Radiation resistant high-stability platinum resistor and preparation method thereof

Abstract

This invention relates to the field of sensor technology, specifically to a radiation-resistant, highly stable platinum resistance thermometer and its preparation method. The platinum resistance thermometer comprises an alumina / silicon nitride substrate, and, sequentially arranged from the inside out, a platinum resistance conductive layer, a 200-400nm radiation-resistant layer, and a protective layer on the substrate. The preparation method includes custom-configured platinum resistance paste, screen printing, and high-temperature sintering under argon protection to form the conductive layer. After laser trimming, the radiation-resistant layer is prepared by atomic layer deposition. The protective layer is then formed by platinum wire bonding, glass paste screen printing, and high-temperature sintering, ultimately yielding the radiation-resistant, highly stable platinum resistance thermometer. The platinum resistance thermometer prepared by this invention achieves a resistance accuracy of ±0.01Ω at 0℃, and a resistance drift of ≤0.5% under γ-ray irradiation of not less than 100kGy. It exhibits excellent vibration resistance and high / low temperature stability, meeting the high-precision temperature measurement requirements of complex operating conditions such as nuclear reactors, aerospace, and extreme industrial measurement and control.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, specifically to a radiation-resistant, highly stable platinum resistance thermometer and its preparation method. Background Technology

[0002] Temperature is a core monitoring parameter in industrial production and special extreme operating conditions. Its high-precision and high-stability measurement is an important foundation for ensuring safe equipment operation, achieving precise process control, and improving system operating efficiency. Platinum resistance thermometers, with their advantages of stable temperature coefficient of resistance, high temperature measurement accuracy, good linearity, and wide applicable temperature range, have become the mainstream sensing element for temperature measurement in the medium and high temperature range. They are widely used in nuclear power, aerospace, high-end equipment manufacturing, and other fields, and related technologies are continuously developing towards extreme environment resistance, long service life, and high reliability.

[0003] In the nuclear power field, temperature measurement of core equipment such as the main pump of the third-generation nuclear power plant has put forward stringent requirements for platinum resistance thermometers. The industry clearly stipulates that the design life of platinum resistance thermometers for nuclear power is no less than 10 years, and they must maintain stable temperature measurement accuracy and structural integrity under the combined extreme conditions of high temperature, high pressure, strong gamma ray irradiation and continuous vibration. This is also the core direction and key indicator of the current research and development of platinum resistance thermometer technology for nuclear power.

[0004] Currently, platinum resistance thermometers used in the nuclear power field are mainly of traditional wire-wound and thin-film structures. Although both have basic temperature measurement capabilities under normal operating conditions, they have significant technical defects when used for long-term service in the combined extreme conditions of nuclear power plant reactors, making it difficult to meet the actual usage requirements of nuclear power scenarios. The specific analysis is as follows:

[0005] 1. Wire-wound platinum resistance thermometer

[0006] Due to the limitations of the winding process itself, wire-wound platinum resistance thermometers have inherent problems such as loose structure and poor vibration resistance. When used under vibration conditions for a long time, they are prone to problems such as poor contact of the wire core and loose connection terminals, which will directly lead to increased resistance drift and a rapid decrease in temperature measurement accuracy.

[0007] 2. Thin-film platinum resistance thermometer

[0008] Although thin-film platinum resistance thermometers have a compact structure and good spatial adaptability, under the current manufacturing process, the uniformity of the conductive film grains is poor and the bonding force between the film and the substrate is weak. Under the conditions of strong nuclear power radiation and wide temperature range, problems such as film peeling and migration and diffusion of impurity elements are prone to occur, which in turn cause a continuous decrease in temperature measurement accuracy. Some products even fail directly during their service life.

[0009] In summary, both wire-wound and thin-film platinum resistance thermometers suffer from issues such as easily diminished temperature measurement accuracy, insufficient radiation resistance, and poor long-term stability. They cannot simultaneously meet the comprehensive requirements of nuclear power plant reactors for high precision, radiation resistance, vibration resistance, and long lifespan. Furthermore, these problems with wire-wound and thin-film platinum resistance thermometers not only affect the precise control of reactor power regulation and cooling system operation, leading to a decrease in nuclear power plant operating efficiency, but also pose serious safety hazards due to inaccurate temperature monitoring, directly restricting the overall safety and stability of the nuclear power plant operation.

[0010] Therefore, there is an urgent need to develop a new platinum resistance thermometer structure design and fabrication process to solve the technical problems of large resistance drift, poor structural stability, and easy failure of platinum resistance thermometers under combined extreme operating conditions, improve the overall adaptability of platinum resistance thermometers to the harsh operating conditions of nuclear power plants, and ensure the accuracy and long-term reliability of nuclear reactor temperature monitoring. Summary of the Invention

[0011] The purpose of this invention is to address the shortcomings of existing technologies by providing a radiation-resistant, highly stable platinum resistance thermometer and its preparation method. Through an integrated process design encompassing customized platinum resistance slurry configuration, screen printing, high-temperature firing, atomic layer deposition (ALD) radiation-resistant layer preparation, protective layer composite coating, precision lead welding, and protective layer composite encapsulation, the overall performance of the prepared platinum resistance thermometer is significantly improved. It achieves a resistance accuracy of ±0.01Ω at 0℃, a temperature coefficient stability of ≤±0.002% / ℃ within the temperature range of -200℃ to 800℃, a resistance drift rate of ≤0.5% under gamma-ray irradiation doses of not less than 100kGy, a long-term stability error of ≤±0.3℃, and no structural loosening or failure issues under vibration frequencies of 10Hz to 2000Hz. The platinum resistance thermometer described in this invention combines high purity, excellent radiation resistance, strong high and low temperature stability, and outstanding structural resistance to harsh environments, fully meeting the performance requirements for high-precision temperature monitoring under complex operating conditions such as nuclear reactors, aerospace, and extreme industrial measurement and control.

[0012] The objective of this invention is achieved through the following approach:

[0013] A radiation-resistant and highly stable platinum resistance thermometer includes an alumina or silicon nitride substrate, and a platinum resistance conductive layer, a radiation-resistant layer, and a protective layer arranged sequentially from the inside to the outside on the substrate. The radiation-resistant layer has a thickness of 200–400 nm, and the conductive layer is fixedly connected to platinum wire leads.

[0014] A method for preparing a radiation-resistant and highly stable platinum resistance thermometer includes the following steps:

[0015] 1) Preparation of platinum resistance paste

[0016] By weight, 75%–85% of platinum powder and 5%–10% of glass powder are ball-milled and mixed, and then ground and mixed evenly with 10%–15% of organic carrier under water bath heating to obtain platinum resistance slurry.

[0017] 2) Preparation of platinum resistance conductive layer

[0018] The prepared platinum resistance paste is screen-printed onto the surface of an alumina or silicon nitride substrate, and then sintered at high temperature to form a platinum resistance conductive layer with a thickness of 10 to 30 μm on the substrate surface.

[0019] 3) Lead wire soldering

[0020] One end of the platinum wire lead is fixedly connected to the platinum resistance conductive layer by sintering using platinum resistance paste.

[0021] 4) Preparation of radiation-resistant layer

[0022] Atomic layer deposition (ALD) was carried out using trimethylaluminum (TMA) precursor with a purity of ≥99.99% and water vapor as a reactant under inert gas protection. The deposition temperature was 200℃~250℃, the single purge time was 5s~20s, the deposition time was 25h~30h, and the deposition thickness was 200nm~400nm.

[0023] In step 4) of this invention, controlling the deposition temperature between 200℃ and 250℃ ensures a sufficient and self-limiting surface reaction between the precursor and the reactant. This guarantees uniform growth, high density, and excellent adhesion of the radiation-resistant layer, while preventing thermal damage to the platinum resistance conductive layer and ceramic substrate caused by high temperatures, thus ensuring that the core performance of the platinum resistance remains unaffected. If the deposition temperature is below 200℃, the reaction between the precursor and water vapor is insufficient, resulting in a slow surface reaction rate. This leads to a decrease in the density of the radiation-resistant layer, making it prone to problems such as porosity, voids, and poor adhesion, significantly reducing its radiation resistance and failing to provide effective protection. If the deposition temperature is above 250℃, it easily triggers thermal decomposition of the precursor, leading to an increase in the density of defects in the film layer and a decrease in uniformity. At the same time, excessively high temperatures can cause resistance drift and glass phase flow in the platinum resistance, severely affecting the resistance accuracy and long-term stability of the platinum resistance.

[0024] Controlling the single purging time to 5-20 seconds ensures the thorough removal of unreacted precursors, reaction byproducts, and excess water vapor from the reaction chamber. This effectively prevents residual gases from undergoing gas-phase side reactions, ensuring the integrity of the self-limiting reaction in a single atomic layer deposition cycle. Consequently, it improves the purity and density of the radiation-resistant layer, guaranteeing that the film's protective performance meets standards. If the single purging time is less than 5 seconds, the purging is insufficient, and unreacted precursors and byproducts will remain in the chamber, easily triggering gas-phase reactions and causing defects such as impurities, voids, and pinholes in the film, reducing its uniformity and density. If the single purging time is longer than 20 seconds, it excessively prolongs the overall preparation cycle, reducing production efficiency. Furthermore, excessively long purging times can over-erase the adsorbed groups on the film surface, affecting the continuity and uniformity of film formation and hindering the formation of a high-quality radiation-resistant layer.

