:

[0035] Step 1: Cleaning: Polish the ceramic substrate, then place it in an alcohol container, immerse it completely in the solution, and vibrate ultrasonically for 10 minutes at a temperature of 30°C, and then rinse it thoroughly with deionized water.

[0036] Step 2: Mixing: The glass raw materials are fully mixed according to the mass ratio. The components by weight percentage are 10% SiO2, 40% Bi2O3, 30% CaO, 10% TiO2, 1% Al2O3, 3% La2O3, 0.5% MnO2, and 5.5% B2O3;

[0037] Step 3: Melting: Melt the glass raw materials mixed in the second step in a melting furnace at high temperature, and the melting and heat preservation time is 1 hour;

[0038] Step 4: Water quenching: Pour the melted liquid obtained in step 3 into flowing deionized water, quickly cool it to room temperature, and then take it out to obtain glass frit;

[0039] Step 5, ball milling: The glass material prepared in the fourth step is placed in a ball mill for ball milling, and the ball milling method adopts a step-by-step gradient ball milling scheme, specifically S1, ball milling speed of 30 rpm, ball milling time of 1 h, S2, ball milling speed of 200 rpm, ball milling time of 1 h, S3, ball milling speed of 500 rpm, ball milling time of 0.5 h, then the ball milled material is taken out and sieved, and the sieved average particle size is 20 μm, and then a glass powder is obtained;

[0040] Step 6: Slurry preparation: Take 60% of the glass powder prepared in step 5, add 1% PVB plasticizer, 35% methanol organic solvent, 2% sodium hexametaphosphate dispersant, and 2% fumed silica thixotropic agent, stir thoroughly at 30 rpm for 12 hours, and mix until molten.

[0041] Step 7: Coating and welding: The slurry prepared in step 6 is evenly coated on the ceramic welding area. After the core is assembled, it is placed in a vacuum furnace and sintered at 460°C. After the program is completed, it is cooled in the furnace and taken out to complete the preparation of the environmentally friendly glass slurry welded ceramic pressure sensor.

[0042] Example 2

[0043] Reference Figure 1 A method for preparing an environmentally friendly welding glass paste for connecting ceramics comprises the following steps:

[0044] Step 1: Cleaning: Polish the ceramic substrate, then place it in an alcohol container, immerse it completely in the solution, and ultrasonically vibrate for 20 minutes at a temperature of 40°C, and then rinse it thoroughly with deionized water.

[0045] Step 2: Mixing: The glass raw materials are fully mixed according to the mass ratio. The components by weight percentage are 15% SiO2, 50% Bi2O3, 15% CaO, 10% TiO2, 2% Al2O3, 3% La2O3, 1% MnO2, and 4% B2O3;

[0046] Step 3: Melting: Melt the glass raw materials mixed in the second step in a melting furnace at high temperature, and the melting and heat preservation time is 2.5 hours;

[0047] Step 4: Water quenching: Pour the melted liquid obtained in step 3 into flowing deionized water, quickly cool it to room temperature, and then take it out to obtain glass frit;

[0048] Step 5, ball milling: The glass material prepared in the fourth step is placed in a ball mill for ball milling, and the ball milling method adopts a step-by-step gradient ball milling scheme, specifically S1, ball milling speed 45 rpm, ball milling time 2 h, S2, ball milling speed 300 rpm, ball milling time 1.5 h, S3, ball milling speed 600 rpm, ball milling time 1.5 h, then the ball milled material is taken out and sieved, and the sieved average particle size is 35 μm, and then a glass powder is obtained;

[0049] Step 6: Slurry preparation: Take 72% by weight of the glass powder prepared in step 5, add 0.5% of a plasticizer selected from ethyl phthalate, 25.5% of an organic solvent selected from ethanol, 1% of a dispersant selected from Span 85, and 1% of an organic bentonite thixotropic agent, stir thoroughly at 45 rpm for 25 hours, and mix until uniformly mixed until molten;

[0050] Step 7: Coating and welding: The slurry prepared in step 6 is evenly coated on the ceramic welding area. After the core is assembled, it is placed in a vacuum furnace and sintered at 520°C. After the program is completed, it is cooled in the furnace and taken out to complete the preparation of the environmentally friendly glass slurry welded ceramic pressure sensor.

[0051] Example 3

[0052] Reference Figure 1 A method for preparing an environmentally friendly welding glass paste for connecting ceramics comprises the following steps:

[0053] Step 1: Cleaning: Polish the ceramic substrate, then place it in an alcohol container, immerse it completely in the solution, and ultrasonically vibrate for 25 minutes at 40°C, then rinse thoroughly with deionized water.

