Ceramic chip and nitrogen-oxygen sensor

Abstract

The utility model relates to a ceramic chip and a nitrogen oxygen sensor, the ceramic chip comprises a plurality of layers of ceramic substrates, and the plurality of layers of ceramic substrates comprise an aluminum oxide substrate on the outer layer and a zirconium oxide substrate on the inner layer; the lead is arranged on the ceramic substrate and is used for connecting an external circuit; the heating electrode is printed on the ceramic substrate; the positive and negative electrodes are hidden in the multilayer ceramic substrate; the measuring electrode is used for measuring a medium to be detected and generating an induction signal; and the reference electrode is isolated from the measuring electrode and is used for providing a reference potential. The utility model has the advantages of higher mechanical strength, measurement accuracy and production efficiency, and lower manufacturing complexity and cost.

Description

Technical Field

[0001] The utility model relates to the field of chip design, in particular to a ceramic chip and a nitrogen oxygen sensor. Background Art

[0002] Traditional ceramic chips usually use a 15-layer substrate stacking structure, with each substrate printed with conductive materials, insulating layers or functional layers before stacking and sintering. The insulating layer is usually printed on the zirconium oxide substrate with alumina slurry, and the heating electrode is printed on the insulating layer to form a multi-layer complex structure of the overall chip. This design requires more than 180 processes, including multiple printing, drying, stacking and high-temperature sintering to achieve the final performance.

[0003] However, this structure has significant disadvantages. First, the flatness of the insulating layer and the heating electrode is difficult to ensure, resulting in inconsistent electrode resistance, affecting the CPK index required for mass production. Secondly, an insulating layer that is too thin or uneven will lead to a breakdown risk, and in severe cases, damage to the chip. In addition, the substrate is not strong enough and is easily damaged during lamination or processing, eventually resulting in the entire chip being scrapped. The P+ electrode is exposed and lacks effective protection. It is easily damaged or even exploded during use. These problems significantly increase the difficulty of production and the defective rate. Utility Model Content

[0004] In view of the shortcomings of the prior art described above, the purpose of the present utility model is to provide a ceramic chip and a nitrogen oxide sensor, which significantly improves the mechanical strength, measurement accuracy and production efficiency of the chip by optimizing the material combination and structural layout, while reducing the manufacturing complexity and cost.

[0005] To achieve the above purpose, the utility model adopts the following technical solutions.

[0006] In a first aspect, the utility model provides a ceramic chip, comprising:

[0007] A multilayer ceramic substrate, wherein the multilayer ceramic substrate comprises an outer aluminum oxide substrate and an inner zirconium oxide substrate;

[0008] Leads, arranged on the ceramic substrate, for connecting to an external circuit;

[0009] A heating electrode, printed on the ceramic substrate;

[0010] Positive and negative electrodes are hidden in the multi-layer ceramic substrate;

[0011] A measuring electrode, used for measuring the medium to be detected and generating a sensing signal; and

[0012] The reference electrode is isolated from the measuring electrode and is used to provide a reference potential.

[0013] As an implementation mode of the utility model, the multi-layer ceramic substrate includes 8 layers of ceramic substrates, wherein the upper two layers and the lower two layers are aluminum oxide substrates, and the middle four layers are zirconium oxide substrates.

[0014] As an implementation mode of the present utility model, the multilayer ceramic substrate is symmetrically arranged in the thickness direction.

[0015] As an implementation mode of the present utility model, the thickness of the aluminum oxide substrate is 220 μm, and the thickness of the zirconium oxide substrate is 230 μm.

[0016] As an implementation mode of the utility model, the heating electrode is printed on the alumina substrate.

[0017] As an implementation mode of the utility model, the positive and negative electrodes include a positive electrode and a negative electrode, the positive electrode is hidden and arranged on a side of the aluminum oxide substrate close to the zirconium oxide substrate, and the negative electrode is arranged on the zirconium oxide substrate.

[0018] As an implementation mode of the utility model, a positive electrode pore is opened on the alumina substrate at a position corresponding to the positive electrode, and the positive electrode pore is filled with a protective slurry for protecting the positive electrode.

[0019] As an implementation mode of the utility model, the measuring electrode comprises a measuring positive electrode and a measuring negative electrode, and the measuring electrode and the negative electrode are arranged on the same zirconia substrate.

