A high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor and its preparation method

Abstract

The present invention is applicable to the technical field of ceramic high-temperature sensors and provides a high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor and a preparation method thereof. The ceramic high-temperature sensor includes a protective layer, a functional layer, an insulating layer and a support layer in sequence. A metal electrode network is printed on the functional layer and the support layer. The high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor provided by the present invention uses zirconium oxide and aluminum oxide as a matrix, and adds lanthanum oxide and yttrium oxide to optimize the microstructure and performance of the ceramic, so that it has higher high-temperature resistance, mechanical strength and stability. Nano-Al2O3 is doped with platinum-iridium alloy ink to solve the problem of metal-ceramic interface failure at high temperatures. Electrodes made of high-temperature resistant metal ink are printed on the ceramic layer using 3D printing technology. The electrodes have good bonding and conductivity with the ceramic layer and can operate stably in high-temperature environments.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic high-temperature sensors, and in particular relates to a high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor and a preparation method thereof. Background Art

[0002] Accurate measurement in high-temperature environments is crucial for industrial production, aerospace, energy, and other fields. Traditional high-temperature sensors suffer from low accuracy, poor stability, and short service life when operating in high-temperature environments. Furthermore, they struggle to meet the demands of complex shapes and high-performance applications. Therefore, the development of a novel multilayer, shaped ceramic high-temperature sensor is crucial. Summary of the Invention

[0003] The present invention provides a high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor, aiming to solve the above-mentioned problems.

[0004] The present invention is achieved as follows: a high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor, which includes a protective layer, a functional layer, an insulating layer and a support layer in sequence, and a metal electrode network is printed on the functional layer and the support layer. The functional layer and the support layer both include the following raw materials in mass percentage: 60-75% aluminum oxide, 15-25% zirconium oxide, 5-10% yttrium oxide, 0.5-2% lanthanum oxide, 0.3-0.7% modified quercetin, and 1-3% modified mannitol.

[0005] Preferably, the thickness of the protective layer is 0.05-0.1 mm, the thickness of the functional layer is 0.2-0.4 mm, the thickness of the insulating layer is 0.1-0.2 mm, and the thickness of the support layer is 0.5-0.6 mm.

[0006] Preferably, the insulating layer is made of porous aluminum oxide, and the protective layer comprises the following raw materials in percentage by mass: 60-65% zirconium oxide, 25-30% nano-silicon carbide, 3-5% yttrium oxide, and 2-6% lanthanum oxide.

[0007] Preferably, the preparation method of the modified quercetin is as follows: dissolving quercetin in NH3•H2O buffer solution at pH=9, and adding Al 3＋： Quercetin = 1:3 Al(NO3)3 solution was added, the temperature was raised to 80-90℃ and stirred for 1-2h to generate Al-quercetin complex, vacuum dried at 70-80℃, and crushed to D50 = 1.2μm. The crushed Al-quercetin complex and carbon nanotubes were ultrasonically treated in dimethylformamide solvent (35-45kHz, 1-2h), and the mass ratio of carbon nanotubes to quercetin was 1:8-12. After filtration, vacuum drying was performed to obtain modified quercetin.

[0008] First, aluminum nitrate solution is introduced to 3＋Ion chelation sites form a precursor complex with higher thermal stability, the carbonization temperature is increased, the continuity of the carbon film is improved, the grain boundary bonding strength is increased, and the carbon nanotubes are grafted onto the quercetin molecular skeleton through π-π conjugation to improve the mechanical properties of the ceramic layer. The conductivity of the carbon network generated by the subsequent high-temperature decomposition of the modified quercetin is improved. The phenolic hydroxyl groups of quercetin form a hydrogen bond network with the surface of the ceramic particles, which reduces the activation energy of grain boundary migration. The nano-carbon film generated by subsequent high-temperature decomposition has improved mechanical properties.

[0009] Preferably, the preparation method of the modified mannitol is as follows: mannitol and Al(OH)3 are mixed in a mass ratio of 1:0.3-0.5, melt eutectic treatment is carried out at 140-145°C, and then crushed to D50=20μm after cooling. The crushed particles are reacted with epichlorohydrin in a molar ratio of 1:0.1-0.3 under alkaline conditions at 60-70°C for 2-3h, and then mixed with SiO2 nanospheres and melt-stirred at 160°C. After cooling, crushed to D50=15μm, and the mass ratio of mannitol to SiO2 nanospheres is 2-4:1 to obtain modified mannitol.

[0010] A three-dimensional network is formed by cross-linking with epichlorohydrin, controlling the pore distribution and improving the mechanical properties of the ceramic layer. Honeycomb pores are generated by decomposition during the sintering process. Nano-Al2O3 (particle size 30-50nm) generated by thermal decomposition becomes the grain boundary strengthening phase of the ceramic matrix, achieving a synergistic improvement in the strength, toughness and functionality of the ceramic matrix.

[0011] Preferably, the metal ink used in the metal electrode network includes the following raw materials in mass percentage: 40-50% platinum-iridium alloy nanoparticles (particle size 20-50nm), 5-10% nano-Al2O3 particles (particle size 50-100nm), 15-20% ethyl cellulose binder, and 20-30% α-terpineol solvent. Ultrasonic dispersion (power 200-300W, time 30-40min) and then ball milling (speed 300-400rpm, time 1-2h) are performed to form a stable suspension. Nano-Al2O3 doping significantly improves the oxidation resistance and interfacial bonding strength of the metal ink.

