Low-cost non-gold electrode pressure core, manufacturing method and pressure sensor

Abstract

The invention discloses a low-cost non-gold electrode pressure core body, a manufacturing method and a pressure sensor, and relates to the technical field of pressure core bodies, the low-cost non-gold electrode pressure core body comprises a ceramic base, an elastic membrane, a silk-screen electrode, sealing glass and a PIN needle; the opposite surfaces of the ceramic base and the elastic diaphragm are respectively provided with a silk-screen electrode, and sealing glass is used for sealing in the sintering process to form a capacitance cavity for pressure measurement; the PINs penetrate through the back face of the ceramic base and are connected with the silk-screen electrodes in a conducting mode. The silk-screen electrode is made of organic slurry containing platinum, palladium or alloy thereof, and a conductive film layer is formed after sintering; compared with a traditional gold electrode and silver electrode structure, the structure can maintain the stability of long-term output of a pressure signal, remarkably reduces the cost of an electrode material, has good sintering compatibility, chemical stability and mechanical reliability, and can be widely applied to capacitive pressure sensors, such as capacitive pressure sensors. The device is suitable for pressure measurement in high-temperature, high-humidity and temperature circulation environments.

Description

Technical Field

[0001] This invention relates to the field of pressure core technology, and in particular to a low-cost non-gold electrode pressure core, its manufacturing method, and a pressure sensor. Background Technology

[0002] Capacitive pressure sensors are widely used in automotive, industrial control, and smart devices due to their simple structure, high sensitivity, and good stability. These pressure cores typically consist of upper and lower ceramic substrates. Electrodes are printed on the substrate surfaces to form a sealed cavity, causing a change in capacitance under external pressure, thus achieving pressure measurement. Several pressure core fabrication methods are currently available and adopted by the industry.

[0003] In existing solutions, electrodes are printed on thin and thick ceramic substrates respectively, and isolation blocks are formed using special pastes. The two substrates are then bonded together through a pressing process to form an integral capacitor structure. This solution can meet the basic requirements for capacitor formation, but since gold or silver paste is commonly used as screen printing material for the electrodes, the material cost is high, and there are problems such as high-temperature oxidation and complex recycling.

[0004] In existing solutions, a whole-plate ceramic substrate processing method is adopted. Through whole-plate cleaning, whole-plate electrode printing, whole-plate glass printing, whole-plate sintering and cutting, mass production is achieved, which improves yield and consistency. However, this solution still uses precious metal gold paste or silver paste as electrode material. Gold electrodes are expensive, while silver electrodes have a large film thickness, which will reduce the spacing between capacitor plates and reduce the measurable pressure range. At the same time, silver has poor chemical stability and is easily oxidized under high temperature conditions, causing the output signal to drift.

[0005] In existing solutions, a capacitor structure is formed by fitting a substrate with electrodes and sealing edges into the sealing groove, auxiliary groove, and sintering cavity of the main body, filling it with sealing slurry, and then co-firing it at low temperature. This structure can improve sealing reliability, but its electrodes still mostly rely on gold or silver paste materials.

[0006] In addition, as a precious metal, gold's price has been affected by factors such as the global economy, inflation, and safe-haven demand, and has risen to a high level over the past decade. Although silver is inexpensive, it is unstable and easily oxidized, which is not conducive to the reliable control of long-term signal output. Furthermore, traditional precious metal electrodes require additional waste slurry recycling processes, which further increases the manufacturing cycle and production costs, hindering the promotion and application of large-scale, low-cost sensor products.

[0007] To reduce costs, some studies have attempted to use other metals or alloys as alternative materials. However, limitations remain in areas such as ceramic sintering temperature window, electrode adhesion, and electrochemical stability of electrodes under high humidity and high temperature conditions. As a result, a mature and industrially viable non-gold electrode solution has not yet been developed. In particular, capacitive pressure sensors have extremely high stability requirements. Once the electrode material oxidizes, its resistance increases, or its charge migrates, the capacitance value will drift over time, making it difficult to guarantee the sensor's range, sensitivity, and zero-point stability.

[0008] In summary, the existing technology has at least the following technical problems: Existing capacitive pressure sensors suffer from technical problems such as high overall manufacturing cost of gold-based electrodes, easy oxidation of silver-based electrodes, increased resistance, and unstable performance at high temperatures. There is a lack of non-gold metal electrode pressure core structures that combine high stability, sinterability, and low cost. Summary of the Invention

[0009] The purpose of this invention is to provide a low-cost non-gold electrode pressure core, manufacturing method, and pressure sensor to solve the technical problems of existing capacitive pressure sensors, such as high overall manufacturing cost of gold-based electrodes, easy oxidation of silver-based electrodes, increased resistance, and unstable performance at high temperatures. It also addresses the lack of a non-gold metal electrode pressure core structure that combines high stability, sinterability, and low cost.

