Ruthenium oxide-based conductive paste, temperature sensor and preparation method thereof

Abstract

The invention provides ruthenium oxide-based conductive paste, a temperature sensor and a preparation method of the ruthenium oxide-based conductive paste, the paste comprises 10-30 wt% of a conductive phase, the conductive phase adopts ruthenium oxide powder, and the ruthenium oxide powder has a submicron-scale particle size; the glass phase is prepared from BaO, B2O3, SiO2 and Al2O3, and the glass phase is prepared from the following components in percentage by weight; the organic carrier comprises terpilenol, and further comprises at least one of ethyl cellulose, rosin, butanol and polyvinyl alcohol; and 0.5-5 wt% of a modifier, wherein the modifier comprises at least one of manganese dioxide, cerium dioxide and titanium dioxide. Through mutual cooperation of all the components, the slurry has excellent machinability and low-temperature electrical property stability, material component optimization and an MEMS compatible process are considered, the sensitivity, response linearity and working stability of a ruthenium oxide sensor in a deep hypothermia region are improved, and the sensitivity, response linearity and working stability of the ruthenium oxide sensor in a deep hypothermia region are improved. The problems that an existing low-temperature temperature sensor is insufficient in sensitivity, unstable in film layer, high in preparation cost and the like are solved.

Description

Technical Field

[0001] This application relates to the interdisciplinary field of low-temperature sensor materials and microelectronics technology, specifically to ruthenium oxide-based conductive paste, temperature sensor, and its preparation method. Background Technology

[0002] In cutting-edge technology fields such as quantum computing, spacecraft cryogenic monitoring, cryogenic medicine, and astronomical exploration, there is an urgent need for temperature sensors with high sensitivity, low noise, and wide response range to measure extremely low temperatures ranging from below 1K to tens of K.

[0003] A search of existing patents revealed that Chinese patent CN108369845A discloses a thermistor and its application device. The thermistor composition includes a ruthenium oxide (RuO2) electrode layer and an electrode layer structure made of noble metal materials. It focuses on the ohmic contact characteristics and bonding reliability of the electrodes and wiring, but does not cover the RuO2 slurry system, glass phase design, or optimization of deep low-temperature response performance. Another patent, CN118089974A, involves a method for manufacturing a RuO2 temperature sensor using co-sintering technology, co-sintering the electrodes and sensitive film onto a substrate to improve low-temperature structural reliability. It uses a screen printing process to apply the RuO2 sensitive layer, but does not disclose the specific slurry ratio, nor does it detail the design of the glass phase, organic carrier, and modifier system; it only provides a brief description of the overall structure and process. It is suitable for thick-film processes, but does not optimize the ultra-low temperature response performance. US Patent 8617428B2 discloses a thick-film resistor or heating element system containing silver (Ag) and RuO2. While suitable for high-temperature heating or general resistor applications, its conductive phase is predominantly Ag and is not optimized for low-temperature environments or sensor performance. Its primary goal is to achieve a high resistance layer and low-cost manufacturing, rather than low-temperature response performance. Patent application CN118919124A discloses a resistor paste and its preparation method. The conductive phase uses cheaper ruthenium oxide and silver powder instead of expensive ruthenium powder. The appropriate addition of different oxides has varying effects on improving the temperature coefficient. However, its conductive phase is also predominantly ruthenium oxide and silver powder, and it is not optimized for low-temperature environments or sensor performance.

[0004] Kikkawa T et al. published an article in the journal Physical Review Applied titled "Cryogenic spin Peltier effect detected by a RuO2-AlO2". x On-chip microthermometer. 2023, 20(5):054006, introduces a method based on RuO2-AlO xA bilayer on-chip thermistor is used to detect the spin Peltier effect below 2K. This device, fabricated using co-sputtering technology on an ultrathin film, exhibits excellent micro-area response and thermoelectric detection sensitivity. However, this type of sensor system primarily serves the needs of integrated quantum spin transport experiments. Its fabrication process is complex and cannot be adapted to thick-film screen printing platforms. Furthermore, its temperature response characteristics are highly dependent on sputtering conditions and film thickness control, making it difficult to extend to large-area, conventional platform-based cryogenic temperature measurement scenarios.

[0005] Ruthenium oxide has become a research hotspot for alternative materials due to its excellent negative temperature coefficient, thermal stability, and material reliability in the low-temperature region. However, most of the mainstream ruthenium oxide conductive pastes on the market are imported, with undisclosed compositions, unstable performance, and a lack of systematic optimization for deep cryogenic applications. Currently, mainstream cryogenic temperature sensors include CERNOX, RX-102A, and RuO2-BR, but they have the following shortcomings:

[0006] Limited sensitivity: For example, the RX-102A sensor has a temperature coefficient of only about -9.5% / K near 1.5K, and the response slows down at deeper temperatures.

[0007] High manufacturing costs: Most of the above-mentioned components rely on foreign processes, making it difficult to produce them domestically and customize them in large quantities.