[0025] By controlling the deposition time to 25-30 hours, the thickness of the radiation-resistant layer can be stably controlled within the range of 200-400 nm. Within this thickness range, the radiation-resistant layer provides excellent radiation resistance, insulation performance, and long-term protection, effectively resisting radiation damage to the internal platinum resistance thermometer. It also avoids problems such as excessive internal stress, cracking, warping, and poor adhesion caused by excessively thick films, thus balancing protective performance and structural stability. If the deposition time is less than 25 hours, the resulting film thickness is less than 200 nm, resulting in insufficient radiation resistance and poor barrier properties, failing to effectively protect the internal platinum resistance thermometer functional layer. Its insulation and reliability are insufficient to meet the requirements of harsh environments. If the deposition time exceeds 30 hours, the film thickness is greater than 400 nm, leading to significant accumulation of internal stress, which easily results in defects such as cracking, detachment, and warping. Simultaneously, it increases thermal resistance, reduces the temperature measurement accuracy of the platinum resistance thermometer, prolongs the preparation cycle, increases production costs, and is detrimental to industrial production.

[0026] This invention, through the coordinated control of deposition temperature, purging time, and deposition time, can prepare a radiation-resistant layer with uniform thickness, dense structure, no pinholes, strong adhesion, and excellent radiation resistance. It can effectively suppress the damage of radiation to the conductive layer of platinum resistance thermometers and improve the resistance stability, insulation reliability, and service life of platinum resistance thermometers under extreme radiation environments.

[0027] 5) Prepare the protective layer

[0028] Glass paste is coated onto the radiation-resistant layer and the surface of the platinum wire connection using screen printing. After high-temperature sintering, a protective layer with a thickness of 20-50 μm is formed, ultimately producing a radiation-resistant and highly stable platinum resistance thermometer.

[0029] Preferably, in step 1), the platinum powder is spherical platinum powder with a purity ≥99.99%, a particle size of 0.50μm~1.50μm accounting for ≥90% of the platinum powder, and a specific surface area of ​​1.0~2.0m². 2 / g.

[0030] Preferably, in step 1), the ball milling method is as follows: the mixture of platinum powder and glass powder is ball milled by alternating forward and reverse rotation, with each forward and reverse rotation lasting 1 to 3 hours, the ball milling speed being 200 to 300 r / min, and the ball milling time being 10 to 12 hours.

[0031] In step 1) of this invention, the present invention uses an alternating forward and reverse ball milling method to ball mill the mixed powder of platinum powder and glass powder. This effectively overcomes the stratification and segregation phenomena caused by differences in density and particle size of the mixed powder during unidirectional ball milling. Simultaneously, this alternating ball milling method can forcibly change the flow field distribution within the milling jar, enhancing the impact, shearing, and dispersing effects of the grinding balls on the mixed powder. This not only significantly improves the mixing uniformity and crushing efficiency of the mixed powder but also effectively avoids problems such as localized overheating, powder sticking to the wall, ball sticking, and agglomeration that easily occur during unidirectional ball milling. This ensures that the platinum powder and glass powder are uniformly dispersed at the microscale. A detailed analysis follows:

[0032] By controlling the duration of each forward and reverse rotation to 1–3 hours, it is possible to ensure sufficient interaction between the grinding balls and the mixed powder in each rotation, achieving effective mixing and crushing of the powder. Furthermore, timed reversals continuously suppress powder stratification and segregation, ensuring the stability and uniformity of the entire ball milling process. If the duration is too short and the reversals are too frequent, the flow field within the mill jar will be unstable, making it difficult for the grinding balls to generate effective impact, thus reducing mixing and crushing efficiency. Conversely, if the duration is too long, it resembles a unidirectional, long-duration ball milling process, making the mixed powder prone to re-stratification and segregation, leading to a decrease in mixing uniformity.

[0033] Controlling the ball milling speed to 200–300 r / min ensures sufficient impact and shear force from the grinding balls to achieve both fine crushing of the glass powder and thorough dispersion of the platinum powder. This effectively avoids problems such as excessive plastic deformation, flake formation, and agglomeration of the platinum powder caused by excessive speed and impact force, balancing mixing uniformity, powder refinement, and platinum powder morphology stability. If the ball milling speed is below 200 r / min, the impact force of the grinding balls is insufficient, resulting in inadequate grinding. This not only makes it difficult to achieve the required powder fineness and insufficient mixing strength but also leads to stratification and segregation of platinum and glass powder, significantly reducing milling efficiency. If the ball milling speed is above 300 r / min, the impact force of the grinding balls is too strong, causing excessive crushing, deformation, and agglomeration of the platinum powder, and making it prone to sticking to the grinding balls and jar. Simultaneously, the glass powder will be over-pulverized, resulting in an abnormally large specific surface area. Furthermore, it may exacerbate wear on the grinding balls and grinding jar, introducing more impurities and ultimately affecting the electrical performance and long-term reliability of subsequent platinum resistance thermometer products.

[0034] Controlling the total ball milling time to 10–12 hours ensures thorough mixing, crushing, and refining of platinum powder and glass powder, resulting in uniform powder fineness, absence of large particles, and good dispersibility. This also avoids over-milling caused by excessively long total milling times. If the total milling time is less than 10 hours, the mixing and crushing of the powder are insufficient, leaving many large particles and agglomerates. This leads to poor fineness and uniformity of the subsequently prepared platinum resistance slurry, making it prone to defects such as pinholes, pitting, resistance drift, and poor product consistency during sintering. If the total milling time exceeds 12 hours, over-milling of the powder will exacerbate platinum powder deformation, cold welding, and sticking to the container. It will also cause the glass powder to become too fine, deteriorating sintering performance and leading to problems such as blistering, cracking, decreased insulation performance, and poor adhesion of the sintered film. Furthermore, it reduces production efficiency and affects batch stability.

[0035] Preferably, in step 2), the screen printing method is as follows: the platinum resistance paste is printed onto the substrate surface twice, wherein the first printing speed is 0.2-0.3 m / s and the second printing speed is 0.5-0.6 m / s; after the two printings are completed, the substrate is left to stand for 2-10 hours.

[0036] In step 2) of this invention, a two-stage printing method is adopted. The first printing allows the platinum resistance paste to initially spread and adhere to the substrate surface, forming a uniform base film. The second printing can level, thicken, and densify the film layer, effectively eliminating defects such as pinholes, missing prints, thin spots, and uneven edges that are easily generated by single printing. This results in a film layer with uniform thickness, a smooth surface, and excellent density, significantly improving the resistance accuracy and stability. The specific analysis is as follows:

[0037] The first printing speed is controlled at 0.2 to 0.3 m / s. This slower printing speed allows the platinum resistance paste to have sufficient time to impregnate and spread between the screen and the substrate, ensuring that the platinum resistance paste is fully transferred to the substrate surface. The resulting film has good continuity and strong adhesion, and can effectively avoid problems such as insufficient impregnation, discontinuous film, and fuzzy edges caused by excessive speed.

[0038] If the first printing speed is below 0.2m / s, it is easy to cause paste accumulation, excessive film thickness, edge overflow, and poor flatness. If the first printing speed is above 0.3m / s, the paste transfer will be insufficient, which will easily lead to missing prints, pinholes, thin and uneven film, resulting in large resistance drift.

[0039] The second printing speed is controlled at 0.5-0.6 m / s. On the basis of the uniform base film formed by the first printing, the printing speed is appropriately increased, which is conducive to further compaction and smoothing of the film layer, reducing surface ripples and burrs, improving the density and smoothness of the film layer, and improving production efficiency.

[0040] If the second printing speed is lower than 0.5m / s, it is easy to cause the film layer to be too thick, the surface leveling to be poor, and cracking or uneven shrinkage to occur after drying. If the second printing speed is higher than 0.6m / s, it is easy to cause incomplete printing, loose film layer, and local material shortage, resulting in a decrease in the stability and consistency of resistance.

[0041] After two printing cycles, allowing the film to stand for 2–10 hours allows the solvent in the printed film to evaporate slowly and fully level out, gradually releasing internal stress. This avoids problems such as rapid shrinkage, blistering, cracking, and pinholes caused by direct drying, significantly improving the film's smoothness, density, and adhesion. If the standing time is less than 2 hours, insufficient solvent evaporation and leveling can easily lead to blistering, cracking, and edge lifting during subsequent drying. If the standing time exceeds 10 hours, the film surface is prone to skinning and unevenness due to excessive solvent evaporation.

[0042] By coordinating the control of the printing speed and resting time in the two printing cycles, this invention can obtain a platinum resistance film layer with uniform thickness, smooth surface, dense structure without pinholes, and strong adhesion, effectively improving the resistance accuracy, consistency, insulation performance, and long-term reliability of thick film platinum resistance.

[0043] Preferably, in step 2), the high-temperature sintering of the platinum resistance conductive layer is carried out under the protection of argon gas with a purity of ≥99.99%.

[0044] In step 2) of this invention, argon gas with a purity of ≥99.99% is used as a protective gas. This effectively isolates impurities such as oxygen and water vapor in the air from contacting the conductive layer of the platinum resistance thermometer at high temperatures, preventing the platinum element from undergoing an oxidation reaction to generate platinum oxide impurities. This prevents problems such as oxidation failure and abnormal resistance drift of the conductive layer. At the same time, it can reduce the damage of impurity gases to the microstructure of the conductive layer, ensuring that the conductive layer forms a uniform, dense, and strongly adherent microstructure, thereby significantly improving the resistance accuracy, stability, and long-term reliability of the platinum resistance thermometer.

[0045] Preferably, in step 5), the mass percentage of each component of the glass slurry is: 15%–25% organic carrier, 10%–20% alcohol, and the remainder is glass powder.

[0046] Preferably, the glass powder has a particle size of 1-10 μm and a softening point of 900℃-1100℃. The mass percentage of each component of the glass powder is as follows: aluminum oxide (Al2O3) 5%-10%, barium carbonate (BaCO3) 10%-20%, strontium carbonate (SrCO3) 5%-10%, boric acid (H3BO3) 20%-35%, magnesium oxide (MgO) 1%-5%, calcium oxide (CaO) 1%-8%, lanthanum oxide (La2O3) 1%-5%, zirconium oxide (ZrO2) 0-3%, and the balance is silicon oxide (SiO2).