[0010] The preferred technical solutions among the many technical solutions provided by this invention can produce a variety of technical effects, which are described in detail below.

[0011] To address the aforementioned technical problems, the present invention provides the following technical solution: This invention provides a low-cost non-gold electrode pressure core, comprising a ceramic substrate and an elastic diaphragm; a screen-printed electrode disposed on the front side of the ceramic substrate, with the elastic diaphragm facing the ceramic substrate; a sealing glass disposed between the ceramic substrate and the elastic diaphragm for sealing the screen-printed electrode and connecting the ceramic substrate and the elastic diaphragm to form a pressure core; and a PIN pin disposed on the back side of the ceramic substrate, the PIN pin passing through the body of the ceramic substrate and conductively connected to the screen-printed electrode; wherein the screen-printed electrode is made of an organic paste, the organic paste containing at least one or more of platinum, palladium, platinum alloys, and palladium alloys; and the screen-printed electrode forms a conductive film layer after sintering, thereby reducing the material cost of the screen-printed electrode while meeting the long-term capacitive pressure signal output stability requirements of the pressure core.

[0012] In one embodiment, the screen-printed electrode is made of the organic paste that is platinum-based, palladium-based, or a mixture of platinum and palladium, and the screen-printed electrode forms the conductive film layer that is platinum-based, palladium-based, or a mixture of platinum and palladium after sintering.

[0013] In one embodiment, the elastic diaphragm and the ceramic substrate are combined to form a capacitor cavity.

[0014] In one embodiment, the sealing glass covers the annular region outside the capacitor cavity, and the ceramic substrate and the elastic diaphragm are sintered together to form a continuous glass sealing ring, thereby improving the reliability of the sealing and dielectric stability of the capacitor cavity.

[0015] In one embodiment, the screen-printed electrode includes a fixed electrode disposed on the ceramic substrate and a variable electrode disposed on the elastic diaphragm; the fixed electrode and the variable electrode are spaced apart from each other through the capacitor cavity to form a capacitor plate structure.

[0016] In one approach, the sintered thickness of the screen-printed electrode is within 2–8 μm to reduce the resistance of the fixed electrode and the variable electrode and to avoid excessive reduction in the height of the capacitor cavity.

[0017] In one embodiment, the ceramic substrate is provided with a transmission through-hole, and the PIN pin passes through the transmission through-hole and penetrates the main body of the ceramic substrate; the PIN pin is fixed to the ceramic substrate by sealing the gap between the PIN pin and the transmission through-hole with glass paste, or it is pressed into the transmission through-hole with a press-in structure and fixed to the ceramic substrate, and is connected and conductive to the screen-printed electrode.

[0018] A method for manufacturing a low-cost non-gold electrode pressure core is also provided, which includes the following steps: S1, screen printing electrodes: screen printing fixed electrodes and variable electrodes of platinum-based, palladium-based or platinum-palladium mixed-based materials on a ceramic substrate and an elastic diaphragm, respectively. S2, Screen Printing Glass Paste: On the sealing surface between the ceramic substrate and the elastic diaphragm, screen print an annular glass paste along the annular area of ​​the outer edge of the screen printing electrode; S3. Assembly and sintering: The ceramic substrate and the elastic diaphragm are assembled and sintered to solidify the screen-printed electrode and the glass paste to form a sealing glass, and a capacitor cavity is formed between the ceramic substrate and the elastic diaphragm and enclosed by the sealing glass. S4. Pin implantation: Implant PIN pins into the ceramic substrate and connect the PIN pins to the screen printing electrode for conductivity. The screen-printed electrodes use organic pastes based on platinum, palladium, or a mixture of platinum and palladium.

[0019] In one embodiment, the sintering temperature of the screen-printed electrode and the glass paste is controlled at 800–960°C to improve the adhesion of the screen-printed electrode and to improve the chemical stability of the screen-printed motor containing platinum, palladium, or a platinum-palladium alloy at high temperatures.

[0020] A low-cost non-gold electrode pressure core is also provided for assembling a pressure sensor. The low-cost non-gold electrode pressure core is used to assemble a capacitive pressure sensor to maintain a stable pressure measurement signal output in high temperature, high humidity or temperature cycling environments.

