Organic silver paste for sintering ceramic capacitive pressure sensor and two-stage sheet

Abstract

The invention relates to the technical field of pressure sensors for automobiles, in particular to organic silver paste for sintering a ceramic capacitive pressure sensor and a two-stage sheet, and discloses two electrodes of the ceramic capacitive pressure sensor sintered by the organic silver paste prepared by mixing resin silver, a resinate mixing agent, an additive and an organic carrier. The ceramic capacitive pressure sensor not only can ensure the accuracy of measured values, but also can ensure that the electrodes sintered on the ceramic thin sheet and the ceramic thick sheet are not easy to fall off, 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 automobile pressure sensors, in particular to a ceramic capacitive pressure sensor and an organic silver paste for sintering a two-stage sheet. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] At present, the pressure sensors used most in new energy vehicles and traditional enterprises are ceramic capacitive pressure sensors. Ceramic capacitive pressure sensors include ceramic thin sheets and ceramic thick sheets, and organic gold paste is brushed on the thin sheets and thick sheets respectively. Then, the gold paste is sintered on the thin sheets and thick sheets through high-temperature sintering at 750℃~950℃ to form two electrodes. This not only ensures the deformation of the ceramic capacitive pressure sensor under pressure, but also ensures the adhesion of the gold paste, thereby ensuring that the detection value of the ceramic capacitive pressure sensor sintered with organic gold paste is stable and accurate.

[0004] Then, due to the high cost of organic gold paste, the overall cost of the current ceramic capacitive pressure sensor is high. In order to reduce costs, other metal pastes are used instead of gold paste to sinter the two electrodes on the ceramic capacitive pressure sensor. However, there are problems such as large measurement value deviation, poor adhesion, easy falling off, and strong surface graininess. It is urgent to find a new metal paste that can not only solve the problem of measurement value accuracy, but also solve the problem that the electrodes sintered on thin and thick ceramic sheets are not easy to fall off. Summary of the Invention

[0005] In order to solve the problem that the cost of forming electrodes of the current ceramic capacitive pressure sensor by sintering organic gold paste is high and a metal paste that can replace the organic gold paste is urgently needed, 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 made by mixing resin silver, resinate mixture, additives and organic carrier can not only ensure the accuracy of the measured values, but also ensure that the electrodes sintered on the ceramic thin sheet and the ceramic thick sheet are not easy to fall off, thereby greatly reducing the production cost of the ceramic capacitive pressure sensor.

[0006] To achieve the above objectives, the invention provides the following technical solution: an organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor, comprising 55-75% resin silver, 1-10% resinate mixture, 0.5-2% additives and 20%-40% organic carrier.

[0007] The present invention provides an organic silver paste for sintering a two-stage sheet of a ceramic capacitive pressure sensor. The resin silver is prepared from NaOH, 2-ethylhexanoic acid, and silver nitrate. The preparation method is as follows: a: Dissolve 2.32 g (0.058 mol) of NaOH in 50 mL of deionized water and 8.36 g (0.058 mol) of 2-ethylhexanoic acid in 50 mL of methanol, then mix the 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 and filter twice to obtain a white precipitate. Wash with distilled water and methanol, and then vacuum dry to obtain a white powder.

[0008] The invention provides an organic silver paste for sintering a two-stage sheet of a ceramic capacitive pressure sensor, wherein the MoI ratio of NaOH, 2-ethylhexanoic acid and silver nitrate is 1:1:1.

[0009] The invention provides an organic silver paste for sintering a two-stage piece of a ceramic capacitive pressure sensor. The resinate mixture comprises one or more elements selected from the group consisting of Rh, Si, Bi and Cr.

[0010] The invention provides an organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor. The resinate mixture is obtained by mixing 0.5% rhodium isooctanoate, 2% bismuth 2-ethylhexanoate, 2% organosilicon and 1% chromium neodecanoate.

[0011] The invention provides an organic silver paste for sintering a two-stage piece of a ceramic capacitive pressure sensor, wherein the additive is oleic acid or glycerol.

