A method for preparing a porous CZO layer gas sensor chip

Abstract

The present invention discloses a method for preparing a porous CZO layer gas sensor chip, comprising the following steps: S1 pretreatment: S2 low temperature drying; S3 heat treatment; S4 grinding; S5 molding; S6 sintering; S7 electrode coating; S8 multi-layer loading electrode CZO substrate bonding; S9 high temperature sintering; S10 chip detection. The present invention improves the performance problems of low sensitivity, poor selectivity, long response time and low automation of the preparation process of the existing gas sensor. The present invention adopts a sol-gel method to prepare a porous cerium-zirconium oxide (CZO) layer, which further improves the sensitivity and response speed of the sensor chip compared to the currently commonly used materials such as YSZ, Al2O3, and ZrO2, while significantly reducing the preparation time and production cost. By optimizing the process parameters, the present invention effectively solves the problems of complex preparation process and poor stability in the traditional method. Accurate control and real-time monitoring of the preparation process are achieved, greatly improving production efficiency and product quality.

Description

Technical Field

[0001] The invention belongs to the technical field of gas sensor chip preparation, and in particular relates to a method for preparing a porous CZO layer gas sensor chip. Background Art

[0002] The basic principle of the sol-gel method: The sol-gel method (Sol-Gel method) is to generate a sol through the hydrolysis and polycondensation reaction of metal organic compounds or metal salts in a solution, and then form a gel through drying and sintering. This method has the advantages of mild reaction conditions, controllable composition and easy doping.

[0003] Cerium oxide stabilized zirconia (CeO-ZrO, CZO for short) is a material widely used in gas sensors, catalysts and solid oxide fuel cells (SOFC) and other fields. Its unique high temperature stability and oxygen ion conductivity make it one of the important materials in high temperature gas sensing and environmental monitoring. Sol-gel method is a common chemical synthesis method that can prepare high-purity, uniform and porous materials at a relatively low temperature, and is therefore suitable for the preparation of porous CZO layers.

[0004] Existing gas sensor chips usually use a mask preparation method to process multi-layer mixed-pressure ceramic materials, which has high requirements for production equipment and a low degree of full automation of the production line. On the other hand, due to the high requirements for the overall cleanliness of the workshop during the mask preparation process and the easy introduction of fine dust during the preparation process, it will be difficult for the gas sensor chip to maintain good performance and reliability in application scenarios such as multiple uses and long-term exposure to high-temperature and high-pressure gases. The sensitivity and selectivity of the gas response in complex environments have a low yield rate.

[0005] Therefore, the existing structure and defects are studied and improved, and a method for preparing a porous CZO layer gas sensor chip is provided, in order to achieve a more practical purpose. Summary of the invention

[0006] In view of at least one problem in the prior art, an object of the present invention is to provide a method for preparing a porous CZO layer gas sensor chip.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for preparing a porous CZO layer gas sensor chip comprises the following steps:

[0009] S1 pretreatment: preparation of precursor solution: dissolving 0.05-0.2 mol / L cerium oxide and 0.05-0.2 mol / L zirconium oxide precursors in a solvent, then adding a stabilizer and a template and stirring at a temperature of 20-30°C for 0.5-2 hours to promote hydrolysis and polycondensation of the precursors to form a uniform sol;

[0010] S2 low temperature drying: drying the sol at 40-60°C for 24-48 hours to form a gel layer;

[0011] S3 heat treatment: heat the gel at 300-400°C for 2-4 hours to remove the template;

[0012] S4 grinding: firstly crush the heat-treated gel solid, and then send the crushed particles into a high-efficiency grinding machine for mechanical grinding to obtain gel powder of 50nm-500nm;

[0013] S5 molding: using a mold of a specific shape to press the gel powder into shape, with a pressure range of 50-100MPa;

[0014] S6 sintering: sintering at a high temperature of 1200-1500°C for 2-6 hours to obtain a porous CZO substrate with a specified shape structure;

[0015] S7 electrode coating: Use precious metals as electrodes and connect the electrodes to the porous CZO substrate by screen printing or sputtering.

[0016] S8 Multilayer loaded electrode CZO substrate bonding: Use high temperature resistant adhesive for bonding, at room temperature to 100°C, pressure 0.5-2MPa, for 1-2 hours;

[0017] S9 high temperature sintering: sintering the bonded multilayer loaded electrode CZO substrate at 800-1000°C for 1-3 hours;

[0018] S10 chip detection: Use test tooling to detect the chip.

[0019] Preferably, the stabilizer is 2-10 wt % such as one of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), and the template is 0.1-1 wt % CTAB (cetyltrimethylammonium bromide).