[0008] Poor process adaptability: It cannot be directly integrated into MEMS chips or flexible platforms, making it difficult to expand application scenarios. Summary of the Invention

[0009] To address one of the shortcomings of the prior art, the purpose of this application is to provide a ruthenium oxide-based conductive paste, a temperature sensor, and a method for preparing the same.

[0010] A first aspect of this application provides a ruthenium oxide-based conductive paste, wherein the paste comprises, by weight percentage:

[0011] The conductive phase comprises 10–30 wt%, wherein the conductive phase is ruthenium oxide powder having a submicron particle size;

[0012] The glass phase comprises 30–55 wt%, wherein the glass phase includes BaO, B2O3, SiO2, and Al2O3;

[0013] The organic carrier comprises 20-45 wt%, and the organic carrier includes terpineol, and also includes at least one of ethyl cellulose, rosin, butanol and polyvinyl alcohol;

[0014] The modifier is 0.5-5 wt%, and the modifier includes at least one of manganese dioxide, cerium dioxide and titanium dioxide.

[0015] Optionally, the ruthenium oxide powder has a particle size of 50 nm to 2 μm.

[0016] Optionally, the ruthenium oxide powder has a particle size of 200–600 nm.

[0017] Optionally, the mass ratio of each material in the glass phase is BaO:B2O3:SiO2:Al2O3 = (2.5~3.5):(2.5~3.5):(1~2.5):(2~3.5).

[0018] A second aspect of this application provides a method for preparing the ruthenium oxide-based conductive paste, comprising:

[0019] The glass phase, conductive phase, and modifier are mixed and then ball-milled.

[0020] The ball-milled mixed powder is screened through a sieve to obtain slurry powder;

[0021] The slurry powder is mixed evenly with an organic carrier and stirred to obtain a ruthenium oxide-based conductive slurry.

[0022] Optionally, the glass phase, conductive phase and modifier are mixed and then ball-milled, wherein the ball-milling time is 10-12 hours and the ball-milling speed is 260-480 r / min.

[0023] Optionally, the slurry powder is mixed evenly with the organic carrier, and a modifier is added and stirred, wherein the stirring temperature is 60-80°C and the stirring time is 5-8 hours.

[0024] A third aspect of this application provides a method for fabricating a ruthenium oxide temperature sensor, comprising:

[0025] The ruthenium oxide-based conductive paste is provided, and the paste is printed onto a substrate by screen printing, wherein conductive electrodes are printed on the substrate.

[0026] A ruthenium oxide temperature sensor was obtained through sintering.

[0027] Optionally, the sintering process yields a ruthenium oxide temperature sensor, wherein the sintering temperature is 740-950℃.

[0028] In a fourth aspect, this application provides a ruthenium oxide temperature sensor, which is prepared using the above-described method for preparing a ruthenium oxide temperature sensor.

[0029] The ruthenium oxide-based conductive paste provided in this application, through the synergistic effect of its components, exhibits excellent processability and low-temperature electrical performance stability. It also takes into account material composition optimization and MEMS compatibility, which helps to improve the sensitivity, response linearity and working stability of ruthenium oxide sensors in the deep low-temperature region. This solves the problems of insufficient sensitivity, unstable film layer and high manufacturing cost of current low-temperature temperature sensors.

[0030] Other technical effects resulting from the additional features will be further illustrated in the corresponding embodiments. Attached Figure Description

[0031] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0032] Figure 1 The image shows a high-temperature steady-state damp heat test pattern of a conductive paste for a ruthenium oxide temperature sensor according to an exemplary embodiment.

[0033] Figure 2 This is a test pattern of the basic performance of the conductive electrode of a ruthenium oxide temperature sensor according to an exemplary embodiment;

[0034] Figure 3 This is a schematic diagram of the structure of a temperature sensor according to an exemplary embodiment;

[0035] Figure 3 In the diagram: 1 is the substrate, 2 is the temperature-sensitive membrane, and 3 is the wiring lead-out terminal. Detailed Implementation

[0036] The present application will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these all fall within the protection scope of the present application. Parts not described in detail in the following embodiments can be implemented using existing technology.

[0037] With the development of quantum computing, low-temperature physics, and other fields, cryogenic temperature sensors are playing an increasingly important role. In the cryogenic field (T<77K), conventional sensors such as metal thermocouples and platinum resistors often suffer from insufficient sensitivity, unstable response, or structural failure at extremely low temperatures due to limitations in conductivity mechanisms, materials, or packaging heat capacity. Ruthenium oxide thick-film resistors, however, possess the potential for stable temperature measurement in the cryogenic region due to their excellent negative temperature coefficient (NTC). However, existing ruthenium oxide sensors have the following problems:

[0038] Poor bonding of conductive particles: The conductive phase in the slurry has a wide particle size distribution and fails to form a continuous conductive channel, resulting in low-temperature conductivity relying on an isolated tunneling mechanism and unstable response.