[0012] The present invention also provides a method for preparing the above-mentioned high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor, comprising the following steps:

[0013] preparing a ceramic slurry;

[0014] Green forming of each layer;

[0015] Printing and preliminary curing of metal electrode networks on functional and support layers;

[0016] The ceramic layers are stacked and assembled in sequence to form a green body;

[0017] Co-sintering is performed to form an integrated multi-layer structure.

[0018] Preferably, the ceramic slurry is prepared by:

[0019] Functional layer and support layer slurry: Alumina, zirconium oxide, yttrium oxide, and lanthanum oxide are mixed in appropriate proportions and ball-milled to a D50 of 0.5 μm to obtain a ceramic powder. A hyperbranched polyimide dispersant (0.5 wt%) is added to ethanol and trichloroethylene (7:3 volume ratio) to obtain a mixture. The ceramic powder is added to the mixture and ball-milled for 1-3 hours until uniform. Modified quercetin is then added and ball-milled for another hour. Modified mannitol is then added and mixed at a low speed for 30-40 minutes. The mixture is then vacuum-mixed (-0.1 MPa for 30 minutes). The viscosity is controlled at 5000 ± 200 mPa·s.

[0020] Protective layer slurry: The nano-silicon carbide is acid-washed (HF:HNO3=1:3, 30-50min), then mixed with zirconium oxide, yttrium oxide, and lanthanum oxide, and planetary ball milled for 1-3h (zirconia tank, ethanol medium, 400rpm).

[0021] Preferably, the green body forming of each layer is specifically as follows: the protective layer is formed by gradient tape casting, and the nano-silicon carbide content changes continuously from 5-25% along the thickness direction; the functional layer is formed by tape casting and dried at 50°C to form a Y-shaped corrugated structure; the insulating layer is formed by dry pressing; the support layer is formed by compression molding, using a three-dimensional truss mold, a pressure of 20-25MPa, and holding pressure for 5-10min.

[0022] Preferably, the printing and preliminary curing of the metal electrode network on the functional layer and the support layer are specifically as follows: using 3D printing technology to print out the metal electrode pattern. After printing is completed, the printed ceramic layer is placed in an infrared heating device and heated at 100-150°C for 5-10 minutes for preliminary curing. The preferred printing speed is 10-50mm / s, the layer height is 0.05-0.1mm, and the nozzle temperature is 40-60°C to ensure uniform deposition and preliminary curing of the metal ink. Micron-level precision and adaptability to complex morphologies are achieved through 3D printing, which is higher than the accuracy of traditional screen printing.

[0023] Preferably, the sequentially stacking and assembling of the ceramic layers specifically comprises: stacking the printed ceramic layers in a designed order, and cold isostatic pressing (CIP, pressure 200-250 MPa, time 25-35 min) to form a green body.

[0024] Preferably, the co-sintering to form an integrated multilayer structure is specifically as follows: placing the laminated green blank into a high-temperature sintering furnace, introducing Ar-H2 mixed gas (H2 volume fraction 5%) to prevent metal oxidation, heating at a rate of 5°C / min to 600°C, keeping warm for 1-2h, continuing to heat to 1500-1600°C, keeping warm for 1-2h, and cooling at a rate of 3°C / min to room temperature.

[0025] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0026] The ceramic material of the high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor provided by the present invention is based on zirconium oxide and aluminum oxide, with lanthanum oxide and yttrium oxide added to optimize the microstructure and performance of the ceramic, so that it has higher high-temperature resistance, mechanical strength and stability. By adding modified quercetin, phenolic hydroxyl groups form a hydrogen bond network with the surface of ceramic particles, reducing the activation energy of grain boundary migration, and the nano-carbon film generated by high-temperature decomposition improves the mechanical properties. By adding modified mannitol, honeycomb pores are decomposed during the sintering process, and the nano-Al2O3 generated by thermal decomposition becomes the grain boundary strengthening phase of the ceramic matrix, achieving a synergistic improvement in the strength, toughness and functionality of the ceramic matrix; nano-Al2O3 is doped with platinum-iridium alloy ink to solve the problem of metal-ceramic interface failure at high temperatures. Electrodes made of high-temperature resistant metal ink are printed on the ceramic layer using 3D printing technology. The electrodes have good bonding and conductivity with the ceramic layer and can work stably in high-temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a flow chart of a method for preparing a high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor provided by the present invention. DETAILED DESCRIPTION

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0029] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0030] Example 1

[0031] An embodiment of the present invention provides a high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor, which includes a protective layer, a functional layer, an insulating layer and a support layer in sequence. Preferably, the protective layer has a thickness of 0.1 mm, the functional layer has a thickness of 0.3 mm, the insulating layer has a thickness of 0.1 mm, and the support layer has a thickness of 0.6 mm. A metal electrode network is printed on the functional layer and the support layer. The functional layer and the support layer both include the following raw materials in mass percentage: 60% aluminum oxide, 25% zirconium oxide, 10% yttrium oxide, 2% lanthanum oxide, 0.5% modified quercetin, and 2.5% modified mannitol.

[0032] The insulating layer is made of porous aluminum oxide, and the protective layer comprises the following raw materials in percentage by mass: 60% zirconium oxide, 30% nano-silicon carbide, 5% yttrium oxide, and 5% lanthanum oxide.