[0020] Preferably, the precious metal in step S7 includes gold (Au) and platinum (Pt).

[0021] Preferably, in step S7, the screen mesh number is 200-400 mesh, the printing pressure is 2-5N / cm², and the printing speed is 50-100mm / s.

[0022] Preferably, the high temperature resistant adhesive comprises silicone adhesive and glass powder.

[0023] Preferably, the porous CZO layer gas sensor chip comprises a first CZO substrate, a second CZO substrate, a third CZO substrate, a fourth CZO substrate, a fifth CZO substrate, a sixth CZO substrate, a first chamber electrode, a second chamber electrode and a heating electrode; the first CZO substrate, the second CZO substrate, the third CZO substrate, the fourth CZO substrate, the fifth CZO substrate and the sixth CZO substrate are bonded to each other; the first chamber electrode and the second chamber electrode are arranged in the second CZO substrate; a cavity is provided in the fourth CZO substrate; a reference electrode is provided on the third CZO substrate located in the cavity; a heating electrode is provided on the surface of the fifth CZO substrate located on one side of the sixth CZO substrate; a main pump electrode is provided on the outer side of the first CZO substrate; and a porous alumina protective layer is provided on the outer side of the main pump electrode.

[0024] Preferably, the high-efficiency grinding mill includes a grinding mill body, a first grinding groove is provided at the upper end of the grinding mill body, the first grinding groove is in a truncated cone shape, a matching and rotatable grinding truncated cone is provided in the first grinding groove, a plurality of grinding strips are provided on the first grinding groove and the grinding truncated cone, a second grinding groove is provided below the first grinding groove, a funnel-shaped collecting plate is provided in the second grinding groove and is used to collect materials after grinding the grinding truncated cone, a ring-shaped filter screen is provided on the collecting plate, a first collecting ring plate is fixedly connected in the second grinding groove and is used to collect materials after screening by the filter screen, the first collecting ring plate is inclined, a first discharging ring groove is provided on the first collecting ring plate, a first discharging hopper is provided on one side of the grinding mill body, and the first discharging hopper is connected to the discharging end of the first discharging ring groove.

[0025] Preferably, the material screened by the filter screen falls into the bottom of the second grinding trough, a rotatable rotating shaft is provided in the middle of the second grinding trough, a fixed rod is provided on one side of the rotating shaft, a grinding wheel is rotatably connected and used for extruding and grinding the material at the bottom of the grinding trough at the end of the fixed rod, a collecting box that moves synchronously with the grinding wheel is provided at one end of the grinding wheel, the bottom of the collecting box is slidably connected to the bottom of the second grinding trough, and a collecting trough for the material to pass through is provided in the collecting box, a fixedly connected separation plate is provided in the collecting trough, both ends of the separation plate are inclined, and the bottom of the separation plate slides with the bottom of the second grinding trough The separation plate is provided with a material storage trough, and a plurality of screening holes connected with the material storage trough are provided on the separation plate, the material storage trough has a conical cross-section, and a conveying trough is provided at the bottom of the material storage trough, a rotatable conveying auger is provided in the conveying trough, a conveying pipe is provided on one side of the collecting box, the conveying pipe is connected with the conveying trough, and the conveying auger is arranged in the conveying pipe, a second discharging ring groove in a circular shape is provided in the middle of the second grinding trough, the output end of the conveying pipe is located in the second discharging ring groove, the second discharging ring groove is inclined, and a second discharging hopper connected with the discharging end of the second discharging ring groove is provided on one side of the grinding mill body.

[0026] Preferably, the filter screen, the first discharge ring groove, the storage groove and the second discharge ring groove are all provided with a vibration motor.

[0027] Preferably, a rotatable conveying ring is provided in the collecting trough, a plurality of fixedly connected push plates are provided on the conveying ring, and a first rubber belt which can be squeezed and deformed and is used to push the material onto the separation plate is provided at the bottom of each push plate.

[0028] Compared with the prior art, the present invention has the following technical effects:

[0029] The present invention aims to improve the performance problems of existing gas sensors, such as low sensitivity, poor selectivity, long response time, and low automation of the preparation process. The present invention adopts a sol-gel method to prepare a porous cerium oxide-zirconium (CZO) layer, which further improves the sensitivity and response speed of the sensor chip compared to the currently commonly used materials such as YSZ, Al2O3, and ZrO2, while significantly reducing the preparation time and production cost. By optimizing the process parameters, the present invention effectively solves the problems of complex preparation process and poor stability in traditional methods. Based on the newly developed process control system, the present invention realizes precise control and real-time monitoring of the preparation process, greatly improving production efficiency and product quality.