[0047] Preferably, the mass percentage of each component of the organic carrier is as follows: n-butanol 10%–15%, terpineol 25%–35%, butyl acetate 10%–15%, dibutyl phthalate 10%–15%, ethylene glycol ethyl ether acetate 5%–10%, 1,4-butyrolactone 3%–5%, and the balance is ethyl cellulose.

[0048] In this invention, the organic carrier used is a customized formulation that differs from conventional systems. Conventional organic carriers typically contain only ethyl cellulose, terpineol, dibutyl phthalate (DBP), and a small amount of alcohol / ester auxiliary solvents. This invention, however, adds four key solvents—n-butanol, butyl acetate, ethylene glycol ethyl ether acetate, and 1,4-butyrolactone—to the conventional organic carrier components, forming an optimized system with a reasonable boiling point gradient, progressively enhanced solubility, suitable rheological properties, and no residue after sintering. The specific synergistic effects of each component are as follows:

[0049] n-Butanol: It can reduce the overall viscosity of the paste, improve the smoothness of screen printing, and prevent the phenomenon of surface skinning before sufficient leveling after printing; at the same time, it can also improve the wettability of ethyl cellulose, reduce problems such as jagged edges and rough edges in printed lines, and effectively ensure the line accuracy and dimensional consistency of the platinum resistance conductive layer.

[0050] Butyl acetate: It can strongly dissolve ethyl cellulose, avoid resin agglomeration and particle texture, reduce sagging and line collapse, ensure the line accuracy and edge neatness of platinum resistance thermometers, reduce the surface tension of the paste, and make the platinum paste more wettable on the substrate and prevent pinholes.

[0051] Ethylene glycol ethyl ether acetate: It has a slow evaporation rate, which can effectively control the overall evaporation gradient of the paste, ensuring that it does not dry and form a skin for a long time after printing. It also ensures stable viscosity during printing, while improving the density and smoothness of the film during drying and sintering, preventing the film from bubbling and cracking, and preventing the platinum layer from being damaged by solvent boiling.

[0052] ④1,4-Butyrolactone: It can further enhance the solubility of ethyl cellulose, improve the adhesion between the paste and the ceramic substrate, and regulate the fluidity of the paste during printing; during the high-temperature sintering process under argon protection, it can be completely decomposed without residue and without producing carbon impurities, effectively reducing resistance drift, improving the purity and stability of the conductive layer, and ensuring the high precision and high stability of the platinum resistance thermometer.

[0053] ⑤ Ethyl cellulose: It can provide suitable viscosity, thixotropy and film strength for platinum resistance paste, ensuring that the paste does not drip or collapse during screen printing. The printed film has good shape retention and structural stability, providing skeletal support for the precise forming of the platinum resistance conductive layer.

[0054] Terpineol: As a medium-to-high boiling point main solvent, it has mild dissolving properties and stable evaporation rate, which can fully wet platinum powder particles and substrates. At the same time, it has good compatibility with ethyl cellulose, ensuring the overall dispersion uniformity and storage stability of the slurry.

[0055] Dibutyl phthalate: It can improve the film toughness of organic carriers, reduce the brittleness of dried film layers, prevent the film layers from cracking and falling off under laser trimming, wire bonding and subsequent high and low temperature, vibration and irradiation conditions, and improve the structural robustness of platinum resistance conductive layers.

[0056] In summary, the organic carrier described in this invention enables platinum resistance thermometer paste to possess excellent screen printing compatibility, film formation properties, dispersion stability, and sintering cleanliness. It significantly improves the uniformity, density, adhesion, and dimensional accuracy of the platinum conductive layer, resulting in a final platinum resistance thermometer conductive layer with uniform thickness, high density, strong adhesion, and low defect rate. This ensures high precision, low drift, radiation resistance, and high stability of the platinum resistance thermometer, meeting the high-precision temperature measurement requirements of extreme conditions in nuclear industry, aerospace, and other fields.

[0057] Preferably, the glass powder is prepared as follows:

[0058] 1) Weigh each component of the glass powder according to its mass percentage, and mix all the glass powder components thoroughly to obtain the glass powder mixture raw material;

[0059] 2) The ball mill is used to perform the first stage ball milling on the glass powder mixture obtained in step 1) by alternating forward and reverse rotation. The time interval between each alternation is 1 to 2 hours, the ball milling speed is 200 r / min, and the ball milling time is 5 to 6 hours, so as to obtain the glass powder mixture after the first stage ball milling.

[0060] In the first stage of ball milling in this invention, the ball mill is used in an alternating forward and reverse rotation mode, with each rotation lasting 1-2 hours, the milling speed at 200 r / min, and the milling time lasting 5-6 hours. This ball milling condition is mild and primarily aims to initially mix, break up raw material agglomerates, and crush coarse particles. It ensures that the various raw material components of the glass powder are fully and uniformly mixed, while avoiding excessive powder breakage due to excessively high milling speed. At the same time, the alternating forward and reverse rotation effectively suppresses stratification and segregation caused by differences in density and particle size, preventing problems such as powder sticking to the walls and sticking to balls. Ultimately, a uniformly dispersed glass powder mixture without obvious large particles is obtained, laying a good foundation for the subsequent second stage of fine grinding and high-temperature sintering.

[0061] If the ball milling speed is below 200 r / min, the mixing and crushing capacity of the ball mill will be insufficient, leading to uneven mixing of the glass powder raw materials and incomplete removal of coarse particles, thus failing to achieve the expected results of the initial ball milling. If the ball milling speed is above 200 r / min, the glass powder raw materials are prone to excessive refinement, and even local overheating and agglomeration may occur, thereby affecting the uniformity of subsequent high-temperature sintering. If the duration of a single forward and reverse rotation is less than 1 hour, the frequent reversal will lead to an unstable ball milling flow field and reduced ball milling efficiency. If the duration of a single forward and reverse rotation is greater than 2 hours, it is close to unidirectional long-term ball milling, and the powder is prone to re-stratification and segregation, resulting in a decrease in mixing uniformity. If the total ball milling time is less than 5 hours, the mixing and crushing of the glass powder raw materials will be insufficient, leaving behind coarse particles and agglomerates. If the total ball milling time exceeds 6 hours, the glass powder is prone to over-milling, resulting in abnormal particle size distribution, which is not conducive to the smooth progress of the subsequent second-stage fine grinding and high-temperature sintering processes.

[0062] 3) The ball mill is used to perform a second stage of ball milling on the glass powder mixture obtained in step 2) by alternating forward and reverse rotation. The time interval between each alternation is 1 to 2 hours, the ball milling speed is 300 r / min, and the ball milling time is 3 to 5 hours, so as to obtain the glass powder mixture after the second stage of ball milling.

[0063] In the second stage of ball milling of this invention, based on the initial uniform mixing of raw materials achieved by the first stage of ball milling, the ball mill continues to use an alternating forward and reverse rotation ball milling method, controlling the duration of each alternation of forward and reverse rotation to be 1-2 hours, increasing the ball milling speed to 300 r / min, and continuously ball milling for 3-5 hours. Under the premise of ensuring the uniformity of raw materials, by appropriately increasing the ball milling speed, the glass powder raw materials can be further refined and the particles can be fined, effectively eliminating the coarse particles remaining after the first stage of ball milling, making the glass powder particle size more uniform and the dispersion better. At the same time, it can avoid the problem of excessive powder crushing caused by ball milling at high speed for a long time, and ensure the subsequent sintering performance of the glass powder raw materials.

[0064] If the ball mill speed is below 300 r / min, the fineness of the ball milling is insufficient, and the particle size of the glass powder cannot meet the requirements of subsequent processes. If the speed is above 300 r / min, the glass powder is prone to excessive breakage, resulting in an abnormally large specific surface area, which can easily lead to defects such as porosity and uneven melting during subsequent high-temperature sintering. If the ball milling time is less than 3 hours, the glass powder particles are not finely refined, the particle size is too large, and the uniformity of mixing of various components is insufficient. If the ball milling time exceeds 5 hours, the powder is prone to over-milling, ball sticking, and can sticking, leading to fluctuations in the performance of the glass powder and affecting the quality of subsequent high-temperature sintering.

[0065] 4) The glass powder mixture obtained in step 3) is sintered at a temperature of 1500±50℃ for 2-3 hours to obtain glass material;

[0066] In this invention, the temperature range of 1500±50℃ allows for complete melting of the glass batch and uniform diffusion of components. Simultaneously, it ensures the complete removal of air bubbles from the melt, achieving clarification and homogenization. This guarantees uniform glass composition, absence of unmelted residue, and no obvious stones or streaks, ultimately resulting in a dense and stable glass material. Furthermore, controlling the holding time to 2–3 hours ensures complete melting of the glass raw materials and complete reaction of components while avoiding excessive energy consumption and high-temperature volatilization of glass components caused by excessively long holding times.

[0067] If the sintering temperature is below 1450℃, the glass raw material will not melt sufficiently, leaving unmelted particles. Furthermore, the melt will have high viscosity and poor clarity, leading to uneven composition and large performance fluctuations in the final glass powder. If the sintering temperature is above 1550℃, high-temperature volatilization of glass components and overheating of the melt will occur, introducing bubbles and impurities. Simultaneously, the high temperature will exacerbate the erosion of the sintering crucible, thus affecting the purity and performance stability of the glass powder. If the holding time is less than 2 hours, the melting and homogenization of the glass raw material will be incomplete, resulting in defects such as component segregation and residual bubbles within the glass. If the holding time exceeds 3 hours, it will exacerbate the volatilization of glass components, increase production energy consumption, reduce production efficiency, and may even cause irreversible changes in the glass's properties.

[0068] 5) The glass material obtained in step 4) is subjected to water quenching to obtain glass slag;

[0069] 6) Grind the glass slag obtained in step 5) to obtain glass powder with a particle size of 1 to 10 μm.