[0033] Furthermore, the preparation method of the modified quercetin is as follows: dissolving quercetin in NH3•H2O buffer solution with pH=9, and adding Al 3＋： Quercetin was added to Al(NO3)3 solution at a ratio of 1:3, heated to 80℃ and stirred for 1h to generate Al-quercetin complex, dried in vacuum at 70℃, and crushed to D50=1.2μm. The crushed Al-quercetin complex and carbon nanotubes were ultrasonically treated in dimethylformamide solvent (35kHz, 1h), and the mass ratio of carbon nanotubes to quercetin was 1:8. After filtration, vacuum drying was performed to obtain modified quercetin.

[0034] Furthermore, the preparation method of the modified mannitol is as follows: mannitol and Al(OH)3 are mixed in a mass ratio of 1:0.3, melt-eutectic treated at 140°C, and crushed to D50=20μm after cooling. The crushed particles are reacted with epichlorohydrin in a molar ratio of 1:0.1 under alkaline conditions at 60°C for 2h, then mixed with SiO2 nanospheres and melt-stirred at 160°C, and crushed to D50=15μm after cooling. The mass ratio of mannitol to SiO2 nanospheres is 2:1 to obtain modified mannitol.

[0035] In this embodiment, the metal ink used in the metal electrode network includes the following raw materials in percentage by mass: 40% platinum-iridium alloy nanoparticles (particle size 20 nm), 5% Al2O3 nanoparticles (particle size 50 nm), 15% ethyl cellulose binder, and 20% α-terpineol solvent. The metal ink is ultrasonically dispersed (power 200 W, time time 30 minutes) and then ball milled (speed 300 rpm, time time 1 hour) to form a stable suspension.

[0036] The present invention also provides a method for preparing the above-mentioned high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor, such as Figure 1 As shown, the following steps are included:

[0037] 1) Preparation of ceramic slurry

[0038] Functional layer and support layer slurry: Alumina, zirconium oxide, yttrium oxide, and lanthanum oxide were mixed in appropriate proportions and ball-milled to a D50 of 0.5 μm to obtain a ceramic powder. A hyperbranched polyimide dispersant (0.5 wt%) was added to ethanol and trichloroethylene (7:3 volume ratio) to obtain a mixture. The ceramic powder was added to the mixture and ball-milled for 1 hour until uniform. Modified quercetin was then added and ball-milled for another 1 hour. Modified mannitol was then added and mixed at a low speed for 30 minutes. Vacuum stirring was then applied (-0.1 MPa for 30 minutes) to control the viscosity at 4800 mPa·s. Protective layer slurry: Nano-silicon carbide was acid-washed (HF:HNO3 = 1:3 for 30 minutes) and then mixed with zirconium oxide, yttrium oxide, and lanthanum oxide. The mixture was then planetary ball-milled for 1 hour (zirconia tank, ethanol medium, 400 rpm).

[0039] 2) Green forming of each layer

[0040] The protective layer is formed by gradient tape casting, with the nano-silicon carbide content continuously changing from 5-25% along the thickness direction. The functional layer is formed by tape casting and dried at 50°C to form a Y-shaped corrugated structure. The insulating layer is formed by dry pressing. The support layer is formed by compression molding using a three-dimensional truss mold with a pressure of 20MPa and a holding pressure of 5 minutes.

[0041] 3) Printing and initial curing of metal electrode networks on functional and support layers

[0042] Use 3D printing technology to print out the metal electrode pattern. After printing is completed, the printed ceramic layer is placed in an infrared heating device and heated at 100°C for 5 minutes for preliminary curing. The preferred printing speed is 10mm / s, the layer height is 0.05mm, and the nozzle temperature is 40°C to ensure uniform deposition and preliminary curing of the metal ink.

[0043] 4) Assemble the ceramic layers in sequence to form a green body

[0044] The printed ceramic layers are stacked in the designed order and cold isostatically pressed (CIP, pressure 200 MPa, time 25 min) to form a green body;

[0045] 5) Co-sintering to form an integrated multi-layer structure

[0046] The laminated green billet was placed in a high-temperature sintering furnace, and Ar-H2 mixed gas (H2 volume fraction 5%) was introduced to prevent metal oxidation. The temperature was raised at a rate of 5°C / min to 600°C, kept at that temperature for 1 hour, and then continued to be raised to 1500°C, kept at that temperature for 1 hour, and cooled to room temperature at a rate of 3°C / min.

[0047] Example 2

[0048] An embodiment of the present invention provides a high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor, which includes a protective layer, a functional layer, an insulating layer and a support layer in sequence. Preferably, the protective layer has a thickness of 0.1 mm, the functional layer has a thickness of 0.3 mm, the insulating layer has a thickness of 0.1 mm, and the support layer has a thickness of 0.6 mm. A metal electrode network is printed on the functional layer and the support layer. The functional layer and the support layer both include the following raw materials in mass percentage: 65% aluminum oxide, 23% zirconium oxide, 8% yttrium oxide, 2% lanthanum oxide, 0.5% modified quercetin, and 1.5% modified mannitol.

[0049] The insulating layer is made of porous aluminum oxide, and the protective layer comprises the following raw materials in percentage by mass: 62% zirconium oxide, 28% nano-silicon carbide, 4% yttrium oxide, and 6% lanthanum oxide.

[0050] Furthermore, the preparation method of the modified quercetin is as follows: dissolving quercetin in NH3•H2O buffer solution with pH=9, and adding Al 3＋： Quercetin was added to Al(NO3)3 solution at a ratio of 1:3, heated to 80℃ and stirred for 1h to generate Al-quercetin complex, dried in vacuum at 70℃, and crushed to D50=1.2μm. The crushed Al-quercetin complex and carbon nanotubes were ultrasonically treated in dimethylformamide solvent (35kHz, 1h), and the mass ratio of carbon nanotubes to quercetin was 1:8. After filtration, vacuum drying was performed to obtain modified quercetin.