[0054] Step 2: Mixing: The glass raw materials are fully mixed according to the mass ratio. The components by weight percentage are 10% SiO2, 60% Bi2O3, 10% CaO, 10% TiO2, 1.5% Al2O3, 3% La2O3, 0.5% MnO2, and 5% B2O3;

[0055] Step 3: Melting: Melt the glass raw materials mixed in the second step in a melting furnace at high temperature, and the melting and heat preservation time is 4 hours;

[0056] Step 4: Water quenching: Pour the melted liquid obtained in step 3 into flowing deionized water, quickly cool it to room temperature, and then take it out to obtain glass frit;

[0057] Step 5, ball milling: The glass material prepared in the fourth step is placed in a ball mill for ball milling, and the ball milling method adopts a step-by-step gradient ball milling scheme, specifically S1, ball milling speed 50 rpm, ball milling time 2.5 h, S2, ball milling speed 350 rpm, ball milling time 2.5 h, S3, ball milling speed 650 rpm, ball milling time 1 h, then the ball milled material is taken out and sieved, and the sieved average particle size is 50 μm, and then a glass powder is obtained;

[0058] Step 6. Slurry preparation: Take 70% of the glass powder prepared in the fifth step, add a plasticizer selected from 1% PVB and 2% ethyl acetate, an organic solvent selected from 15% methanol and 9% ethanol, a dispersant selected from 1% Span 85 and 0.5% triethanolamine, and a thixotropic agent selected from 0.5% fumed silica and 1.5% organic bentonite, stir thoroughly, speed 50 rpm, stirring time: 31h, mix evenly until molten state.

[0059] Step 7: Coating and welding: The slurry prepared in step 6 is evenly coated on the ceramic welding area. After assembling the core, place it in a vacuum furnace and sinter it at 600℃. After the process is completed, cool it in the furnace and take it out to complete the preparation of the environmentally friendly glass slurry welding ceramic pressure sensor.

[0060] Example 4

[0061] Reference Figure 1 A method for preparing an environmentally friendly welding glass paste for connecting ceramics comprises the following steps:

[0062] Step 1: Cleaning: Polish the ceramic substrate, then place it in an alcohol container, immerse it completely in the solution, and vibrate ultrasonically for 30 minutes at a temperature of 50°C, and then rinse it thoroughly with deionized water.

[0063] Step 2: Mixing: The glass raw materials are fully mixed according to the mass ratio. The components by weight percentage are 20% SiO2, 19% Bi2O3, 35% CaO, 10% TiO2, 3% Al2O3, 7% La2O3, 2% MnO2, and 4% B2O3;

[0064] Step 3: Melting: Melt the glass raw materials mixed in the second step in a melting furnace at high temperature, and the melting and heat preservation time is 5 hours;

[0065] Step 4: Water quenching: Pour the melted liquid obtained in step 3 into flowing deionized water, quickly cool it to room temperature, and then take it out to obtain glass frit;

[0066] Step 5, ball milling: The glass material prepared in the fourth step is placed in a ball mill for ball milling, and the ball milling method adopts a step-by-step gradient ball milling scheme, specifically S1, ball milling speed 60 rpm, ball milling time 3 h, S2, ball milling speed 400 rpm, ball milling time 3 h, S3, ball milling speed 700 rpm, ball milling time 2 h, then the ball milled material is taken out and sieved, and the sieved average particle size is 60 μm, and then a glass powder is obtained;

[0067] Step 6. Slurry preparation: Take 80% of the glass powder prepared in the fifth step, add a plasticizer selected from 5% ethyl acetate, an organic solvent selected from 11% toluene, a dispersant selected from 2% triethanolamine, and a thixotropic agent selected from 2% polyamide wax, stir thoroughly, speed 60 rpm, stirring time: 36h, mix evenly until molten state.

[0068] Step 7: Coating and welding: The slurry prepared in step 6 is evenly coated on the ceramic welding area. After the core is assembled, it is placed in a vacuum furnace and sintered at 660°C. After the process is completed, it is cooled in the furnace and taken out to complete the preparation of the environmentally friendly glass slurry welded ceramic pressure sensor.