[0070] This invention, through the synergistic control of two-stage alternating forward and reverse ball milling and precise high-temperature sintering, can prepare high-quality glass powder with uniform mixing, suitable particle size, stable composition, and no impurities or bubbles. This significantly improves the product consistency and reliability of the glass powder, thereby enabling the subsequent high-performance platinum resistance thermometers to have better insulation performance, film adhesion, sintering quality, and long-term stability.

[0071] The beneficial effects of this invention are as follows:

[0072] 1. Dual optimization of platinum resistance conductive layer process and formula lays the foundation for high-precision temperature measurement.

[0073] This invention employs a customized platinum resistance slurry, combined with a high-temperature sintering process using screen printing and argon protection to prepare the platinum resistance conductive layer. By optimizing the platinum resistance slurry formulation, using high-purity platinum powder with specific particle size and morphology, combined with customized glass powder and organic carrier, and precisely controlling the sintering parameters, the conductive layer forms a dense network structure with uniform grains, and the thickness is precisely controlled between 10 and 30 μm. This not only effectively removes organic binders and volatile impurities from the slurry, achieving a high-level purity standard for the platinum resistance conductive layer, but also reduces the migration and diffusion of impurity elements under strong irradiation, fundamentally reducing the risk of resistance drift. Simultaneously, it further enhances the structural density and conductivity of the platinum resistance conductive layer, significantly reducing contact resistance and ensuring the consistency of the temperature coefficient of resistance (TCR), achieving a resistance accuracy of ±0.01Ω at 0℃, providing a core guarantee for high-precision temperature measurement of platinum resistance thermometers.

[0074] 2. An atomic layer deposition technique is used to prepare a radiation-resistant layer, achieving a dual improvement in radiation resistance and structural stability.

[0075] This invention leverages the atomically controllable advantages of atomic layer deposition (ALD) technology, using high-purity trimethylaluminum as a precursor to achieve uniform coating of radiation-resistant atomic particles on the surface and interface of the conductive layer. This results in a dense film with a thickness of 200–400 nm, a thickness deviation of ≤2 nm, and no pinhole defects. Simultaneously, this radiation-resistant layer effectively mitigates the difference in thermal expansion coefficients between the conductive and protective layers, suppressing film delamination and cracking caused by interfacial stress concentration under high-temperature conditions, and strengthening interlayer adhesion. Furthermore, it effectively blocks direct bombardment of the conductive layer by irradiated particles, preventing damage to the microstructure of the conductive layer. This ensures that the resistance drift rate of the platinum resistance thermometer is ≤0.5% under γ-ray irradiation doses of not less than 100 kGy, significantly reducing the failure rate of resistance drift or even failure under high-irradiation environments and significantly improving the radiation resistance and structural stability of the platinum resistance thermometer.

[0076] 3. The composite protective layer expands its adaptability to various operating conditions, ensuring long-term reliability.

[0077] The composite protective layer of this invention is made from customized glass paste through screen printing and high-temperature sintering. Its dense and insulating structure possesses excellent high-temperature resistance and corrosion resistance, effectively improving the temperature resistance of platinum resistance thermometers, resisting oxidation and thermal aging under high-temperature environments, and delaying performance degradation. It also comprehensively isolates the internal conductive layer, radiation-resistant layer, and lead welding areas from external media such as moisture and corrosive gases, preventing performance degradation caused by contact with external media. Simultaneously, the protective layer completely covers the welding areas of the leads and conductive layer, effectively strengthening the sealing and robustness of the welded structure. Through precise welding technology using high-purity platinum wire leads, the temperature coefficient stability of the platinum resistance thermometer within the temperature range of -200℃ to 800℃ is ≤±0.002% / ℃, and the long-term stability error is ≤±0.3℃. This effectively ensures the accuracy and long-term reliability of temperature monitoring under extreme conditions such as high temperature, high voltage, and strong corrosion, significantly expanding the operating range of the platinum resistance thermometer.

[0078] 4. Collaborative design of the entire process enables a comprehensive improvement in overall performance and resistance to harsh environments.

[0079] This invention features a fully automated process, from raw material formulation and layer preparation to overall packaging, with precise control and synergistic optimization across all stages. The tightly bonded and complementary layers form a multi-layered, stable composite structure consisting of a substrate, conductive layer, radiation-resistant layer, and protective layer. Combined with a precision welding process using high-purity platinum wire leads, this results in superior overall performance for the platinum resistance thermometer. It overcomes the limitations of traditional platinum resistance thermometers, such as easily diminished temperature measurement accuracy and insufficient radiation resistance, while significantly enhancing the structure's resistance to vibration and thermal stress. This allows for long-term stable operation under extreme conditions of vibration (10Hz–2000Hz), high temperature and pressure, and strong radiation, meeting the design life requirement of at least 10 years in the nuclear power industry. The platinum resistance thermometer described in this invention is not only suitable for the demanding temperature measurement scenarios of nuclear power plant reactors but also adaptable to the high-precision temperature monitoring needs of complex fields such as aerospace and extreme industrial control. It provides reliable data support for temperature monitoring and process control in various complex scenarios, exhibiting both excellent practicality and versatility. Attached Figure Description

[0080] Figure 1 This is a cross-sectional view of the radiation-resistant and highly stable platinum resistance thermometer of the present invention.

[0081] Among them, 1 is the substrate, 2 is the platinum resistance conductive layer, 3 is the radiation resistant layer, 4 is the protective layer, and 5 is the platinum wire lead.

[0082] Figure 2 This is a flowchart of the preparation method of the radiation-resistant and highly stable platinum resistance thermometer of the present invention. Detailed Implementation

[0083] like Figure 1As shown in Figure 2, a method for preparing a radiation-resistant, highly stable platinum resistance thermometer includes the following steps:

[0084] 1) Preparation of glass powder

[0085] 1-1) Mixing of glass powder raw materials

[0086] Weigh each component of the glass powder according to the following mass percentages:

[0087] The glass powder consists of 5%–10% aluminum oxide (Al2O3), 10%–20% barium carbonate (BaCO3), 5%–10% strontium carbonate (SrCO3), 20%–35% boric acid (H3BO3), 1%–5% magnesium oxide (MgO), 1%–8% calcium oxide (CaO), 1%–5% lanthanum oxide (La2O3), 0–3% zirconium oxide (ZrO2), with the balance being silicon oxide (SiO2). After weighing, all glass powder components are thoroughly mixed to ensure uniform dispersion of each component, without agglomeration or segregation, thus obtaining a mixed glass powder raw material.

[0088] 1-2) First stage ball milling

[0089] The ball mill uses alternating forward and reverse rotation to initially ball mill the glass powder mixture obtained in step 1-1) to break up agglomerates and achieve preliminary dispersion of the components. The specific parameters for the first stage of ball milling are: the duration of each forward and reverse rotation ball milling cycle is 1-2 hours, the ball milling speed is controlled at 200 r / min, and the ball milling time lasts for 5-6 hours. After ball milling, a uniformly dispersed glass powder mixture without obvious large particles is obtained.

[0090] 1-3) Second stage ball milling

[0091] Building upon the first stage of ball milling, the ball mill continues to use alternating forward and reverse rotation to further refine the glass powder mixture obtained in steps 1-2), thereby reducing particle size, improving the uniformity of mixing, and preventing component segregation during subsequent high-temperature sintering. The specific parameters for the second stage of ball milling are as follows: the time interval between each ball milling cycle is 1–2 hours, the ball milling speed is increased to 300 r / min, and the milling time lasts 3–5 hours. After ball milling, a glass powder mixture with fine, uniformly dispersed particles and no agglomeration is obtained.

[0092] 1-4) High-temperature sintering

[0093] The glass powder mixture obtained in steps 1-3) is placed in a high-temperature sintering furnace and sintered at 1500±50℃ for 2-3 hours to allow the oxide components to fully melt, diffuse and undergo chemical reactions, completely eliminating pores and impurities in the raw materials, forming a glass melt with uniform composition and compact structure. After cooling, a dense glass material is obtained.

[0094] 1-5) Water-quenched slag

[0095] The high-temperature glass material obtained in steps 1-4) is quickly immersed in room-temperature water for water quenching. The internal stress generated by the sudden temperature change makes the glass material brittle and shatter, resulting in irregular glass slag. This effectively reduces the difficulty of the subsequent fine grinding and powder making process, while avoiding the formation of coarse crystals due to slow cooling of the glass material, thus ensuring the fineness and uniformity of the glass powder.

[0096] 1-6) Fine grinding

[0097] The glass slag obtained in steps 1-5) is placed in a fine grinding equipment for grinding. The particle size is monitored in real time during the grinding process until a glass powder with a particle size of 1-10 μm, uniform particle size, no impurities, and good dispersibility is obtained. The powder is then sealed and stored for later use.

[0098] The glass powder prepared by this invention can be directly used in the preparation of subsequent platinum resistance paste and glass paste.

[0099] 2) Preparation of organic carriers

[0100] 2-1) Weigh the organic carrier raw materials

[0101] Weigh each component of the organic carrier according to the following mass percentages:

[0102] The following ingredients were weighed: 10%–15% n-butanol, 25%–35% terpineol, 10%–15% butyl acetate, 10%–15% dibutyl phthalate, 5%–10% ethylene glycol ethyl ether acetate, 3%–5% 1,4-butyrolactone, and the balance being ethyl cellulose. After weighing, a pure organic carrier raw material was obtained.

[0103] 2-2) Water bath heating and mixing

[0104] Place the organic carrier raw material obtained in step 2-1) into a container equipped with a stirring device, place it in a constant temperature water bath at 40-50℃, and heat and stir at a uniform speed for 5-10 minutes to allow the components to initially dissolve and fully mix, thereby obtaining a uniform organic carrier mixed raw material.