[0020] As an embodiment of the utility model, the reference electrode is arranged on a zirconia substrate, and a reference air pore is opened on the zirconia substrate at a position corresponding to the reference electrode. The reference air pore is partially filled with a buffer slurry for buffering the reference air.

[0021] In a second aspect, the utility model provides a nitrogen oxygen sensor, comprising:

[0022] A nitrogen oxygen sensor comprises a ceramic chip as described in any one of the first aspects above.

[0023] In summary, compared with the prior art, the utility model includes at least one of the following beneficial technical effects: by optimizing the material and structure of the multilayer ceramic substrate, the performance and reliability of the chip are significantly improved. Specifically, the structure formed by the outer aluminum oxide substrate and the inner zirconium oxide substrate effectively reduces the deformation during the sintering process and enhances the mechanical strength of the chip; the hidden positive and negative electrodes are protected by macroporous aluminum oxide slurry, which greatly improves the durability and corrosion resistance of the electrodes; the heating electrode is directly printed on the substrate to ensure the uniformity and efficiency of heating; the measuring electrode and the reference electrode are isolated, providing accurate signal detection and a stable reference potential. The overall design process is simplified and the number of layers is reduced, while ensuring the performance consistency and reliability during mass production and reducing manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 It is a structural schematic diagram of a specific embodiment of a ceramic chip of the utility model.

[0026] Description of reference numerals:

[0027] 100, ceramic substrate; 110, alumina substrate; 120, zirconia substrate;

[0028] 200, lead wire;

[0029] 300. Heating electrode;

[0030] 400, positive and negative electrodes; 410, positive electrode; 420, negative electrode; 430, protective slurry;

[0031] 500, measuring electrode; 510, measuring positive electrode; 520, measuring negative electrode;

[0032] 600. Reference electrode; 610. Buffer slurry. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0034] It should be noted that the description order of the following embodiments is not intended to limit the preferred order of the embodiments of the present application. In addition, in the following embodiments, the description of each embodiment has its own emphasis, and for parts not described in detail in one embodiment, reference can be made to the relevant description of other embodiments.

[0035] Ceramic chips are high-performance electronic components with ceramic materials (such as alumina, zirconia, etc.) as the substrate and integrated multi-layer functional structures. They are widely used in sensors, electronic circuits and power devices. Its core features are the excellent electrical insulation, high temperature stability and mechanical strength of ceramic materials, which enable it to work in harsh environments, such as high temperature, high pressure or corrosive environments. Ceramic chips usually contain multi-layer structures such as measuring electrodes, reference electrodes, heating electrodes, etc., which are used to realize functions such as gas detection, temperature sensing or signal transmission. They are key components in automotive exhaust sensors and industrial detection equipment.

[0036] At present, the ceramic chips in nitrogen oxide sensors are made of 15 layers of substrates which are printed separately and then stacked. The entire process has more than 180 steps. The preparation process is extremely complicated, time-consuming and labor-intensive.

[0037] At present, the trial production of the insulating layer is realized by printing alumina slurry on the zirconia substrate. The heating electrode is printed on the insulating layer. Since the flatness of the insulating layer cannot be guaranteed during printing, the flatness of the heating electrode cannot be guaranteed. If the heating electrode is not flat, the consistency of the resistance value will be poor, and the CPK of the resistance value will not meet the mass production requirement of >1.67. In addition, since the resistance value may be too high locally, the temperature in this area will be too high, causing the chip to explode when it is started.

[0038] The uneven printing of the insulating layer will cause some individual points to be thinner, and the insulation of this point will be poor. When a certain temperature is reached, a large current will penetrate this point, causing the entire chip measurement system to collapse.

[0039] The currently confirmed effective insulation thickness is above 28μm. However, due to the characteristics of alumina insulation slurry, the thickness of each print can only reach about 7μm. Therefore, in order to achieve the designed thickness, it usually takes 4 prints to complete. Moreover, each print needs to be dried before the next print can be made. Therefore, the entire process is cumbersome and lengthy, wasting manpower and material resources.

[0040] Poor printing of the insulating layer can also cause a small amount of electrons to migrate from the heating layer to the measuring layer after the chip temperature rises, resulting in reduced measurement accuracy.