[0030] The present invention prepares a porous electrode by a sol-gel method, has a uniform and stable porous structure, and increases the sensing surface area. The porous structure ensures good stability and uniformity of the gas sensor chip, while improving the adsorption and reaction efficiency of the gas. The sensor chip has good durability and repeatability, and can maintain its performance and reliability under multiple uses and long-term exposure to the gas. The sensitivity and selectivity of the sensor to the gas are improved to ensure that the concentration of NOx can be accurately detected in a complex environment.

[0031] The present invention has low-temperature operating performance. Compared with traditional NOx sensors that often need to work at high temperatures, by optimizing the sol-gel method and materials, the sensor can be operated efficiently at a lower temperature and reduce energy consumption.

[0032] On the other hand, based on the simplicity and controllability of the preparation process, the present invention simplifies the sensor preparation process through the sol-gel method, improves the controllability and consistency of the preparation process, reduces production costs and increases yield.

[0033] With reference to the following description and the accompanying drawings, the specific embodiments of the present invention are disclosed in detail, indicating the manner in which the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope thereby.

[0034] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0035] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying creative labor.

[0037] Figure 1 The present invention provides a production process flow chart.

[0038] Figure 2 This is a schematic diagram of the structure of the gas sensor chip provided by the present invention.

[0039] Figure 3 This is a test curve diagram provided by the present invention.

[0040] Figure 4 The present invention is a schematic diagram of the three-dimensional structure of the high-efficiency grinding mill provided by the present invention.

[0041] Figure 5 This is a schematic diagram of the three-dimensional structure of the collecting plate, the first discharging trough and the grinding wheel provided by the present invention.

[0042] Figure 6 This is a schematic diagram of the cross-sectional connection structure of the grinding truncated table, rotating shaft and collecting tube provided by the present invention.

[0043] Figure 7 This is a schematic diagram of the three-dimensional connection structure of the collection box provided by the present invention.

[0044] Figure 8 This is a schematic diagram of the three-dimensional connection structure of the separation plate, conveying ring and push plate provided by the present invention.

[0045] Fig. 9 This is a schematic diagram of the three-dimensional connection structure of the push plate and the adjustment plate provided by the present invention.

[0046] Explanation of the numbers in the figure: 1. grinding mill body; 11. grinding table; 12. first grinding groove; 13. first discharge hopper; 14. second discharge hopper; 15. grinding motor; 16. rotating shaft; 2. collecting plate; 21. filter screen; 22. first discharge ring groove; 23. guide pipe; 24. collecting pipe; 3. second grinding groove; 31. collecting box; 311. push plate; 3111. ejection spring; 3112. adjusting plate; 3113. second rubber belt; 3114. adjusting groove; 3115. first rubber belt; 312. conveying roller; 313. screening hole; 314. separating block; 3141. storage trough; 3142. conveying trough; 315. conveying pipe; 316. conveying ring strip; 32. grinding wheel; 33. feeding box; 34. second discharge ring groove. DETAILED DESCRIPTION

[0047] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0048] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be another element centered thereon. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be another element centered thereon at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0050] Example 1, please refer to Figure 1 and Figure 3 , a method for preparing a porous CZO layer gas sensor chip, comprising the following steps:

[0051] Step 1) Pretreatment:

[0052] Preparation of precursor solution: Dissolve 0.05-0.2 mol / L of cerium oxide and 0.05-0.2 mol / L of zirconium oxide precursors in a suitable solvent, such as ethanol or water.

[0053] Stabilizer and template: Add 2-10wt% of polyvinyl alcohol (PVA) or polyvinyl pyrrolidone (PVP) as a stabilizer, and the template can be 0.1-1wt% of CTAB (hexadecyltrimethylammonium bromide).

[0054] Reaction conditions: Stir at 20-30°C for 0.5-2 hours to promote the hydrolysis and polycondensation of the precursor to form a uniform sol.

[0055] Step 2) Low temperature drying:

[0056] Drying conditions: Dry the sol at 40-60°C for 24-48 hours to form a gel layer.

[0057] Step 3) Heat treatment:

[0058] Heat treatment temperature: Heat the gel at 300-400°C for 2-4 hours to remove the template.

[0059] Step 4) Grinding:

[0060] Grinding process: The heat-treated gel solid is first crushed, and then the crushed particles are sent to a high-efficiency grinding machine for mechanical grinding to obtain gel powder of 50nm-500nm magnitude.