[0105] 2-3) Constant temperature insulation

[0106] The organic carrier mixture obtained in step 2-2) is transferred to a constant temperature incubator and kept at a constant temperature of 100±20℃ for 3-5 hours to ensure that all components are fully dissolved and deeply integrated, eliminate micro bubbles in the system, and obtain a homogeneous, stable, sediment-free, and highly fluid organic carrier product. It is then sealed and stored for later use.

[0107] The organic carrier product prepared by this invention has good dispersibility and compatibility, and can effectively disperse solid components such as glass powder and platinum powder, providing a high-quality dispersion carrier for the subsequent preparation of platinum resistance paste and glass paste, while ensuring that the paste has suitable viscosity and printing performance.

[0108] 3) Preparation of glass slurry

[0109] The proportioning and uniformity of the glass paste in this invention directly affect the density, insulation, and radiation resistance of the platinum resistance protective layer. The components of the glass paste are weighed according to the following mass percentages:

[0110] Step 2) Prepare 15%–25% organic carrier, 10%–20% alcohol, and the remainder is the glass powder prepared in Step 1); after weighing, put all glass slurry components into a mixing device and stir and mix thoroughly until the glass slurry system is uniform and fine, without particles or lumps and with moderate fluidity (to ensure smooth subsequent screen printing, uniform coating, no pinholes, and no broken lines), and obtain qualified glass slurry, seal it for later use in the subsequent formation of the protective layer of this invention.

[0111] 4) Preparation of platinum resistance paste

[0112] The platinum resistance paste in this invention is the core raw material for preparing the conductive layer. Its uniformity and dispersion directly determine the conductivity, structural density and radiation resistance of the conductive layer.

[0113] Weigh each component of the platinum resistance slurry according to the following mass percentages:

[0114] The glass powder prepared in step 1) comprises 5%–10%, the organic carrier prepared in step 2) comprises 10%–15%, and the remainder is platinum powder; wherein the platinum powder is spherical, with a purity ≥99.99%, a particle size of 0.50μm–1.50μm accounting for ≥90%, and a specific surface area of ​​1.0–2.0m². 2 / g, this specification of platinum powder can ensure the conductivity efficiency and structural stability of the conductive layer, reduce resistance drift under irradiation environment, and ensure the conductivity and stability of the conductive layer.

[0115] First, platinum powder and glass powder are placed in a ball mill and ball milled using alternating forward and reverse rotation. This ensures that the platinum powder and glass powder are fully dispersed and uniformly mixed, preventing platinum powder agglomeration from affecting conductivity. Simultaneously, the glass powder is evenly coated on the surface of the platinum powder, improving the adhesion between the subsequent conductive layer and the substrate. Specific parameters are: a single ball milling cycle of forward and reverse rotation is 1–3 hours; the ball milling speed is controlled at 200–300 r / min; and the total ball milling time is 10–12 hours.

[0116] After ball milling and mixing, the organic carrier prepared in step 2) is added to the mixture. Under constant temperature water bath heating conditions of 40-50℃, the mixture is continuously ground for 15-30 minutes until the mixture is uniform and fine, without particle agglomeration, without bubbles, and the fluidity meets the requirements of screen printing. A qualified platinum resistance paste is obtained, which is sealed and stored for later use in the preparation of the platinum resistance conductive layer.

[0117] 5) Preparation of platinum resistance conductive layer

[0118] The conductive layer of a platinum resistance thermometer is the core structure that enables it to measure temperature. Its thickness uniformity, structural density, and resistance accuracy directly determine the temperature measurement accuracy and radiation resistance stability of the platinum resistance thermometer.

[0119] First, using a 300-mesh screen, the platinum resistance paste prepared in step 4) is printed onto the surface of an alumina or silicon nitride substrate in two steps. The purpose of printing in two steps is to avoid defects such as coating cracking and pinholes caused by excessive thickness in a single printing, while improving the uniformity and density of the conductive layer thickness.

[0120] The specific operating parameters are as follows: the first printing speed is 0.2–0.3 m / s to ensure uniform spread of the paste; the second printing speed is 0.5–0.6 m / s to compensate for minor defects in the first printing and increase the coating thickness; during each printing, the squeegee and screen are at a 40–60° angle to ensure uniform coating of the paste on the substrate surface and avoid missed or incomplete printing. After the two printings are completed, the substrate is placed in a clean environment and left to stand for 2–10 hours to allow the solvent in the paste to initially evaporate, preventing bubbles from forming during subsequent sintering due to rapid solvent evaporation, which could lead to pores in the conductive layer.

[0121] After settling, the substrate is placed in a sintering furnace and sintered at high temperature under argon gas with a purity of ≥99.99% to prevent oxidation of the conductive layer and ensure its conductivity and structural stability. Specific sintering parameters are as follows: the heating rate is controlled at 5–10℃ / min to avoid excessive heating that could cause cracking of the substrate or conductive layer; the sintering temperature is controlled at 1000℃–1150℃, and held for 30–60 minutes to allow the organic carrier to fully decompose and volatilize, and the platinum particles and glass powder to fully sinter, forming a platinum resistance conductive layer with a thickness of 10–30 μm, a dense structure, and excellent conductivity.

[0122] After forming the platinum resistance conductive layer, the platinum resistance conductive layer needs to be laser-trimmed according to the preset circuit structure, and the trimming process is monitored in real time to accurately control the resistance value of the platinum resistance conductive layer, so that the resistance accuracy of the platinum resistance conductive layer at 0℃ is ≤±0.01Ω, ensuring the temperature measurement accuracy and consistency of the platinum resistance and meeting the usage requirements in radiation-resistant environments.

[0123] 6) Lead wire soldering

[0124] The leads are used to electrically connect the platinum resistance thermometer to the external circuit. The quality of the soldering directly affects the conductivity stability and service life of the platinum resistance thermometer. It is necessary to ensure that the solder joints are firm and the contact resistance is low, and to avoid detachment or poor contact under irradiation, high temperature, and vibration environments. The specific operation is as follows:

[0125] This invention employs two platinum wire leads, both of which are soldered to a conductive layer (located on the same side), forming an electrode area at the soldering location. During soldering, the platinum resistance paste prepared in step 4) is used as the soldering medium, and platinum wire leads with a purity ≥99.99% (resistance temperature coefficient of (3851±6)×10⁻⁶) are soldered. -6 / ℃ -1 After aligning one end of the platinum wire with the electrode area of ​​the conductive layer, they are tightly connected. It is important to note that the purity and temperature coefficient of resistance of the platinum wire must be strictly controlled to ensure it matches the conductivity of the conductive layer, thereby reducing temperature measurement errors.

[0126] After the connection is completed, it is first dried to remove the solvent in the slurry, and then placed in a sintering furnace and sintered at 1000℃ for 20-30 minutes. This allows the platinum wire lead to be metallurgically bonded to the conductive layer through the platinum resistance slurry, ultimately forming a strong and stable electrical welded connection. After the weld is completed, the other end of the lead is extended outward to facilitate subsequent connection with external circuits.

[0127] 7) Preparation of radiation-resistant layer

[0128] The radiation-resistant layer in this invention is used to connect the conductive layer and the protective layer. Its density directly affects the interlayer bonding force and the radiation resistance of the platinum resistance thermometer. It can effectively block element diffusion between the conductive layer and the protective layer, reduce interfacial stress, and avoid interlayer delamination under radiation environment. Therefore, it is precisely prepared using atomic layer deposition technology. The specific operation is as follows:

[0129] The substrate with the platinum resistance conductive layer is placed in an atomic layer deposition device. First, a trimethylaluminum (TMA) precursor with a purity of ≥99.99% is introduced to allow the precursor to be uniformly adsorbed on the surface of the platinum resistance conductive layer. Then, water vapor (pure water) is introduced as a reactant to react chemically with the precursor, forming a thin layer deposition on the surface of the platinum resistance conductive layer.

[0130] During the deposition process, an inert gas (nitrogen) is continuously introduced for purging. Nitrogen serves two purposes: firstly, as a purging gas, with each purging cycle controlled at 5-20 seconds, it efficiently removes unreacted precursors and byproducts from the chemical reaction within the chamber, preventing pinholes and defects in the radiation-resistant layer caused by residual impurities and ensuring the film's density and uniformity; secondly, as an inert protective atmosphere, it isolates the chamber from oxygen and moisture, preventing oxidation of the high-purity platinum resistance conductive layer at the deposition temperature. It also prevents incompletely formed active layers from reacting with impurities during deposition, ensuring the integrity of the layer structure. Simultaneously, the deposition temperature is controlled at 200℃-250℃, and the deposition time lasts 25-30 hours, ultimately forming a dense and uniform radiation-resistant layer with a thickness of 200-400 nm on the outer surface of the platinum resistance conductive layer, completely encapsulating it.

[0131] It is worth noting that, in this invention, the lead wire bonding operation described in step 6) can also be adjusted to be performed after the radiation-resistant layer is prepared in step 7), specifically including:

[0132] During the deposition of the radiation-resistant layer, the electrode area of ​​the platinum resistance conductive layer is reserved to avoid being covered by the radiation-resistant layer. After the radiation-resistant layer is formed, the reserved electrode area is wire-welded, and finally the overall structure is encapsulated by a protective layer.