[0039] Outdated glass phase system design: Although traditional glass phases based on PbO and ZnO can lower the sintering temperature, they are not environmentally friendly and have poor interfacial wettability, making them prone to stress cracking.

[0040] Organic carrier systems are easy to separate and have poor fluidity, resulting in inconsistent printed film thickness, large film shrinkage, and numerous pores and high surface roughness after sintering.

[0041] Modifiers lack systematic design: most processes do not clearly define the specific role of different metal oxides in sensing mechanisms (such as grain boundary regulation and tunneling enhancement), which restricts their performance improvement in the low-temperature region.

[0042] To address the aforementioned problems, this application provides a ruthenium oxide-based conductive paste suitable for cryogenic temperature measurement, thereby resolving these issues.

[0043] This application embodiment starts from the overall material system and establishes a ruthenium oxide-based conductive paste design with "controllable microstructure and adjustable conduction mechanism" as the core.

[0044] In one embodiment of this application, the ruthenium oxide-based conductive paste comprises, by weight percentage:

[0045] The conductive phase consists of 10–30 wt% ruthenium oxide powder, which has a submicron particle size.

[0046] The glass phase consists of 30–55 wt%, including BaO, B2O3, SiO2, and Al2O3.

[0047] The organic carrier is 20-45 wt%, and the organic carrier includes terpineol, as well as at least one of ethyl cellulose, rosin, butanol and polyvinyl alcohol;

[0048] Modifier 0.5-5 wt%, including at least one of manganese dioxide (MnO2), cerium dioxide (CeO2) and titanium dioxide (TiO2).

[0049] Optimization of tunneling conductivity mechanism: In this application, the RuO2 powder particle size is controlled at the submicron scale to ensure the formation of a dense nearest-neighbor structure after sintering. At deep cryogenic temperatures (e.g., 1–10 K), electrons mainly conduct electricity through a tunneling mechanism (MottVRH model). Appropriate particle size distribution and grain boundary control can optimize the localization length and tunneling probability, thereby improving temperature-sensitive performance.

[0050] Glass phase wetting enhances conductive channels: The designed glass phase system (B2O3–SiO2–BaO–Al2O3) has low viscosity and good fluidity, which can coat and wet RuO2 particles during sintering, so that a stable "conductive-glass-conductive" three-phase interface structure is formed between conductive particles. This is conducive to forming a stable and repeatable current path, while improving mechanical bonding and long-term stability.

[0051] Modifiers regulate grain boundary barriers: Transition metal oxides such as MnO2 and CeO2 can form oxygen vacancies or change the local charge distribution at grain boundaries at high temperatures, thereby adjusting the barrier height and carrier density and optimizing the tunneling path.

[0052] Controllable Rheology and Film Formation in Organic Systems: The organic phase controls the thixotropy, volatilization rate, and particle arrangement of the slurry before sintering. Terpineol, as an organic carrier solvent, combines with ethyl cellulose, rosin, butanol, and polyvinyl alcohol to form a synergistic volatilization-polymerization system. This maintains a stable film morphology before sintering, reduces sagging and burrs, and results in extremely low carbon residue during sintering, which is beneficial for obtaining a clean interface.

[0053] By systematically optimizing the particle size and content of the conductive phase, the composition and proportion of the glass phase, the rheological system of the organic carrier, and the type and amount of modifier, this slurry possesses excellent processability, low-temperature electrical performance stability, and batch consistency. It can significantly improve the sensitivity, response linearity, and operational stability of ruthenium oxide sensors in the deep cryogenic region, achieving high sensitivity, low noise, and wide-temperature resistance response. It solves the technical problems of discontinuous conductivity, response drift, uneven sintering shrinkage, and unstable temperature-sensitive curves in traditional ruthenium oxide thick-film sensors in the low-temperature region. It is suitable for temperature measurement scenarios in the deep cryogenic region (0.95K-77K) and has significant scientific research value and engineering application prospects.

[0054] The embodiments described above provide a novel controllable ruthenium oxide conductive paste through the synergistic effect of its components. The paste exhibits excellent processability and low-temperature electrical performance stability, while also considering material composition optimization and MEMS compatibility. This helps improve the sensitivity, response linearity, and operational stability of ruthenium oxide sensors in the deep low-temperature region, solving the problems of insufficient sensitivity, unstable film layer, and high manufacturing cost of current low-temperature temperature sensors.

[0055] The embodiments described above employ a thick-film conductive paste system. By controlling the RuO2 particle size, glass phase composition, and the introduction of modifiers (such as MnO2), a high-sensitivity temperature response (sensitivity ≥ -20.5% / K) is achieved within the temperature range of 0.95–77K. This system possesses higher compatibility in industrial preparation and wider applicability, making it suitable for various cryogenic environments such as liquid helium cooling systems, aerospace temperature measurement, and cryogenic instruments.