[0012] The present invention provides an organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor. 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; and the organic solvent comprises one or more of terpineol and alcohol ester dodecanol.

[0013] The invention provides an organic silver paste for sintering a two-stage piece of a ceramic capacitive pressure sensor, the organic silver paste has a fineness of ≤5 μm and a viscosity of 40-80 Pa.s.

[0014] The present invention provides a ceramic capacitive pressure sensor, comprising a ceramic thick sheet, a ceramic thin sheet, and electrodes respectively attached to the ceramic thick sheet and the ceramic thin sheet, wherein the electrodes are sintered by organic silver paste.

[0015] The present invention provides a ceramic capacitive pressure sensor, wherein the thickness of the electrode formed by sintering and polishing the organic silver paste and attached to the ceramic thick sheet is 1μm-2.3μm; the thickness of the electrode formed by sintering and polishing the organic silver paste and attached to the ceramic thin sheet is 0.4μm-2.3μm.

[0016] The present invention provides a ceramic capacitive pressure sensor, wherein 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.

[0017] The present invention provides a ceramic capacitive pressure sensor, wherein the thickness of the protective layer attached to the ceramic thick sheet after sintering and polishing is 2.2μm-3.8μm; the thickness of the protective layer attached to the ceramic thin sheet after sintering and polishing is 1.3μm-3.35μm.

[0018] The present invention provides a ceramic capacitive pressure sensor, wherein glass glue is provided on the connection surface of the ceramic thick sheet or the ceramic thin sheet to which the electrode is attached. The glass glue is sintered to seal the ceramic thick sheet and the ceramic thin sheet to form a sealed cavity, and the electrodes on the ceramic thick sheet and the ceramic thin sheet are arranged in the sealed cavity.

[0019] Compared with the prior art, the invention has the following beneficial effects: the present invention provides an organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor. The present invention uses an organic silver paste made by mixing resin silver, a resinate mixture, an additive, and an organic carrier to sinter two electrodes of the ceramic capacitive pressure sensor. The resin silver mainly provides a conductive phase, the resinate mixture improves the density and adhesion of the film after sintering, the organic carrier allows the resin silver and the resinate mixture to be evenly dispersed, and has good printability; the additive allows the paste to maintain a good printing state. This not only ensures the accuracy of the measured values, but also ensures that the electrodes sintered on the ceramic thin sheet and the ceramic thick sheet are not easy to fall off, thereby greatly reducing the production cost of the ceramic capacitive pressure sensor. The functions of the protective coating include: 1. preventing silver migration during use of the two electrodes formed by sintering the organic silver paste; 2. further protecting the two electrodes and preventing them from falling off; 3. preventing the silver on the two electrodes from oxidizing; 4. It also isolates the air contact in the sealed cavity from causing silver oxidation, and prevents the pressure sensitive element from short-circuiting due to the deformation of the pressure-bearing surface / pressure-sensing surface ceramic substrate (ceramic sheet) under several times overload pressure. The function of the glass glue is to ensure that a gap d is formed between the two electrodes and to seal the two electrodes around, sealing the two electrodes in the same area. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The figure is a structural schematic diagram of the ceramic capacitive pressure sensor of the present invention.

[0021] Among them, 10. Ceramic thick sheet, 20. Electrode, 30. Protective layer, 40. Sealing cavity, 50. Glass glue, 60. Ceramic thin sheet. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] In the description of the invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are 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 operate in a specific orientation, and therefore cannot be understood as a limitation on the invention.

[0024] In the description of the invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "disposed" should be understood broadly. For example, they may refer to fixed connection or disposition, detachable connection or disposition, or integral connection or disposition. Those skilled in the art will understand the specific meanings of the above terms in the invention based on the specific circumstances.

