Ceramic Capacitive Pressure Sensor and Organic Silver Paste for Sintering Two-Stage Sheets

Abstract

The present invention relates to the technical field of automotive pressure sensors, and specifically to a ceramic capacitive pressure sensor and an organic silver paste for sintering two-stage wafers. The two electrodes of the ceramic capacitive pressure sensor sintered with the organic silver paste prepared by mixing resin silver, resinate mixture, additives and an organic carrier can not only ensure the accuracy of the measured values, but also ensure that the electrodes sintered on the ceramic thin wafers and ceramic thick wafers are not easily detached, thereby greatly reducing the production cost of the ceramic capacitive pressure sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive pressure sensors, and specifically to a ceramic capacitive pressure sensor and an organic silver paste for sintering two-stage sheets. Background Art

[0002] The descriptions in this section only provide background information related to the present disclosure and do not constitute prior art.

[0003] Currently, ceramic capacitive pressure sensors are widely used in new energy vehicles and traditional enterprises. A ceramic capacitive pressure sensor includes a ceramic thin sheet and a ceramic thick sheet, and organic gold paste is brushed on the thin sheet and the thick sheet respectively, and then sintered at a high temperature of 750 °C to 950 °C. The gold paste is sintered on the thin sheet and the thick sheet to form two electrodes, which not only ensures the deformation of the ceramic capacitive pressure sensor under pressure, but also ensures the adhesion of the gold paste, and further ensures the stable and accurate detection value of the ceramic capacitive pressure sensor sintered by the organic gold paste.

[0004] However, due to the high cost of the organic gold paste, the overall cost of the current ceramic capacitive pressure sensor is relatively high. In order to reduce the cost, when using other metal pastes to replace the gold paste for sintering the two electrodes on the ceramic capacitive pressure sensor, there are problems such as large deviation in measurement values, poor adhesion, easy detachment, and strong surface particle sense. At present, there is an urgent need to find a new metal paste that can not only solve the accuracy problem of measurement values, but also solve the problem that the electrodes sintered on the ceramic thin sheet and the ceramic thick sheet are not easily detached. Summary of the Invention

[0005] In order to solve the problem that the current ceramic capacitive pressure sensor has a high cost of sintering electrodes through organic gold paste and there is an urgent need to find a metal paste that can replace the organic gold paste, the present invention provides an organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor. The two electrodes of the ceramic capacitive pressure sensor sintered by the organic silver paste made by mixing resin silver, resin acid salt mixture, additive and organic carrier can not only ensure the accuracy of measurement values, but also ensure that the electrodes sintered on the ceramic thin sheet and the ceramic thick sheet are not easily detached, thereby greatly reducing the production cost of the ceramic capacitive pressure sensor.

[0006] To achieve the above object, the invention provides the following technical solution: An organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor, the organic silver paste is composed of 55 - 75% resin silver, 1 - 10% resin acid salt mixture, 0.5 - 2% additive and 20% - 40% organic carrier, and the resin acid salt mixture is obtained by mixing 0.5% rhodium isooctanoate, 2% bismuth 2-ethylhexanoate, 2% organosilicon and 1% chromium neodecanoate.

[0007] The present invention provides an organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor. The resin silver is prepared from NaOH, 2-ethylhexanoic acid, and silver nitrate, and the preparation method and ratio are as follows:

[0008] a: Dissolve 2.32 g (0.058 mol) of NaOH in 50 mL of deionized water, and at the same time dissolve 8.36 g (0.058 mol) of 2-ethylhexanoic acid in 50 mL of methanol. Then mix the above two solutions to form solution A;

[0009] b: Dissolve 9.85 g (0.058 mol) of silver nitrate in 50 mL of deionized water to form solution B;

[0010] c: Then drip solution B into solution A and stir. Finally, wash with methanol, filter twice to obtain a white precipitate, wash with distilled water and methanol, and then vacuum dry to obtain a white powder.

[0011] The present invention provides an organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor. The molar ratio of NaOH, 2-ethylhexanoic acid, and silver nitrate is 1:1:1.