[0021] The beneficial effects of this invention are as follows: (1) Significantly reduce the material cost of the pressure core Existing gold-based electrodes suffer from drawbacks such as high price, difficulty in recycling, and large market fluctuations. This technical solution avoids the high cost of gold by using platinum, palladium, or their alloys as screen printing electrode materials. Platinum and palladium have long been cheaper and less volatile than gold, resulting in a significant reduction in electrode material costs and thus lowering the overall manufacturing cost of the pressure core of the capacitive pressure sensor.

[0022] (2) Maintain high stability and long-term reliability of the electrodes Platinum, palladium, and their alloys have excellent chemical stability and are not easily oxidized in high-temperature air, thus maintaining stable electrode resistance and capacitance characteristics over a long period of time. The screen-printed electrode of this invention forms a continuous and dense conductive film layer after sintering, enabling the pressure core to maintain stable signal output in humid and hot environments, temperature cycles, and high-temperature scenarios, thus solving the problems of easy oxidation and signal drift of silver electrodes.

[0023] (3) Achieve good sintering performance that matches ceramic materials. By employing an organic slurry system adapted to ceramic sintering processes, the platinum / palladium electrode of this invention can form a highly adhesive bonding interface with the ceramic substrate and elastic diaphragm during sintering, without delamination, cracking, or other defects, giving the pressure core high mechanical reliability and high temperature resistance. This technical characteristic allows the pressure core to be directly used in capacitive pressure sensors for high-temperature sensitive applications.

[0024] (4) Simple structure, strong process compatibility, and suitable for mass production. This technical solution only sets screen-printed electrodes on the opposing surfaces of the ceramic substrate and the elastic diaphragm, and uses sealing glass for sealing and bonding. The structure is simple and easy to mass-produce using existing ceramic processing equipment and screen printing technology. It does not require an additional precious metal recycling process and greatly improves manufacturing efficiency.

[0025] (5) A pressure core solution that achieves both performance and cost This technical solution achieves a comprehensive performance breakthrough with low cost, high reliability, high stability and high process compatibility through the application of non-gold metal electrodes. It fills the technical gap in the existing pressure core material system that lacks low-cost and stable electrodes, and has significant industrial application value.

[0026] In summary, this technical solution addresses the problems of high manufacturing cost, unstable materials, and poor process compatibility in existing pressure core technologies, while providing a low-cost, sinterable, highly stable, and novel non-gold metal electrode pressure core structure. Attached Figure Description

[0027] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the first cross-sectional structure of the low-cost non-gold electrode pressure core of the present invention. Figure 2 This is a schematic diagram of the second cross-sectional structure of the low-cost non-gold electrode pressure core of the present invention; Figure 3 This is a top view schematic diagram of the elastic diaphragm structure of the low-cost non-gold electrode pressure core of the present invention; Figure 4 This is a schematic diagram of the preparation steps of the organic slurry of the present invention; Figure 5 This is a schematic diagram of the steps in the manufacturing method of the low-cost non-gold electrode pressure core of the present invention.

[0029] The reference numerals in the attached figures are as follows: 1. Ceramic base; 11. Transmission perforation; 2. Elastic diaphragm; 3. Screen-printed electrode; 31. Fixed electrode; 32. Variable electrode; 4. Sealing the glass; 5. Pressure core; 6. Pins; 7. Capacitor cavity. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0031] This invention provides a low-cost non-gold electrode pressure core, manufacturing method, and pressure sensor. The low-cost non-gold electrode pressure core includes a ceramic substrate, an elastic diaphragm, a screen-printed electrode, a sealing glass, and a PIN needle. Screen-printed electrodes are respectively disposed on the opposing surfaces of the ceramic substrate and the elastic diaphragm, and are sealed together by the sealing glass during sintering to form a capacitive cavity for pressure measurement. The PIN needle passes through the back of the ceramic substrate and is conductively connected to the screen-printed electrode. The screen-printed electrode is made of an organic paste containing platinum, palladium, or their alloys, and forms a conductive film layer after sintering. Compared to traditional gold and silver electrode structures, this invention can maintain the stability of long-term pressure signal output and significantly reduce electrode material costs. It also has good sintering compatibility, chemical stability, and mechanical reliability, and can be widely used in capacitive pressure sensors, suitable for pressure measurement in high-temperature, high-humidity, and temperature cycling environments. It effectively solves the technical problems of existing capacitive pressure sensors, such as high overall manufacturing cost of gold-based electrodes, easy oxidation of silver-based electrodes, increased resistance, and unstable performance at high temperatures. It also addresses the lack of a non-gold metal electrode pressure core structure that combines high stability, sinterability, and low cost.