[0025] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0026] The present invention provides an organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor. The present design uses an organic silver paste made by mixing resin silver, a resinate mixture, an additive, and an organic carrier to sinter the two electrodes of the ceramic capacitive pressure sensor. The resin silver mainly provides a conductive phase, the resinate mixture improves the density and adhesion of the film layer after sintering, the organic carrier allows the resin silver and the resinate mixture to be evenly dispersed while having good printability, and the additive allows the paste to maintain a good printing state. This not only ensures the accuracy of the measured values, but also ensures that the electrodes 20 sintered on the ceramic thin sheet 60 and the ceramic thick sheet 10 are not easy to fall off, thereby greatly reducing the production cost of the ceramic capacitive pressure sensor. Example 1

[0027] An organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor comprises 55-75% silver resin, 1-10% resinate mixture, 0.5-2% additives, and 20%-40% organic carrier. The silver resin mainly provides a conductive phase, the resinate mixture improves the density and adhesion of the film after sintering, the organic carrier allows the silver resin and the resinate mixture to be evenly dispersed, and has good printability. The additive allows the paste to maintain a good printing state.

[0028] Preferably, resin silver is prepared from NaOH, 2-ethylhexanoic acid and silver nitrate, and its preparation method is as follows: a: dissolving 2.32g (0.058mol) of NaOH in 50mL of deionized water, and dissolving 8.36g (0.058mol) of 2-ethylhexanoic acid in 50mL of methanol, and then mixing the above two solutions to form solution A; b: dissolving 9.85g (0.058mol) of silver nitrate in 50mL of deionized water to form solution B; c: then dropping solution B into solution A and stirring, and finally washing with methanol, filtering twice to obtain a white precipitate, washing with distilled water and methanol, and then vacuum drying to obtain a white powder.

[0029] The Mole ratio of NaOH, 2-ethylhexanoic acid and silver nitrate is 1:1:1.

[0030] In a specific embodiment, the resinate mixture includes one or more elements selected from the group consisting of Rh, Si, Bi, and Cr.

[0031] The resinate mixture is prepared by mixing 0.5% rhodium isooctanoate, 2% bismuth 2-ethylhexanoate, 2% organic silicon and 1% chromium neodecanoate.

[0032] The additive is oleic acid or glycerol.

[0033] In a specific embodiment, the organic vehicle 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; and the organic solvent includes one or more of terpineol and terpineol.

[0034] The preparation method thereof is: a preparation method of an organic silver paste, which specifically comprises the following steps: s1. Mix the above materials in the above proportions; s2, rolling the mixed material on a three-axis rolling mill; s3. The rolled slurry is sieved through a sieve with a mesh size of 325 or above to obtain the final organic silver paste.

[0035] The organic silver paste produced has a measured fineness of ≤5μm and a viscosity of 40-80Pa.s.

[0036] The organic silver paste produced by the above ratio and the ceramic thin sheet and ceramic thick sheet electrodes produced by sintering can not only ensure the accuracy of the measurement values ​​of the ceramic capacitive pressure sensor, but also ensure that the electrodes sintered on the ceramic thin sheet and ceramic thick sheet are not easy to fall off.

[0037] The relevant data of the manufactured ceramic capacitive pressure sensor can be found in Example 2. Example 2

[0038] like Figure 1 As shown, a ceramic capacitive pressure sensor includes a ceramic thick sheet 10, a ceramic thin sheet 60, and electrodes 20 attached to the ceramic thick sheet 10 and the ceramic thin sheet 60 respectively, wherein the electrodes 20 are formed by sintering the organic silver paste in Example 1.

[0039] like Figure 1 As shown, the 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 .

[0040] Preferably, the protective layer 30 is a protective glue (GOS), which is printed and sintered on the outer surface of the electrode 20 to completely seal the electrode. The functions are as follows: 1. Preventing silver migration during use of the two electrodes 20 formed by sintering organic silver paste; 2. Further protecting the two electrodes 20 to prevent them from falling off; 3. Preventing oxidation of the silver on the two electrodes 20; 4. At the same time, it also isolates the air contact in the sealed cavity 40 from causing silver oxidation, and the deformation of the ceramic substrate of the force-bearing surface / pressure-sensing surface of the pressure sensor under several times overload pressure, resulting in contact between the upper and lower electrodes. Since the contact surface is still insulating protective glue, short circuit is avoided.