[0012] The present invention provides an organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor. The additive is oleic acid or glycerol.

[0013] The present invention provides an organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor. The organic carrier includes 70-80% of an organic solvent and 20-40% of an organic resin; the organic resin includes one or more of ethyl cellulose, alkyd resin, and amino resin; the organic solvent includes one or more of terpineol and alcohol ester 12.

[0014] The present invention provides an organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor, with a fineness ≤ 5 μm and a viscosity of 40-80 Pa·s.

[0015] The present invention provides a ceramic capacitive pressure sensor, including a ceramic thick sheet, a ceramic thin sheet, and electrodes respectively attached to the ceramic thick sheet and the ceramic thin sheet. The electrodes are sintered by an organic silver paste.

[0016] The present invention provides a ceramic capacitive pressure sensor. The thickness of the electrode formed by sintering and grinding the organic silver paste attached to the ceramic thick sheet is 1 μm - 2.3 μm; the thickness of the electrode formed by sintering and grinding the organic silver paste attached to the ceramic thin sheet is 0.4 μm - 2.3 μm.

[0017] The present invention provides a ceramic capacitive pressure sensor. A protective layer is coated on the surface of the electrode that is not in contact with the ceramic thick sheet and the ceramic thin sheet.

[0018] The present invention provides a ceramic capacitive pressure sensor. After sintering and polishing, the thickness of the protective layer attached to the thick ceramic sheet is 2.2 μm - 3.8 μm; after sintering and polishing, the thickness of the protective layer attached to the thin ceramic sheet is 1.3 μm - 3.35 μm.

[0019] The present invention provides a ceramic capacitive pressure sensor. Glass glue is provided on the connection surface of the thick ceramic sheet or the thin ceramic sheet to which the electrodes are attached. After sintering, the glass glue seals and connects the thick ceramic sheet and the thin ceramic sheet to form a sealed cavity, and the electrodes on the thick ceramic sheet and the thin ceramic sheet are arranged in the sealed cavity.

[0020] Compared with the prior art, the beneficial effects of the invention are as follows: The present invention provides an organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor. The two electrodes of the ceramic capacitive pressure sensor sintered with the organic silver paste prepared by mixing resin silver, resinate mixture, additive and organic carrier are designed. The main function of resin silver is to provide a conductive phase. The function of the resinate mixture is to improve the denseness and adhesion of the film layer after sintering. The function of the organic carrier is to enable resin silver and the resinate mixture to be evenly dispersed and have good printability at the same time. The function of the additive is to keep the slurry in a good printing state. Therefore, it can not only ensure the accuracy of the measured value, but also ensure that the electrodes sintered on the thin ceramic sheet and the thick ceramic sheet are not easy to fall off, thereby greatly reducing the production cost of the ceramic capacitive pressure sensor.

[0021] The functions of coating the protective layer include: 1. Prevent silver migration during the use of the two electrodes sintered with the organic silver paste; 2. Secondly, further protect the two electrodes to prevent peeling off; 3. Prevent silver on the two electrodes from oxidizing; 4. At the same time, it also isolates the air contact in the sealed cavity to cause silver oxidation, and when the pressure-sensitive element is under several times of overload pressure, the ceramic substrate (thin ceramic sheet) of the force-receiving surface / sensing surface deforms, resulting in the upper and lower electrodes contacting. Since the contact surface is the protective glue, the capacitive sensitive element is prevented from short-circuiting.

[0022] The function of the glass glue is to ensure that a gap d is formed between the two electrodes and to seal the periphery of the two electrodes, sealing the two electrodes in the same area. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of a ceramic capacitive pressure sensor of the present invention.

[0024] Among them, 10. thick ceramic sheet, 20. electrode, 30. protective layer, 40. sealed cavity, 50. glass glue, 60. thin ceramic sheet. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the invention with reference to the accompanying drawings in the embodiments of the invention. Obviously, the described embodiments are only a part of the embodiments of the invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the invention without creative efforts shall fall within the scope of protection of the invention.