[0032] The first implementation of a low-cost non-gold electrode pressure core, for example Figure 1 and Figure 3 As shown, the device includes a ceramic base 1 and an elastic diaphragm 2; a screen-printed electrode 3 disposed on the front side of the ceramic base 1 with the elastic diaphragm 2 facing the ceramic base 1; a sealing glass 4 disposed between the ceramic base 1 and the elastic diaphragm 2 for sealing the screen-printed electrode 3 and connecting the ceramic base 1 and the elastic diaphragm 2 to form a pressure core 5; and a PIN pin 6 disposed on the back side of the ceramic base 1, the PIN pin 6 passing through the body of the ceramic base 1 and conductively connected to the screen-printed electrode 3; wherein, the screen-printed electrode 3 is made of an organic paste, the organic paste containing metal materials including at least one or more of platinum, palladium, platinum alloy, and palladium alloy; and the screen-printed electrode 3 forms a conductive film layer after sintering, so that the pressure core 5 can reduce the material cost of the screen-printed electrode 3 while meeting the long-term capacitive pressure signal output stability requirements.

[0033] Specifically, the low-cost non-gold electrode pressure core provided by this technical solution addresses the problems of high manufacturing costs, limited electrode stability, and insufficient sinterability caused by the widespread use of gold or silver paste electrodes in existing capacitive pressure sensors. By using organic pastes of platinum, palladium, or their alloys as the screen printing electrode material 3, and combining this with structural optimization of the ceramic substrate 1, elastic diaphragm 2, and sealing glass 4, a dual breakthrough in performance and cost is achieved, resulting in several practical technical benefits: significantly reducing the material cost of the pressure core 5; existing gold-based electrodes suffer from high prices, difficulty in recycling, and large market fluctuations; this technical solution avoids the high cost of gold by using platinum, palladium, or their alloys as the screen printing electrode material 3; in particular, the price of platinum and palladium has long been lower than that of gold and has lower volatility, resulting in a significant reduction in electrode material costs, thereby reducing the overall manufacturing cost of the capacitive pressure sensor pressure core 5.

[0034] Maintaining high stability and long-term reliability of the electrodes; Platinum, palladium and their alloys have excellent chemical stability and are not easily oxidized in high-temperature air, thus maintaining the stability of electrode resistance and capacitance characteristics for a long time; The screen-printed electrode 3 of this invention forms a continuous and dense conductive film layer after sintering, enabling the pressure core 5 to maintain stable signal output in humid and hot environments, temperature cycles and high-temperature scenarios, solving the problems of easy oxidation and signal drift of silver electrodes.

[0035] Achieving good sintering performance that matches ceramic materials; by adopting an organic slurry system adapted to ceramic sintering process, the platinum / palladium electrode of the present invention can form a highly adhesive bonding interface with the ceramic substrate 1 and the elastic diaphragm 2 during the sintering process, without delamination, cracking or other defects, so that the pressure core 5 has high mechanical reliability and high temperature resistance; this technical feature allows the pressure core 5 to be directly used in capacitive pressure sensors for high temperature sensitive scenarios.

[0036] With its simple structure, strong process compatibility, and suitability for mass production, this technical solution only sets the screen-printed electrode 3 on the opposing surfaces of the ceramic base 1 and the elastic diaphragm 2, and uses the sealing glass 4 for sealing and bonding. The structure is simple and easy to use existing ceramic processing equipment and screen printing process for large-scale production. It does not require an additional precious metal recycling process, and the manufacturing efficiency is greatly improved.

[0037] This invention presents a pressure core solution that achieves both high performance and cost-effectiveness. By applying non-gold metal electrodes, this solution achieves a comprehensive performance breakthrough in terms of low cost, high reliability, high stability, and high process compatibility. It fills the technological gap in the existing pressure core material system, which lacks low-cost and stable electrodes, and has significant industrial application value.

[0038] This technical solution addresses the problems of high manufacturing cost, unstable materials, and poor process compatibility in existing pressure core technologies, while providing a low-cost, sinterable, highly stable, novel non-gold metal electrode pressure core structure.

[0039] As one alternative implementation method: Regarding the composition and function of the aforementioned screen-printed electrode 3 and conductive film layer, this embodiment is, for example... Figure 1 and Figure 3 As shown, the screen printing electrode 3 is made of a platinum-based, palladium-based, or platinum-palladium mixed-based organic paste, and the screen printing electrode 3 forms a platinum-based, palladium-based, or platinum-palladium mixed-based conductive film layer after sintering.

[0040] When applied, the conductive film layer formed by the screen-printed electrode 3 of platinum-based, palladium-based or platinum-palladium mixed base after sintering is stably bonded to the surface of ceramic base 1 and elastic diaphragm 2. During the high-temperature sintering process, the metal particles are sintered densely and form a continuous conductive path, thereby ensuring the low resistivity of the fixed electrode 31 of ceramic base 1 and the variable electrode 32 of elastic diaphragm 2 as well as the stability of capacitive signal transmission.