[0041] Currently, the thickness of the ceramic chip substrate in the nitrogen oxygen sensor is 120μm. The substrate needs to be torn off the PET film before lamination. If the tearing force of this batch of substrates is too large, the substrate will be torn and the entire piece will be scrapped.

[0042] At the same time, due to the thin thickness of the existing substrate, the strength of the single layer is poor, such as the chamber layer and the ventilation layer. The original structure may cause the collapse of the chamber or the ventilation layer during lamination or warm isostatic pressing. In particular, the chamber layer may have imperceptible tiny damage, causing it to explode after the chip is heated.

[0043] In addition, the positive electrode (P+ electrode) is currently printed on the top surface and is only protected by printing a layer of aluminum oxide on the surface, so it is easy to be damaged or even exploded during use.

[0044] Based on this, refer to Figure 1 The embodiment of the utility model provides a ceramic chip, including a multilayer ceramic substrate 100, a lead 200, a heating electrode 300, a positive and negative electrode 400, a measuring electrode 500 and a reference electrode 600.

[0045] The outer layer of the multilayer ceramic substrate 100 is composed of an aluminum oxide substrate 110 , and the inner layer is composed of a zirconium oxide substrate 120 , so as to achieve an optimal combination of mechanical strength, insulation and thermal stability of different materials.

[0046] In some embodiments, the number of ceramic substrates 100 can be adjusted according to functional requirements, for example, a symmetrical structure design is adopted, and a common eight-layer structure is formed by sandwiching four layers of zirconium oxide between two layers of aluminum oxide.

[0047] In some embodiments, the thickness of the ceramic substrate 100 can be customized according to the sintering shrinkage rate, for example, the thickness of the alumina substrate 110 can be 220 μm, and the thickness of the zirconia substrate 120 can be 230 μm, to ensure minimal deformation during the sintering process.

[0048] In some embodiments, the layers of the ceramic substrate 100 may be bonded together by a high temperature co-firing process to enhance inter-layer stability and overall strength.

[0049] In some embodiments, conductive paste or insulating paste may be added to the surface of each ceramic substrate 100 according to design requirements to achieve functional distribution and insulation protection of electrodes.

[0050] Furthermore, as an embodiment of the present invention, the multilayer ceramic substrate 100 includes 8 layers of ceramic substrates 100 , wherein the upper two layers and the lower two layers are aluminum oxide substrates 110 , and the middle four layers are zirconium oxide substrates 120 .

[0051] Specifically, the multilayer ceramic substrate 100 is composed of 8 layers, of which the upper two layers and the lower two layers are made of alumina substrate 110, which mainly provides excellent mechanical strength and insulation performance, and reduces the risk of deformation during sintering through symmetrical design; the middle four layers are made of zirconium oxide substrate 120, which has high thermal conductivity and electrochemical stability, and can support the functional areas of the chip, such as the stable operation of the measuring electrode 500. This layered structure optimizes the overall performance through the combination of different materials, while ensuring the reliability and accuracy of the chip under high temperature, high pressure and complex environment.

[0052] Further, as an embodiment of the present invention, the thickness of the aluminum oxide substrate 110 is 220 μm, and the thickness of the zirconium oxide substrate 120 is 230 μm.

[0053] Specifically, the thickness of the aluminum oxide substrate 110 is 220 μm, and the thickness of the zirconium oxide substrate 120 is 230 μm. Such thickness design is mainly to adapt to the different shrinkage characteristics of the two materials during the sintering process, that is, the sintering shrinkage of aluminum oxide is 18%, and that of zirconium oxide is 21%. Since zirconium oxide has a large shrinkage range, if the thickness ratio is not matched during the sintering process, it is easy to cause the overall deformation of the substrate or even cracks due to the uneven internal shrinkage force. Therefore, by appropriately increasing the initial thickness of the zirconium oxide substrate 120 (230 μm is slightly thicker than 220 μm), the size of the two materials can be matched after sintering, thereby effectively balancing the stress and ensuring the flatness and overall strength of the substrate after sintering.

[0054] In addition, this thickness design also improves the mechanical strength of the substrate, making it more stable and reliable in subsequent processing and applications, and reducing production defects.

[0055] Further, as an embodiment of the present invention, the heating electrode 300 can be directly printed on a side of the outermost alumina substrate 110 close to the zirconia substrate 120 to provide uniform heat distribution.