[0026] In the description of the invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0027] In the description of the invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "setting" should be understood in a broad sense. For example, they can be fixedly connected and set, or detachably connected and set, or integrally connected and set. For those of ordinary skill in the art, the specific meanings of the above terms in the invention can be understood according to specific situations.

[0028] In order to better understand the above technical solutions, the following will describe the above technical solutions in detail with reference to the accompanying drawings of the specification and specific embodiments.

[0029] The present invention provides an organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor. In this design, the two electrodes of the ceramic capacitive pressure sensor sintered with the organic silver paste made by mixing resin silver, resinate mixture, additives and an organic carrier. The main function of resin silver is to provide a conductive phase. The function of the resinate mixture is to improve the density and adhesion of the film layer after sintering. The function of the organic carrier is to enable the resin silver and the resinate mixture to be evenly dispersed and have good printability at the same time. The function of the additive is to keep the slurry in a good printing state. Thus, it can not only ensure the accuracy of the measured value, but also ensure that the electrodes 20 sintered on the ceramic thin sheet 60 and the ceramic thick sheet 10 are not easy to fall off, and further greatly reduce the production cost of the ceramic capacitive pressure sensor. Embodiment 1

[0030] An organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor, comprising 55-75% resin silver, 1-10% resin acid salt mixture, 0.5-2% additive and 20%-40% organic carrier. The main function of the resin silver is to provide a conductive phase. The function of the resin acid salt mixture is to improve the compactness and adhesion of the film layer after sintering. The function of the organic carrier is to enable the resin silver and the resin acid salt mixture to be evenly dispersed and have good printability at the same time. The function of the additive is to keep the paste in a good printing state.

[0031] Preferably, the resin silver is prepared from NaOH, 2-ethylhexanoic acid and silver nitrate, and its preparation method is as follows: a: Dissolve 2.32 g (0.058 mol) of NaOH in 50 mL of deionized water, and at the same time dissolve 8.36 g (0.058 mol) of 2-ethylhexanoic acid in 50 mL of methanol, then mix the above two solutions to form solution A; b: Dissolve 9.85 g (0.058 mol) of silver nitrate in 50 mL of deionized water to form solution B; c: Then drop solution B into solution A and stir, finally wash with methanol, filter twice to obtain a white precipitate, wash with distilled water and methanol, and then vacuum dry to obtain a white powder.

[0032] The Mol ratio of NaOH, 2-ethylhexanoic acid and silver nitrate is 1:1:1.

[0033] The resin acid salt mixture is obtained by mixing 0.5% rhodium isooctanoate, 2% bismuth 2-ethylhexanoate, 2% organosilicon and 1% chromium neodecanoate.

[0034] The additive is oleic acid or glycerol.

[0035] In a specific embodiment, the organic carrier includes 70-80% organic solvent and 20-40% organic resin; the organic resin includes one or more of ethyl cellulose, alkyd resin, and amino resin; the organic solvent includes one or more of terpineol and alcohol ester twelve.

[0036] Its preparation method is: A preparation method of an organic silver paste, specifically including the following steps:

[0037] s1. Mix the above materials in the above proportions;

[0038] s2. Roll the mixed materials with a three-roll mill;

[0039] s3. Sieve the rolled paste through a sieve with a mesh size of more than 325 meshes to obtain the final organic silver paste.

[0040] The fineness of the prepared organic silver paste is measured to be ≤5 μm, and the viscosity is 40-80 pa·s.

[0041] The organic silver paste produced through the above-mentioned ratio, and the ceramic thin film and ceramic thick film electrodes produced through sintering can not only ensure the accuracy of the measured values of the ceramic capacitive pressure sensor, but also ensure that the electrodes sintered on the ceramic thin film and ceramic thick film are not easily detached.