[0041] The interface formed between the platinum-based, palladium-based, or platinum-palladium mixed-based conductive film and the ceramic substrate has good resistance to temperature changes and humid and hot environments. It works synergistically with the sealed cavity formed by the sealing glass 4 to ensure the long-term reliability of the capacitor structure formed by the whole combination. By using non-gold metal electrode materials, the electrode cost can be significantly reduced while maintaining high stability, solving the problem of high manufacturing cost caused by the reliance on gold paste in existing electrodes.

[0042] Regarding the function of capacitor cavity 7, this implementation is as follows: Figure 1 As shown, the elastic diaphragm 2 and the ceramic base 1 are combined to form a capacitor cavity 7.

[0043] In application, the capacitor cavity 7 forms the sensing gap between the fixed electrode 31 and the variable electrode 32. The elastic diaphragm 2 undergoes slight deformation under external pressure, causing a controllable change in the height of the capacitor cavity 7 and resulting in a linear or quasi-linear change in capacitance with pressure. The capacitor cavity 7 and the conductive film together constitute a pressure-sensitive structure. The elastic properties of the diaphragm, the sealing performance of the capacitor cavity 7, and the stability of the fixed electrode 31 and the variable electrode 32 collectively determine the sensitivity, linearity, and temperature stability of the pressure response. By precisely controlling the height of the capacitor cavity 7 and the sealing structure, the pressure measurement range can be improved and zero-point drift reduced, enabling the pressure core 5 of this technical solution to operate stably in complex environments.

[0044] Regarding the specific structure of the connection between the elastic diaphragm 2 and the ceramic base 1, this embodiment is as follows: Figure 1 and Figure 3As shown, the sealing glass 4 covers the annular area outside the capacitor cavity 7. After merging the ceramic base 1 and the elastic diaphragm 2, a continuous glass sealing ring is formed by sintering, so as to improve the sealing performance and dielectric stability of the capacitor cavity 7.

[0045] During application, the sealing glass 4 softens and wets the surfaces of the ceramic substrate 1 and the elastic diaphragm 2 during sintering, eventually solidifying to form a continuous glass sealing ring. This gives the capacitor cavity 7 high airtightness and prevents external moisture and contaminants from penetrating. The glass sealing structure is compatible with the sintering process of the screen-printed electrode 3, preventing electrode oxidation or delamination, and can compensate for minor processing errors between the substrate and the diaphragm, achieving reliable structural bonding. The synergistic effect of the glass seal, the capacitor cavity 7, and the electrode structure enables the pressure core 5 to maintain excellent dielectric stability and reduce signal drift under temperature cycling, high humidity, and high pressure environments.

[0046] Regarding the specific structure of the aforementioned screen-printed electrode 3, this embodiment is, for example... Figure 1 and Figure 3 As shown, the screen printing electrode 3 includes a fixed electrode 31 disposed on the ceramic substrate 1 and a variable electrode 32 disposed on the elastic diaphragm 2; the fixed electrode 31 and the variable electrode 32 are spaced apart from each other through the capacitor cavity 7 to form a capacitor plate structure.

[0047] In application, the fixed electrode 31 and the variable electrode 32 are respectively positioned at corresponding positions on the ceramic base 1 and the elastic diaphragm 2, and the two form a parallel plate capacitor structure through the capacitor cavity 7; the variable electrode 32 changes the distance between itself and the fixed electrode 31 as the diaphragm deforms, making the capacitance value highly sensitive to pressure changes; this structure works in conjunction with the stability of the conductive film layer and the sealing performance of the sealing glass 4 to accurately convert external pressure into an electrical signal; by optimizing the electrode shape, area and relative position, the pressure response sensitivity is further improved and the hysteresis is reduced, so that the overall pressure core 5 has excellent measurement accuracy.

[0048] A second implementation of a low-cost non-gold electrode pressure core, for example Figure 1 and Figure 3 As shown, the difference between this embodiment and the first embodiment is that the thickness of the screen-printed electrode 3 after sintering is within 2–8 μm, so as to reduce the resistance of the fixed electrode 31 and the variable electrode 32 and avoid excessive reduction in the height of the capacitor cavity 7.