[0056] In some specific embodiments of this application, the particle size of ruthenium oxide powder is 50 nm to 2 μm.

[0057] Preferably, the ruthenium oxide powder has a particle size of 200–600 nm. The conductive phase RuO2 has a weight percentage of 15 wt%.

[0058] In the above embodiments of this application, by setting the content of the conductive phase RuO2 and the particle size of the powder, a continuous conductive network (i.e., a dense nearest-neighbor structure) is maintained after high-temperature sintering.

[0059] The glass phase described above uses borosilicate glass powder, which is a B2O3–SiO2–BaO–Al2O3 system. Preferably, the weight percentage of the glass phase is 35 wt%.

[0060] In some specific embodiments of this application, the mass ratio of each material in the glass phase is BaO:B2O3:SiO2:Al2O3 = (2.5~3.5):(2.5~3.5):(1~2.5):(2~3.5).

[0061] The mass of B2O3 accounts for 15–50% of the mass of the glass phase. Preferably, the B2O3 content is 35% of the total mass of the glass phase.

[0062] The embodiments described above in this application employ a B2O3–SiO2–BaO–Al2O3 quaternary system, which has a low softening point (approximately 650–700℃), facilitating wetting and filling during the sintering process.

[0063] In the above embodiments of this application, the addition of modifiers can effectively reduce grain boundary resistance, improve charge carrying capacity, and suppress nonlinear resistance drift in the low-temperature range; after high-temperature precursor heat treatment, a slurry structure with excellent rheological properties is formed, which can improve the compactness, stability and temperature response of the sintered film, with a temperature coefficient of -20.5% / K.

[0064] Preferably, manganese dioxide (MnO2) is used as the modifier. MnO2 is particularly suitable for low-temperature regions because its electronic state density is more sensitive to temperature changes, thus amplifying the rate of resistance change corresponding to small temperature variations. This effectively improves the dispersion stability of the slurry and the temperature coefficient of resistance of the sintered film, making the resistance change with temperature more significant, and reducing the noise level by approximately 20% compared to before the addition of MnO2.

[0065] In the above embodiments of this application, the organic carrier has a weight percentage of up to 100 wt%, mainly including terpineol, and also including at least one of ethyl cellulose, rosin, butanol and polyvinyl alcohol, which has good wettability and volatility, ensuring the uniformity and morphology controllability of the screen-printed film.

[0066] In the embodiments described above, the slurry mainly comprises a nano-ruthenium oxide conductive phase, a borosilicate glass phase, an organic carrier, and trace modifiers. Ruthenium oxide serves as the conductive phase, the glass phase is a B2O3–SiO2–BaO–Al2O3 system, the organic carrier is, for example, a modified terpineol-ethyl cellulose system, and the modifier is selected from metal oxides such as MnO2, CeO2, or TiO2. Through the selection and precise proportioning of the components in the conductive slurry, a negative temperature coefficient characteristic can be exhibited in the temperature range of 0.95K to 77K, with a temperature coefficient better than -20.5% / K, achieving low noise and high sensitivity temperature response characteristics. The above-mentioned slurry possesses a superior temperature coefficient (better than -20.5% / K) and lower cost, making it particularly suitable for the fabrication of high-precision resistive temperature sensors with a temperature range of 0.95K to 77K.

[0067] Another embodiment of this application provides a method for preparing the above-mentioned ruthenium oxide-based conductive paste, comprising:

[0068] S1. Mix the glass phase powder, conductive phase powder and modifier powder, and then ball mill them;

[0069] S2. The ball-milled mixed powder is screened through a sieve to obtain slurry powder;

[0070] S3. Mix the slurry powder with the organic carrier evenly, add it to a reagent bottle, place a magnetic stirrer, and stir to obtain ruthenium oxide-based conductive slurry.

[0071] In some specific embodiments of this application, in S1, the glass phase powder, conductive phase powder and modifier powder are mixed and then ball-milled in a ball mill for 10 to 12 hours and at a speed of 260 to 480 r / min.

[0072] Specifically, in S2, the ball-milled mixed powder is screened through a 400-mesh sieve to obtain ruthenium oxide temperature sensor slurry mixed powder.

[0073] Specifically, the purpose of ball milling the slurry powder, setting an appropriate ball milling time and speed, and using a sieve is to make the slurry powder particles more uniform. Powder particles smaller than 38μm are screened and stirred to avoid the formation of large powder particles due to agglomeration, so as to avoid further affecting the uniform mixing with the organic carrier.

[0074] In some specific embodiments of this application, the slurry powder is mixed evenly with the organic carrier and stirred, wherein the stirring temperature is 60-80°C and the stirring time is 5-8 hours.

[0075] Specifically, the slurry powder is mixed with the organic carrier in a reagent bottle, and a magnetic stirrer is added in a water bath at 60-80°C for 5-8 hours to obtain the ruthenium oxide temperature sensor conductive slurry.