[0051] Furthermore, the preparation method of the modified mannitol is as follows: mannitol and Al(OH)3 are mixed in a mass ratio of 1:0.3, melt-eutectic treated at 140°C, and crushed to D50=20μm after cooling. The crushed particles are reacted with epichlorohydrin in a molar ratio of 1:0.1 under alkaline conditions at 60°C for 2h, then mixed with SiO2 nanospheres and melt-stirred at 160°C, and crushed to D50=15μm after cooling. The mass ratio of mannitol to SiO2 nanospheres is 2:1 to obtain modified mannitol.

[0052] In this embodiment, the metal ink used in the metal electrode network includes the following raw materials in percentage by mass: 40% platinum-iridium alloy nanoparticles (particle size 20 nm), 5% Al2O3 nanoparticles (particle size 50 nm), 15% ethyl cellulose binder, and 20% α-terpineol solvent. The metal ink is ultrasonically dispersed (power 200 W, time time 30 minutes) and then ball milled (speed 300 rpm, time time 1 hour) to form a stable suspension.

[0053] The present invention also provides a method for preparing the above-mentioned high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor, such as Figure 1 As shown, the following steps are included:

[0054] 1) Preparation of ceramic slurry

[0055] Functional layer and support layer slurry: Alumina, zirconium oxide, yttrium oxide, and lanthanum oxide were mixed in appropriate proportions and ball-milled to a D50 of 0.5 μm to obtain a ceramic powder. A hyperbranched polyimide dispersant (0.5 wt%) was added to ethanol and trichloroethylene (7:3 volume ratio) to obtain a mixture. The ceramic powder was added to the mixture and ball-milled for 1 hour until uniform. Modified quercetin was then added and ball-milled for another 1 hour. Modified mannitol was then added and mixed at a low speed for 30 minutes. Vacuum stirring was then applied (-0.1 MPa for 30 minutes) to control the viscosity at 4800 mPa·s. Protective layer slurry: Nano-silicon carbide was acid-washed (HF:HNO3 = 1:3 for 30 minutes) and then mixed with zirconium oxide, yttrium oxide, and lanthanum oxide. The mixture was then planetary ball-milled for 1 hour (zirconia tank, ethanol medium, 400 rpm).

[0056] 2) Green forming of each layer

[0057] The protective layer is formed by gradient tape casting, with the nano-silicon carbide content continuously changing from 5-25% along the thickness direction. The functional layer is formed by tape casting and dried at 50°C to form a Y-shaped corrugated structure. The insulating layer is formed by dry pressing. The support layer is formed by compression molding using a three-dimensional truss mold with a pressure of 20MPa and a holding pressure of 5 minutes.

[0058] 3) Printing and initial curing of metal electrode networks on functional and support layers

[0059] Use 3D printing technology to print out the metal electrode pattern. After printing is completed, the printed ceramic layer is placed in an infrared heating device and heated at 100°C for 5 minutes for preliminary curing. The preferred printing speed is 10mm / s, the layer height is 0.05mm, and the nozzle temperature is 40°C to ensure uniform deposition and preliminary curing of the metal ink.

[0060] 4) Assemble the ceramic layers in sequence to form a green body

[0061] The printed ceramic layers are stacked in the designed order and cold isostatically pressed (CIP, pressure 200 MPa, time 25 min) to form a green body;

[0062] 5) Co-sintering to form an integrated multi-layer structure

[0063] The laminated green billet was placed in a high-temperature sintering furnace, and Ar-H2 mixed gas (H2 volume fraction 5%) was introduced to prevent metal oxidation. The temperature was raised at a rate of 5°C / min to 600°C, kept at that temperature for 1 hour, and then continued to be raised to 1500°C, kept at that temperature for 1 hour, and cooled to room temperature at a rate of 3°C / min.

[0064] Example 3

[0065] An embodiment of the present invention provides a high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor, which includes a protective layer, a functional layer, an insulating layer and a support layer in sequence. Preferably, the protective layer has a thickness of 0.1 mm, the functional layer has a thickness of 0.3 mm, the insulating layer has a thickness of 0.1 mm, and the support layer has a thickness of 0.6 mm. A metal electrode network is printed on the functional layer and the support layer. The functional layer and the support layer both include the following raw materials in mass percentage: 68% aluminum oxide, 22% zirconium oxide, 7% yttrium oxide, 1% lanthanum oxide, 0.3% modified quercetin, and 1.7% modified mannitol.

[0066] The insulating layer is made of porous aluminum oxide, and the protective layer comprises the following raw materials in percentage by mass: 63% zirconium oxide, 28% nano-silicon carbide, 4% yttrium oxide, and 5% lanthanum oxide.

[0067] Furthermore, the preparation method of the modified quercetin is as follows: dissolving quercetin in NH3•H2O buffer solution with pH=9, and adding Al 3＋： Quercetin = 1:3 was added to Al(NO3)3 solution, the temperature was raised to 85℃ and stirred for 1.5h to generate Al-quercetin complex, which was vacuum dried at 75℃ and crushed to D50 = 1.2μm. The crushed Al-quercetin complex and carbon nanotubes were ultrasonically treated in dimethylformamide solvent (40kHz, 1.5h). The mass ratio of carbon nanotubes to quercetin was 1:10. After filtration, vacuum drying was carried out to obtain modified quercetin.