[0049] When applied, if the thickness of the screen-printed electrode 3 is controlled within 2–8 μm after sintering, it can ensure that the electrode layer has sufficient conductivity without causing the height of the capacitor cavity 7 to decrease due to excessive thickness, thus avoiding affecting the pressure measurement range and sensitivity. This thickness range can also effectively reduce the accumulation of internal stress in the electrode, prevent defects such as cracking and detachment after high-temperature sintering, and improve the reliability of bonding with the ceramic substrate. By controlling the thickness of the screen-printed electrode 3 in a synergistic balance with the material system, the roughness of the ceramic surface, and the sealing height of the sealing glass 4, the pressure core 5 achieves the optimal balance between cost, performance, and reliability.

[0050] A third implementation of a low-cost non-gold electrode pressure core, for example Figure 2 As shown, the difference between this embodiment and the first embodiment is that the ceramic base 1 is provided with a transmission through hole 11, and the PIN needle 6 passes through the transmission through hole 11 and penetrates the main body of the ceramic base 1; the PIN needle 6 is fixed to the ceramic base 1 by sealing the gap between the PIN needle 6 and the transmission through hole 11 with glass paste, or it is pressed into the transmission through hole 11 with a press-in structure and fixed to the ceramic base 1, and connected to the screen printing electrode 3 for conduction.

[0051] When applied, the PIN pin 6 passes through the transmission hole 11 of the ceramic base 1 and is connected to the screen printing electrode 3, enabling the external circuit to reliably read the capacitive pressure signal. The PIN pin 6 is fixed to the ceramic base 1 through glass paste sealing or press-fit structure, which can effectively enhance mechanical stability and improve insulation performance, avoiding loosening, air leakage or poor connection problems during long-term use.

[0052] The electrical connection structure of the PIN pin 6, together with the screen printing electrode 3, the sealing glass 4, and the ceramic base 1, forms a complete signal path, enabling the pressure core 5 to have good electrical reliability under vibration, temperature changes, and humid and hot environments.

[0053] In addition, PIN6 uses nickel-plated copper needles, stainless steel needles, or composite metal needles to improve conductivity and corrosion resistance.

[0054] A fourth embodiment of a low-cost non-gold electrode pressure core, for example Figure 1 , Figure 3 and Figure 4 As shown, the difference between this embodiment and the first embodiment is that the organic slurry is composed of metal powder, organic carrier, binder and dispersant.

[0055] The metal powder includes platinum powder, palladium powder, or platinum-palladium alloy powder. The average particle size of the metal powder is controlled at 0.3–1.5 μm, accounting for 45%–75% of the volume fraction. It is used as a conductive phase to ensure that a continuous metal network is formed after the screen-printed electrode 3 is sintered, thereby improving the conductivity of the electrode.

[0056] The organic carrier includes terpineol or α-terpineol or a mixture of terpineol and α-terpineol, with a content of 15%–35% by mass, and is used to adjust the viscosity of the organic paste, improve the paste flowability and diffusion stability of the organic paste during the screen printing process, thereby forming a uniform screen printing electrode path.

[0057] The binder uses ethyl cellulose (EC) at a content of 1%–8% by mass to enhance the adhesion between the organic slurry and the ceramic surface of the ceramic substrate 1 and the elastic diaphragm 2, and to prevent the organic slurry from falling off before sintering.

[0058] The dispersants include sodium stearate, lithium stearate, and polyvinylpyrrolidone (PVP), with a content of 0.1%–3% by mass. They are used to improve the dispersion uniformity of platinum, palladium, or platinum-palladium alloy powder in the organic carrier component, reduce the risk of agglomeration, and ensure the sintering density and conductivity continuity of the screen-printed electrode 3.

[0059] The overall viscosity of the organic paste needs to be controlled within the range of 8–30 Pa·s at an ambient temperature of 25°C. This is to improve the edge forming performance of the screen-printed electrode 3, reduce the diffusion and collapse, and maintain the thickness uniformity of the screen-printed circuit.

[0060] The preparation steps of organic slurry, such as Figure 4 As shown, this includes A1, weighing: Weigh the metal powder, organic carrier, binder and dispersant according to the above formula; A2. Mixing: Use a planetary mixer to mix for 20–40 minutes to fully dissolve the binder; A3. Grinding and fusion: Grind the metal powder 3-6 times using a three-roll mill to ensure uniform dispersion. A4. Degassing: Allow to stand for 4–12 hours to degas, and obtain a uniform and stable organic paste for screen printing electrode 3.

[0061] In application, the obtained organic paste was screen-printed onto a ceramic substrate 1 and an elastic diaphragm 2 to form a screen-printed electrode 3. In the subsequent sintering process at 800–960℃, a continuous conductive metal phase was formed, achieving a stable performance with an adhesion strength ≥12MPa and a resistivity ≤20μΩ·cm. This verifies that platinum, palladium, or platinum-palladium alloy systems can replace traditional gold pastes and be used for electrode forming of capacitive pressure cores 5.