[0041] As shown in Table 1, the thickness of the electrode before, after and after polishing of the organic silver paste printed on the ceramic sheet 60 in this design is tested, as well as the thickness of the protective glue printed on the ceramic sheet 60 before, after and after polishing.

[0042] Table 1

[0043] As shown in Table 2, the thickness of the electrode before, after and after polishing of the organic silver paste printed on the ceramic thick sheet 10 in this design is tested; the thickness of the protective glue printed on the ceramic thick sheet 10 before, after and after polishing is tested; and the thickness of the glass glue printed on the ceramic thick sheet 10 before, after and after polishing is tested.

[0044] Table 2

[0045] Summarize: 1. The protective glue in Table 1 and Table 2 needs to be sintered at a high temperature of 500℃~700℃ and then polished. The glass glue 50 in Table 2 needs to be sintered at a high temperature of 500℃~700℃. After sintering, the electrode resistance is tested: the electrode 20 sintered with organic silver paste has an average resistance of about 1.2Ω, and the electrode 20 sintered with organic gold paste has an average resistance of about 1.9Ω. The measurement method is to use a multimeter to measure the resistance of 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, the better the conductivity and the smaller the loss. ; That is, gold paste is better than silver paste in terms of conductivity and damage, but because the resistance values ​​of the two electrodes on the ceramic thin sheet and the ceramic thick sheet sintered with gold paste and silver paste are very different, the energy consumption can be ignored; as shown in Tables 1 and 2, the thickness of the electrode 20 formed on the ceramic thick sheet 10 after sintering and polishing with organic silver paste is 1μm-2.3μm, and the preferred average thickness is 1.62μm; the thickness of the electrode 20 formed on the ceramic thin sheet 60 after sintering and polishing with organic silver paste is 0.4μm-2.3μm, and the preferred average thickness is 1 .06μm, wherein the thickness of the organic silver paste attached to the ceramic thick sheet 10 and the ceramic thin sheet 60 determines the cost of the ceramic capacitor. After sintering, the organic silver paste attached to the ceramic thick sheet 10 and the ceramic thin sheet 60 is thinner, and the cost is also reduced under the condition of the same area. The thickness of the protective layer attached to the ceramic thick sheet 10 after sintering and polishing is 2.2μm-3.8μm, preferably with an average thickness of 3.11μm; the thickness of the protective layer attached to the ceramic thin sheet 60 after sintering and polishing is 1.3μm-3.35μm, preferably with an average thickness of 2. 25μm; the thickness of the glass glue 50 attached to the ceramic thick sheet 10 after sintering and polishing is 18.2μm-22.51μm, and the preferred average thickness is 19.79μm. The function is to form a gap d between the two electrodes 20, to seal the two electrodes 20 around, and to seal the two electrodes 20 in the sealing cavity 40. The thickness of the glass glue 50 after sintering can be adjusted as needed to adjust the capacitance output value. The adhesion thickness of the glass glue and the protective glue can be adjusted as needed to ensure that the ceramic capacitor meets the measurement requirements.

[0046] 2. A layer of protective glue is respectively covered on the silver electrodes 20 sintered on the ceramic thick sheet 10 and the ceramic thin sheet 60 to prevent the silver from migrating from the silver electrode 20 to the other side of the substrate. At the same time, because the ceramic thick sheet 10 and the ceramic thin sheet 60 are sintered and sealed by the glass glue 50 to form a sealed cavity 40, the air in the sealed cavity 40 is isolated from contact with the electrode 20, causing silver oxidation. In addition, when the pressure sensor is subjected to several times overload pressure, the pressure surface / pressure-sensing surface of the ceramic substrate deforms, causing the upper and lower electrodes to contact. Since the contact surface is still covered with insulating protective glue, a short circuit is avoided, which causes damage to the pressure sensor.

[0047] 3. Using silver paste, the height of the glass glue 50 can be increased to raise the upper and lower plates, as well as the gap d between the two electrodes 20, thereby balancing the increase in ceramic capacitance after replacing the gold paste with silver paste. Silicon balls are also added to the glass glue to control the minimum gap.