[0042] For the relevant data of the produced ceramic capacitive pressure sensor, please refer to Embodiment 2. Embodiment Two

[0043] As Figure 1 shown, a ceramic capacitive pressure sensor includes a ceramic thick film 10, a ceramic thin film 60, and electrodes 20 respectively attached to the ceramic thick film 10 and the ceramic thin film 60, wherein the electrodes 20 are sintered through the organic silver paste in Embodiment 1.

[0044] As Figure 1 shown, a protective layer 30 is coated on the surface of the electrodes 20 that is not in contact with the ceramic thick film 10 and the ceramic thin film 60.

[0045] Preferably, the protective layer 30 is a protective glue (GOS). The protective glue is sintered on the outer surface of the electrodes 20 after printing to completely seal the electrodes, and its functions are as follows: 1. Prevent silver migration from occurring between the two electrodes 20 sintered by the organic silver paste during use; 2. Secondly, further protect the two electrodes 20 to prevent detachment; 3. Prevent the silver on the two electrodes 20 from oxidizing; 4. At the same time, it also isolates the air in the sealed cavity 40 from contacting and causing silver oxidation, and prevents the ceramic substrate on the force-receiving surface / sensing pressure surface of the pressure sensor from deforming under several times of overload pressure, resulting in the upper and lower electrodes contacting. Since the contact surface is still the insulating protective glue, short circuit is avoided.

[0046] As shown in Table 1, this is the test of the electrode thickness on the ceramic thin film 60 before, after printing and sintering, and after polishing with the organic silver paste in this design, as well as the test of the protective glue thickness on the ceramic thin film 60 before, after printing and sintering, and after polishing.

[0047] Table 1

[0048]

[0049] As shown in Table 2, this is the test of the electrode thickness on the ceramic thick film 10 before, after printing and sintering, and after polishing with the organic silver paste in this design, the test of the protective glue thickness on the ceramic thick film 10 before, after printing and sintering, and after polishing, as well as the test of the glass glue thickness on the ceramic thick film 10 before, after printing and sintering, and after polishing.

[0050] Table 2

[0051]

[0052] Summary:

[0053] 1. In Tables 1 and 2, the protective glue needs to be sintered at a high temperature of 500°C to 700°C and then polished. The glass glue 50 in Table 2 needs to be sintered at a high temperature of 500°C to 700°C. After sintering, the electrode resistance is tested: for the electrode 20 sintered with organic silver paste, the average resistance value is about 1.2 Ω, and for the electrode 20 sintered with organic gold paste, the average resistance value is about 1.9 Ω. The measurement method is to use a multimeter to measure the resistance value at the two longest points of the gold / silver pattern on the same ceramic thin sheet 60 or ceramic thick sheet 10. The lower the resistance value, the better the conductivity and the smaller the loss. That is, considering conductivity and damage, the gold paste is superior to the silver paste. However, since the resistance values of the two electrodes on the ceramic thin sheet and ceramic thick sheet sintered with the gold paste and silver paste are very close, the energy consumption can be ignored. As shown in Tables 1 and 2, the thickness of the electrode 20 formed by the organic silver paste sintered and polished and attached to the ceramic thick sheet 10 is 1 μm - 2.3 μm, and the preferred average thickness is 1.62 μm. The thickness of the electrode 20 formed by the organic silver paste sintered and polished and attached to the ceramic thin sheet 60 is 0.4 μm - 2.3 μm, and the preferred average thickness is 1.06 μm. The thickness of the organic silver paste attached to the ceramic thick sheet 10 and ceramic thin sheet 60 determines the cost of the ceramic capacitor. After sintering, the thinner the organic silver paste attached to the ceramic thick sheet 10 and ceramic thin sheet 60, the lower the cost under the same area. The thickness of the protective layer sintered and polished and attached to the ceramic thick sheet 10 is 2.2 μm - 3.8 μm, and the preferred average thickness is 3.11 μm. The thickness of the protective layer sintered and polished and attached to the ceramic thin sheet 60 is 1.3 μm - 3.35 μm, and the preferred average thickness is 2.25 μm. The thickness of the glass glue 50 sintered and polished and attached to the ceramic thick sheet 10 is 18.2 μm - 22.51 μm, and the preferred average thickness is 19.79 μm. Its function is to form a gap d between the two electrodes 20, seal the periphery of the two electrodes 20, seal the two electrodes 20 in the sealed cavity 40, and the thickness of the glass glue 50 after sintering can be adjusted as needed to adjust the capacitance output value. The attached thicknesses of the glass glue and the protective glue can be adjusted as needed to ensure that the ceramic capacitor meets the measurement requirements.