[0076] Specifically, the purpose of setting the above-mentioned stirring temperature is to make the stirred slurry more fluid, so as to achieve uniform mixing. The purpose of controlling the above-mentioned temperature and stirring time is to ensure that the slurry is mixed evenly, while avoiding excessive volatilization of organic carriers due to excessive stirring time.

[0077] The above embodiments of this application have a simple fabrication process, low cost, are applicable to MEMS process platforms, have excellent low-temperature response performance, and are suitable for high-precision temperature measurement applications in extremely low-temperature environments such as aerospace and cryogenic exploration.

[0078] Another embodiment of this application provides a method for fabricating a ruthenium oxide temperature sensor, comprising:

[0079] M1. Provide ruthenium oxide-based conductive paste, and print the paste onto a substrate using screen printing. Conductive electrodes are printed on the substrate.

[0080] M2, after sintering, yields a ruthenium oxide temperature sensor.

[0081] In some specific embodiments of this application, a ruthenium oxide temperature sensor is obtained by sintering, wherein the sintering temperature is 740°C to 950°C.

[0082] For example, the paste is screen-printed onto an alumina ceramic substrate and sintered at 740°C to 950°C for 10 to 90 minutes to form a resistive sensitive film.

[0083] Preferably, the sintering temperature is controlled at 750–880℃; the holding time is controlled at 10–60 min.

[0084] In use, the conductive paste for ruthenium oxide temperature sensors is applied to an insulating substrate such as alumina ceramic via screen printing or doctor blade coating. The printing pattern of the conductive paste is as follows: Figure 1 As shown.

[0085] Similarly, the conductive electrodes for testing are also screen-printed onto the insulating substrate to facilitate testing the properties of the sintered paste. The screen printing pattern used for the conductive electrodes for testing is as follows: Figure 2 As shown.

[0086] The conductive electrode for testing can be printed on an insulating substrate before printing the ruthenium oxide temperature sensor paste. After drying in an oven at 120℃~160℃ for 10~20 minutes, the ruthenium oxide temperature sensor paste can be printed.

[0087] After the above paste is printed on the insulating substrate, it is pre-dried and then sintered under the following process conditions:

[0088] Sintering temperature: 750–880℃;

[0089] Insulation time: 10–60 min;

[0090] Sintering atmosphere: air or a slightly oxygenated atmosphere (oxygen concentration 5–10%);

[0091] Heating / cooling rate: Controlled at 1–5℃ / min to avoid excessive stress on the film layer leading to cracking or peeling.

[0092] The structure of the printed ruthenium oxide temperature sensor is as follows: Figure 3 As shown, it includes a substrate 1, a temperature-sensitive film 2 located above the substrate 1, and a wiring lead-out terminal 3 (i.e., a conductive electrode).

[0093] The embodiments described above in this application significantly improve the sensitivity (better than -20.5% / K) and stability of the sensor in the 0.95–77K temperature range by adjusting the mass fraction of each component of the conductive paste and optimizing the sintering temperature.

[0094] The ruthenium oxide temperature sensor prepared by the above method exhibits a significant negative temperature coefficient response in the temperature range of 0.95K to 77K, and the resistance increases exponentially and monotonically as the temperature decreases.

[0095] After processing with the above-described formula and process, the ruthenium oxide temperature sensor slurry provided in the above embodiments of this application can achieve the following key properties:

[0096] High sensitivity: Within the temperature range of 0.95–77K, the device exhibits a highly stable negative temperature coefficient, with a temperature sensitivity of over -20.5% / K. It has excellent temperature response in the 0.95–77K range, making it suitable for use in deep cryogenic temperature control systems.

[0097] Low-temperature sensitivity optimization: In the 1–40K range, its resistance versus temperature relationship follows the Mott VRH (variable range jump) conductivity model, with a linear correlation coefficient (R0). 2 If the value is greater than 0.995, the response curve is continuous and has strong fit.

[0098] Dense structure and crack-free: SEM observation of the film structure after sintering shows that RuO2 particles are uniformly distributed in the glass matrix, the interface is smooth, and the average porosity is less than 8%, which effectively suppresses performance drift during thermal cycling.

[0099] Strong processing compatibility: The paste is suitable for conventional screen printing platforms, has excellent printing adaptability and film thickness control capabilities, and the drying and sintering processes do not require special atmosphere control, making it a potential material for industrial-scale mass production.

[0100] Simple process and low cost: The screen printing method is simple and low cost.

[0101] Excellent packaging compatibility: The sensors manufactured maintain long-term stability under vacuum welding, glass encapsulation or surface mount encapsulation conditions, making them suitable for use in fields such as spacecraft temperature measurement, liquid helium system control, and quantum device temperature control.