[0056] In some embodiments, the material of the heating electrode 300 may be a metal paste with high conductivity and high temperature resistance (such as platinum paste or palladium paste) to ensure stability and long life in a high temperature environment.

[0057] In some embodiments, the pattern design of the heating electrode 300 may adopt a spiral shape, a wave shape, or other uniformly distributed geometric structures to improve the heating efficiency and avoid local overheating.

[0058] In some embodiments, the electrode thickness can be optimized according to the power requirement, which can be achieved through multiple printing and drying processes.

[0059] In addition, both ends of the heating electrode 300 are connected to an external power source through the lead wires 200 to form a closed circuit, thereby ensuring a stable flow of current and enabling the ceramic chip to operate normally under high temperature conditions.

[0060] Furthermore, as an embodiment of the utility model, the positive and negative electrodes 400 include a positive electrode 410 and a negative electrode 420 , the positive electrode 410 is hidden and arranged on one side of the aluminum oxide substrate 110 close to the zirconium oxide substrate 120 , and the negative electrode 420 is arranged on the zirconium oxide substrate 120 .

[0061] Specifically, the positive electrode 410 (P+ electrode) is hidden inside the alumina substrate 110 , and multiple protections are provided by the alumina substrate 110 to enhance its high temperature resistance and oxidation resistance, while reducing the risk of mechanical damage.

[0062] In some embodiments, the material of the positive electrode 410 may be platinum, palladium or other highly conductive metal paste, and precise layout may be achieved through printing technology.

[0063] The negative electrode 420 (P-electrode) is printed on the surface of the zirconia substrate 120 to ensure electrical connection with the functional layer.

[0064] The positive and negative electrodes 400 are isolated by substrate materials to avoid circuit short circuit while ensuring insulation performance.

[0065] In addition, the thickness and geometry of the positive and negative electrodes 400 can be optimized according to the current requirements to ensure their long-term stability and consistency in high temperature and complex environments.

[0066] Furthermore, as an embodiment of the present invention, a positive electrode pore is opened on the alumina substrate 110 at a position corresponding to the positive electrode 410 , and the positive electrode pore is filled with a protective slurry 430 for protecting the positive electrode 410 .

[0067] Specifically, positive electrode pores are opened at the position of the alumina substrate 110 close to the P+ electrode, and the protective slurry 430 filled in the pores can be an alumina slurry with high porosity, which can provide good mechanical protection and maintain the air permeability and conductivity of the electrode.

[0068] After the slurry is filled, it undergoes multiple drying and sintering processes to solidify to ensure the stability and uniformity of the protective layer; this design effectively prevents the P+ electrode from mechanical damage, chemical corrosion or external oxidation in high temperature or harsh environments, while maintaining the electrical connection performance and long-term stability of the electrode.

[0069] Furthermore, as an embodiment of the present invention, the measuring electrode 500 includes a measuring positive electrode 510 and a measuring negative electrode 520 , and the measuring electrode 500 and the negative electrode 420 are disposed on the same zirconia substrate 120 .

[0070] Specifically, the measuring positive electrode 510 (M1 electrode) and the measuring negative electrode 520 (M2 electrode) in the measuring electrode 500 are used to detect the signal of the medium and provide the corresponding potential respectively. The M1 electrode directly senses the change of the gas to be measured and generates a signal; the M2 electrode is used to cooperate with the M1 electrode to accurately detect the signal through the potential difference between the two. The measuring electrode 500 and the negative electrode 420 (P-electrode) can be set on the same zirconia substrate 120. With the excellent electrochemical performance and high temperature stability of the zirconia substrate 120, the reliability of signal conduction and the measurement accuracy are ensured.

[0071] In addition, the M1 electrode and the M2 electrode are isolated from the functional area by the zirconium oxide substrate 120 to prevent signal interference, and the P-electrode provides a negative connection path to the external circuit, thereby forming a complete current loop. This design simplifies the interlayer structure and improves the stability between electrodes and the overall performance of the chip.

[0072] In some embodiments, the M1 electrode is used as the measuring positive electrode 510, which is in direct contact with the medium to be detected, and is used to sense changes in the gas and generate signals. Therefore, multiple electrodes need to be arranged to cover a larger detection area to improve the sensitivity and stability of signal sensing; and the M2 electrode is used as the measuring negative electrode 520, and its function is mainly to form a reference potential with the M1 electrode. Therefore, only one electrode is needed to provide a stable reference signal, reducing design complexity and material consumption, while avoiding signal interference and improving detection accuracy and reliability.