[0054] 2. A layer of protective glue is respectively covered on the silver electrodes 20 sintered on the ceramic thick sheet 10 and ceramic thin sheet 60, which can prevent the silver migration of the silver electrode 20 to the silver on the other side substrate. At the same time, since the ceramic thick sheet 10 and ceramic thin sheet 60 are sintered and sealed through the glass glue 50 to form a sealed cavity 40, the air in the sealed cavity 40 is isolated from contacting the electrode 20 to cause silver oxidation, and when the pressure sensor is under several times of overload pressure, the ceramic substrate of the stress surface / sensing surface deforms, resulting in the upper and lower electrodes contacting. Since the contact surface is still the insulating protective glue, short circuit is avoided and the pressure sensor is damaged.

[0055] 3. Using silver paste, the upper and lower plates can be lifted by increasing the height of the glass glue 50, and the gap d value between the two electrodes 20 can be increased, so as to balance the increase in the ceramic capacitance value after the gold paste is replaced by silver paste. And silicon balls for controlling the minimum gap are added to the glass glue.

[0056] 4. When the organic silver paste includes 55% resin silver, 1% resin acid salt mixture, 0.5% additive and 20% organic carrier, the height of the organic silver paste of the ceramic thick film after sintering and polishing can be 1μm - 2.3μm, and the height of the organic silver paste of the ceramic thin film after sintering and polishing can be 0.4μm - 2.3μm; when the organic silver paste includes 75% resin silver, 10% resin acid salt mixture, 2% additive and 40% organic carrier, the height of the organic silver paste of the ceramic thick film after sintering and polishing can be 1μm - 2.3μm, and the height of the organic silver paste of the ceramic thin film after sintering and polishing can be 0.4μm - 2.3μm. Its ratio has no absolute linear relationship with the thickness attached to the ceramic thin film and the ceramic thick film.

[0057] As Figure 1 shown, the thickness of the electrode 20 formed by the organic silver paste attached to the ceramic thick film 10 after sintering and polishing is 1μm - 2.3μm, and the preferred average thickness is 1.62μm; the thickness of the electrode 20 formed by the organic silver paste attached to the ceramic thin film 60 after sintering and polishing is 0.4μm - 2.3μm, and the preferred average thickness is 1.06μm.

[0058] The thickness of the protective layer attached to the ceramic thick film 10 after sintering and polishing is 2.2μm - 3.8μm, and the preferred average thickness is 3.11μm; the thickness of the protective layer attached to the ceramic thin film 60 after sintering and polishing is 1.3μm - 3.35μm, and the preferred average thickness is 2.25μm.

[0059] As Figure 1 shown, the present invention provides a ceramic capacitive pressure sensor, wherein glass glue 50 is coated on the connecting surface of the ceramic thick film 10 or the ceramic thin film 60 sintered with organic silver paste. After sintering, the glass glue 50 seals and connects the ceramic thick film 10 and the ceramic thin film 60 to form a sealed cavity 40. The electrodes 20 on the ceramic thick film 10 and the ceramic thin film 60 are arranged in the sealed cavity 40. Its function is to form a gap d between the two electrodes 20, seal the periphery of the two electrodes 20, seal the two electrodes 20 in the sealed cavity 40, and the thickness of the glass glue 50 after sintering can be adjusted as needed to adjust the capacitance output value.