[0102] The ruthenium oxide-based conductive paste described in the above embodiments of this application can be widely used in cryogenic sensors, temperature control modules for quantum devices, temperature control nodes for superconducting systems, and cryogenic physics experimental platforms. It is particularly suitable for the following typical application scenarios: spacecraft cabin temperature control systems (<20K); temperature monitoring of the liquid helium temperature zone (4.2K) in cryogenic storage and transportation equipment; temperature control modules (<10K) of quantum computing chips and their adjacent components; temperature measurement of cables or nodes in superconducting magnet systems (such as MRI); and multi-point temperature control or distributed thermal mapping systems in basic cryogenic physics experimental platforms.

[0103] Compared with commercially available products (such as the RX-102 series from Lake Shore in the United States), the embodiments described above in this application have significant advantages in terms of material system controllability, response curve customizability, and cost adaptability, and can form the core foundation of a new generation of deep cryogenic temperature sensing materials and devices.

[0104] The preferred features in the above embodiments can be used individually in any embodiment, or in any combination thereof, provided they do not conflict with each other. Furthermore, parts not described in detail in the embodiments can be implemented using existing technologies.

[0105] The following examples and comparative examples will be used to further illustrate this application in order to better understand the above-mentioned technical solutions. It should be understood that the following are only some examples and are not intended to limit this application.

[0106] Application Example 1:

[0107] Preparation of Ruthenium Oxide Slurry

[0108] Component ratio (total slurry mass 10g):

[0109] RuO2 (200nm): 15wt%;

[0110] Glass phase (BaO:B2O3:SiO2:Al2O3 = 3:3:2:3): 38 wt%;

[0111] MnO2: 2wt%;

[0112] Organic carrier (terpineol + ethyl cellulose): balance to 100% wt%.

[0113] Preparation process:

[0114] The conductive phase, glass phase, and modifier powder were premixed using a ball milling method.

[0115] Add an organic carrier to prepare a homogeneous slurry (viscosity controlled between 30,000 and 60,000 mPa·s);

[0116] Printed onto an alumina ceramic substrate using screen printing;

[0117] Sinter at 850℃ in air atmosphere for 10 minutes.

[0118] Performance testing:

[0119] Temperature range: 0.95–77K;

[0120] Sensitivity -20.5% / K;

[0121] The resistance is approximately 1.1kΩ (300K);

[0122] Deviation <1%.

[0123] Application Example 2:

[0124] Preparation of Ruthenium Oxide Slurry

[0125] Component ratio (total slurry mass 10g):

[0126] RuO2 (200nm): 10wt%;

[0127] Glass phase (BaO:B2O3:SiO2:Al2O3 = 3:3:2:3): 38 wt%;

[0128] MnO2: 2wt%;

[0129] Organic carrier (terpineol + ethyl cellulose): balance to 100% wt%.

[0130] Preparation process: Same as application example 1.

[0131] Performance testing:

[0132] Temperature range: 0.95–77K;

[0133] Sensitivity -17.6% / K;

[0134] The resistance is approximately 2.9kΩ (300K);

[0135] Deviation <3%.

[0136] Application Example 3:

[0137] Preparation of Ruthenium Oxide Slurry

[0138] Component ratio (total slurry mass 10g):

[0139] RuO2 (200nm): 20wt%;

[0140] Glass phase (BaO:B2O3:SiO2:Al2O3 = 3:3:2:3): 38 wt%;

[0141] MnO2: 2wt%;

[0142] Organic carrier (terpineol + ethyl cellulose): balance to 100% wt%. Preparation process: same as application example 1.

[0143] Performance testing:

[0144] Temperature range: 0.95–77K;

[0145] Sensitivity -12.2% / K;

[0146] The resistance is approximately 0.9kΩ (300K);

[0147] Deviation <1%.

[0148] Application Example 4:

[0149] Preparation of Ruthenium Oxide Slurry

[0150] Component ratio (total slurry mass 10g):

[0151] RuO2 (200nm): 30wt%;

[0152] Glass phase (BaO:B2O3:SiO2:Al2O3 = 3:3:2:3): 38 wt%;

[0153] MnO2: 2wt%;

[0154] Organic carrier (terpineol + ethyl cellulose): slurry balance to 100% wt%. Preparation process: same as application example 1.

[0155] Performance testing:

[0156] Temperature range: 0.95–77K;

[0157] Sensitivity -7.5% / K;

[0158] The resistance is approximately 0.39kΩ (300K);

[0159] Deviation <1%.

[0160] Application Example 5:

[0161] The difference from Application Example 1 is that the organic carrier is changed to terpineol + rosin; and the ruthenium oxide slurry is prepared...

[0162] Component ratio (total slurry mass 10g):

[0163] RuO2 (200nm): 15wt%;

[0164] Glass phase (BaO:B2O3:SiO2:Al2O3 = 3:3:2:3): 38 wt%; MnO2: 2 wt%;

[0165] Organic carrier (terpineol + rosin): balance to 100% wt%.

[0166] Preparation process: Same as application example 1.

[0167] Performance testing:

[0168] Temperature range: 0.95–77K;

[0169] Sensitivity -11.2% / K;

[0170] The resistance is approximately 2.3kΩ (300K);

[0171] Deviation <3%.