[0062] Based on the above embodiments of low-cost non-gold electrode pressure cores, a method for manufacturing a low-cost non-gold electrode pressure core is provided, such as... Figure 1 , Figure 3 and Figure 5As shown, the process includes the following steps: S1, screen printing electrode 3: a fixed electrode 31 and a variable electrode 32 of platinum-based, palladium-based or platinum-palladium mixed-based material are screen printed on the ceramic substrate 1 and the elastic diaphragm 2, respectively. S2, Screen printing glass paste: On the sealing surface between the ceramic base 1 and the elastic diaphragm 2, screen print an annular glass paste along the annular area of ​​the outer edge of the screen printing electrode 3. S3, Sintering: The ceramic substrate 1 and the elastic diaphragm 2 are sintered together to solidify the screen-printed electrode 3 and the glass paste to form a sealing glass 4, and a capacitor cavity 7 is formed between the ceramic substrate 1 and the elastic diaphragm 2 and enclosed by the sealing glass 4. S4. Inserting pins: Inserting pins 6 into the ceramic base 1 and connecting pins 6 to the screen printing electrode 3 for conduction. Among them, the screen printing electrode 3 uses a platinum-based, palladium-based, or platinum-palladium mixed-based organic paste.

[0063] In step S3, the sintering temperature of the screen printing electrode 3 and the glass paste is controlled at 800–960°C to improve the adhesion of the screen printing electrode 3 and improve the chemical stability of the screen printing motor containing platinum, palladium or platinum-palladium alloy at high temperature.

[0064] In application, this manufacturing method screen-prints platinum-based, palladium-based, or platinum-palladium mixed-based organic paste electrodes on the ceramic substrate 1 and the elastic diaphragm 2, and screen-prints annular glass paste on the outer region of the electrodes. This allows the pattern accuracy of the screen-printed electrode 3 and the positioning of the sealing area to be completed simultaneously, providing a consistent basis for subsequent electrode curing and sealing cavity formation.

[0065] In sintering step S3, the sintering temperature is controlled at 800–960℃, causing the metal powder in the metal-organic slurry to sinter and densify, forming a continuous conductive film layer, which improves the surface adhesion and oxidation resistance of the electrode. At the same time, the glass slurry softens and solidifies at this temperature, forming a continuous sealing glass 4, which together with the ceramic substrate 1 and the elastic diaphragm 2 forms a stable capacitor cavity 7.

[0066] The PIN needle 6 is implanted in step S4, and a highly reliable metal-ceramic electrical connection is formed through glass sealing or press-fit structure, so that the pressure core 5 has good electrical interface stability.

[0067] Throughout the manufacturing process, screen printing, electrode sintering, glass sealing, and PIN pin 6 fixing work together to ensure that the final pressure core 5 can maintain long-term capacitor signal output stability while significantly reducing the material cost and manufacturing complexity of traditional gold-based electrode processes.

[0068] In this method, the sintering process adopts a multi-stage temperature curve of heating-holding-heating-holding sintering-cooling to optimize the sintering density of metal electrode particles. In the heating stage, the temperature is increased to 500°C at a rate of 5°C per minute and held for half an hour. Then, the temperature is increased to 800–960°C at a rate of 3°C per minute and held for half an hour. After that, the temperature is cooled to 80°C in the furnace at a rate of 1°C per minute and then removed and allowed to cool naturally in the room.

[0069] Based on the above embodiments of low-cost non-gold electrode pressure cores, a pressure sensor with a low-cost non-gold electrode pressure core is provided. The low-cost non-gold electrode pressure core is used to assemble a capacitive pressure sensor to maintain a stable pressure measurement signal output in high temperature, high humidity or temperature cycling environments.

[0070] In application, the pressure sensor uses the low-cost non-gold electrode pressure core of the present invention as the core sensitive element. The capacitor structure composed of the fixed electrode 31 and the variable electrode 32 generates a measurable capacitance change under the action of external pressure, and the capacitance signal is transmitted to the signal processing circuit through the PIN pin 6.

[0071] Because the screen-printed electrode 3 is made of platinum-based, palladium-based, or platinum-palladium mixed-based materials, its sintered conductive film layer exhibits high-temperature stability, low resistivity, and excellent oxidation resistance. This ensures that the sensor maintains signal output stability in high-temperature, high-humidity, and temperature cycling environments, thus replacing gold electrodes. Compared to traditional pressure sensors using gold electrodes, this invention significantly reduces material costs while maintaining or even improving environmental adaptability and long-term reliability, achieving a technological transformation towards highly reliable, high-performance, and low-cost pressure sensors.