[0073] Furthermore, as an embodiment of the utility model, the reference electrode 600 is arranged on the zirconia substrate 120, and a reference air pore is opened on the zirconia substrate 120 at the position corresponding to the reference electrode 600, and the reference air pore is partially filled with a buffer slurry 610 for buffering the reference air.

[0074] Specifically, the reference electrode 600 is located on the zirconia substrate 120, and is used to provide a stable reference potential, and cooperates with the measuring electrode 500 to achieve accurate detection of gas concentration. In order to ensure that the reference electrode 600 is always in contact with a stable reference air environment, a reference air pore is opened on the zirconia substrate 120 corresponding to the reference electrode 600, so that external air can enter the area. These pores are partially filled with a buffer slurry 610, which has a high porosity and air permeability. Its function is to adjust the air flow rate entering the pores, prevent external air flow fluctuations from interfering with the reference electrode 600, and form a stable air buffer environment, thereby ensuring that the reference electrode 600 provides a stable reference potential and improving measurement accuracy and chip reliability.

[0075] The embodiment of the utility model further discloses a nitrogen oxygen sensor, which includes the ceramic chip as described in any one of the above embodiments.

[0076] Specifically, the nitrogen oxide sensor integrates the ceramic chip described in the above embodiment as a core functional component to achieve accurate detection of gas (especially nitrogen oxides). The ceramic chip has a multi-layer structure design, including key components such as an aluminum oxide substrate 110, a zirconium oxide substrate 120, a heating electrode 300, positive and negative electrodes 400, a measuring electrode 500 and a reference electrode 600, and can work stably under high temperature and high pressure environments to provide accurate signal sensing and reference potential. By embedding the ceramic chip into the nitrogen oxide sensor, the detection accuracy, reliability and anti-interference performance of the sensor can be significantly improved to meet environmental protection requirements and industrial application needs.

[0077] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A ceramic chip, characterized in that: include: A multilayer ceramic substrate, wherein the multilayer ceramic substrate comprises an outer aluminum oxide substrate and an inner zirconium oxide substrate; Leads, arranged on the ceramic substrate, for connecting to an external circuit; A heating electrode, printed on the ceramic substrate; Positive and negative electrodes are hidden in the multi-layer ceramic substrate; Measuring electrodes, used to measure the medium to be detected and generate sensing signals; as well as The reference electrode is isolated from the measuring electrode and is used to provide a reference potential.

2. The ceramic chip according to claim 1, characterized in that: The multi-layer ceramic substrate comprises 8 layers of ceramic substrates, wherein the upper two layers and the lower two layers are aluminum oxide substrates, and the middle four layers are zirconium oxide substrates.

3. The ceramic chip according to claim 2, characterized in that: The multi-layer ceramic substrate is symmetrically arranged in the thickness direction.

4. The ceramic chip according to claim 2, characterized in that: The thickness of the aluminum oxide substrate is 220 μm, and the thickness of the zirconium oxide substrate is 230 μm.

5. The ceramic chip according to claim 1, characterized in that: The heating electrode is printed on the alumina substrate.

6. The ceramic chip according to claim 1, characterized in that: The positive and negative electrodes include a positive electrode and a negative electrode. The positive electrode is hidden and arranged on a side of the aluminum oxide substrate close to the zirconium oxide substrate, and the negative electrode is arranged on the zirconium oxide substrate.

7. The ceramic chip according to claim 6, characterized in that: A positive electrode pore is opened on the alumina substrate at a position corresponding to the positive electrode, and the positive electrode pore is filled with a protective slurry for protecting the positive electrode.

8. The ceramic chip according to claim 1, characterized in that: The measuring electrode comprises a measuring positive electrode and a measuring negative electrode, and the measuring electrode and the negative electrode are arranged on the same zirconia substrate.

9. The ceramic chip according to claim 1, characterized in that: The reference electrode is arranged on a zirconia substrate, and a reference air pore is opened on the zirconia substrate at a position corresponding to the reference electrode. The reference air pore is partially filled with a buffer slurry for buffering the reference air.

10. A nitrogen oxygen sensor, characterized in that: The nitrogen oxygen sensor comprises the ceramic chip as claimed in any one of claims 1-9.

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