[0172] Application Example 6:

[0173] The modifier component's mass percentage was increased to 5 wt%;

[0174] Preparation of Ruthenium Oxide Slurry

[0175] Component ratio (total slurry mass 10g):

[0176] RuO2 (200nm): 15wt%;

[0177] Glass phase (BaO:B2O3:SiO2:Al2O3 = 3:3:2:3): 38 wt%; Organic carrier (terpineol + ethyl cellulose): balance to 100% wt%; MnO2 (modifier): 5 wt%.

[0178] Preparation process: Same as application example 1.

[0179] Performance testing:

[0180] Test temperature range: 0.95K~77K;

[0181] The resistance is approximately 1.4kΩ (300K);

[0182] Maximum temperature coefficient: -14.2% / K;

[0183] The resistance change is approximately exponential, resulting in good resistance response performance.

[0184] Noise density is lower than (@10Hz);

[0185] Deviation <1%.

[0186] Application Example 7:

[0187] The glass phase content was reduced from 30 wt% in Application Example 1;

[0188] Preparation of Ruthenium Oxide Slurry

[0189] Component ratio (total slurry mass 10g):

[0190] RuO2 (200nm): 15wt%;

[0191] Glass phase (BaO:B2O3:SiO2:Al2O3 = 3:3:2:3): 30 wt%;

[0192] MnO2: 2wt%;

[0193] Organic carrier (terpineol + ethyl cellulose): balance to 100% wt%.

[0194] Preparation process: Same as application example 1.

[0195] Performance testing:

[0196] Temperature range: 0.95–77K;

[0197] Sensitivity -19.3% / K;

[0198] The resistance is approximately 0.9kΩ (300K);

[0199] Deviation <1%.

[0200] Application Example 8:

[0201] The proportion of the glass phase component in Application Example 1 was increased from 38% wt% to 55 wt%; ruthenium oxide slurry preparation

[0202] Component ratio (total slurry mass 10g):

[0203] RuO2 (200nm): 15wt%;

[0204] Glass phase (BaO:B2O3:SiO2:Al2O3 = 3:3:2:3): 55 wt%;

[0205] MnO2 (modifier): 2wt%;

[0206] Organic carrier (terpineol + ethyl cellulose): balance to 100% wt%.

[0207] Preparation process: Same as application example 1.

[0208] Performance test (total slurry mass 10g):

[0209] Test temperature range: 0.95K~77K;

[0210] The resistance is approximately 33.7kΩ (300K);

[0211] The temperature coefficient is approximately -4.1% / K;

[0212] Deviation <4%.

[0213] Application Example 9:

[0214] Increase the insulation temperature to 950℃;

[0215] Component ratio (total slurry mass 10g):

[0216] RuO2 (200nm): 15wt%;

[0217] Glass phase (BaO:B2O3:SiO2:Al2O3 = 3:3:2:3): 38 wt%;

[0218] MnO2: 2wt%;

[0219] Organic carrier (terpineol + ethyl cellulose): balance to 100% wt%.

[0220] Preparation process:

[0221] The conductive phase and glass phase powders were premixed using a ball milling method;

[0222] An organic carrier is added to prepare a homogeneous slurry (viscosity controlled between 30,000 and 60,000 mPa·s); the slurry is then printed onto an alumina ceramic substrate using screen printing.

[0223] Sinter at 950℃ in air atmosphere for 10 minutes.

[0224] Performance test (total slurry mass 10g):

[0225] Temperature range: 0.95–77K;

[0226] The resistance is approximately 0.8kΩ (300K);

[0227] Sensitivity -8.1% / K;

[0228] Deviation <1%.

[0229] Application Example 10:

[0230] Lower the insulation temperature to 740℃;

[0231] Component ratio (total slurry mass 10g):

[0232] RuO2 (200nm): 15wt%;

[0233] Glass phase (BaO:B2O3:SiO2:Al2O3 = 3:3:2:3): 38 wt%;

[0234] MnO2: 2wt%;

[0235] Organic carrier (terpineol + ethyl cellulose): balance to 100% wt%.

[0236] Preparation process:

[0237] The conductive phase and glass phase powders were premixed using a ball milling method;

[0238] An organic carrier is added to prepare a homogeneous slurry (viscosity controlled between 30,000 and 60,000 mPa·s); the slurry is then printed onto an alumina ceramic substrate using screen printing.

[0239] Sinter at 740℃ in air atmosphere for 10 minutes.

[0240] Performance test (total slurry mass 10g):

[0241] Temperature range: 0.95–77K;

[0242] The resistance is approximately 3.1kΩ (300K);

[0243] Sensitivity -13.8% / K;

[0244] Deviation <3%.