[0061] Step 5) Molding:

[0062] Molding conditions: Use a mold of a specific shape to press the gel powder into shape at a pressure range of 50-100MPa.

[0063] Step 6) Sintering:

[0064] Sintering temperature and time: Sintering at a high temperature of 1200-1500°C for 2-6 hours to obtain a porous CZO substrate with a specified shape structure.

[0065] Step 7) Pt electrode coating:

[0066] Electrode materials: Precious metals such as gold (Au) and platinum (Pt) are used as electrodes.

[0067] Coating method: The electrodes were connected to the porous CZO substrate by screen printing or sputtering method.

[0068] Screen printing parameters: screen mesh 200-400 mesh, printing pressure 2-5N / cm², printing speed 50-100mm / s.

[0069] Step 8) Multilayer loading electrode CZO substrate bonding:

[0070] Adhesive material: Use a high temperature resistant adhesive such as silicone glue or glass powder.

[0071] Bonding conditions: at room temperature to 100°C, pressure 0.5-2MPa, for 1-2 hours.

[0072] Step 9) High temperature sintering:

[0073] Sintering conditions: Sinter the bonded multilayer loaded electrode CZO substrate at 800-1000°C for 1-3 hours.

[0074] Step 10) Chip detection:

[0075] Testing tooling: Use test tooling to test the chip. The test items include electrical performance, sensitivity, response time, etc.

[0076] Testing standards: According to the design requirements, ensure that all parameters of the sensor chip meet the specifications, and the qualified chips are used as finished sensor chips.

[0077] See also Figure 2The porous CZO layer gas sensor chip includes a first CZO substrate, a second CZO substrate, a third CZO substrate, a fourth CZO substrate, a fifth CZO substrate, a sixth CZO substrate, a first chamber electrode, a second chamber electrode and a heating electrode. The first CZO substrate, the second CZO substrate, the third CZO substrate, the fourth CZO substrate, the fifth CZO substrate and the sixth CZO substrate are bonded to each other. The first chamber electrode and the second chamber electrode are arranged in the second CZO substrate. A cavity is arranged in the fourth CZO substrate. A reference electrode is arranged on the third CZO substrate located in the cavity. A heating electrode is arranged on the surface of the fifth CZO substrate located on one side of the sixth CZO substrate. A main pump electrode is arranged on the outer side of the first CZO substrate. A porous alumina protective layer is arranged on the outer side of the main pump electrode.

[0078] Application of sol-gel method: The porous CZO layer is prepared by sol-gel method. This method can prepare high-purity and uniform oxide thin films at lower temperatures. Formation of porous structure: By controlling the parameters in the sol-gel process, such as the composition of the sol, the gelation time and the drying process, a CZO layer with a specific pore structure is formed. The porous structure can provide a larger specific surface area, which is conducive to the improvement of gas sensing performance. Material selection and proportion: The composition ratio of CZO material (such as the molar ratio of cerium and zirconium) has a significant effect on gas sensing performance. By optimizing the ratio of cerium and zirconium, the sensitivity and selectivity of the material to specific gases can be improved. Gas sensing performance: The application of porous CZO layer in gas sensor chips has the characteristics of high sensitivity and fast response time to specific gases (such as carbon monoxide, nitrogen dioxide, etc.).

[0079] The present invention provides a method for preparing a porous CZO layer gas sensor chip based on the sol-gel method, which improves the sensitivity and reliability of the gas sensor chip by optimizing the zirconium oxide stabilizer. The method for preparing a porous CZO layer gas sensor chip based on the sol-gel method proposed in this scheme realizes the improvement of the preparation method and performance enhancement of the existing nitrogen oxygen sensor ceramic core. Different from the use of YSZ material, by optimizing the zirconium oxide stabilizer and using the sol-gel method to prepare the porous CZO layer, a high-purity, uniform and porous structure material is prepared at a lower temperature. CZO has high oxygen ion conductivity. The porous CZO material used in this scheme provides a large specific surface area, which is conducive to the adsorption and reaction of gas molecules, and improves the sensitivity and response speed of the sensor.

[0080] The present invention adopts the sol-gel method to prepare the porous cerium oxide-zirconium (CZO) layer. There are many steps in the production and preparation process, and the precursor solution preparation process is time-consuming, which will lead to a long production time for each batch of gas sensor chips, and the single-batch production capacity is facing bottleneck limitations. In view of this shortcoming, the present invention has the advantage of low technical requirements for production equipment, and the number of gas sensor chips produced in a single batch can be expanded. By expanding the equipment capacity of each process of the production line, it can adapt to various production capacity requirements. In view of the difficulty of large investment in production equipment in the early stage of new product development, the present invention provides more flexible production line configuration options, which can better match the different production capacity requirements of the company's products at different stages.