[0133] 8) Preparation of protective layer

[0134] The protective layer is the outer protective structure of the platinum resistance thermometer. It must completely cover the radiation-resistant layer and the welding points between the leads and the conductive layer, serving to seal, insulate, and resist radiation. It blocks external moisture, oxygen, and radiation particles from damaging the internal structure, improving the overall stability and service life of the platinum resistance thermometer. The specific operation is as follows:

[0135] Using a 200-mesh screen, the glass paste prepared in step 3) is uniformly coated onto the radiation-resistant layer and the surface of the platinum wire lead solder joints, ensuring complete coverage without any omissions or exposed areas. After coating, it is placed in a sintering furnace and sintered at 850–950℃ for 30–50 minutes to allow the glass paste to fully melt, solidify, and form a dense insulating protective layer with a thickness of 20–50 μm. The sintering temperature and time must be strictly controlled to avoid damage to the radiation-resistant and conductive layers due to excessively high temperatures, and insufficient density of the protective layer due to excessively low temperatures. After sintering, it is cooled to room temperature to finally obtain a radiation-resistant, highly stable platinum resistance thermometer.

[0136] The following are examples of the preparation method of the radiation-resistant and highly stable platinum resistance thermometer described above:

[0137] Example 1

[0138] A method for preparing a radiation-resistant and highly stable platinum resistance thermometer, the specific preparation steps of which are as follows:

[0139] 1) Preparation of glass powder

[0140] Weigh out 35g SiO2, 8g Al2O3, 13g BaCO3, 7g SrCO3, 27g H3BO3, 4g MgO, 6g CaO, and 4g La2O3. After thoroughly mixing the above raw materials, a glass powder mixture is obtained.

[0141] The glass powder mixture was subjected to the first stage of ball milling at a speed of 200 r / min for 6 hours, with alternating forward and reverse rotation for 1.5 hours each time.

[0142] After completing the first stage of ball milling, the second stage of ball milling is carried out. The ball milling speed is 300 r / min and the ball milling time is 3 hours. The forward and reverse rotations are alternated and each alternation lasts for 1 hour.

[0143] After a second ball milling process, the mixed raw materials are placed in a muffle furnace and sintered at 1500℃ for 2 hours to obtain glass material.

[0144] After water quenching the glass material, glass slag is obtained. The glass slag is then ground to a particle size of 1-5 μm to obtain the finished glass powder.

[0145] 2) Preparation of organic carriers

[0146] Weigh out 20g of ethyl cellulose, 9g of n-butanol, 18g of terpineol, 9g of butyl acetate, 8g of dibutyl phthalate, 4g of ethylene glycol ethyl ether acetate, and 3g of 1,4-butyrolactone, and add them all to a beaker.

[0147] Heat the beaker in a 50℃ water bath and stir for 6 minutes to obtain the organic carrier mixture; then put the mixture into a 100℃ constant temperature incubator for 3 hours and take it out to obtain a homogeneous and stable organic carrier product.

[0148] 3) Preparation of platinum resistance paste

[0149] Weigh out 10g of material with a purity ≥99.99%, a particle size distribution of 0.80-1.50μm, and a specific surface area of ​​1.2m². 2 / g of spherical platinum powder, and 1g of glass powder prepared in step 1);

[0150] Platinum powder and glass powder were placed in an agate jar and put into a ball mill for ball milling. The ball milling speed was 300 r / min and the ball milling time was 10 h. The ball milling was alternated between forward and reverse rotation and each alternation lasted for 1 h.

[0151] After ball milling, the mixed powder is taken out and 1.8g of the organic carrier prepared in step 2) is added. The mixture is then ground for 30 minutes under a water bath heating condition at 40℃. After mixing evenly, the platinum resistance slurry is obtained.

[0152] 4) Preparation of the platinum resistance conductive layer

[0153] Using a 300-mesh screen, the platinum resistance paste prepared in step 3) was printed onto the surface of a high-temperature resistant insulating substrate. The squeegee and the screen were at a 45° angle. The first printing speed was 0.3 m / s, and the second printing speed was 0.5 m / s. After the two printings were completed, the substrate was left to stand for 4 hours to remove air bubbles from the paste.

[0154] Before sintering, high-purity argon gas with a purity of ≥99.99% is introduced into the furnace tube for 30 minutes to remove air. During the sintering process, argon gas is continuously introduced for protection. The temperature is raised to 1100℃ at a heating rate of 7℃ / min and held for 60 minutes before being cooled with the furnace to form a platinum resistance conductive layer with a thickness of 10-20μm on the surface of the substrate.

[0155] The conductive layer is laser-trimmed according to the pre-designed circuit structure. The trimming process is monitored in real time to ensure that the resistance accuracy of the conductive layer at 0℃ is ≤±0.01Ω.

[0156] 5) Lead wire soldering

[0157] After adjusting the resistance, select a material with a purity ≥ 99.99% and a temperature coefficient of resistance of (3851±6)×10. -6 / ℃ -1 Using platinum wire as the lead wire, one end of the platinum wire lead wire is connected to the electrode area of ​​the conductive layer using the platinum resistance paste prepared in step 3). After drying, it is sintered at 1000℃ and held for 25 minutes to form an electrical welding connection. The other end of the lead wire extends outward.

[0158] 6) Preparation of radiation-resistant layer

[0159] A radiation-resistant layer was prepared on the outer surface of the conductive layer using atomic layer deposition (ALD). First, a trimethylaluminum (TMA) precursor with a purity ≥99.99% was introduced, followed by water vapor (pure water). Simultaneously, nitrogen gas was introduced into the chamber for purging, with a single purging time of 15 seconds. The deposition temperature was controlled at 250°C, and the deposition time was 30 hours. A dense radiation-resistant layer with a thickness of 280 nm was formed on the outer surface of the conductive layer, and the radiation-resistant layer completely covered the outer surface of the conductive layer.

[0160] 7) Preparation of the protective layer

[0161] Weigh out 10g of the glass powder prepared in step 1), 2.5g of the organic carrier prepared in step 2), and 2g of alcohol, mix them evenly to obtain the glass slurry;

[0162] Glass paste is printed onto the outer surface of the radiation-resistant layer using a 200-mesh screen, and the glass paste completely covers the welding area between the leads and the conductive layer. After printing, it is sintered at 900℃ for 40 minutes and cooled in the furnace to form a dense and insulating composite protective film, thus obtaining a platinum resistance thermometer with high radiation resistance and stability.

[0163] Example 2

[0164] A method for preparing a radiation-resistant and highly stable platinum resistance thermometer, the specific preparation steps of which are as follows:

[0165] 1) Preparation of glass powder

[0166] Weigh out 32g SiO2, 8g Al2O3, 20g BaCO3, 8g SrCO3, 25g H3BO3, 3g MgO, 5g CaO, 2g La2O3, and 1g ZrO2. After thoroughly mixing the above raw materials, a glass powder mixture is obtained.

[0167] The glass powder mixture was subjected to the first stage of ball milling at a speed of 200 r / min for 5 h, with alternating forward and reverse rotation for 1 h each time.

[0168] After completing the first stage of ball milling, the second stage of ball milling is carried out. The ball milling speed is 300 r / min and the ball milling time is 4 hours. The forward and reverse rotations are alternated and each alternation lasts for 1 hour.

[0169] After a second ball milling process, the mixed raw materials were placed in a muffle furnace and sintered at 1480℃ for 3 hours to obtain glass material.

[0170] After water quenching the glass material, glass slag is obtained. The glass slag is then ground to a particle size of 1-10 μm to obtain the finished glass powder.

[0171] 2) Preparation of organic carriers

[0172] Weigh out 30g ethyl cellulose, 10g n-butanol, 30g terpineol, 12g butyl acetate, 8g dibutyl phthalate, 6g ethylene glycol ethyl ether acetate, and 4g 1,4-butyrolactone, and add them all to a beaker.

[0173] Heat the beaker in a 40℃ water bath and stir for 10 minutes to obtain the organic carrier mixture; then put the mixture into a 100℃ constant temperature incubator and keep it warm for 4 hours before taking it out to obtain a homogeneous and stable organic carrier product.

[0174] 3) Preparation of platinum resistance paste

[0175] Weigh out 8g of material with a purity ≥99.99%, a particle size distribution of 0.50-1.00μm, and a specific surface area of ​​1.5m².2 / g of spherical platinum powder, and 0.7g of glass powder prepared in step 1);

[0176] Platinum powder and glass powder were placed in an agate jar and put into a ball mill for ball milling. The ball milling speed was 250 r / min and the ball milling time was 12 h. The ball milling was alternated between forward and reverse rotation and each alternation lasted for 1 h.

[0177] After ball milling, the mixed powder is taken out and 1.3g of the organic carrier prepared in step 2) is added. The mixture is then ground for 20 minutes under a water bath heating condition at 50℃. After mixing evenly, the platinum resistance slurry is obtained.

[0178] 4) Preparation of the platinum resistance conductive layer

[0179] Using a 300-mesh screen, the platinum resistance paste prepared in step 3) is printed onto the surface of a high-temperature resistant insulating substrate. The squeegee and the screen are at a 50° angle. The first printing speed is 0.2 m / s, and the second printing speed is 0.6 m / s. After the two printings are completed, the substrate is left to stand for 5 hours to remove air bubbles from the paste.

[0180] Before sintering, high-purity argon gas with a purity of ≥99.99% is introduced into the furnace tube for 20 minutes to remove air. During the sintering process, argon gas is continuously introduced for protection. The temperature is raised to 1120℃ at a heating rate of 6℃ / min and held for 50 minutes before being cooled with the furnace to form a platinum resistance conductive layer with a thickness of 10-20μm on the surface of the substrate.

[0181] The platinum resistance conductive layer is laser-trimmed according to the pre-designed circuit structure. The trimming process is monitored in real time to ensure that the resistance accuracy of the conductive layer at 0℃ is ≤±0.01Ω.

[0182] 5) Lead wire soldering

[0183] After adjusting the resistance, select a material with a purity ≥ 99.99% and a temperature coefficient of resistance of (3851±6)×10. -6 / ℃ -1 Using platinum wire as the lead wire, one end of the platinum wire lead wire is connected to the electrode area of ​​the platinum resistance conductive layer using the platinum resistance paste prepared in step 3). After drying, it is sintered at 1000℃ and held for 30 minutes to form an electrical welded connection. The other end of the lead wire extends outward.