[0069] Comparative Example 1

[0070] Reference Figure 1 A method for preparing an environmentally friendly welding glass paste for connecting ceramics comprises the following steps:

[0071] Step 1: Cleaning: Polish the ceramic substrate, then place it in an alcohol container, immerse it completely in the solution, and vibrate ultrasonically for 10 minutes at a temperature of 30°C, and then rinse it thoroughly with deionized water.

[0072] The second step is to place the glass raw materials directly in the melting furnace for high temperature melting, and the melting and heat preservation time is 1 hour;

[0073] Step 3: Water quenching: Pour the melted liquid obtained in step 2 into flowing deionized water, quickly cool it to room temperature, and then take it out to obtain glass frit;

[0074] Step 4: ball milling: The glass material prepared in the third step is placed in a ball mill for ball milling, and the ball milling method adopts a step-by-step gradient ball milling scheme, specifically S1, ball milling speed of 30 rpm, ball milling time of 1 h, S2, ball milling speed of 200 rpm, ball milling time of 1 h, S3, ball milling speed of 500 rpm, ball milling time of 0.5 h, then the ball milled material is taken out and sieved, and the sieved average particle size is 20 μm, and then a glass powder is obtained;

[0075] Step 5, slurry preparation: Take 60% by weight of the glass powder prepared in step 4, add 1% PVB plasticizer, 35% methanol organic solvent, 2% sodium hexametaphosphate dispersant, and 2% fumed silica thixotropic agent, stir thoroughly at 30 rpm for 12 hours, and mix until molten.

[0076] Step 6: Coating and welding: The slurry prepared in step 5 is evenly coated on the ceramic welding area. After the core is assembled, it is placed in a vacuum furnace and sintered at 460°C. After the process is completed, it is cooled in the furnace and taken out to complete the preparation of the environmentally friendly glass slurry welded ceramic pressure sensor.

[0077] Comparative Example 2

[0078] Reference Figure 1 A method for preparing an environmentally friendly welding glass paste for connecting ceramics comprises the following steps:

[0079] Step 1: Cleaning: Polish the ceramic substrate, then place it in an alcohol container, immerse it completely in the solution, and vibrate ultrasonically for 10 minutes at a temperature of 30°C, and then rinse it thoroughly with deionized water.

[0080] Step 2: Mixing: The glass raw materials are fully mixed according to the mass ratio. The components by weight percentage are 15% SiO2, 50% Bi2O3, 15% CaO, 10% TiO2, 2% Al2O3, 3% La2O3, 1% MnO2, and 4% B2O3;

[0081] Step 3: Melting: Melt the glass raw materials mixed in the second step in a melting furnace at high temperature, and the melting and heat preservation time is 2.5 hours;

[0082] Step 4, ball milling: The glass material liquid prepared in the third step is placed in a ball mill for ball milling, and the ball milling method adopts a step-by-step gradient ball milling scheme, specifically S1, ball milling speed of 30 rpm, ball milling time of 1 h, S2, ball milling speed of 200 rpm, ball milling time of 1 h, S3, ball milling speed of 500 rpm, ball milling time of 0.5 h, then the ball milled material is taken out and sieved, and the sieved average particle size is 20 μm, and then the glass powder is obtained;

[0083] Step 5, slurry preparation: Take 60% by weight of the glass powder prepared in step 4, add 1% PVB plasticizer, 35% methanol organic solvent, 2% sodium hexametaphosphate dispersant, and 2% fumed silica thixotropic agent, stir thoroughly at 30 rpm for 12 hours, and mix until molten.

[0084] Step 6: Coating and welding: The slurry prepared in step 5 is evenly coated on the ceramic welding area. After the core is assembled, it is placed in a vacuum furnace and sintered at 460°C. After the process is completed, it is cooled in the furnace and taken out to complete the preparation of the environmentally friendly glass slurry welded ceramic pressure sensor.

[0085] The glass powder and slurry samples prepared in Examples 1-4 and Comparative Examples 1-2 were tested and the core welding performance was tested. The specific test results are shown in the figure below:

[0086] Table 1:

[0087] Sample number Glass powder agglomeration Glass paste agglomeration Example 1 none none Example 2 none none Example 3 none none Example 4 none none Comparative Example 1 have have Comparative Example 2 have have

[0088] Table 2:

[0089] Sample number Macro effects Red ink experiment Example 1 The welding area is free of bubbles and has a smooth surface Good welding performance Example 2 The welding area is free of bubbles and has a smooth surface Good welding performance Example 3 The welding area is free of bubbles and has a smooth surface Good welding performance Example 4 The welding area is free of bubbles and has a smooth surface Good welding performance Comparative Example 1 There are bubbles in the welding area and the surface is uneven Poor welding performance Comparative Example 2 There are bubbles in the welding area and the surface is uneven Poor welding performance

[0090] Combined with the above test results, it can be seen that compared with Examples 1-4, the glass powder and slurry in Comparative Example 1 have agglomeration phenomena, bubbles are generated in the core welding area, and the surface of the welding area is not smooth, which is intended to illustrate that the mixing step is crucial. Compared with Examples 1-4, the glass powder and slurry in Comparative Example 2 have agglomeration phenomena, and bubbles are generated in the core welding area, which is intended to illustrate that the water quenching step is crucial.