[0068] Furthermore, the preparation method of the modified mannitol is as follows: mannitol and Al(OH)3 are mixed in a mass ratio of 1:0.4, melt eutectic treatment is carried out at 142.5°C, and then crushed to D50=20μm after cooling. The crushed particles are reacted with epichlorohydrin in a molar ratio of 1:0.2 under alkaline conditions at 65°C for 2.5h, and then mixed with SiO2 nanospheres and melt-stirred at 160°C. After cooling, crushed to D50=15μm, and the mass ratio of mannitol to SiO2 nanospheres is 3:1 to obtain modified mannitol.

[0069] In this embodiment, the metal ink used in the metal electrode network includes the following raw materials in percentage by mass: 45% platinum-iridium alloy nanoparticles (particle size 30 nm), 7.5% Al2O3 nanoparticles (particle size 70 nm), 17.5% ethyl cellulose binder, and 25% α-terpineol solvent. The mixture is ultrasonically dispersed (power 250 W, time 35 minutes) and then ball milled (speed 350 rpm, time 1.5 hours) to form a stable suspension.

[0070] The present invention also provides a method for preparing the above-mentioned high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor, such as Figure 1 As shown, the following steps are included:

[0071] 1) Preparation of ceramic slurry

[0072] Functional layer and support layer slurry: Alumina, zirconium oxide, yttrium oxide, and lanthanum oxide were mixed in proportion and ball-milled to a D50 of 0.5 μm to obtain a ceramic powder. A hyperbranched polyimide dispersant (0.5 wt%) was added to ethanol and trichloroethylene (7:3 volume ratio) to obtain a mixture. The ceramic powder was added to the mixture and ball-milled for 2 hours until uniform. Modified quercetin was then added and ball-milled for another hour. Modified mannitol was added and mixed at a low speed for 35 minutes. Vacuum stirring was then applied (-0.1 MPa for 30 minutes) to control the viscosity at 5000 mPa·s. Protective layer slurry: Nano-silicon carbide was acid-washed (HF:HNO3 = 1:3 for 40 minutes) and then mixed with zirconium oxide, yttrium oxide, and lanthanum oxide. The mixture was then planetary ball-milled for 2 hours (zirconia tank, ethanol medium, 400 rpm).

[0073] 2) Green forming of each layer

[0074] The protective layer is formed by gradient tape casting, with the nano-silicon carbide content continuously varying from 5-25% along the thickness direction. The functional layer is formed by tape casting and dried at 50°C to form a Y-shaped corrugated structure. The insulating layer is formed by dry pressing. The support layer is formed by compression molding using a three-dimensional truss mold with a pressure of 23MPa and a holding pressure of 8 minutes.

[0075] 3) Printing and initial curing of metal electrode networks on functional and support layers

[0076] The metal electrode pattern is printed using 3D printing technology. After printing is completed, the printed ceramic layer is placed in an infrared heating device and heated at 125°C for 8 minutes for preliminary curing. The preferred printing speed is 30 mm / s, the layer height is 0.07 mm, and the nozzle temperature is 50°C to ensure uniform deposition and preliminary curing of the metal ink.

[0077] 4) Assemble the ceramic layers in sequence to form a green body

[0078] The printed ceramic layers are stacked in the designed order and cold isostatically pressed (CIP, pressure 225 MPa, time 30 min) to form a green body;

[0079] 5) Co-sintering to form an integrated multi-layer structure

[0080] The laminated green billet was placed in a high-temperature sintering furnace, and Ar-H2 mixed gas (H2 volume fraction 5%) was introduced to prevent metal oxidation. The temperature was raised at a rate of 5°C / min to 600°C, kept at this temperature for 1.5 hours, and then continued to be raised to 1550°C, kept at this temperature for 1.5 hours, and cooled to room temperature at a rate of 3°C / min.

[0081] Example 4

[0082] An embodiment of the present invention provides a high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor, which includes a protective layer, a functional layer, an insulating layer and a support layer in sequence. Preferably, the protective layer has a thickness of 0.1 mm, the functional layer has a thickness of 0.3 mm, the insulating layer has a thickness of 0.1 mm, and the support layer has a thickness of 0.6 mm. A metal electrode network is printed on the functional layer and the support layer. The functional layer and the support layer both include the following raw materials in mass percentage: 72% aluminum oxide, 22% zirconium oxide, 3% yttrium oxide, 1% lanthanum oxide, 0.4% modified quercetin, and 1.6% modified mannitol.

[0083] The insulating layer is made of porous aluminum oxide, and the protective layer comprises the following raw materials in percentage by mass: 64% zirconium oxide, 29% nano-silicon carbide, 4% yttrium oxide, and 3% lanthanum oxide.

[0084] Furthermore, the preparation method of the modified quercetin is as follows: dissolving quercetin in NH3•H2O buffer solution with pH=9, and adding Al 3＋： Quercetin was added to Al(NO3)3 solution at a ratio of 1:3, heated to 90℃ and stirred for 2h to generate Al-quercetin complex, dried in vacuum at 80℃, and crushed to D50=1.2μm. The crushed Al-quercetin complex and carbon nanotubes were ultrasonically treated in dimethylformamide solvent (45kHz, 2h). The mass ratio of carbon nanotubes to quercetin was 1:12. After filtration, vacuum drying was performed to obtain modified quercetin.