[0060] Preferably, after coating the glass glue 50 on the ceramic thick film 10, it is then sintered and fixed on the electrode 20 and the ceramic thick film 10

[0061] As Figure 1As shown, the calculation formula for capacitance can be expressed as: C = ε0 * εr * S / d, where C represents capacitance, ε0 represents the permittivity of free space; εr represents the permittivity of the insulating material; S represents the area between the two conductor plates; d represents the distance between the two electrodes, that is, the gap between the two electrodes.

[0062] As shown in Table 3, the capacitance values detected for different types of organic pastes after sintering, summary of functional test data (the initial value in the following table is the capacitance value at 0 pressure):

[0063] Table 3

[0064]

[0065] Summary: 1. Currently, under the 8 Mpa pressure test, the organic silver replacement of organic gold solution is verified to be qualified, and the test results meet the requirements.

[0066] 2. Among them, in Table 3, "input" is the number of detections, and "output" is the number of qualified detections;

[0067] 3. The combination verification of gold electrodes and silver electrodes fails. The main reason is that the matching of gold electrodes and silver electrodes is not as good as that of electrodes of the same material, resulting in relatively large changes in both the initial 0-pressure capacitance value and the full-pressure capacitance value, and poor consistency.

[0068] The process flow of this design is as follows: 1. Coat organic silver paste on the ceramic thin sheet 60 and the ceramic thick sheet 10, 2. Sinter the organic silver paste coated on the ceramic thin sheet 60 and the ceramic thick sheet 10 to form electrodes; 3. Grind the electrodes 20, 4. Coat a protective glue on the ground electrodes 20 and then sinter; 5. Finally, coat glass glue on the ceramic thin sheet 60 or the ceramic thick sheet 10, and hermetically connect the ceramic thin sheet 60 and the ceramic thick sheet 10 by sintering to form a sealed cavity 40;

[0069] The process flow for comparison using organic gold paste is as follows: 1. Coat organic gold paste on the ceramic thin sheet 60 and the ceramic thick sheet 10, 2. Sinter the organic gold paste coated on the ceramic thin sheet 60 and the ceramic thick sheet 10 to form electrodes 20; 3. Grind the electrodes 20, 4. Coat glass glue on the ceramic thin sheet 60 or the ceramic thick sheet 10, and hermetically connect the ceramic thin sheet 60 and the ceramic thick sheet 10 by sintering;

[0070] When using organic silver paste to sinter the electrodes 20 on the ceramic thin sheet 60 and the ceramic thick sheet 10, an additional process of sintering protective glue is added, and the other steps are the same; as shown in Table 4, on the premise of the same product and the same chip area, the cost differences between the original design (organic gold paste) and organic silver paste are exemplified as follows:

[0071] Table 4

[0072]

[0073] The weights of the organic gold paste and the organic silver paste in Table 4 are the weights of the wet film, that is, the weights before high-temperature sintering after printing, which is convenient for evaluating the overall cost.

[0074] Summary: The current disclosed design is that the total cost of the thin-film gold electrode + thick-film gold electrode paste is 1.16 yuan. Now it is changed to the thin-film silver electrode & protective glue + thick-film silver electrode & protective glue, and the total cost is 0.528 yuan. The cost reduction is 0.631 yuan, and the reduction rate is 54%. Among them, the functions of the protective glue are as follows: 1. Prevent silver from migrating towards the other substrate; 2. Isolate the silver electrode and the air in the sealing cavity 40 to prevent silver oxidation; 3. When the pressure overload occurs, the ceramic thin sheet 60 deforms greatly, and it is easy to cause contact between the electrodes on the ceramic thin sheet 60 and the electrodes on the ceramic thick sheet 10. By setting the protective glue, short circuit caused by the contact of the two electrodes is prevented, thereby avoiding damage to the pressure sensor; 4. And it can prevent the electrodes 20 after sintering, especially the electrodes 20 on the ceramic thin sheet 60, from falling off between the electrodes 20 and the ceramic thin sheet 60 after multiple deformations; 5. When the organic silver paste includes 55% resin silver, 1% resin acid salt mixture, 0.5% additive and 20% organic carrier, the detected weight of the organic silver paste adhered to the ceramic thin sheet is 0.002796 grams, and the detected weight of the organic silver adhered to the ceramic thick sheet is 0.003653 grams; when the organic silver paste includes 75% resin silver, 10% resin acid salt mixture, 2% additive and 40% organic carrier, the detected weight of the organic silver paste adhered to the ceramic thin sheet is 0.002849 grams, and the detected weight of the organic silver adhered to the ceramic thick sheet is 0.003527 grams. Its ratio has no linear relationship with the weight adhered to the ceramic thin sheet and the ceramic thick sheet.