[0091] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing an environmentally friendly welding glass paste for connecting ceramics, characterized in that: The following steps are involved: Step 1: Cleaning: Polish the ceramic substrate, then place it in an alcohol container, immerse it completely in the solution, and vibrate it ultrasonically for 10-30 minutes at a temperature of 30-50°C, and then rinse it thoroughly with deionized water. Step 2: Mixing: fully mix the glass raw materials according to the mass ratio; Step 3: Melting: Put the glass raw materials mixed in the second step into the melting furnace and melt them at high temperature; Step 4: Water quenching: Pour the melted liquid obtained in step 3 into flowing deionized water, quickly cool it to room temperature, and then take it out to obtain glass frit; Step 5: Ball milling: Place the glass material prepared in step 4 in a ball mill for ball milling, then take out the ball milled material and sieve it to obtain glass powder; Step 6: Slurry preparation: Add the glass powder prepared in step 5 to the plasticizer, organic solvent, dispersant, and thixotropic agent, and then fully stir at a speed of 30-60 rpm for 12-36 hours until the mixture is evenly mixed until it is molten; then, a slurry is obtained; Step 7: Coating and welding: The slurry prepared in step 6 is evenly coated on the ceramic welding area. After the core is assembled, it is placed in a vacuum furnace and sintered at a high temperature of 460-660℃. After the program is completed, it is cooled in the furnace and taken out to complete the preparation of the environmentally friendly glass slurry welded ceramic pressure sensor.

2. The method for preparing an environmentally friendly welding glass paste for connecting ceramics according to claim 1, characterized in that: The components of the glass raw materials in the second step are as follows in percentage by weight: SiO2 10-20%, Bi2O3 10-60%, CaO 10-35%, TiO2 10-15%, Al2O3 1-3%, La2O3 3-7%, MnO2 0.5-2%, and B2O3 4-7%.

3. The method for preparing an environmentally friendly welding glass paste for connecting ceramics according to claim 1, characterized in that: The melting and holding time of the melting operation in the third step is 1-5 hours.

4. The method for preparing an environmentally friendly welding glass paste for connecting ceramics according to claim 1, characterized in that: The ball milling method in the fifth step adopts a step-by-step gradient ball milling scheme, which is as follows: S1, the ball milling speed is 30-60 rpm, and the ball milling time is 1-3h; S2, the ball milling speed is 200-400 rpm, and the ball milling time is 1-3h; S3, the ball milling speed is 500-700 rpm, and the ball milling time is 0.5-2h.

5. The method for preparing an environmentally friendly welding glass paste for connecting ceramics according to claim 1, characterized in that: The average particle size of the sieved particles in the fifth step is 20-60 microns.

6. The method for preparing an environmentally friendly welding glass paste for connecting ceramics according to claim 1, characterized in that: In the sixth step, the glass powder accounts for 60-80% by mass, the plasticizer accounts for 0.1-5% by mass, the organic solvent accounts for 10-40% by mass, the dispersant accounts for 0.1-2% by mass, and the thixotropic agent accounts for 0.1-2% by mass.

7. The method for preparing an environmentally friendly welding glass paste for connecting ceramics according to claim 6, characterized in that: The plasticizer is selected from any one or two of PVB, ethyl phthalate, and ethyl acetate.

8. The method for preparing an environmentally friendly welding glass paste for connecting ceramics according to claim 6, characterized in that: The organic solvent is selected from any one or two of methanol, ethanol and toluene.

9. The method for preparing an environmentally friendly welding glass paste for connecting ceramics according to claim 6, characterized in that: The dispersant is selected from any one or two of sodium hexametaphosphate, Span 85, and triethanolamine.

10. The method for preparing an environmentally friendly welding glass paste for connecting ceramics according to claim 6, characterized in that: The thixotropic agent is selected from any one or two of silica, organic bentonite and polyamide wax.

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