[0085] Furthermore, the preparation method of the modified mannitol is as follows: mannitol and Al(OH)3 are mixed in a mass ratio of 1:0.5, melt eutectic treatment is carried out at 145°C, and then crushed to D50=20μm after cooling. The crushed particles are reacted with epichlorohydrin in a molar ratio of 1:0.3 under alkaline conditions at 70°C for 3h, and then mixed with SiO2 nanospheres and melt-stirred at 160°C. After cooling, crushed to D50=15μm, and the mass ratio of mannitol to SiO2 nanospheres is 4:1 to obtain modified mannitol.

[0086] In this embodiment, the metal ink used in the metal electrode network includes the following raw materials in percentage by mass: 50% platinum-iridium alloy nanoparticles (particle size 50 nm), 10% Al2O3 nanoparticles (particle size 100 nm), 20% ethyl cellulose binder, and 30% α-terpineol solvent. The metal ink is ultrasonically dispersed (power 300 W, time time 40 minutes) and then ball milled (speed 400 rpm, time time 2 hours) to form a stable suspension.

[0087] The present invention also provides a method for preparing the above-mentioned high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor, such as Figure 1 As shown, the following steps are included:

[0088] 1) Preparation of ceramic slurry

[0089] Functional layer and support layer slurry: Alumina, zirconium oxide, yttrium oxide, and lanthanum oxide were mixed in proportion and ball-milled to a D50 of 0.5 μm to obtain a ceramic powder. A hyperbranched polyimide dispersant (0.5 wt%) was added to ethanol and trichloroethylene (7:3 volume ratio) to obtain a mixture. The ceramic powder was added to the mixture and ball-milled for 3 hours until uniform. Modified quercetin was then added and ball-milled for 1 hour. Modified mannitol was added and mixed at a low speed for 40 minutes. Vacuum stirring was performed (-0.1 MPa for 30 minutes) to control the viscosity at 5200 mPa·s. Protective layer slurry: Nano-silicon carbide was acid-washed (HF:HNO3 = 1:3 for 50 minutes) and then mixed with zirconium oxide, yttrium oxide, and lanthanum oxide. The mixture was then planetary ball-milled for 3 hours (zirconia tank, ethanol medium, 400 rpm).

[0090] 2) Green forming of each layer

[0091] The protective layer is formed by gradient tape casting, with the nano-silicon carbide content continuously varying from 5-25% along the thickness direction. The functional layer is formed by tape casting and dried at 50°C to form a Y-shaped corrugated structure. The insulating layer is formed by dry pressing. The support layer is formed by compression molding using a three-dimensional truss mold with a pressure of 25MPa and a holding pressure of 10 minutes.

[0092] 3) Printing and initial curing of metal electrode networks on functional and support layers

[0093] Use 3D printing technology to print out the metal electrode pattern. After printing is completed, the printed ceramic layer is placed in an infrared heating device and heated at 150°C for 10 minutes for preliminary curing. The preferred printing speed is 50mm / s, the layer height is 0.1mm, and the nozzle temperature is 60°C to ensure uniform deposition and preliminary curing of the metal ink.

[0094] 4) Assemble the ceramic layers in sequence to form a green body

[0095] The printed ceramic layers are stacked in the designed order and cold isostatically pressed (CIP, pressure 250 MPa, time 35 min) to form a green body;

[0096] 5) Co-sintering to form an integrated multi-layer structure

[0097] The laminated green billet was placed in a high-temperature sintering furnace, and Ar-H2 mixed gas (H2 volume fraction 5%) was introduced to prevent metal oxidation. The temperature was raised at a rate of 5°C / min to 600°C, kept at this temperature for 2 hours, and then continued to be raised to 1600°C, kept at this temperature for 2 hours, and cooled to room temperature at a rate of 3°C / min.

[0098] Example 5

[0099] An embodiment of the present invention provides a high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor, which includes a protective layer, a functional layer, an insulating layer and a support layer in sequence. Preferably, the protective layer has a thickness of 0.1 mm, the functional layer has a thickness of 0.3 mm, the insulating layer has a thickness of 0.1 mm, and the support layer has a thickness of 0.6 mm. A metal electrode network is printed on the functional layer and the support layer. The functional layer and the support layer both include the following raw materials in mass percentage: 75% aluminum oxide, 16% zirconium oxide, 5% yttrium oxide, 2% lanthanum oxide, 0.7% modified quercetin, and 1.3% modified mannitol.

[0100] The insulating layer is made of porous aluminum oxide, and the protective layer comprises the following raw materials in percentage by mass: 65% zirconium oxide, 30% nano-silicon carbide, 3% yttrium oxide, and 2% lanthanum oxide.

[0101] Furthermore, the preparation method of the modified quercetin is as follows: dissolving quercetin in NH3•H2O buffer solution with pH=9, and adding Al 3＋： Quercetin was added to Al(NO3)3 solution at a ratio of 1:3, heated to 90℃ and stirred for 2h to generate Al-quercetin complex, dried in vacuum at 80℃, and crushed to D50=1.2μm. The crushed Al-quercetin complex and carbon nanotubes were ultrasonically treated in dimethylformamide solvent (45kHz, 2h). The mass ratio of carbon nanotubes to quercetin was 1:12. After filtration, vacuum drying was performed to obtain modified quercetin.

[0102] Furthermore, the preparation method of the modified mannitol is as follows: mannitol and Al(OH)3 are mixed in a mass ratio of 1:0.5, melt eutectic treatment is carried out at 145°C, and then crushed to D50=20μm after cooling. The crushed particles are reacted with epichlorohydrin in a molar ratio of 1:0.3 under alkaline conditions at 70°C for 3h, and then mixed with SiO2 nanospheres and melt-stirred at 160°C. After cooling, crushed to D50=15μm, and the mass ratio of mannitol to SiO2 nanospheres is 4:1 to obtain modified mannitol.