[0048] 4. When the organic silver paste includes 55% resin silver, 1% resinate mixture, 0.5% additives and 20% organic carrier, the height of the organic silver attached to the thick ceramic sheet after sintering and polishing can be between 1μm and 2.3μm, and the height of the organic silver attached to the thin ceramic sheet after sintering and polishing can be between 0.4μm and 2.3μm; when the organic silver paste includes 75% resin silver, 10% resinate mixture, 2% additives and 40% organic carrier, the height of the organic silver attached to the thick ceramic sheet after sintering and polishing can be between 1μm and 2.3μm, and the height of the organic silver attached to the thin ceramic sheet after sintering and polishing can be between 0.4μm and 2.3μm. There is no absolute linear relationship between the ratio and the thickness of the organic silver attached to the thin ceramic sheet and the thick ceramic sheet.

[0049] like Figure 1 As shown, the thickness of the electrode 20 formed by sintering and polishing the organic silver paste and attached to the ceramic thick sheet 10 is 1μm-2.3μm, and the preferred average thickness is 1.62μm; the thickness of the electrode 20 formed by sintering and polishing the organic silver paste and attached to the ceramic thin sheet 60 is 0.4μm-2.3μm, and the preferred average thickness is 1.06μm.

[0050] The thickness of the protective layer attached to the ceramic thick sheet 10 after sintering and polishing is 2.2μm-3.8μm, preferably with an average thickness of 3.11μm; the thickness of the protective layer attached to the ceramic thin sheet 60 after sintering and polishing is 1.3μm-3.35μm, preferably with an average thickness of 2.25μm.

[0051] like Figure 1 As shown, the present invention provides a ceramic capacitive pressure sensor, wherein a glass glue 50 is coated on the connection surface of a ceramic thick sheet 10 or a ceramic thin sheet 60 sintered with an organic silver paste. After sintering, the glass glue 50 seals the ceramic thick sheet 10 and the ceramic thin sheet 60 to form a sealed cavity 40. The electrodes 20 on the ceramic thick sheet 10 and the ceramic thin sheet 60 are arranged in the sealed cavity 40. Its function is to form a gap d between the two electrodes 20, to achieve sealing around the two electrodes 20, and to seal the two electrodes 20 in the sealed cavity 40. The thickness of the glass glue 50 after sintering can be adjusted as needed to adjust the capacitance output value.

[0052] It is preferred that the glass glue 50 is coated on the ceramic thick sheet 10 and then sintered and fixed on the electrode 20 and the ceramic thick sheet 10. like Figure 1As shown, the calculation formula of capacitance can be expressed as: C=ε0*εr*S / d, where C represents capacitance, ε0 represents the dielectric constant in vacuum; εr represents the dielectric constant of 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.

[0053] As shown in Table 3, the capacitance values ​​of different types of organic slurries after sintering are summarized in the functional test data (the initial value in the table below is the capacitance value at zero voltage): Table 3

[0054] Summary: 1. Currently, under the 8Mpa pressure test, the organic silver replacing organic gold solution has been verified to be qualified, and the test results meet the requirements.

[0055] 2. In Table 3, “input” refers to the number of tests, and “output” refers to the number of qualified tests; 3. The combination of gold and silver electrodes failed verification, mainly because the compatibility between gold and silver electrodes is not as good as that of electrodes made of the same material. As a result, the changes in the initial 0-voltage capacitance value and the full-voltage capacitance value are both large and the consistency is poor.