[0245] Application Example 11:

[0246] The modifier was changed from MnO2 to titanium dioxide (TiO2);

[0247] Preparation of Ruthenium Oxide Slurry

[0248] Component ratio (total slurry mass 10g):

[0249] RuO2 (200nm): 15wt%;

[0250] Glass phase (BaO:B2O3:SiO2:Al2O3 = 3:3:2:3): 38 wt%;

[0251] TiO2: 2wt%;

[0252] Organic carrier (terpineol + ethyl cellulose): balance to 100% wt%.

[0253] Preparation process: Same as application example 1.

[0254] Performance testing:

[0255] Test temperature range: 0.95K~77K;

[0256] The resistance is approximately 1.9kΩ (300K);

[0257] Maximum temperature coefficient: -12.7% / K;

[0258] Deviation <2%.

[0259] Comparative Example 1:

[0260] Control group without modifier: The components do not contain modifiers;

[0261] Component ratio (total slurry mass 10g):

[0262] RuO2 (200nm): 15wt%;

[0263] Glass phase (BaO:B2O3:SiO2:Al2O3 = 3:3:2:3): 40 wt%;

[0264] Organic carrier (terpineol + ethyl cellulose): balance to 100% wt%.

[0265] Preparation process: Same as application example 1.

[0266] Performance test results:

[0267] Test temperature range: 0.95K~77K;

[0268] The resistance is approximately 1.8kΩ (300K);

[0269] The formation of microporous structures on the surface of the sintered film leads to resistance fluctuations;

[0270] Sensitivity decreased, and the temperature coefficient became positive, +1.6% / K;

[0271] The noise density increased significantly, and the curve became unstable.

[0272] Based on the above application examples and comparative examples, the following conclusions can be drawn:

[0273] Insufficient organic carrier content: The film structure is loose, and adhesion is reduced; excessive glass phase content: The conductive path is isolated, and sensitivity is reduced. Insufficient sintering temperature: The film is unstable, and the conductive path is incomplete. Modifier role: Adding modifiers can improve the density of the sensor's sensitive film and enhance film stability; it can also change the temperature coefficient of the temperature sensor from a positive value to a negative value, improving sensitivity under deep cryogenic conditions.

[0274] The foregoing has described some specific embodiments of this application. It should be understood that this application is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the substantive content of this application. The above-described preferred features can be used in any combination without conflict.

Claims

1. A ruthenium oxide-based conductive paste, characterized in that, The slurry comprises, by weight percentage: The conductive phase comprises 10–30 wt%, wherein the conductive phase is ruthenium oxide powder having a submicron particle size; The glass phase comprises 30–55 wt%, wherein the glass phase includes BaO, B2O3, SiO2, and Al2O3; The organic carrier comprises 20-45 wt%, and the organic carrier includes terpineol, and also includes at least one of ethyl cellulose, rosin, butanol and polyvinyl alcohol; The modifier is 0.5-5 wt%, and the modifier includes at least one of manganese dioxide, cerium dioxide and titanium dioxide.

2. The ruthenium oxide-based conductive paste according to claim 1, characterized in that, The ruthenium oxide powder has a particle size of 50 nm to 2 μm.

3. The ruthenium oxide-based conductive paste according to claim 1, characterized in that, The ruthenium oxide powder has a particle size of 200–600 nm.

4. The ruthenium oxide-based conductive paste according to claim 1, characterized in that, The mass ratio of each material in the glass phase is BaO:B2O3:SiO2:Al2O3 = (2.5~3.5):(2.5~3.5):(1~2.5):(2~3.5).

5. A method for preparing the ruthenium oxide-based conductive paste according to any one of claims 1-4, characterized in that, include: The glass phase, conductive phase, and modifier are mixed and then ball-milled. The ball-milled mixed powder is screened through a sieve to obtain slurry powder; The slurry powder is mixed evenly with an organic carrier and stirred to obtain a ruthenium oxide-based conductive slurry.

6. The method for preparing ruthenium oxide-based conductive paste according to claim 5, characterized in that, The glass phase, conductive phase and modifier are mixed and then ball-milled, wherein the ball-milling time is 10-12 hours and the ball-milling speed is 260-480 r / min.

7. The method for preparing ruthenium oxide-based conductive paste according to claim 5, characterized in that, The slurry powder is mixed evenly with the organic carrier and stirred, wherein the stirring temperature is 60-80℃ and the stirring time is 5-8 hours.

8. A method for fabricating a ruthenium oxide temperature sensor, characterized in that, include: A ruthenium oxide-based conductive paste according to any one of claims 1-4 is provided, wherein the paste is printed onto a substrate by screen printing, and conductive electrodes are printed on the substrate; A ruthenium oxide temperature sensor was obtained through sintering.

9. The method for preparing the ruthenium oxide temperature sensor according to claim 8, characterized in that, The sintering process yields a ruthenium oxide temperature sensor, wherein the sintering temperature is 740-950℃.

10. A ruthenium oxide temperature sensor, characterized in that, It is prepared using the method for preparing the ruthenium oxide temperature sensor as described in claim 8 or 9.

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