[0103] In this embodiment, the metal ink used in the metal electrode network includes the following raw materials in percentage by mass: 50% platinum-iridium alloy nanoparticles (particle size 50 nm), 10% Al2O3 nanoparticles (particle size 100 nm), 20% ethyl cellulose binder, and 30% α-terpineol solvent. The metal ink is ultrasonically dispersed (power 300 W, time time 40 minutes) and then ball milled (speed 400 rpm, time time 2 hours) to form a stable suspension.

[0104] The present invention also provides a method for preparing the above-mentioned high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor, such as Figure 1 As shown, the following steps are included:

[0105] 1) Preparation of ceramic slurry

[0106] Functional layer and support layer slurry: Alumina, zirconium oxide, yttrium oxide, and lanthanum oxide were mixed in proportion and ball-milled to a D50 of 0.5 μm to obtain a ceramic powder. A hyperbranched polyimide dispersant (0.5 wt%) was added to ethanol and trichloroethylene (7:3 volume ratio) to obtain a mixture. The ceramic powder was added to the mixture and ball-milled for 1-3 hours until uniform. Modified quercetin was then added and ball-milled for another hour. Modified mannitol was added and mixed at a low speed for 40 minutes. Vacuum stirring was performed at -0.1 MPa for 30 minutes, and the viscosity was controlled at 5200 mPa·s. Protective layer slurry: Nano-silicon carbide was acid-washed (HF:HNO3=1:3, 50 minutes), then mixed with zirconium oxide, yttrium oxide, and lanthanum oxide and planetary ball-milled for 3 hours (zirconia tank, ethanol medium, 400 rpm).

[0107] 2) Green forming of each layer

[0108] The protective layer is formed by gradient tape casting, with the nano-silicon carbide content continuously varying from 5-25% along the thickness direction. The functional layer is formed by tape casting and dried at 50°C to form a Y-shaped corrugated structure. The insulating layer is formed by dry pressing. The support layer is formed by compression molding using a three-dimensional truss mold with a pressure of 25MPa and a holding pressure of 10 minutes.

[0109] 3) Printing and initial curing of metal electrode networks on functional and support layers

[0110] Use 3D printing technology to print out the metal electrode pattern. After printing is completed, the printed ceramic layer is placed in an infrared heating device and heated at 150°C for 10 minutes for preliminary curing. The preferred printing speed is 50mm / s, the layer height is 0.1mm, and the nozzle temperature is 60°C to ensure uniform deposition and preliminary curing of the metal ink.

[0111] 4) Assemble the ceramic layers in sequence to form a green body

[0112] The printed ceramic layers are stacked in the designed order and cold isostatically pressed (CIP, pressure 250 MPa, time 35 min) to form a green body;

[0113] 5) Co-sintering to form an integrated multi-layer structure

[0114] The laminated green billet was placed in a high-temperature sintering furnace, and Ar-H2 mixed gas (H2 volume fraction 5%) was introduced to prevent metal oxidation. The temperature was raised at a rate of 5°C / min to 600°C, kept at this temperature for 2 hours, and then continued to be raised to 1600°C, kept at this temperature for 2 hours, and cooled to room temperature at a rate of 3°C / min.

[0115] Comparative Example 1: The difference from Example 3 is that no modified quercetin is contained.

[0116] Comparative Example 2: The difference from Example 3 is that the modified quercetin is replaced by ordinary quercetin.

[0117] Comparative Example 3: The difference from Example 3 is that it does not contain modified mannitol.

[0118] Comparative Example 4: The difference from Example 3 is that the modified mannitol is replaced by ordinary mannitol.

[0119] Comparative Example 5: The difference from Example 3 is that modified quercetin and modified mannitol are not contained.

[0120] Comparative Example 6: The difference from Example 3 is that the modified quercetin is replaced by ordinary quercetin and the modified mannitol is replaced by ordinary mannitol.

[0121] Performance Testing

[0122] 1. The samples of Examples 1-5 and Comparative Examples 1-6 were subjected to performance tests, including bending strength and thermal shock resistance. The test results are shown in Table 1 below:

[0123] Table 1 Flexural strength and thermal shock resistance test results

[0124]

[0125] From the above results, it can be seen that the ceramic high-temperature sensor of the present invention has high bending strength and good thermal shock resistance. By adding modified quercetin and modified mannitol, the two have a synergistic effect and can further improve the performance.

[0126] 2. Metal ink composition performance test

[0127] 1. Conductivity test

[0128] Test method:

[0129] Four-probe method (ASTM F1529): Measures the resistivity of sintered metal electrodes (at room temperature and 1200°C).

[0130] High-temperature in-situ resistance drift test: In a constant temperature environment of 1200°C, the resistance change rate is recorded as a function of time.

[0131] Comparison group:

[0132] This application is metallic ink.

[0133] Traditional ink: pure platinum slurry (without Al2O3 doping).

[0134] 2. Interface bonding strength test

[0135] Test method:

[0136] Micro tensile test (ISO 13779-3): measures the interfacial bonding strength between metal electrodes and ceramic substrates.

[0137] High-temperature shear test (ASTM D1002): Shear force is applied at 1200°C until interfacial failure.

[0138] Comparison group:

[0139] This application is metallic ink.

[0140] Traditional process: screen printing pure platinum paste.