[0081] The present invention aims to improve the existing technology by optimizing the zirconium oxide stabilizer to enhance the sensitivity and reliability of the gas sensor chip. The specific innovations include:

[0082] Optimize the ratio and reaction conditions of the CZO precursor solution to ensure the formation of a uniform sol. Use a specific template and removal method to obtain a more ideal porous structure. Precisely control the sintering temperature and time to ensure the structural stability and sensing performance of the CZO layer.

[0083] Through the above improvements, the present invention has significant improvements in preparation process, material properties and sensing effect compared with the existing solutions, and can better meet the needs of high-temperature gas sensing and environmental monitoring.

[0084] Example 2, the same as Example 1 is not described here, the difference from Example 1 is: please refer to Figure 4 , Figure 5 and Figure 6 The high-efficiency grinding mill comprises a grinding mill body 1, a first grinding groove 12 is provided at the upper end of the grinding mill body 1, the first grinding groove 12 is in a quasi-conical shape, a matching and rotatable grinding truncated table 11 is provided in the first grinding groove 12, a plurality of grinding strips are provided on the first grinding groove 12 and the grinding truncated table 11, a second grinding groove 3 is provided below the first grinding groove 12, a funnel-shaped collecting plate 2 is provided in the second grinding groove 3 for collecting materials after grinding the grinding truncated table 11, a ring-shaped filtering screen 21 is provided on the collecting plate 2, a first collecting ring plate fixedly connected and used for collecting materials after screening by the filtering screen 21 is also provided in the second grinding groove 3, the first collecting ring plate is inclined, a first discharging ring groove 22 is provided on the first collecting ring plate, a first discharging hopper 13 is provided on one side of the grinding mill body 1, and the first discharging hopper 13 is communicated with the discharging end of the first discharging ring groove 22.

[0085] The design of the grinding table 11, the first grinding groove 12 and the grinding strips can make it easier to grind larger particles into granular form. The funnel-shaped design of the collecting plate 2 can better collect particles that fall from the edge of the grinding table 11. The addition of the filter screen 21 and the funnel design of the collecting plate 2 can make the particles automatically move toward the middle. In the process of passing through the filter screen 21, particles that meet the size will automatically be screened and filtered through the filter screen 21, while particles that are too large will automatically move toward the middle of the collecting plate 2, thereby achieving screening and separation of the materials. The first collecting ring plate can collect the screened materials in a unified manner, and through the inclined design, the materials can be automatically discharged through the first discharge hopper 13.

[0086] In this example, see Figure 5 and Figure 7 , Figure 8 The material screened by the filter screen 21 falls into the bottom of the second grinding trough 3. A rotatable rotating shaft 16 is provided in the middle of the second grinding trough 3. A fixed rod is fixedly connected on one side of the rotating shaft 16. A grinding wheel 32 is rotatably connected at the end of the fixed rod and is used for extruding and grinding the material at the bottom of the grinding trough. A collecting box 31 is provided at one end of the grinding wheel 32 and moves synchronously with the grinding wheel 32. The bottom of the collecting box 31 is slidably connected to the bottom of the second grinding trough 3, and a collecting trough for the material to pass through is provided in the collecting box 31. A fixedly connected separation plate is provided in the collecting trough. The two ends of the separation plate are inclined, and the bottom of the separation plate is slidably connected to the bottom of the second grinding trough 3. A material storage trough 3141 is provided in the separation plate. A plurality of screening holes 313 connected with the material storage trough 3141 are provided on the separation plate. The material storage trough 3141 has a conical cross-section and a conveying trough 3142 is provided at the bottom of the material storage trough 3141. A rotatable conveying auger is provided in the conveying trough 3142. A conveying pipe 315 is provided on one side of the collecting box 31. The conveying pipe 315 is connected with the conveying trough 3142, and the conveying auger is arranged in the conveying pipe 315. A second annular discharge ring groove 34 is provided in the middle of the second grinding trough 3. The output end of the conveying pipe 315 is located in the second discharge ring groove 34. The second discharge ring groove 34 is inclined. A second discharge hopper 14 connected with the discharge end of the second discharge ring groove 34 is provided on one side of the grinding mill body 1.