[0072] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described.

Claims

1. A low-cost non-gold electrode pressure core, characterized in that, Includes a ceramic base and an elastic diaphragm; And a screen-printed electrode disposed on the front side of the ceramic substrate, with the elastic diaphragm facing the ceramic substrate; And a sealing glass disposed between the ceramic base and the elastic diaphragm, used to seal the screen-printed electrode and connect and merge the ceramic base and the elastic diaphragm to form a pressure core; And a PIN pin disposed on the back side of the ceramic base, the PIN pin passing through the main body of the ceramic base and being electrically connected to the screen printing electrode; The screen-printed electrode is made of organic paste, and the organic paste contains at least one or more of the following metal materials: platinum, palladium, platinum alloy, and palladium alloy. Furthermore, the screen-printed electrode forms a conductive film layer after sintering, thereby reducing the material cost of the screen-printed electrode while ensuring the stability of the long-term capacitive pressure signal output of the pressure core.

2. The low-cost non-gold electrode pressure core according to claim 1, characterized in that, The screen-printed electrode is made of the organic paste of platinum-based, palladium-based, or platinum-palladium mixture, and the screen-printed electrode forms the conductive film layer of platinum-based, palladium-based, or platinum-palladium mixture after sintering.

3. The low-cost non-gold electrode pressure core according to claim 1, characterized in that, The elastic diaphragm and the ceramic base together form a capacitor cavity.

4. The low-cost non-gold electrode pressure core according to claim 3, characterized in that, The sealing glass covers the annular area outside the capacitor cavity, and the ceramic base and the elastic diaphragm are sintered together to form a continuous glass sealing ring, thereby improving the sealing performance and dielectric stability of the capacitor cavity.

5. The low-cost non-gold electrode pressure core according to claim 4, characterized in that, The screen-printed electrode includes a fixed electrode disposed on the ceramic substrate and a variable electrode disposed on the elastic diaphragm; the fixed electrode and the variable electrode are spaced apart from each other through the capacitor cavity to form a capacitor plate structure.

6. The low-cost non-gold electrode pressure core according to claim 5, characterized in that, The sintered thickness of the screen-printed electrode is within 2–8 μm to reduce the resistance of the fixed electrode and the variable electrode and to avoid excessive reduction in the height of the capacitor cavity.

7. The low-cost non-gold electrode pressure core according to claim 1, characterized in that, The ceramic base is provided with a transmission hole, and the PIN needle passes through the transmission hole and penetrates the main body of the ceramic base; The PIN pin is fixed to the ceramic base by sealing the gap between the PIN pin and the transmission through hole with glass paste, or it is pressed into the transmission through hole and fixed to the ceramic base by a press-in structure, and is connected and conductive to the screen printing electrode.

8. A method for manufacturing a low-cost non-gold electrode pressure core, used to manufacture the low-cost non-gold electrode pressure core according to any one of claims 1 to 7, characterized in that, Includes the following steps, S1. Screen-printed electrodes: Fixed electrodes and variable electrodes based on platinum, palladium, or a mixture of platinum and palladium are screen-printed on a ceramic substrate and an elastic diaphragm, respectively. S2, Screen Printing Glass Paste: On the sealing surface between the ceramic substrate and the elastic diaphragm, screen print an annular glass paste along the annular area of ​​the outer edge of the screen printing electrode; S3. Assembly and sintering: The ceramic substrate and the elastic diaphragm are assembled and sintered to solidify the screen-printed electrode and the glass paste to form a sealing glass, and a capacitor cavity is formed between the ceramic substrate and the elastic diaphragm and enclosed by the sealing glass. S4. Pin implantation: Implant PIN pins into the ceramic substrate and connect the PIN pins to the screen printing electrode for conductivity. The screen-printed electrodes use organic pastes based on platinum, palladium, or a mixture of platinum and palladium.

9. The manufacturing method according to claim 8, characterized in that, The sintering temperature of the screen printing electrode and the glass paste is controlled at 800–960°C to improve the adhesion of the screen printing electrode and to improve the chemical stability of the screen printing motor containing platinum, palladium or platinum-palladium alloy at high temperatures.

10. A pressure sensor with a low-cost non-gold electrode pressure core, assembled using the low-cost non-gold electrode pressure core according to any one of claims 1 to 7, characterized in that, The low-cost non-gold electrode pressure core is used to assemble a capacitive pressure sensor to maintain a stable pressure measurement signal output in high temperature, high humidity or temperature cycling environments.

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