[0141] 3. High temperature oxidation resistance

[0142] Test method:

[0143] Thermogravimetric analysis (TGA): The temperature was raised to 1200°C in an air atmosphere and the mass change was recorded.

[0144] SEM-EDS analysis: Observe the surface morphology and element distribution of the electrode after high-temperature oxidation.

[0145] The test results are shown in Table 2 below:

[0146] Table 2 Metal ink composition performance test table

[0147]

[0148] From the above results, it can be seen that the metal ink of the present invention significantly improves the oxidation resistance and interfacial bonding strength of the metal ink by doping with nano-Al2O3. Compared with traditional screen printing technology, the core indicators such as conductivity and stability are improved by 3-5 times, meeting the sensing needs in extreme environments.

[0149] It should be noted that, for the sake of simplicity, the aforementioned embodiments are described as a series of action combinations. However, those skilled in the art should be aware that the present invention is not limited by the order of the actions described, because according to the present invention, certain steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0150] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the invention. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field can still combine, add, delete or make other adjustments to the features in the various embodiments of the present invention according to the circumstances without conflict, without making creative work, so as to obtain different other technical solutions that do not deviate from the concept of the present invention in essence, and these technical solutions also fall within the scope of protection of the present invention.

Claims

1. A high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor, characterized in that: The invention comprises a protective layer, a functional layer, an insulating layer and a support layer in sequence, wherein a metal electrode network is printed on the functional layer and the support layer, and the functional layer and the support layer each comprise the following raw materials in percentage by mass: 60-75% alumina, 15-25% zirconium oxide, 5-10% yttrium oxide, 0.5-2% lanthanum oxide, 0.3-0.7% modified quercetin, and 1-3% modified mannitol; The preparation method of the modified quercetin is as follows: Quercetin was dissolved in NH3•H2O buffer solution at pH=9, and Al 3＋： Add Al(NO3)3 solution to quercetin in a ratio of 1:3, heat to 80-90°C and stir for 1-2h to generate an Al-quercetin complex, dry in vacuum at 70-80°C, and crush to D50 = 1.2μm. Ultrasonic treatment of the crushed Al-quercetin complex and carbon nanotubes in a dimethylformamide solvent with a mass ratio of carbon nanotubes to quercetin of 1:8-12 is performed, and the mixture is filtered and vacuum dried to obtain modified quercetin. The preparation method of the modified mannitol is as follows: Mannitol and Al(OH)3 are mixed in a mass ratio of 1:0.3-0.5, melt-eutectic treated at 140-145°C, and then pulverized to D50=20μm after cooling. The pulverized particles are reacted with epichlorohydrin in a molar ratio of 1:0.1-0.3 under alkaline conditions at 60-70°C for 2-3h, then mixed with SiO2 nanospheres, melt-stirred at 160°C, cooled and pulverized to D50=15μm, and the mass ratio of mannitol to SiO2 nanospheres is 2-4:1 to obtain modified mannitol.

2. The high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor according to claim 1, characterized in that: The insulating layer is made of porous aluminum oxide, and the protective layer comprises the following raw materials in percentage by mass: 60-65% zirconium oxide, 25-30% nano-silicon carbide, 3-5% yttrium oxide, and 2-6% lanthanum oxide.

3. The high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor according to claim 1, characterized in that: The metal ink used in the metal electrode network includes the following raw materials in percentage by mass: 40-50% of platinum-iridium alloy nanoparticles, 5-10% of nano-Al2O3 particles, 15-20% of ethyl cellulose binder, and 20-30% of α-terpineol solvent are ultrasonically dispersed and then ball-milled to form a stable suspension.

4. The method for preparing a high-temperature co-sintered multi-layer special-shaped ceramic high-temperature sensor according to any one of claims 1 to 3, characterized in that: The steps include: preparing a ceramic slurry; Green forming of each layer; Printing and preliminary curing of metal electrode networks on functional and support layers; The ceramic layers are stacked and assembled in sequence to form a green body; Co-sintering is performed to form an integrated multi-layer structure; The ceramic slurry preparation is specifically as follows: Functional layer and support layer slurry: Alumina, zirconium oxide, yttrium oxide, and lanthanum oxide are mixed in appropriate proportions and ball-milled to a D50 of 0.5 μm to obtain a ceramic powder. A hyperbranched polyimide dispersant is added to ethanol and trichloroethylene to obtain a mixture. The ceramic powder is added to the mixture and ball-milled for 1-3 hours until uniform. Modified quercetin is then added and ball-milled for another hour. Modified mannitol is then added and the mixture is stirred at a low speed for 30-40 minutes, followed by vacuum stirring. Protective layer slurry: acid-wash the nano-silicon carbide, then mix it with zirconium oxide, yttrium oxide, and lanthanum oxide, and planetary ball mill for 1-3 hours; The green body forming of each layer is specifically as follows: The protective layer is formed by gradient tape casting, with the nano-silicon carbide content continuously changing from 5-25% along the thickness direction. The functional layer is formed by tape casting and dried at 50°C to form a Y-shaped corrugated structure. The insulating layer is formed by dry pressing. The support layer is formed by compression molding using a three-dimensional truss mold with a pressure of 20-25MPa and a holding pressure of 5-10 minutes. The printing and preliminary curing of the metal electrode network on the functional layer and the support layer are specifically as follows: 3D printing technology is used to print out the metal electrode pattern. After printing is completed, the printed ceramic layer is placed in an infrared heating device and heated at 100-150°C for 5-10 minutes for preliminary curing.

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