[0056] The process flow of this design is as follows: 1. coating an organic silver paste on the ceramic thin sheet 60 and the ceramic thick sheet 10; 2. sintering the organic silver paste coated on the ceramic thin sheet 60 and the ceramic thick sheet 10 to form an electrode; 3. polishing the electrode 20; 4. coating a protective adhesive on the polished electrode 20 and then sintering; 5. finally coating glass adhesive on the ceramic thin sheet 60 or the ceramic thick sheet 10, and sealing the ceramic thin sheet 60 and the ceramic thick sheet 10 by sintering to form a sealed cavity 40; The process flow of using organic gold paste is as follows: 1. coating the organic gold paste on the ceramic thin sheet 60 and the ceramic thick sheet 10; 2. sintering the organic gold paste coated on the ceramic thin sheet 60 and the ceramic thick sheet 10 to form the electrode 20; 3. polishing the electrode 20; 4. coating glass glue on the ceramic thin sheet 60 or the ceramic thick sheet 10, and sealing the ceramic thin sheet 60 and the ceramic thick sheet 10 by sintering; When using organic silver paste to sinter the electrodes 20 on the ceramic thin sheet 60 and the ceramic thick sheet 10, the sintering protective adhesive step is added, and the other steps are the same. As shown in Table 4, under the premise of the same product and the same grade area, the cost difference between the original design (organic gold paste) and the organic silver paste is as follows: Table 4

[0057] The weights of the organic gold paste and organic silver paste in Table 4 are wet film weights, i.e., the weights just after printing and before high-temperature sintering, which facilitates the evaluation of the overall cost.

[0058] Summary: The current public design has a total cost of 1.16 yuan for thin gold electrode + thick gold electrode slurry, which is now changed to a total cost of 0.528 yuan for thin silver electrode & protective glue + thick silver electrode & protective glue, with a cost reduction of 0.631 yuan, a reduction of 54%; Among them: the role of the protective glue is: 1. Prevent silver from migrating toward the other side of the substrate; 2. Isolate the silver electrode and the air in the sealed cavity 40 to prevent silver oxidation; 3. When the pressure is overloaded, the ceramic sheet 60 is greatly deformed, which can easily cause the electrode on the ceramic sheet 60 to contact the electrode on the ceramic thick sheet 10. By setting the protective glue, the two electrodes are prevented from short-circuiting, thereby causing damage to the pressure sensor; 4. It can also prevent the sintered electrode 20, especially the ceramic sheet 60, from After multiple deformations, the electrode 20 causes the electrode 20 to fall off from the ceramic sheet 60; 5. When the organic silver paste includes 55% resin silver, 1% resinate mixture, 0.5% additives and 20% organic carrier, the organic silver paste adhesion test weight of the ceramic thin sheet is: 0.002796 grams, and the organic silver adhesion test weight of the ceramic thick sheet is: 0.003653 grams; when the organic silver paste includes 75% resin silver, 10% resinate mixture, 2% additives and 40% organic carrier, the organic silver paste adhesion test weight of the ceramic thin sheet is: 0.002849 grams, and the organic silver adhesion test weight of the ceramic thick sheet is: 0.003527 grams. There is no linear relationship between the ratio and the weight attached to the ceramic thin sheet and the ceramic thick sheet.

[0059] Note: The prices on this page are conservative market prices. The current international pure gold price is 610 yuan / gram, and the international pure silver price is 8 yuan / gram.

[0060] The above are only specific embodiments of the invention, but the scope of protection of the invention is not limited to them. Any changes or substitutions that are not conceived through creative work should be included in the scope of protection of the invention. Therefore, the scope of protection of the invention should be based on the scope of protection defined in the claims.

Claims

1. An organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor, characterized in that: The invention comprises 55-75% of silver resin, 1-10% of resin acid salt mixture, 0.5-2% of additive and 20%-40% of organic carrier.

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 resinate mixture includes one or more elements of Rh, Si, Bi and Cr.

5. The organic silver paste for sintering two-stage sheets of a ceramic capacitive pressure sensor as claimed in claim 4, characterized in that: The resinate mixture is obtained by mixing 0.5% rhodium isooctanoate, 2% bismuth 2-ethylhexanoate, 2% organic silicon and 1% chromium neodecanoate.

6. 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.

7. 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.

8. 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.

9. 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 claims 1 to 8.

10. A ceramic capacitive pressure sensor as claimed in claim 9, 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.

11. A ceramic capacitive pressure sensor as claimed in claim 9, 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).

12. A ceramic capacitive pressure sensor as claimed in claim 11, 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.

13. A ceramic capacitive pressure sensor as claimed in claim 11, 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).

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