[0184] 6) Preparation of radiation-resistant layer

[0185] A radiation-resistant layer was prepared on the outer surface of the platinum resistance conductive layer using atomic layer deposition (ALD). First, a trimethylaluminum (TMA) precursor with a purity ≥99.99% was introduced, followed by water vapor (pure water). Simultaneously, nitrogen gas was introduced into the chamber for purging, with a single purging time of 10 seconds. The deposition temperature was controlled at 200℃, and the deposition time was 28 hours. A dense radiation-resistant layer with a thickness of 250 nm was formed on the outer surface of the conductive layer, and the radiation-resistant layer completely covered the outer surface of the platinum resistance conductive layer.

[0186] 7) Preparation of the protective layer

[0187] Weigh out 6g of the glass powder prepared in step 1), 2g of the organic carrier prepared in step 2), and 2g of alcohol, mix them evenly to obtain the glass slurry;

[0188] Glass paste is printed onto the outer surface of the radiation-resistant layer using a 200-mesh screen, and the glass paste completely covers the welding area between the leads and the conductive layer. After printing, it is sintered at 900℃ for 30 minutes and cooled in the furnace to form a dense and insulating composite protective film, thus obtaining a platinum resistance thermometer with high radiation resistance and stability.

[0189] Example 3

[0190] A method for preparing a radiation-resistant and highly stable platinum resistance thermometer, the specific preparation steps of which are as follows:

[0191] 1) Preparation of glass powder

[0192] Weigh out 20g SiO2, 6g Al2O3, 12g BaCO3, 6g SrCO3, 20g H3BO3, 3g MgO, 6g CaO, 3g La2O3, and 2g ZrO2. After thoroughly mixing the above raw materials, a glass powder mixture is obtained.

[0193] The glass powder mixture was subjected to the first stage of ball milling at a speed of 200 r / min for 4 hours, with alternating forward and reverse rotation for 2 hours each time.

[0194] After completing the first stage of ball milling, the second stage of ball milling is carried out. The ball milling speed is 300 r / min and the ball milling time is 5 hours. The forward and reverse rotations are alternated and each alternation lasts for 1 hour.

[0195] After a second ball milling process, the mixed raw materials are placed in a muffle furnace and sintered at 1510℃ for 2.5 hours to obtain glass material.

[0196] After water quenching the glass material, glass slag is obtained. The glass slag is then ground to a particle size of 1-10 μm to obtain the finished glass powder.

[0197] 2) Preparation of organic carriers

[0198] Weigh out 40g ethyl cellulose, 14g n-butanol, 33g terpineol, 15g butyl acetate, 15g dibutyl phthalate, 7g ethylene glycol ethyl ether acetate, and 4g 1,4-butyrolactone, and add them all to a beaker.

[0199] The beaker was heated and stirred in a 45°C water bath for 10 minutes to obtain a mixed organic carrier material. The mixed material was then placed in a 100°C constant temperature incubator for 5 hours and then removed to obtain a homogeneous and stable organic carrier product.

[0200] 3) Preparation of platinum resistance paste

[0201] Weigh out 15g of material with a purity ≥99.99%, a particle size distribution of 0.60-1.20μm, and a specific surface area of ​​1.8m². 2 / g of spherical platinum powder, and 1.8g of glass powder prepared in step 1);

[0202] Platinum powder and glass powder were placed in an agate jar and put into a ball mill for ball milling. The ball milling speed was 200 r / min and the ball milling time was 12 h. The ball milling was alternated between forward and reverse rotation and each alternation lasted for 1 h.

[0203] After ball milling, the mixed powder is taken out, and 2.5g of the organic carrier prepared in step 2) is added. The mixture is then ground for 25 minutes under a water bath heating condition at 50℃. After mixing evenly, the platinum resistance slurry is obtained.

[0204] 4) Preparation of the platinum resistance conductive layer

[0205] Using a 300-mesh screen, the platinum resistance paste prepared in step 3) was printed onto the surface of a high-temperature resistant insulating substrate. The squeegee and the screen were at a 40° angle. The first printing speed was 0.3 m / s, and the second printing speed was 0.6 m / s. After the two printings were completed, the substrate was left to stand for 6 hours to remove air bubbles from the paste.

[0206] Before sintering, high-purity argon gas with a purity of ≥99.99% is introduced into the furnace tube for 30 minutes to remove air. During the sintering process, argon gas is continuously introduced for protection. The temperature is raised to 1150℃ at a heating rate of 8℃ / min and held for 50 minutes before being cooled with the furnace to form a platinum resistance conductive layer with a thickness of 10-20μm on the surface of the substrate.

[0207] The platinum resistance conductive layer is laser-trimmed according to the pre-designed circuit structure. The trimming process is monitored in real time to ensure that the resistance accuracy of the conductive layer at 0℃ is ≤±0.01Ω.

[0208] 5) Lead wire soldering

[0209] Select materials with a purity ≥ 99.99% and a temperature coefficient of resistance of (3851 ± 6) × 10⁻⁶. -6 / ℃-1 Using platinum wire as the lead wire, one end of the platinum wire lead wire is connected to the electrode area of ​​the conductive layer using the platinum resistance paste prepared in step 3). After drying, it is sintered at 1000℃ and held for 25 minutes to form an electrical welding connection. The other end of the lead wire extends outward.

[0210] 6) Preparation of radiation-resistant layer

[0211] After the resistance is adjusted, an atomic layer deposition technique is used to prepare a radiation-resistant layer on the outer surface of the platinum resistance conductive layer. First, a trimethylaluminum (TMA) precursor with a purity of ≥99.99% is introduced, followed by water vapor (pure water). At the same time, nitrogen gas is introduced into the chamber for purging, with a single purging time of 20s. The deposition temperature is controlled at 220℃ and the deposition time is 30h. A dense radiation-resistant layer with a thickness of 260nm is formed on the outer surface of the platinum resistance conductive layer, and the radiation-resistant layer completely covers the outer surface of the platinum resistance conductive layer.

[0212] 7) Preparation of the protective layer

[0213] Weigh 20g of the glass powder prepared in step 1), 5g of the organic carrier prepared in step 2), and 4g of alcohol, mix them evenly to obtain the glass slurry.

[0214] Glass paste is printed onto the outer surface of the radiation-resistant layer using a 200-mesh screen, and the glass paste completely covers the welding area between the leads and the conductive layer. After printing, it is sintered at 860℃ for 45 minutes and cooled in the furnace to form a dense and insulating composite protective film, thus obtaining a platinum resistance thermometer with high radiation resistance and stability.

[0215] Based on the radiation-resistant and highly stable platinum resistance thermometers (all Pt100 type) prepared in Examples 1-3 above, and in accordance with national / industry standards and technical specifications for platinum resistance thermometers used in the nuclear power field, the samples prepared in Examples 1-3 were subjected to specific tests on resistance accuracy, temperature coefficient of resistance, radiation resistance, thermal aging stability, and vibration resistance.

[0216] Three radiation-resistant, high-stability platinum resistance thermometers prepared in Examples 1, 2, and 3 were selected and labeled as Sample 1-1 / 1-2 / 1-3, Sample 2-1 / 2-2 / 2-3, and Sample 3-1 / 3-2 / 3-3, respectively. All samples were brand new finished products that had not undergone any working condition tests.

[0217] 1. Test Basis

[0218] (1) Resistance value and temperature coefficient of resistance (TCR) test: according to JJG 229-2010 "Verification procedure for industrial platinum and copper resistance thermometers";

[0219] (2) Radiation resistance test: Test parameters were formulated in accordance with EJ / T1197-2007 "Test Methods and Environmental Conditions for Quality Appraisal of Safety-Grade Electrical Equipment in Nuclear Power Plants" and the 10-year cumulative radiation dose requirements of platinum resistance thermometers in the nuclear power field.

[0220] (3) Thermal aging stability test: Refer to the accelerated aging test method in EJ / T 1197-2007 standard and match the accelerated aging parameters designed for high temperature conditions of nuclear power plants;

[0221] (4) Vibration resistance test: The test parameters are set according to GB / T 2423.10-2008 "Environmental testing of electrical and electronic products - Part 2: Test methods - Test Fc: Vibration (sine)" and combined with the vibration conditions of nuclear power reactor equipment.

[0222] 2. Test methods and test parameters

[0223] (1) Basic electrical performance tests (resistance value R0, temperature coefficient of resistance TCR)

[0224] In a 0℃ constant temperature oil bath, the standard resistance value (R0, designed to be 100Ω±0.01Ω) of the sample at 0℃ was tested using a high-precision DC resistance tester (accuracy ±0.0001Ω). Within a temperature range of -50℃ to 100℃, the resistance value of the sample was tested at 10℃ intervals. The temperature coefficient of resistance (TCR) was calculated according to JJG 229-2010 "Verification Procedure for Industrial Platinum and Copper Resistance Temperature Detectors". The designed target for this invention is (3851±6)×10⁻⁶. -6 / ℃.

[0225] (2) Radiation resistance test

[0226] The sample was irradiated with gamma rays at a dose rate of (1±0.5) kGy / h, with a cumulative dose ≥100kGy (matching the 10-year cumulative dose requirement in the nuclear power field). After irradiation, the R0 and TCR of the sample were tested in a constant temperature environment at 0℃, and the resistance drift rate was calculated. The design goal of this invention is a resistance drift rate ≤0.5%.

[0227] (3) Thermal aging stability test

[0228] The irradiated samples were placed in a high-temperature sintering furnace, and the accelerated aging temperature was set to 400℃ with a thermal aging time of 38.4h (calculated according to the accelerated aging formula of EJ / T 1197-2007 standard, equivalent to long-term high-temperature service under nuclear power conditions). After thermal aging, the samples were cooled to room temperature and the R0 and TCR of the samples were tested in a constant temperature environment of 0℃ to verify the performance stability after thermal aging.