[0087] The rotation of the grinding wheel 32 can squeeze and grind the material at the bottom of the second grinding groove 3 again, so that the material can reach the set size, and the design of the collecting box 31 and the separation plate can make the material squeezed by the grinding wheel 32 move along the inclined surface of the separation plate to the screening hole 313 when passing through the separation plate, so that the particles that meet the size can enter the storage groove 3141, and the particles that are larger than the size will return to the second grinding groove 3 along the inclined surface again, and continue to be squeezed and ground by the grinding wheel 32 again. Such a design can separate the particles that meet the size in time after grinding, thereby effectively preventing the repeated squeezing and grinding process from causing the size of a large part of the material to be much smaller than the set size, thereby making the ground material unusable;

[0088] The conveying auger can convey the collected materials to the second discharge ring groove 34 through the conveying pipe 315 , and the materials can be automatically separated through the inclined second discharge ring groove 34 .

[0089] In this example, see Figure 5 , Figure 6 The other end of the second grinding wheel 32 is provided with a feed box 33 which moves synchronously with the second grinding wheel 32. The bottom of the feed box 33 is slidably connected to the second grinding groove 3, and the bottom of the feed box 33 is provided with a placement groove for evenly placing the materials. A collecting hole is provided at the center of the bottom of the collecting plate 2, and a fixedly connected collecting pipe 24 is provided at the bottom of the collecting hole. The bottom of the collecting pipe 24 is sealed and inclined, and a guide pipe 23 is provided at the discharge end of the bottom of the collecting pipe 24. The output end of the guide pipe 23 is fixedly connected to the feed box 33, and the guide pipe 23 is communicated with the placement groove.

[0090] The design of the collecting tube 24, the guide tube 23 and the feed box 33 enables the material separated by the filter screen 21 to enter the collecting tube 24 through the collecting hole and enter the feed box 33 through the guide tube 23, thereby achieving uniform stacking of the material in a ring shape at the bottom of the second grinding tank 3, which is convenient for the grinding wheel 32 to squeeze and grind the material.

[0091] In this embodiment, vibration motors are disposed in the filter screen 21 , the first discharge ring groove 22 , the storage groove 3141 and the second discharge ring groove 34 .

[0092] In this example, see Figure 8 The collecting tank is provided with a rotatable conveying ring 316, and the conveying ring 316 is provided with a plurality of fixedly connected push plates 311, and the bottom of each push plate 311 is provided with a first rubber belt 3115 that can be squeezed and deformed and is used to push the material onto the separation plate. The conveying ring 316 is provided with two conveying rollers 312 for driving the conveying ring 316 to rotate, and the conveying rollers 312 are rotatably connected to the collecting tank, and the conveying ring 316 is inclined.

[0093] The inclined design of the conveying ring 316 can better push the material in the second grinding groove 3 to the top of the separation plate; the design of the push plate 311 and the first rubber belt 3115 can utilize the rotation of the conveying ring 316 to enable the material to move more easily to the separation plate, thereby enabling the material to be better screened and separated.

[0094] In this example, see Figure 8 and Fig. 9 The feeding end of the collecting trough is provided with an outwardly inclined and figure-eight guide groove, and both ends of the push plate 311 are provided with adjustment grooves 3114. A slidingly connected adjustment plate 3112 is provided in the adjustment groove 3114, and an ejection spring 3111 is provided in the adjustment groove 3114 for driving the adjustment plate 3112 to automatically pop out, and a second rubber belt 3113 with the same height as the first rubber belt 3115 is provided at the bottom of the adjustment plate 3112.

[0095] Because the grinding wheel 32 squeezes the material into a flat shape, the design of the guide groove can make the material better collected in the collecting groove. The addition of the adjusting plate 3112 can use the adjusting plate 3112 and the second rubber belt 3113 to push the material particles at the guide groove directly to the collecting groove, effectively preventing the accumulation of materials at the guide groove. The design of the ejector spring 3111 can use the elasticity of the spring, combined with the extrusion of the inclined surface of the guide groove, to make the adjusting plate 3112 automatically squeeze into the push plate 311 during the process of entering the collecting groove from the guide groove. When the push plate 311 moves from the collecting groove to the guide groove, the elasticity of the spring will drive the adjusting plate 3112 to automatically expand outward. This design not only realizes the unified pushing of all materials in the guide groove, but also does not affect the overall stable operation.

[0096] In this embodiment, a driving motor is provided on one side of the collection box 31, and the output end of the driving motor is connected to the conveying auger, and the conveying auger is connected to the conveying roller 312 through a chain. A grinding motor 15 is provided at the bottom of the mill body 1, and the output end of the grinding motor 15 is connected to a rotating shaft 16, and the upper end of the rotating shaft 16 is movably and sealedly connected to pass through the center of the collection tube 24, and the upper end of the rotating shaft 16 is fixedly connected to the grinding truncated table 11; a fixedly connected connecting rod is provided on the rotating shaft 16, and the connecting rod is respectively connected and fixed to the collection box 31 and the feed box 33.