[0075] Note: The price of the content on this page is the current conservative price in the market. The current international original price of pure gold is 610 yuan / gram, and the international original price of pure silver is 8 yuan / gram. The above is only the specific implementation manner of the invention, but the protection scope of the invention is not limited thereto. Any change or replacement that can be thought of without creative work should be covered within the protection scope of the invention. Therefore, the protection scope of the invention should be subject to the protection scope defined by the claims.

Claims

1. An organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor, characterized in that: The organic silver paste is composed of 55-75% of resin silver, 1-10% of a resinate mixture, 0.5-2% of an additive and 20%-40% of an organic carrier, and the resinate mixture is obtained by mixing 0.5% of rhodium isooctanoate, 2% of bismuth 2-ethylhexanoate, 2% of organic silicon and 1% of chromium neodecanoate.

2. The organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor as claimed in claim 1, characterized in that: The silver resin is prepared from NaOH, 2-ethylhexanoic acid and silver nitrate.

3. The organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor as claimed in claim 2, characterized in that: The Mol ratio of the NaOH, 2-ethylhexanoic acid and silver nitrate is 1:1:

1.

4. The organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor as claimed in claim 1, characterized in that: The additive is oleic acid or glycerol.

5. The organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor as claimed in claim 1, characterized in that: The organic carrier comprises 70-80% of an organic solvent and 20-40% of an organic resin; the organic resin comprises one or more of ethyl cellulose, alkyd resin, and amino resin; the organic solvent comprises one or more of pinene alcohol and alcohol ester dodecahydrate.

6. The organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor as claimed in claim 1, characterized in that: Its fineness is ≤5μm and its viscosity is 40~80pa.s.

7. A ceramic capacitive pressure sensor, characterized in that: It comprises a ceramic thick sheet (10), a ceramic thin sheet (60), and electrodes (20) respectively attached to the ceramic thick sheet (10) and the ceramic thin sheet (60), wherein the electrodes (20) are formed by sintering the organic silver paste according to any one of claims 1 to 6.

8. A ceramic capacitive pressure sensor as claimed in claim 7, characterized in that: The thickness of the electrode (20) formed by sintering and polishing the organic silver paste and attached to the ceramic thick sheet (10) is 1 μm-2.3 μm; the thickness of the electrode (20) formed by sintering and polishing the organic silver paste and attached to the ceramic thin sheet (60) is 0.4 μm-2.3 μm.

9. A ceramic capacitive pressure sensor as claimed in claim 7, characterized in that: A protective layer (30) is coated on the surface of the electrode (20) that is not in contact with the ceramic thick sheet (10) and the ceramic thin sheet (60).

10. A ceramic capacitive pressure sensor as claimed in claim 9, characterized in that: The thickness of the protective layer (30) attached to the ceramic thick sheet (10) after sintering and grinding is 2.2 μm-3.8 μm; the thickness of the protective layer (30) attached to the ceramic thin sheet (60) after sintering and grinding is 1.3 μm-3.35 μm.

11. A ceramic capacitive pressure sensor as claimed in claim 9, characterized in that: Glass glue (50) is provided on the connection surface of the ceramic thick sheet (10) or the ceramic thin sheet (60) to which the electrode (20) is attached. The glass glue (50) seals and connects the ceramic thick sheet (10) and the ceramic thin sheet (60) after sintering to form a sealed cavity (40). The electrodes (20) on the ceramic thick sheet (10) and the ceramic thin sheet (60) are provided in the sealed cavity (40).

Images