[0229] (4) Vibration resistance test

[0230] After the thermal aging test, the sample was fixed on a sinusoidal vibration test bench and subjected to a three-direction (X / Y / Z axis) frequency scanning vibration test. The frequency scanning range was 10Hz to 2000Hz, the displacement amplitude (peak-to-peak value) was 0.15mm, and the acceleration amplitude (peak value) was 20m / s² (2g). Each direction was continuously vibrated for 2 hours and 30 minutes (10 cycles), and the total vibration time was 7 hours and 30 minutes. After the vibration was completed, the R0 and TCR of the sample were tested in a constant temperature environment of 0℃. At the same time, the appearance and structural integrity of the sample were visually inspected (no cracks, detachment, or loosening).

[0231] 3. Test Results and Analysis

[0232]

[0233] Table 1. Basic electrical performance test results (average values) of platinum resistance thermometers in Examples 1-3

[0234] As shown in Table 1, the standard resistance values ​​of the platinum resistance thermometers prepared in Examples 1-3 at 0℃ are all within the design range of 100Ω ± 0.01Ω, and their temperature coefficients of resistance are also all within (3851 ± 6) × 10. -6 Within the design range of / ℃, the basic electrical performance indicators of the platinum resistance thermometers in Examples 1-3 fully meet the design requirements of this invention, and the temperature measurement accuracy meets the high-precision temperature measurement requirements in the nuclear power field.

[0235]

[0236] Table 2. Test results (average values) of the radiation resistance performance of platinum resistance thermometers in Examples 1-3.

[0237] As shown in Table 2, the platinum resistance thermometers prepared in Examples 1-3 exhibited resistance drift rates far below the design requirement of 0.5% after irradiation with ≥100kGy of gamma rays, and their resistance temperature coefficients remained unchanged. This further demonstrates that the platinum resistance thermometers prepared in this invention have excellent radiation resistance performance, can withstand the strong radiation conditions of nuclear power reactors, and avoid resistance drift and temperature measurement accuracy decay caused by radiation.

[0238]

[0239] Table 3. Results of platinum resistance thermometer thermal aging stability tests in Examples 1-3 (average values)

[0240] As shown in Table 3, the platinum resistance thermometers prepared in Examples 1-3 exhibited extremely low resistance drift after accelerated thermal aging at 400℃, and all samples showed no structural defects such as cracking or detachment. The temperature coefficient of resistance remained stable, indicating that the platinum resistance thermometers prepared in this invention have excellent high-temperature thermal aging stability and can be used for a long time under the high-temperature conditions of nuclear power plants, avoiding performance degradation and structural failure caused by thermal aging.

[0241]

[0242] Table 4. Test results (average values) of the vibration resistance performance of platinum resistance thermometers in Examples 1-3

[0243] As shown in Table 4, the platinum resistance thermometers prepared in Examples 1-3 exhibited negligible resistance drift after sinusoidal vibration in three directions from 10Hz to 2000Hz. Furthermore, all samples showed no structural problems such as loosening or poor contact. This indicates that the platinum resistance thermometers prepared in this invention have excellent vibration resistance performance and can withstand the continuous vibration conditions of nuclear power reactors, thus solving the technical defects of poor vibration resistance of traditional wire-wound platinum resistance thermometers.

[0244] In summary, the Pt100 platinum resistors prepared using the radiation-resistant and highly stable platinum resistor preparation method described in Examples 1-3 fully meet the design requirements in terms of their basic electrical properties (R0, TCR). Furthermore, after testing under combined extreme conditions including ≥100 kGy γ-ray irradiation, accelerated thermal aging at 400℃, and sinusoidal vibration from 10 Hz to 2000 Hz, the resistance drift rate is significantly lower than the design threshold of 0.5%, the resistance temperature coefficient remains stable, and the samples exhibit no structural defects such as cracking, detachment, or loosening. All performance indicators meet the high-precision temperature measurement requirements of complex conditions such as nuclear reactors, aerospace, and extreme industrial measurement and control. This also verifies the feasibility, stability, and repeatability of the preparation method described in this invention, enabling industrial-scale mass production.

[0245] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A radiation-resistant, highly stable platinum resistance thermometer, characterized in that, It includes an alumina or silicon nitride substrate, and a platinum resistance conductive layer, a radiation-resistant layer, and a protective layer arranged sequentially from the inside to the outside on the substrate, wherein the thickness of the radiation-resistant layer is 200-400 nm, and the conductive layer is fixedly connected to a platinum wire lead.

2. A method for preparing a radiation-resistant, high-stability platinum resistance thermometer as described in claim 1, characterized in that, Includes the following steps: 1) Preparation of platinum resistance paste By weight, 75%–85% of platinum powder and 5%–10% of glass powder are ball-milled and mixed, and then ground and mixed evenly with 10%–15% of organic carrier under water bath heating to obtain platinum resistance slurry. 2) Preparation of platinum resistance conductive layer The prepared platinum resistance paste is screen-printed onto the surface of an alumina or silicon nitride substrate, and then sintered at high temperature to form a platinum resistance conductive layer with a thickness of 10 to 30 μm on the substrate surface. 3) Lead wire soldering One end of the platinum wire lead is fixedly connected to the platinum resistance conductive layer by sintering using platinum resistance paste. 4) Preparation of radiation-resistant layer Using trimethylaluminum with a purity of ≥99.99% as a precursor and water vapor as a reactant, atomic layer deposition was carried out under inert gas protection at a deposition temperature of 200℃~250℃, a deposition time of 25h~30h, a single purging time of 5s~20s, and a deposition thickness of 200nm~400nm. 5) Prepare the protective layer Glass paste is coated onto the radiation-resistant layer and the surface of the platinum wire connection using screen printing. After high-temperature sintering, a protective layer with a thickness of 20-50 μm is formed, ultimately producing a radiation-resistant and highly stable platinum resistance thermometer.

3. The method for preparing a radiation-resistant, high-stability platinum resistance thermometer according to claim 2, characterized in that, In step 1), the platinum powder is a spherical platinum powder with a purity of ≥ 99.99%, a particle size of 0.50 μm to 1.50 μm, a specific surface area of 1.0 to 2.0 m 2 / g, and a particle size distribution of 0.50 μm to 1.50 μm.

4. The method for preparing a radiation-resistant, high-stability platinum resistance thermometer according to claim 2, characterized in that, In step 1), the ball milling method is as follows: the mixture of platinum powder and glass powder is ball milled by alternating forward and reverse rotation, with each forward and reverse rotation lasting 1 to 3 hours, the ball milling speed being 200 to 300 r / min, and the ball milling time being 10 to 12 hours.

5. The method for preparing a radiation-resistant, high-stability platinum resistance thermometer according to claim 2, characterized in that, In step 2), the screen printing method is as follows: the platinum resistance paste is printed onto the substrate surface twice, wherein the printing speed is 0.2 to 0.3 m / s for the first printing and 0.5 to 0.6 m / s for the second printing; after the two printings are completed, the substrate is left to stand for 2 to 10 hours.

6. The method for preparing a radiation-resistant, highly stable platinum resistance thermometer according to claim 2, characterized in that, In step 2), the high-temperature sintered platinum resistance conductive layer needs to be sintered under argon gas protection with a purity of ≥99.99%.

7. The method for preparing a radiation-resistant, highly stable platinum resistance thermometer according to claim 2, characterized in that, In step 5), the mass percentage of each component of the glass slurry is: 15% to 25% organic carrier, 10% to 20% alcohol, and the remainder is glass powder.

8. The method for preparing a radiation-resistant, highly stable platinum resistance thermometer according to claim 2 or 7, characterized in that, The glass powder has a particle size of 1-10 μm and a softening point of 900℃-1100℃. The mass percentage of each component in the glass powder is as follows: 5%-10% aluminum oxide, 10%-20% barium carbonate, 5%-10% strontium carbonate, 20%-35% boric acid, 1%-5% magnesium oxide, 1%-8% calcium oxide, 1%-5% lanthanum oxide, 0-3% zirconium oxide, and the balance is silicon oxide.

9. The method for preparing a radiation-resistant, highly stable platinum resistance thermometer according to claim 2 or 7, characterized in that, The organic carrier comprises the following components by mass percentage: n-butanol 10%–15%, terpineol 25%–35%, butyl acetate 10%–15%, dibutyl phthalate 10%–15%, ethylene glycol ethyl ether acetate 5%–10%, 1,4-butyrolactone 3%–5%, with the balance being ethyl cellulose.

10. The method for preparing a radiation-resistant, high-stability platinum resistance thermometer according to claim 2 or 7, characterized in that, The glass powder is prepared as follows: 1) Weigh each component of the glass powder according to its mass percentage, and mix all the glass powder components thoroughly to obtain the glass powder mixture raw material; 2) The ball mill is used to perform the first stage ball milling on the glass powder mixture obtained in step 1) by alternating forward and reverse rotation. The time interval between each alternation is 1 to 2 hours, the ball milling speed is 200 r / min, and the ball milling time is 5 to 6 hours, so as to obtain the glass powder mixture after the first stage ball milling. 3) The ball mill is used to perform a second stage of ball milling on the glass powder mixture obtained in step 2) by alternating forward and reverse rotation. The time interval between each alternation is 1 to 2 hours, the ball milling speed is 300 r / min, and the ball milling time is 3 to 5 hours, so as to obtain the glass powder mixture after the second stage of ball milling. 4) The glass powder mixture obtained in step 3) is sintered at a temperature of 1500±50℃ for 2-3 hours to obtain glass material; 5) The glass material obtained in step 4) is subjected to water quenching to obtain glass slag; 6) Grind the glass slag obtained in step 5) to obtain glass powder with a particle size of 1 to 10 μm.

Images