[0097] In this embodiment, the pore sizes of the filter screen 21 and the sieve holes 313 are both 500 nm.

[0098] When this embodiment is used:

[0099] The crushed particles are sent into the first grinding groove 12, and the grinding motor 15 is started to drive the rotating shaft 16 to rotate so that the grinding table 11 and the grinding wheel 32 move. The particles entering the first grinding groove 12 are extruded and ground between the grinding table 11, the grinding bars and the first grinding groove 12. The ground particles fall from the edge of the grinding table 11 and fall onto the collecting plate 2 by gravity. The tilting of the collecting plate 2 and the vibration of the vibration motor can make the material automatically pass through the filter sieve holes, and the particles that meet the size automatically enter the first discharge ring groove 22 and are discharged through the first discharge hopper 13.

[0100] The larger particles enter the collecting pipe 24 through the collecting hole due to gravity, and then enter the feed box 33 through the guide groove, so that the material particles are placed in a ring shape at the bottom of the second grinding groove 3. The grinding wheel 32 passes through the material particles during the rotation process, and automatically squeezes and grinds the material particles. During the synchronous movement of the collecting box 31, the driving motor is started to drive the conveying auger to rotate. Through the guide groove, the collecting groove, the separation block 314 and the screening hole 313, the crushed material particles can be screened in time, and the material particles that meet the size are transported by the auger. The particles are discharged into the second discharge ring groove 34 through the inclined second discharge ring groove 34 and into the second discharge hopper 14, while the particles with larger sizes are placed again through the inclined surface of the separation block 314 to wait for the next rolling. This method can effectively prevent the situation that a large part of the particles in the material are rolled too small due to repeated rolling, resulting in the grinding particle size not meeting the standard. Moreover, the separation block 314 can not only screen the particles after rolling, but also turn the particles, so that the particles can be better and more fully rolled into particles of the required size.

[0101] During the movement of the collecting box 31, the driving motor also drives the conveying ring 316 to rotate synchronously, thereby driving the push plate 311 and the adjusting plate 3112 to move, so that the materials in the collecting tank can be better pushed onto the separation plate, so as to better perform screening and separation;

[0102] The materials coming out of the first discharge hopper 13 and the second discharge hopper 14 are screened again with a 50nm sieve, and particles smaller than 50nm are screened and separated to obtain particles of 50nm-500nm, thereby ensuring the quality of subsequent manufactured products.

[0103] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present application should not be determined with reference to the above description, but should be determined with reference to the appended claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to be a waiver of the subject matter, nor should it be considered that the inventors did not consider the subject matter to be part of the disclosed inventive subject matter.

Claims

1. A method for preparing a porous CZO layer gas sensor chip, The method comprises the following steps, characterized in that: S1 pretreatment: preparation of precursor solution: dissolving 0.05-0.2 mol / L cerium oxide and 0.05-0.2 mol / L zirconium oxide precursors in a solvent, then adding a stabilizer and a template and stirring at a temperature of 20-30°C for 0.5-2 hours to promote hydrolysis and polycondensation of the precursors to form a uniform sol; S2 low temperature drying: drying the sol at 40-60°C for 24-48 hours to form a gel layer; S3 heat treatment: heat the gel at 300-400°C for 2-4 hours to remove the template; S4 grinding: firstly crush the heat-treated gel solid, and then send the crushed particles into a high-efficiency grinding machine for mechanical grinding to obtain gel powder of 50nm-500nm; S5 molding: using a mold of a specific shape to press the gel powder into shape, with a pressure range of 50-100MPa; S6 sintering: sintering at a high temperature of 1200-1500°C for 2-6 hours to obtain a porous CZO substrate with a specified shape structure; S7 electrode coating: Use precious metals as electrodes and connect the electrodes to the porous CZO substrate by screen printing or sputtering; S8 Multilayer loaded electrode CZO substrate bonding: Use high temperature resistant adhesive for bonding, at room temperature to 100°C, pressure 0.5-2MPa, for 1-2 hours; S9 high temperature sintering: sintering the bonded multilayer loaded electrode CZO substrate at 800-1000°C for 1-3 hours; S10 chip testing: Use test tools to test the chip; The high-efficiency grinding mill comprises a grinding mill body, wherein a first grinding groove is provided at the upper end of the grinding mill body, the first grinding groove is in a quasi-truncated cone shape, a matching and rotatable grinding truncated cone is provided in the first grinding groove, a plurality of grinding strips are provided on the first grinding groove and the grinding truncated cone, a second grinding groove is provided below the first grinding groove, a collecting plate in a quasi-funnel shape for collecting materials after grinding on the grinding truncated cone is provided in the second grinding groove, a filtering screen in a circular ring shape is provided on the collecting plate, a first collecting ring plate fixedly connected and used for collecting materials after screening by the filtering screen is also provided in the second grinding groove, the first collecting ring plate is in an inclined shape, a first discharging ring groove is provided on the first collecting ring plate, a first discharging hopper is provided on one side of the grinding mill body, and the first discharging hopper is communicated with the discharging end of the first discharging ring groove; The material screened by the filter screen falls into the bottom of the second grinding trough, a rotatable rotating shaft is provided in the middle of the second grinding trough, a fixed rod is provided on one side of the rotating shaft, a grinding wheel is provided at the end of the fixed rod for rotatably connecting and used for extruding and grinding the material at the bottom of the grinding trough, a collecting box is provided at one end of the grinding wheel for synchronous movement with the grinding wheel, the bottom of the collecting box is slidably connected to the bottom of the second grinding trough, and a collecting trough for the material to pass through is provided in the collecting box, a fixedly connected separation plate is provided in the collecting trough, both ends of the separation plate are inclined, and the bottom of the separation plate is slidably connected to the bottom of the second grinding trough A material storage trough is provided in the separation plate, and a plurality of screening holes connected with the material storage trough are provided on the separation plate, the material storage trough has a conical cross-section, and a conveying trough is provided at the bottom of the material storage trough, a rotatable conveying auger is provided in the conveying trough, a conveying pipe is provided on one side of the collecting box, the conveying pipe is connected with the conveying trough, and the conveying auger is arranged in the conveying pipe, a second discharging ring groove in a circular shape is provided in the middle of the second grinding trough, the output end of the conveying pipe is located in the second discharging ring groove, the second discharging ring groove is inclined, and a second discharging hopper connected with the discharging end of the second discharging ring groove is provided on one side of the grinding mill body.

2. The method for preparing a porous CZO layer gas sensor chip according to claim 1, characterized in that: The stabilizer is one of 2-10wt% polyvinyl alcohol (PVA) and 2-10wt% polyvinyl pyrrolidone (PVP), and the template is 0.1-1wt% CTAB.

3. The method for preparing a porous CZO layer gas sensor chip according to claim 1, characterized in that: The noble metal in step S7 includes one or more combinations of gold (Au) and platinum (Pt).

4. The method for preparing a porous CZO layer gas sensor chip according to claim 1, characterized in that: In step S7, the screen mesh number is 200-400 meshes, the printing pressure is 2-5N / cm², and the printing speed is 50-100mm / s.

5. The method for preparing a porous CZO layer gas sensor chip according to claim 1, characterized in that: The high temperature resistant adhesive comprises one or more combinations of silicone adhesive and glass powder.

6. The method for preparing a porous CZO layer gas sensor chip according to claim 1, characterized in that: The porous CZO layer gas sensor chip comprises a first CZO substrate, a second CZO substrate, a third CZO substrate, a fourth CZO substrate, a fifth CZO substrate, a sixth CZO substrate, a first chamber electrode, a second chamber electrode and a heating electrode. The first CZO substrate, the second CZO substrate, the third CZO substrate, the fourth CZO substrate, the fifth CZO substrate and the sixth CZO substrate are bonded to each other. The first chamber electrode and the second chamber electrode are arranged in the second CZO substrate. A cavity is arranged in the fourth CZO substrate. A reference electrode is arranged on the third CZO substrate located in the cavity. A heating electrode is arranged on the surface of the fifth CZO substrate located on one side of the sixth CZO substrate. A main pump electrode is arranged on the outer side of the first CZO substrate. A porous alumina protective layer is arranged on the outer side of the main pump electrode.

7. The method for preparing a porous CZO layer gas sensor chip according to claim 1, characterized in that: The filter screen, the first discharge ring groove, the storage groove and the second discharge ring groove are all provided with vibration motors.

8. The method for preparing a porous CZO layer gas sensor chip according to claim 1, characterized in that: A rotatable conveying ring is provided in the collecting trough, and a plurality of fixedly connected push plates are provided on the conveying ring. The bottom of each push plate is provided with a first rubber belt that can be squeezed and deformed and is used to push the material onto the separation plate.

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